Transmission Activity
Dano58
about, however, is the transmission 'activity'.... By that I mean that
it seems to downshift when you take your foot off the gas and are
slowing down. This is confirmed by watching the tachometer tick upwards
as you feel the transmission downshifting. Since our last van was a '99
Windstar (I was happy when it would simply UPshift!) and my other car
is a 6-speed Audi A4, I guess I'm not used to the electronics in the
latest transmissions. Is this really the case - that the car
downshifts? Or is my transmission about to fall out!
Thanks.
Dan D
Central NJ USA
'07 Odyssey EX
Unquestionably Confused
I noticed the same thing with my 2006 Accord EX. Read the owner's
manual, at least I think that's where I read it, and there was an
explanation that made sense to me. It DID take some getting used to
though. No doubt about it.
IIRC, the computer senses a number of things including braking, incline,
etc and decides whether to just let you coast or to downshift to provide
extra braking. Now, with 8,000 miles under my belt on the car, I rarely
notice it.
Joe LaVigne
Yep, they downshift.
It is used to help your brakes last longer, and to help aggressive braking
stop faster.
This is a good thing.
Andy & Carol
up your rotors..read up on it.
"Dano58" <dan.d...@gmail.com> wrote in message
news:1167769779.3...@v33g2000cwv.googlegroups.com...
Gordon McGrew
<af...@worldnet.att.net> wrote:
>It called "Logic Grade" , that is why you won't grind
>up your rotors..read up on it.
I would think that it would hurt your gas mileage though. At least it
would if you are anticipating a stop and just want to coast until the
light changes. Is it possible that it waits for you to touch the
brake pedal before it downshifts? That would make more sense.
On the upside, completing the downshift earlier makes it ready to
accelerate on short notice. All-in-all, that is one reason why I
prefer manual transmissions. The AT will never have enough sensors
until they put in one that can read my mind.
jim beam
> On Wed, 03 Jan 2007 03:07:21 GMT, "Andy & Carol"
> <af...@worldnet.att.net> wrote:
>
>> It called "Logic Grade" , that is why you won't grind
>> up your rotors..read up on it.
>
> I would think that it would hurt your gas mileage though. At least it
> would if you are anticipating a stop and just want to coast until the
> light changes. Is it possible that it waits for you to touch the
> brake pedal before it downshifts? That would make more sense.
which is precisely what it does do - it takes the signal from the brake
pedal switch.
>
> On the upside, completing the downshift earlier makes it ready to
> accelerate on short notice. All-in-all, that is one reason why I
> prefer manual transmissions. The AT will never have enough sensors
> until they put in one that can read my mind.
you haven't driven an automatic lately.
Tegger
@v33g2000cwv.googlegroups.com:
Your tranny is fine.
The extremely sophisticated electronics installed these days have
considerable control over shift behavior. In addition, the transmission
will actually "learn" your driving style and adjust its behavior for that.
Some people find newer transmissions' behavior disconcerting when compared
to older designs.
The very best thing you can do for your transmission is to change the fluid
precisely according to the maintenance schedule, and to ONLY ever use Honda
genuine ATF-Z1 fluid. If you want to change the fluid MORE often, that's
even better.
--
Tegger
The Unofficial Honda/Acura FAQ
www.tegger.com/hondafaq/
Dano58
intelligent transmissions. Of course, I could read the manual but every
time I think about it, the car isn't actually here....!
Dan D
'07 Odyssey EX
Central NJ USA
Dano58
JXStern
wrote:
>The extremely sophisticated electronics installed these days have
>considerable control over shift behavior. In addition, the transmission
>will actually "learn" your driving style and adjust its behavior for that.
>
>Some people find newer transmissions' behavior disconcerting when compared
>to older designs.
I wish they would supply a flow chart or other documentation.
J.
Brian Smith
> Thanls for all of the responses. I figured it was a function of these
> intelligent transmissions. Of course, I could read the manual but every
> time I think about it, the car isn't actually here....!
Take the Manual in the house, then when you're in the reading room, you
can find out all about the vehicle.
dgk
<spamv...@bad.example.net> wrote:
>Gordon McGrew wrote:
>> On Wed, 03 Jan 2007 03:07:21 GMT, "Andy & Carol"
>> <af...@worldnet.att.net> wrote:
>>
>>> It called "Logic Grade" , that is why you won't grind
>>> up your rotors..read up on it.
>>
>> I would think that it would hurt your gas mileage though. At least it
>> would if you are anticipating a stop and just want to coast until the
>> light changes. Is it possible that it waits for you to touch the
>> brake pedal before it downshifts? That would make more sense.
>
>which is precisely what it does do - it takes the signal from the brake
>pedal switch.
>
>>
>> On the upside, completing the downshift earlier makes it ready to
>> accelerate on short notice. All-in-all, that is one reason why I
>> prefer manual transmissions. The AT will never have enough sensors
>> until they put in one that can read my mind.
>
>you haven't driven an automatic lately.
>
My understanding is that the cars do learn how you drive. Now, I'm not
really a car guy, but I'm a computer programmer. I can certainly see
how the computers could learn how you drive and act on it, but it
would also need to understand that a car can have more than one
driver. Until you actually have to log-in, it might get confused. Now
is this the guy with the lead foot or the lady with the sweet
disposition?
Perhaps they'll start using retinal scans or fingerprint detectors on
the steering wheel. It should be a good theft-prevention model, until
you try letting your designated driver take you home and it won't
start. And then it won't start for you because you're drunk.
Maybe we'd best forget the whole idea.
Gordon McGrew
<spamv...@bad.example.net> wrote:
>Gordon McGrew wrote:
>> On Wed, 03 Jan 2007 03:07:21 GMT, "Andy & Carol"
>> <af...@worldnet.att.net> wrote:
>>
>>> It called "Logic Grade" , that is why you won't grind
>>> up your rotors..read up on it.
>>
>> I would think that it would hurt your gas mileage though. At least it
>> would if you are anticipating a stop and just want to coast until the
>> light changes. Is it possible that it waits for you to touch the
>> brake pedal before it downshifts? That would make more sense.
>
>which is precisely what it does do - it takes the signal from the brake
>pedal switch.
>
>>
>> On the upside, completing the downshift earlier makes it ready to
>> accelerate on short notice. All-in-all, that is one reason why I
>> prefer manual transmissions. The AT will never have enough sensors
>> until they put in one that can read my mind.
>
>you haven't driven an automatic lately.
Well, I'm sure they have improved somewhat since they made the one for
my '98 Ody, but I would be surprised if they now know in which gear I
want to do compression braking. I'm pretty sure they don't downshift
in anticipation of me wanting to do hard acceleration two seconds
before I touch the gas pedal. How does it know that, even though I am
doing a steady 40 mph, I want to stay in second gear to be ready to
make a move in traffic? Does it know not to downshift just before we
crest the hill? For my Ody, I would be happy if it just didn't
downshift when I hit Resume on the CC 4 mph below the target speed. I
would hope they have at least fixed that.
Bottom line is they are OK for average (or worse) drivers in light
traffic. But I definitely don't like them in heavy city traffic and
they just don't belong in any sports car IMO.
jim beam
> On Tue, 02 Jan 2007 22:06:04 -0800, jim beam
> <spamv...@bad.example.net> wrote:
>
>> Gordon McGrew wrote:
>>> On Wed, 03 Jan 2007 03:07:21 GMT, "Andy & Carol"
>>> <af...@worldnet.att.net> wrote:
>>>
>>>> It called "Logic Grade" , that is why you won't grind
>>>> up your rotors..read up on it.
>>> I would think that it would hurt your gas mileage though. At least it
>>> would if you are anticipating a stop and just want to coast until the
>>> light changes. Is it possible that it waits for you to touch the
>>> brake pedal before it downshifts? That would make more sense.
>> which is precisely what it does do - it takes the signal from the brake
>> pedal switch.
>>
>>> On the upside, completing the downshift earlier makes it ready to
>>> accelerate on short notice. All-in-all, that is one reason why I
>>> prefer manual transmissions. The AT will never have enough sensors
>>> until they put in one that can read my mind.
>> you haven't driven an automatic lately.
>
> Well, I'm sure they have improved somewhat since they made the one for
> my '98 Ody, but I would be surprised if they now know in which gear I
> want to do compression braking. I'm pretty sure they don't downshift
> in anticipation of me wanting to do hard acceleration two seconds
> before I touch the gas pedal.
no, they provide a handy little lever that allows you to take care of
that by hand.
> How does it know that, even though I am
> doing a steady 40 mph, I want to stay in second gear to be ready to
> make a move in traffic?
see above.
> Does it know not to downshift just before we
> crest the hill?
press the brake and you'll find out. they have grade control logic.
increasing speed + zero gas = downshift.
> For my Ody, I would be happy if it just didn't
> downshift when I hit Resume on the CC 4 mph below the target speed. I
> would hope they have at least fixed that.
>
> Bottom line is they are OK for average (or worse) drivers in light
> traffic. But I definitely don't like them in heavy city traffic and
> they just don't belong in any sports car IMO.
tell that to porsche - last i heard, their autos were faster than their
sticks.
Gordon McGrew
<spamv...@bad.example.net> wrote:
Right, you can force the downshift or hold the gear manually but a.
then its not automatic and b. it is clumsy to shift especially on the
steering column.
>
>> Does it know not to downshift just before we
>> crest the hill?
>
>press the brake and you'll find out. they have grade control logic.
>increasing speed + zero gas = downshift.
My comment is that the transmission downshifts when I dont want it
too, i.e. just before cresting the hill when I would manually just
stay in the higher gear for a few more seconds.
>> For my Ody, I would be happy if it just didn't
>> downshift when I hit Resume on the CC 4 mph below the target speed. I
>> would hope they have at least fixed that.
>>
>> Bottom line is they are OK for average (or worse) drivers in light
>> traffic. But I definitely don't like them in heavy city traffic and
>> they just don't belong in any sports car IMO.
>
>tell that to porsche - last i heard, their autos were faster than their
>sticks.
That is because most Porsche buyers are people who want to show off
how rich/cool they are and don't really care about driving it or even
know how.
Joe LaVigne
>
> Bottom line is they are OK for average (or worse) drivers in light
> traffic. But I definitely don't like them in heavy city traffic and
> they just don't belong in any sports car IMO.
I would agree that they do not belong on any sports car, but IMO, the only
time I really WANT an Auto is for heavy city traffic.
jim beam
but don't say it can't hold a gear because it can! you can leave it in
full auto or you can manually over-ride - the ultimate in choice. i
agree with you about column shifts however - i can't stand them.
>
>>> Does it know not to downshift just before we
>>> crest the hill?
>> press the brake and you'll find out. they have grade control logic.
>> increasing speed + zero gas = downshift.
>
> My comment is that the transmission downshifts when I dont want it
> too, i.e. just before cresting the hill when I would manually just
> stay in the higher gear for a few more seconds.
dude, you said auto's couldn't hold a gear - they can. and grade logic
means they select the right gear, certainly a good deal better than some
of the individuals that pop up here from time to time putting their
sticks into neutral and coasting down hills. modern autos are not only
programmed to shift right, they also learn what the driver likes.
>
>>> For my Ody, I would be happy if it just didn't
>>> downshift when I hit Resume on the CC 4 mph below the target speed. I
>>> would hope they have at least fixed that.
>>>
>>> Bottom line is they are OK for average (or worse) drivers in light
>>> traffic. But I definitely don't like them in heavy city traffic and
>>> they just don't belong in any sports car IMO.
>> tell that to porsche - last i heard, their autos were faster than their
>> sticks.
>
> That is because most Porsche buyers are people who want to show off
> how rich/cool they are and don't really care about driving it or even
> know how.
eh? how does criticizing [without basis] driver skill address the
ability of a computer-controlled transmission to shift faster than a
stick? makes no sense.
bottom line, you're welcome to drive whatever you want, but don't
criticize autos on the basis of fud - it's simply not justified.
Gordon McGrew
Sorry, I misread the post. I thought you were saying that the ATs
were *selling* faster than the MTs.
My preference for MT is not based on how fast it shifts but rather the
ability to integrate the shifts seamlessly into driving. This
requires decisions based on information that the computer cannot
possibly know. May not matter much for a minivan, but it is
fundamental for a sports car.
The problem with most (virtually all) ATs is that they are biased
toward automatic operation and discourage manual operation. Also, I
don't particularly care for the slippage of the torque converter. I
understand that VW has a paddle shift AT that is actually built like
an MT. This has potential if the AT function can be completely
disabled, i.e. it never makes a shift without a command from the
driver. (Not that I would buy a VW under any circumstances.)
>bottom line, you're welcome to drive whatever you want, but don't
>criticize autos on the basis of fud - it's simply not justified.
fud?
Gordon McGrew
It depends on your attitude. For me, the only joy in "stop and go"
traffic is seeing how far I can go without touching the clutch or the
brake. When traffic is heavy but moving, I like the control that I
get from an MT.
jim beam
> On Fri, 05 Jan 2007 21:48:16 -0800, jim beam
> <spamv...@bad.example.net> wrote:
>
>
>>>>> Bottom line is they are OK for average (or worse) drivers in light
>>>>> traffic. But I definitely don't like them in heavy city traffic and
>>>>> they just don't belong in any sports car IMO.
>>>> tell that to porsche - last i heard, their autos were faster than their
>>>> sticks.
>>> That is because most Porsche buyers are people who want to show off
>>> how rich/cool they are and don't really care about driving it or even
>>> know how.
>> eh? how does criticizing [without basis] driver skill address the
>> ability of a computer-controlled transmission to shift faster than a
>> stick? makes no sense.
>
> Sorry, I misread the post. I thought you were saying that the ATs
> were *selling* faster than the MTs.
>
> My preference for MT is not based on how fast it shifts but rather the
> ability to integrate the shifts seamlessly into driving. This
> requires decisions based on information that the computer cannot
> possibly know. May not matter much for a minivan, but it is
> fundamental for a sports car.
that's your perception. unless you've driven a modern auto, especially
a sports auto, you're just making uninformed assumptions and using them
as your basis for criticism.
>
> The problem with most (virtually all) ATs is that they are biased
> toward automatic operation and discourage manual operation.
how? my auto has the shift in exactly the same place as where the stick
would be. i see no difference. the transmission even has a no-lock
gate between 3rd & 4th [commonest manual override] especially so you
/can/ flip up and down at will.
> Also, I
> don't particularly care for the slippage of the torque converter.
eh? what "slippage" is that? how does its mechanical function differ
from a clutch [other than it has a much better efficiency range and is
much smoother of course]?
> I
> understand that VW has a paddle shift AT that is actually built like
> an MT.
as are a lot of the euro "autos".
> This has potential if the AT function can be completely
> disabled, i.e. it never makes a shift without a command from the
> driver.
dude, have you ever driven an auto? you have pretty much full control
over everything except clutching action - except for the fact that it
won't let you select wrong gears of course.
> (Not that I would buy a VW under any circumstances.)
>
>> bottom line, you're welcome to drive whatever you want, but don't
>> criticize autos on the basis of fud - it's simply not justified.
>
> fud?
fear. uncertainty. doubt. if there is no technical argument against
something, people resort to fud.
here's another nugget for you - automatics are banned from f1. like
certain types of ground effects, they gave too much advantage to the
[better funded] teams that had them. the compromise is paddle shift,
but even then, interpretation of the ban has been taken to the limit
since a lot of the control functions are still automatic.
Gordon McGrew
<spamv...@bad.example.net> wrote:
If you put it in 4, will it ever downshift into 3 by itself? When you
shift into 3 does it effectively double clutch?
>
>> Also, I
>> don't particularly care for the slippage of the torque converter.
>
>eh? what "slippage" is that? how does its mechanical function differ
>from a clutch [other than it has a much better efficiency range and is
>much smoother of course]?
Well, as you point out, I don't have any experience with modern high
end luxury cars, but I note that at least more modest cars generally
have a significantly greater 0-60 speed and a lower mpg rating. Since
they now mostly have five gears, I would assume that means they are
slipping. Actually, the slipping is partly by design, the so-called
torque multiplier effect. Basically, if you are cruising along and
you give it a little gas, but not enough to force a downshift, you
will see the rpms jump up immediately.
The ultimate "torque multiplier" is a CVT. A lot of people don't like
them at all, but others say they get used to it. (The perception
problem is so bad that some manufacturers program virtual gears into
them thereby defeating the chief advantage of the CVT.) I only rode
in one CVT car, a Nissan luxury sedan in Japan and it wasn't bad in
that application. He drove it fairly aggressively too - we hit almost
180 kph on the expressway. I would like to try one of these. I don't
know if I would like it or not.
>> I
>> understand that VW has a paddle shift AT that is actually built like
>> an MT.
>
>as are a lot of the euro "autos".
>
>> This has potential if the AT function can be completely
>> disabled, i.e. it never makes a shift without a command from the
>> driver.
>
>dude, have you ever driven an auto? you have pretty much full control
>over everything except clutching action - except for the fact that it
>won't let you select wrong gears of course.
Will it let you start out in 5th gear? Not that I want to do that,
but the point is I don't like it downshifting or upshifting without my
command.
>> (Not that I would buy a VW under any circumstances.)
>>
>>> bottom line, you're welcome to drive whatever you want, but don't
>>> criticize autos on the basis of fud - it's simply not justified.
>>
>> fud?
>
>fear. uncertainty. doubt. if there is no technical argument against
>something, people resort to fud.
Well, I would certainly prefer an MT to the AT in my 98 Ody, but of
course that was not an option.
Perhaps newer, high dollar vehicles are better set up for manual
shifting, and have fewer compromises but then that raises the point:
Why not just have an MT? They are cheaper, more durable and I like
the way they work just fine. For my purposes and preferences, I see
no benefit to an AT whatsoever.
I presume I will never again be able to buy a large, cargo carrying
vehicle (eg. my old Volvo 245 station wagon) with an MT so I assume I
will have to go with 2007 technology sooner or later. I will let you
know what I think.
>here's another nugget for you - automatics are banned from f1. like
>certain types of ground effects, they gave too much advantage to the
>[better funded] teams that had them. the compromise is paddle shift,
>but even then, interpretation of the ban has been taken to the limit
>since a lot of the control functions are still automatic.
I would first point out that torque converters are not banned AFAIK,
but they are not used either. I would be curious to know whether and
how ATs would be used in F1 if they were not banned. I can imagine
the programming: if rpm >= redline then upshift, if downshift RPM <
redline then downshift. The situation is a little different on the
road and the technology is bound to be different and more compromised.
I seem to recall Ferrari had an AT at one time in F1. I dont' recall
if it was a clear advantage but I do recall that on a couple of
occasions it decided to downshift into 2nd when it should have been in
5th. That was exciting. Not relevant to the argument but an amusing
story. It may have been an early paddle shifter rather than a true AT
jim beam
yes, absolutely. it does it on "kickdown" acceleration /and/ it does it
on braking. not gentle braking, but harder braking.
> When you
> shift into 3 does it effectively double clutch?
pointless exercise on an automatic. but even then, on the modern autos,
in conjunction with electronic throttle, yes, the engine revs /are/
meshed to the gear on shift.
>
>>> Also, I
>>> don't particularly care for the slippage of the torque converter.
>> eh? what "slippage" is that? how does its mechanical function differ
>>from a clutch [other than it has a much better efficiency range and is
>> much smoother of course]?
>
> Well, as you point out, I don't have any experience with modern high
> end luxury cars, but I note that at least more modest cars generally
> have a significantly greater 0-60 speed and a lower mpg rating. Since
> they now mostly have five gears, I would assume that means they are
> slipping.
there's no slipping unless the lock-up clutch is released. see below.
> Actually, the slipping is partly by design, the so-called
> torque multiplier effect.
yes, that's what a torque converter does.
> Basically, if you are cruising along and
> you give it a little gas, but not enough to force a downshift, you
> will see the rpms jump up immediately.
that's because the lockup clutch is released to allow more torque. more
flexibility than a stick where you'd have to shift.
>
> The ultimate "torque multiplier" is a CVT.
that's different - it's not a torque multiplier. if is however a great
way of achieving absolute optimum gear for all conditions.
> A lot of people don't like
> them at all, but others say they get used to it. (The perception
> problem is so bad that some manufacturers program virtual gears into
> them thereby defeating the chief advantage of the CVT.)
absolutely! i drove a "real" cvt one when i was in europe years ago,
and yes it is /real/ weird at first. but it's amazing how much you can
get out of a small 2-cylinder engine when it's got perfect gearing.
quite fun! this particular model had 2 independent drives too, so not
only did you have optimum gearing, you had limited slip diff benefits in
snow & ice too.
http://www.ritzsite.demon.nl/DAF/DAF_cars_p2.htm
> I only rode
> in one CVT car, a Nissan luxury sedan in Japan and it wasn't bad in
> that application. He drove it fairly aggressively too - we hit almost
> 180 kph on the expressway. I would like to try one of these. I don't
> know if I would like it or not.
if you're not used to traditional automatics, the transition is easy.
if you're used to traditional autos, its weird for a few minutes because
it doesn't "shift", but beyond that, they're actually very impressive.
>
>>> I
>>> understand that VW has a paddle shift AT that is actually built like
>>> an MT.
>> as are a lot of the euro "autos".
>>
>>> This has potential if the AT function can be completely
>>> disabled, i.e. it never makes a shift without a command from the
>>> driver.
>> dude, have you ever driven an auto? you have pretty much full control
>> over everything except clutching action - except for the fact that it
>> won't let you select wrong gears of course.
>
> Will it let you start out in 5th gear? Not that I want to do that,
> but the point is I don't like it downshifting or upshifting without my
> command.
no, but it'll start in 2nd. mine will anyway. useful in snow.
regarding shifting, it'll shift down any time on command, providing
doing so doesn't over-rev the engine - it won't let you do that.
regarding up-shifting, you can hold it back until you're ready, and even
then, it'll wait until it's certain you mean it - if you have your foot
down. if you're not driving hard, it's academic.
>
>>> (Not that I would buy a VW under any circumstances.)
>>>
>>>> bottom line, you're welcome to drive whatever you want, but don't
>>>> criticize autos on the basis of fud - it's simply not justified.
>>> fud?
>> fear. uncertainty. doubt. if there is no technical argument against
>> something, people resort to fud.
>
> Well, I would certainly prefer an MT to the AT in my 98 Ody, but of
> course that was not an option.
>
> Perhaps newer, high dollar vehicles are better set up for manual
> shifting, and have fewer compromises but then that raises the point:
> Why not just have an MT? They are cheaper, more durable and I like
> the way they work just fine. For my purposes and preferences, I see
> no benefit to an AT whatsoever.
i used to think that. then i had a knee injury that prevented me
driving a stick for some months, so i bought an auto. and every time
i've driven a stick since, it's been a real chore. that was nearly 20
years ago. it may be that there's some bad autos out there, but the way
i have my civic set up [the shift pattern is adjustable], the shift
points are pretty much dead on where i'd have them manually, and for
other stuff, i over-ride.
>
> I presume I will never again be able to buy a large, cargo carrying
> vehicle (eg. my old Volvo 245 station wagon) with an MT so I assume I
> will have to go with 2007 technology sooner or later. I will let you
> know what I think.
>
>> here's another nugget for you - automatics are banned from f1. like
>> certain types of ground effects, they gave too much advantage to the
>> [better funded] teams that had them. the compromise is paddle shift,
>> but even then, interpretation of the ban has been taken to the limit
>> since a lot of the control functions are still automatic.
>
> I would first point out that torque converters are not banned AFAIK,
> but they are not used either.
correct - they're heavy.
> I would be curious to know whether and
> how ATs would be used in F1 if they were not banned. I can imagine
> the programming: if rpm >= redline then upshift, if downshift RPM <
> redline then downshift. The situation is a little different on the
> road and the technology is bound to be different and more compromised.
> I seem to recall Ferrari had an AT at one time in F1. I dont' recall
> if it was a clear advantage but I do recall that on a couple of
> occasions it decided to downshift into 2nd when it should have been in
> 5th. That was exciting. Not relevant to the argument but an amusing
> story. It may have been an early paddle shifter rather than a true AT
>
maybe a problem with the sequencing mechanicals? who knows.
i think in due course, semi autos will replace sticks. at least in
sports cars. they offer faster, more accurate shifting, and computer
control knows more about the potentials of the system than the driver
does a lot of the time. a friend has a tiptronic carrera - hold the
shift lever and put your foot down, and it'll select the lowest gear for
the speed to give fastest acceleration, and you can revert to auto from
there so it shifts up through in the fastest possible time. trust me -
it's fun!
Gordon McGrew
<spamv...@bad.example.net> wrote:
It is not a bad thing, I just don't care for it. If I want to
downshift, I can do that. If I don't want to, I don't like the car
doing it on its own.
>> When you
>> shift into 3 does it effectively double clutch?
>
>pointless exercise on an automatic. but even then, on the modern autos,
>in conjunction with electronic throttle, yes, the engine revs /are/
>meshed to the gear on shift.
That is what I mean. I figured they had fixed that aspect which is
the worst part of the older ATs.
>>>> Also, I
>>>> don't particularly care for the slippage of the torque converter.
>>> eh? what "slippage" is that? how does its mechanical function differ
>>>from a clutch [other than it has a much better efficiency range and is
>>> much smoother of course]?
>>
>> Well, as you point out, I don't have any experience with modern high
>> end luxury cars, but I note that at least more modest cars generally
>> have a significantly greater 0-60 speed and a lower mpg rating. Since
>> they now mostly have five gears, I would assume that means they are
>> slipping.
>
>there's no slipping unless the lock-up clutch is released. see below.
>
>> Actually, the slipping is partly by design, the so-called
>> torque multiplier effect.
>
>yes, that's what a torque converter does.
>
>> Basically, if you are cruising along and
>> you give it a little gas, but not enough to force a downshift, you
>> will see the rpms jump up immediately.
>
>that's because the lockup clutch is released to allow more torque. more
>flexibility than a stick where you'd have to shift.
But that is the slippage. The engine speeds up races up ahead of any
change in vehicle speed. It is like a slipping clutch. As for more
torque (horsepower really) a lot of that is eaten up by the
inefficiency of the torque converter. On cars where you can get a MT
or AT with the same engine, the MT is almost always faster and gets
better mileage.
>> The ultimate "torque multiplier" is a CVT.
>
>that's different - it's not a torque multiplier.
Neither is the conventional AT, it just has a clever design to let the
engine speed up ahead of the vehicle speed without shifting. It is
basically like a limited range CVT.
>if is however a great
>way of achieving absolute optimum gear for all conditions.
I agree that it has a big theoretical advantage, especially compared
to a conventional AT.
>> A lot of people don't like
>> them at all, but others say they get used to it. (The perception
>> problem is so bad that some manufacturers program virtual gears into
>> them thereby defeating the chief advantage of the CVT.)
>
>absolutely! i drove a "real" cvt one when i was in europe years ago,
>and yes it is /real/ weird at first. but it's amazing how much you can
>get out of a small 2-cylinder engine when it's got perfect gearing.
>quite fun! this particular model had 2 independent drives too, so not
>only did you have optimum gearing, you had limited slip diff benefits in
>snow & ice too.
>http://www.ritzsite.demon.nl/DAF/DAF_cars_p2.htm
That was the original CVT. Do you remember who offered the first CVT
in the US. (I don't think they ever sold the Daffodil here.)
>> I only rode
>> in one CVT car, a Nissan luxury sedan in Japan and it wasn't bad in
>> that application. He drove it fairly aggressively too - we hit almost
>> 180 kph on the expressway. I would like to try one of these. I don't
>> know if I would like it or not.
>
>if you're not used to traditional automatics, the transition is easy.
>if you're used to traditional autos, its weird for a few minutes because
>it doesn't "shift", but beyond that, they're actually very impressive.
Again though, I am not sure they are any faster or more efficient than
a good MT. Consumer Reports tested the Versa with MT and with CVT.
The MT version was 0.6 seconds faster to 60 and got one more mpg. (And
CR panned that MT.) They also tested MT and (conventional) AT
versions of Fit, Rio, Accent and Yaris. In each case the MT was 2 - 3
seconds faster and got 2 more mpg, so the CVT was clearly better than
an AT but not as good as even a mediocre MT, at last on raw numbers.
And yet, there is hardly a proliferation of CVTs on the market. Most
of them seem to be on hybrids in fact.
I appreciate that many people prefer AT, and if you have a bad knee,
there isn't much choice. But I really enjoy driving the MT. I
haven't encountered an AT yet that I could actually say I enjoyed, but
I certainly haven't driven many new ones.
>> I presume I will never again be able to buy a large, cargo carrying
>> vehicle (eg. my old Volvo 245 station wagon) with an MT so I assume I
>> will have to go with 2007 technology sooner or later. I will let you
>> know what I think.
>>
>>> here's another nugget for you - automatics are banned from f1. like
>>> certain types of ground effects, they gave too much advantage to the
>>> [better funded] teams that had them. the compromise is paddle shift,
>>> but even then, interpretation of the ban has been taken to the limit
>>> since a lot of the control functions are still automatic.
>>
>> I would first point out that torque converters are not banned AFAIK,
>> but they are not used either.
>
>correct - they're heavy.
>
>> I would be curious to know whether and
>> how ATs would be used in F1 if they were not banned. I can imagine
>> the programming: if rpm >= redline then upshift, if downshift RPM <
>> redline then downshift. The situation is a little different on the
>> road and the technology is bound to be different and more compromised.
>> I seem to recall Ferrari had an AT at one time in F1. I dont' recall
>> if it was a clear advantage but I do recall that on a couple of
>> occasions it decided to downshift into 2nd when it should have been in
>> 5th. That was exciting. Not relevant to the argument but an amusing
>> story. It may have been an early paddle shifter rather than a true AT
>>
>maybe a problem with the sequencing mechanicals? who knows.
It was a computer glitch. As they say, to error is human. To really
foul things up requires a computer.
>i think in due course, semi autos will replace sticks. at least in
>sports cars. they offer faster, more accurate shifting, and computer
>control knows more about the potentials of the system than the driver
>does a lot of the time. a friend has a tiptronic carrera - hold the
>shift lever and put your foot down, and it'll select the lowest gear for
>the speed to give fastest acceleration, and you can revert to auto from
>there so it shifts up through in the fastest possible time. trust me -
>it's fun!
I am open to that, but it has to come down to Civic level before it
will have any relevance to me. I am sure that a Porsche would be fun
no matter what kind of transmission it has.
BTW, you might want to review my post in this thread from 2005:
I had no idea they would work that way, it just seemed like the
logical way to do it.
jim beam
why not? it's just like you'd have on a stick.
but i don't understand the problem - what's wrong with it? engines are
not perfect across all rev ranges - why not let a computer manage the
efficiency curves - for that's what's happening.
> It is like a slipping clutch. As for more
> torque (horsepower really) a lot of that is eaten up by the
> inefficiency of the torque converter.
how is a slipping clutch more efficient? [it's not.]
> On cars where you can get a MT
> or AT with the same engine, the MT is almost always faster and gets
> better mileage.
not so with the modern autos. and that's one of the big things about
honda autos - it's basically a standard transmission with clutch packs
instead of synchros. inherently more efficient than planetary gears.
>
>>> The ultimate "torque multiplier" is a CVT.
>> that's different - it's not a torque multiplier.
>
> Neither is the conventional AT, it just has a clever design to let the
> engine speed up ahead of the vehicle speed without shifting. It is
> basically like a limited range CVT.
no dude, they're totally different. "torque multiplier" is something a
torque converter can do - hence its name. everything else is ratio
control, be it continuously variable or discrete.
>
>> if is however a great
>> way of achieving absolute optimum gear for all conditions.
>
> I agree that it has a big theoretical advantage, especially compared
> to a conventional AT.
compared to /any/ transmission. there are mechanical efficiency issues
with the friction interface, but that is more than outweighed by ratio
flexibility and ability to keep the engine at its most efficient.
>
>>> A lot of people don't like
>>> them at all, but others say they get used to it. (The perception
>>> problem is so bad that some manufacturers program virtual gears into
>>> them thereby defeating the chief advantage of the CVT.)
>> absolutely! i drove a "real" cvt one when i was in europe years ago,
>> and yes it is /real/ weird at first. but it's amazing how much you can
>> get out of a small 2-cylinder engine when it's got perfect gearing.
>> quite fun! this particular model had 2 independent drives too, so not
>> only did you have optimum gearing, you had limited slip diff benefits in
>> snow & ice too.
>> http://www.ritzsite.demon.nl/DAF/DAF_cars_p2.htm
>
> That was the original CVT. Do you remember who offered the first CVT
> in the US. (I don't think they ever sold the Daffodil here.)
subaru?
>
>>> I only rode
>>> in one CVT car, a Nissan luxury sedan in Japan and it wasn't bad in
>>> that application. He drove it fairly aggressively too - we hit almost
>>> 180 kph on the expressway. I would like to try one of these. I don't
>>> know if I would like it or not.
>> if you're not used to traditional automatics, the transition is easy.
>> if you're used to traditional autos, its weird for a few minutes because
>> it doesn't "shift", but beyond that, they're actually very impressive.
>
> Again though, I am not sure they are any faster or more efficient than
> a good MT.
well, the daf was only 650cc iirc, and 0-30, that wasn't much to touch it.
> Consumer Reports tested the Versa with MT and with CVT.
> The MT version was 0.6 seconds faster to 60 and got one more mpg. (And
> CR panned that MT.) They also tested MT and (conventional) AT
> versions of Fit, Rio, Accent and Yaris. In each case the MT was 2 - 3
> seconds faster and got 2 more mpg, so the CVT was clearly better than
> an AT but not as good as even a mediocre MT, at last on raw numbers.
that depends on the management system. the modern cvt's "simulate" gear
shifts which is the dumbest damned thing since it's not utilizing the
inherent benefit of the system! on that basis, i'm not surprised.
>
> And yet, there is hardly a proliferation of CVTs on the market. Most
> of them seem to be on hybrids in fact.
that's consumer and mechanic inertia - nothing to do with benefits or
reliability. trust me on that one - i've driven the daf for an extended
period and it's a great system.
indeed.
Dano58
I've driven the CVT in an Audi A4 loaner and thought it was weird at
first (as someone else noted). But it also had 'sport' settings where
it would 'shift' thru seven 'gears'. There are more CVT's out there
than you think - off the top of my head, I can think of the Audi (A4
non-quattro auto models), Ford Freestyle cross-over, and Nissan Altima,
Murano, Maxima and Versa.* I think some version of the Ford Five
Hundred has it as well. So, they are becoming more popular.
The best compromise seems to be the automated manual transmissions -
they are a true manual trans with an automated clutch. No torque
converter. ( http://en.wikipedia.org/wiki/Direct-Shift_Gearbox )
Audi's DSG is commonly considered the best example, although BMW has
one (whch regularly gets panned for poor auto shifting). Porsche may
have one as well. I've driven the DSG and it is excellent, very fast
shifting and a decent auto mode as well. But I still prefer a
conventional manual transmission.
For the Ody, I'm prefectly happy with an automatic.
*Oh, Wiki has a list of CVT equipped autos world-wide.
* Audi A4 2.0/1.8T/2.4/3.0/2.5 TDI
* Audi A6 2.0/1.8T/2.4/3.0/2.5 TDI
* Dodge Caliber
* Fiat Punto 1.2 L
* Ford Escape Hybrid 2.3 L 4 cyl
* Ford Five Hundred 3.0 L 6 cyl
* Ford Focus C-MAX 1.6 L TDCi 110 PS
* Ford Freestyle 3.0 L 6 cyl
* Honda Civic HX 1.7 L 4 cyl
* Honda Civic Hybrid 1.3 L 4 cyl
* Honda City 1.5 L
* Honda HR-V 1.6 L
* Honda Insight 1.0 L 3 cyl
* Honda Jazz 1.4L / Honda Fit 1.3 L/1.5 L
* Hyundai Azera 3.8 Lambda
* Hyundai Sonata 3.3 Lambda
* Jeep Compass 2.4 L
* Lexus GS450h 3.5 L 6 cyl
* Lexus RX400h 3.3 L 6 cyl
* Mercedes-Benz A-Class
* Mercedes-Benz B-Class
* Mercury Montego 3.0 L 6 cyl
* Microcar MC1/MC2 505cc 2 cyl diesel or petrol
* Microcar Virgo 505cc 2 cyl diesel or petrol
* Mitsubishi Colt 1.5 L MIVEC 4 cyl with INVECS-III CVT
(Asian-Oceanian version only, 72 kW)
* Mitsubishi Lancer 1.6 L/1.8 L MIVEC 4 cyl with INVECS-III CVT
(Asian version only)
* MG F/MG TF 1.8L
* BMW MINI One and Cooper.
* Nissan Altima (from 2007)
* Nissan Cube
* Nissan Maxima (from 2007)
* Nissan Micra 1.0 L/1.3 L
* Nissan Murano 3.5 L
* Nissan Primera 2.0 L
* Nissan Sentra (from 2007)
* Nissan Serena 2.0 L
* Nissan Skyline 350GT-8
* Nissan Tiida / Versa
* Opel Vectra 1.8 L
* Rover 25
* Rover 45
* Rover Streetwise
* Saturn ION Quad Coupe (2003-2004)
* Saturn VUE 2.2 L AWD (2002-2005), 2.2 FWD (2002-2004)
* Subaru R1
* Subaru R2
* Subaru Stella
* Toyota Highlander Hybrid 3.3 L 6 cyl
* Toyota Camry Hybrid 2.4L 4 cyl
* Toyota Prius 1.5 L 4 cyl
Dan D
'04 A4 1.8Tq 6-speed
z
jim beam wrote:
> > On the upside, completing the downshift earlier makes it ready to
> > accelerate on short notice. All-in-all, that is one reason why I
> > prefer manual transmissions. The AT will never have enough sensors
> > until they put in one that can read my mind.
>
> you haven't driven an automatic lately.
Yeah, my friend's Prelude of mid -80s did same thing.
Gordon McGrew
>Interesting discussion I started here, I guess....!
>
>I've driven the CVT in an Audi A4 loaner and thought it was weird at
>first (as someone else noted). But it also had 'sport' settings where
>it would 'shift' thru seven 'gears'. There are more CVT's out there
>than you think - off the top of my head, I can think of the Audi (A4
>non-quattro auto models), Ford Freestyle cross-over, and Nissan Altima,
>Murano, Maxima and Versa.* I think some version of the Ford Five
>Hundred has it as well. So, they are becoming more popular.
>
>The best compromise seems to be the automated manual transmissions -
>they are a true manual trans with an automated clutch. No torque
>converter. ( http://en.wikipedia.org/wiki/Direct-Shift_Gearbox )
>Audi's DSG is commonly considered the best example, although BMW has
>one (whch regularly gets panned for poor auto shifting). Porsche may
>have one as well. I've driven the DSG and it is excellent, very fast
>shifting and a decent auto mode as well. But I still prefer a
>conventional manual transmission.
>
>For the Ody, I'm prefectly happy with an automatic.
I would really prefer that Honda would make a Volvo 240 wagon with
performance suspension and an MT, but I have pretty much given up
hope.
>*Oh, Wiki has a list of CVT equipped autos world-wide.
See my comments below. Few of these are currently available in the
US,. If you eliminate the hybrids, I think there are only about
three. Partly this is due to most CVTs being designed for small
engines.
Most CVT designs seem to be reliable and the efficiency improvement is
significant compared to conventional ATs. I really think that the
test drive turns off a lot of buyers because it is so unconventional.
Honda is apparently selling a "7-speed CVT" - talk about an oxymoron.
This is a sure sign that buyers are turned off by normal CVT
operation. Hybrids may be the thing that brings CVTs out of the
closet.
See comments below.
> * Audi A4 2.0/1.8T/2.4/3.0/2.5 TDI
> * Audi A6 2.0/1.8T/2.4/3.0/2.5 TDI
> * Dodge Caliber
> * Fiat Punto 1.2 L
> * Ford Escape Hybrid 2.3 L 4 cyl
> * Ford Five Hundred 3.0 L 6 cyl
> * Ford Focus C-MAX 1.6 L TDCi 110 PS
> * Ford Freestyle 3.0 L 6 cyl
> * Honda Civic HX 1.7 L 4 cyl
> * Honda Civic Hybrid 1.3 L 4 cyl
The only US Civic currently offered with a CVT is the Hybrid.
> * Honda City 1.5 L
I haven't heard of a Honda City in a long, long time. Are they still
sold?
> * Honda HR-V 1.6 L
Never sold in US.
> * Honda Insight 1.0 L 3 cyl
Discontinued - will probably be replaced.
> * Honda Jazz 1.4L / Honda Fit 1.3 L/1.5 L
No CVT in US market.
I am a little skeptical of those dates. I didn't think they were on
the market that long before it was discovered that every single one of
them breaks. And GM wonders why it is going out of business. LOL
> * Subaru R1
> * Subaru R2
> * Subaru Stella
Subaru Justy (probably equals one of above models) was sold with a CVT
in the US for a few years in the 90's. Subaru hasn't sold a CVT in
the US since.
Gordon McGrew
<spamv...@bad.example.net> wrote:
>>>>>> The problem with most (virtually all) ATs is that they are biased
>>>>>> toward automatic operation and discourage manual operation.
>>>>> how? my auto has the shift in exactly the same place as where the stick
>>>>> would be. i see no difference. the transmission even has a no-lock
>>>>> gate between 3rd & 4th [commonest manual override] especially so you
>>>>> /can/ flip up and down at will.
>>>> If you put it in 4, will it ever downshift into 3 by itself?
>>> yes, absolutely. it does it on "kickdown" acceleration /and/ it does it
>>> on braking. not gentle braking, but harder braking.
>>
>> It is not a bad thing, I just don't care for it. If I want to
>> downshift, I can do that. If I don't want to, I don't like the car
>> doing it on its own.
>
>why not? it's just like you'd have on a stick.
Not sure I understand. My GS-R never downshifts on its own.
It is just a personal preference. I like the engine to be positively
coupled to the wheels.
>> It is like a slipping clutch. As for more
>> torque (horsepower really) a lot of that is eaten up by the
>> inefficiency of the torque converter.
>
>how is a slipping clutch more efficient? [it's not.]
No, I understand that (unlike a slipping clutch) there is a benefit to
the slip designed into the AT. I just don't like the feel of it and
the benefit is more than eaten up by the inefficiencies that come with
it.
>> On cars where you can get a MT
>> or AT with the same engine, the MT is almost always faster and gets
>> better mileage.
>
>not so with the modern autos. and that's one of the big things about
>honda autos - it's basically a standard transmission with clutch packs
>instead of synchros. inherently more efficient than planetary gears.
Looking at the differences between the ATs in the econo cars tested by
CR, Honda looks about as good as the other ATs (except for the CVT.)
>>>> The ultimate "torque multiplier" is a CVT.
>>> that's different - it's not a torque multiplier.
>>
>> Neither is the conventional AT, it just has a clever design to let the
>> engine speed up ahead of the vehicle speed without shifting. It is
>> basically like a limited range CVT.
>
>no dude, they're totally different. "torque multiplier" is something a
>torque converter can do - hence its name. everything else is ratio
>control, be it continuously variable or discrete.
OK, explain it to me. My understanding is that it is just a trick to
get the engine running at a slightly higher rpm to produce more power.
Kind of like a mini downshift. All car transmissions are torque
multipliers. They take high rpm/low torque and turn it into low rpm
high torque. If it were perfectly efficient, the power output would
be equal to input but of course it is always less. No way to get more
power out unless you put more power in, i.e. run the engine at higher
rpm.
>>> if is however a great
>>> way of achieving absolute optimum gear for all conditions.
>>
>> I agree that it has a big theoretical advantage, especially compared
>> to a conventional AT.
>
>compared to /any/ transmission. there are mechanical efficiency issues
>with the friction interface, but that is more than outweighed by ratio
>flexibility and ability to keep the engine at its most efficient.
The why doesn't the Versa with a CVT get better mileage or accelerate
faster than the Versa with an MT? Unfortunately, there are few cars
which allow you to directly compare CVT vs. MT.
>>>> A lot of people don't like
>>>> them at all, but others say they get used to it. (The perception
>>>> problem is so bad that some manufacturers program virtual gears into
>>>> them thereby defeating the chief advantage of the CVT.)
>>> absolutely! i drove a "real" cvt one when i was in europe years ago,
>>> and yes it is /real/ weird at first. but it's amazing how much you can
>>> get out of a small 2-cylinder engine when it's got perfect gearing.
>>> quite fun! this particular model had 2 independent drives too, so not
>>> only did you have optimum gearing, you had limited slip diff benefits in
>>> snow & ice too.
>>> http://www.ritzsite.demon.nl/DAF/DAF_cars_p2.htm
>>
>> That was the original CVT. Do you remember who offered the first CVT
>> in the US. (I don't think they ever sold the Daffodil here.)
>
>subaru?
That is what I recall. The car was called the Justy.
>>>> I only rode
>>>> in one CVT car, a Nissan luxury sedan in Japan and it wasn't bad in
>>>> that application. He drove it fairly aggressively too - we hit almost
>>>> 180 kph on the expressway. I would like to try one of these. I don't
>>>> know if I would like it or not.
>>> if you're not used to traditional automatics, the transition is easy.
>>> if you're used to traditional autos, its weird for a few minutes because
>>> it doesn't "shift", but beyond that, they're actually very impressive.
>>
>> Again though, I am not sure they are any faster or more efficient than
>> a good MT.
>
>well, the daf was only 650cc iirc, and 0-30, that wasn't much to touch it.
I think the Honda 600 would have blown its petals off. ;-)
>> Consumer Reports tested the Versa with MT and with CVT.
>> The MT version was 0.6 seconds faster to 60 and got one more mpg. (And
>> CR panned that MT.) They also tested MT and (conventional) AT
>> versions of Fit, Rio, Accent and Yaris. In each case the MT was 2 - 3
>> seconds faster and got 2 more mpg, so the CVT was clearly better than
>> an AT but not as good as even a mediocre MT, at last on raw numbers.
>
>that depends on the management system. the modern cvt's "simulate" gear
>shifts which is the dumbest damned thing since it's not utilizing the
>inherent benefit of the system! on that basis, i'm not surprised.
Does the Versa do that? CR didn't mention it.
>> And yet, there is hardly a proliferation of CVTs on the market. Most
>> of them seem to be on hybrids in fact.
>
>that's consumer and mechanic inertia - nothing to do with benefits or
>reliability. trust me on that one - i've driven the daf for an extended
>period and it's a great system.
Maybe. I would gladly trade the AT in my Ody for one if it was proven
reliable. Not all are. The on in the Saturn Vue was a disaster, but
I guess you have to expect that from GM. The Japanese units don't
seem to have any problems.
jim beam
> On Sun, 07 Jan 2007 15:20:11 -0800, jim beam
> <spamv...@bad.example.net> wrote:
>
>>>>>>> The problem with most (virtually all) ATs is that they are biased
>>>>>>> toward automatic operation and discourage manual operation.
>>>>>> how? my auto has the shift in exactly the same place as where the stick
>>>>>> would be. i see no difference. the transmission even has a no-lock
>>>>>> gate between 3rd & 4th [commonest manual override] especially so you
>>>>>> /can/ flip up and down at will.
>>>>> If you put it in 4, will it ever downshift into 3 by itself?
>>>> yes, absolutely. it does it on "kickdown" acceleration /and/ it does it
>>>> on braking. not gentle braking, but harder braking.
>>> It is not a bad thing, I just don't care for it. If I want to
>>> downshift, I can do that. If I don't want to, I don't like the car
>>> doing it on its own.
>> why not? it's just like you'd have on a stick.
>
> Not sure I understand. My GS-R never downshifts on its own.
if it doesn't, then there's something wrong. how old is it?
that's what the lockup clutch in the torque converter is for.
>
>>> It is like a slipping clutch. As for more
>>> torque (horsepower really) a lot of that is eaten up by the
>>> inefficiency of the torque converter.
>> how is a slipping clutch more efficient? [it's not.]
>
> No, I understand that (unlike a slipping clutch) there is a benefit to
> the slip designed into the AT. I just don't like the feel of it and
> the benefit is more than eaten up by the inefficiencies that come with
> it.
you'd hate cvt. there's no "relationship" between revs and engine speed
at all.
>
>>> On cars where you can get a MT
>>> or AT with the same engine, the MT is almost always faster and gets
>>> better mileage.
>> not so with the modern autos. and that's one of the big things about
>> honda autos - it's basically a standard transmission with clutch packs
>> instead of synchros. inherently more efficient than planetary gears.
>
> Looking at the differences between the ATs in the econo cars tested by
> CR, Honda looks about as good as the other ATs (except for the CVT.)
you're looking at fuel economy, right?
>
>
>>>>> The ultimate "torque multiplier" is a CVT.
>>>> that's different - it's not a torque multiplier.
>>> Neither is the conventional AT, it just has a clever design to let the
>>> engine speed up ahead of the vehicle speed without shifting. It is
>>> basically like a limited range CVT.
>> no dude, they're totally different. "torque multiplier" is something a
>> torque converter can do - hence its name. everything else is ratio
>> control, be it continuously variable or discrete.
>
> OK, explain it to me. My understanding is that it is just a trick to
> get the engine running at a slightly higher rpm to produce more power.
> Kind of like a mini downshift. All car transmissions are torque
> multipliers.
ok, yes, but we're talking about different things. torque converters
can increase torque output from a little to a lot in a very limited rev
range. ratio change is something different and that's what the gears
are for.
> They take high rpm/low torque and turn it into low rpm
> high torque. If it were perfectly efficient, the power output would
> be equal to input but of course it is always less. No way to get more
> power out unless you put more power in, i.e. run the engine at higher
> rpm.
see above.
>
>>>> if is however a great
>>>> way of achieving absolute optimum gear for all conditions.
>>> I agree that it has a big theoretical advantage, especially compared
>>> to a conventional AT.
>> compared to /any/ transmission. there are mechanical efficiency issues
>> with the friction interface, but that is more than outweighed by ratio
>> flexibility and ability to keep the engine at its most efficient.
>
> The why doesn't the Versa with a CVT get better mileage or accelerate
> faster than the Versa with an MT? Unfortunately, there are few cars
> which allow you to directly compare CVT vs. MT.
civic hx was significantly more fuel efficient than the stick.
don't know. given "consumer demand", i expect so.
>
>>> And yet, there is hardly a proliferation of CVTs on the market. Most
>>> of them seem to be on hybrids in fact.
>> that's consumer and mechanic inertia - nothing to do with benefits or
>> reliability. trust me on that one - i've driven the daf for an extended
>> period and it's a great system.
>
> Maybe. I would gladly trade the AT in my Ody for one if it was proven
> reliable. Not all are. The on in the Saturn Vue was a disaster, but
> I guess you have to expect that from GM. The Japanese units don't
> seem to have any problems.
i've never heard of problems with the civic hx.
Gordon McGrew
<spamv...@bad.example.net> wrote:
>Gordon McGrew wrote:
>> On Sun, 07 Jan 2007 15:20:11 -0800, jim beam
>> <spamv...@bad.example.net> wrote:
>>
>>>>>>>> The problem with most (virtually all) ATs is that they are biased
>>>>>>>> toward automatic operation and discourage manual operation.
>>>>>>> how? my auto has the shift in exactly the same place as where the stick
>>>>>>> would be. i see no difference. the transmission even has a no-lock
>>>>>>> gate between 3rd & 4th [commonest manual override] especially so you
>>>>>>> /can/ flip up and down at will.
>>>>>> If you put it in 4, will it ever downshift into 3 by itself?
>>>>> yes, absolutely. it does it on "kickdown" acceleration /and/ it does it
>>>>> on braking. not gentle braking, but harder braking.
>>>> It is not a bad thing, I just don't care for it. If I want to
>>>> downshift, I can do that. If I don't want to, I don't like the car
>>>> doing it on its own.
>>> why not? it's just like you'd have on a stick.
>>
>> Not sure I understand. My GS-R never downshifts on its own.
>
>if it doesn't, then there's something wrong. how old is it?
It is a '94 with a 5-speed manual transmission. What kind of MT cars
have you driven that shift themselves???
But it isn't engaged all the time. When it disengages, that is when
it "slips" and I do not find that satisfying as a driver. Like I said
a the outside, it is a preference for MT. I like to drive cars and
the MT is more enjoyable than the ATs I have driven. I don't like it
shifting when I don't want it to and I don't like the slippy feel of
the torque converter. The fact that the MT is usually faster and more
fuel efficient is a bonus.
>
>>
>>>> It is like a slipping clutch. As for more
>>>> torque (horsepower really) a lot of that is eaten up by the
>>>> inefficiency of the torque converter.
>>> how is a slipping clutch more efficient? [it's not.]
>>
>> No, I understand that (unlike a slipping clutch) there is a benefit to
>> the slip designed into the AT. I just don't like the feel of it and
>> the benefit is more than eaten up by the inefficiencies that come with
>> it.
>
>you'd hate cvt. there's no "relationship" between revs and engine speed
>at all.
I think you are probably right. That is why I mentioned the fact that
the CVT isn't very popular in the US (if anywhere) and I think it is
because lots of people hate it. Why else would Honda sell a 7-speed
CVT?
OTOH, it probably appeals to - or at least doesn't repulse - the
hybrid buyer because it befits the unconventional nature of the car. I
realize there are technical benefits to the combination of hybrid and
CVT, but I am saying that the unconventional nature of the CVT is less
of a negative when you are already committed to buying an
unconventional vehicle. If you are attracted to the hybrid because it
is unconventional, the CVT is a plus.
>>>> On cars where you can get a MT
>>>> or AT with the same engine, the MT is almost always faster and gets
>>>> better mileage.
>>> not so with the modern autos. and that's one of the big things about
>>> honda autos - it's basically a standard transmission with clutch packs
>>> instead of synchros. inherently more efficient than planetary gears.
>>
>> Looking at the differences between the ATs in the econo cars tested by
>> CR, Honda looks about as good as the other ATs (except for the CVT.)
>
>you're looking at fuel economy, right?
Fuel economy was significantly better for the MTs but the biggest
difference was acceleration. The MTs blew the doors off the ATs. In
terms of 0 - 60 time differences, the Yaris AT was the best - "only"
2.1 seconds slower than the MT version. Even the slowest MT car, the
Kia Rio was faster than the Versa CVT. The fastest AT car, the Yaris,
was 1.4 seconds slower than the Versa CVT.
>>
>>>>>> The ultimate "torque multiplier" is a CVT.
>>>>> that's different - it's not a torque multiplier.
>>>> Neither is the conventional AT, it just has a clever design to let the
>>>> engine speed up ahead of the vehicle speed without shifting. It is
>>>> basically like a limited range CVT.
>>> no dude, they're totally different. "torque multiplier" is something a
>>> torque converter can do - hence its name. everything else is ratio
>>> control, be it continuously variable or discrete.
>>
>> OK, explain it to me. My understanding is that it is just a trick to
>> get the engine running at a slightly higher rpm to produce more power.
>> Kind of like a mini downshift. All car transmissions are torque
>> multipliers.
>
>ok, yes, but we're talking about different things. torque converters
>can increase torque output from a little to a lot in a very limited rev
>range. ratio change is something different and that's what the gears
>are for.
You understand that the ATs torque output at a certain rpm (i.e. power
transmitted) is higher when the torque multiplication is active. There
are only two way this can happen. The first is to increase the
efficiency of the transmission. I think we can dismiss that. The
other way is to increase the power input. The only way to do that is
to increase the throttle opening or increase the rpm. The throttle
opening is determined by your foot (and it wouldn't be much of a trick
for the torque multiplier to be just an extra jerk on the throttle and
it wouldn't do much good if the throttle were already wide open.)
However, rpm is largely controlled by the transmission. The
transmission allows the engine to run a little faster and therefore
produce more power which is transmitted to the wheels. This is what I
meant by a mini downshift.
>> They take high rpm/low torque and turn it into low rpm
>> high torque. If it were perfectly efficient, the power output would
>> be equal to input but of course it is always less. No way to get more
>> power out unless you put more power in, i.e. run the engine at higher
>> rpm.
>
>see above.
>
>>
>>>>> if is however a great
>>>>> way of achieving absolute optimum gear for all conditions.
>>>> I agree that it has a big theoretical advantage, especially compared
>>>> to a conventional AT.
>>> compared to /any/ transmission. there are mechanical efficiency issues
>>> with the friction interface, but that is more than outweighed by ratio
>>> flexibility and ability to keep the engine at its most efficient.
>>
>> The why doesn't the Versa with a CVT get better mileage or accelerate
>> faster than the Versa with an MT? Unfortunately, there are few cars
>> which allow you to directly compare CVT vs. MT.
>
>civic hx was significantly more fuel efficient than the stick.
I gather that was the CVT-equipped model. They don't sell it anymore.
I guess people hated it more than high fuel costs.
Like I said, they hate it just like you think I would. (Actually I
would love to try one, I do think it is a neat idea and it would be
fun for a while at least. Only after the novelty wore off could I
tell you if I like it or hate it. I actually suspect that I would
like it more than a conventional AT.)
Here is an interesting review I found. (It indicates that the Versa
CVT does not have "gears," so the fact that it was slower and less
fuel efficient than the "clunky" MT is significant.) I made one
editorial comment in brackets.
--quote--
But the CVT is the one that shines. Its proprietary design, benefiting
from Nissan's global cooperation with French carmaker Renault, is
uncanny in the way it maintains optimal engine rpm within the most
fuel-efficient torque range. It senses, for example, when the Versa is
proceeding downhill and glides effortlessly into a lower gear range to
slow the car with engine braking. [What if you don't want engine
braking? It is wasting kinetic energy = fuel. What it needs in a
powerful computer with optical sensors to look ahead, evaluate the
situation and decide whether engine braking is advantageous.]
Conversely, under pedal-to-the-floor acceleration, the CVT instantly
launches the engine to its max-torque rpm, then keeps it there
unchanged until a desired highway speed is reached.
This goes against every traditional sensation of driving, wherein gear
changes trigger a momentary drop in rpm as the higher gear ratio is
engaged. There's a lot of mechanical inefficiency in that traditional
gear-change syncopation; and Versa's CVT eliminates it. When first
experiencing the CVT's behavior, it feels wrong, sounds noisy. In
truth, however, it's mostly the lack of noticeable gear changes that's
merely thwarting a driver's subconscious expectation of rising-falling
rpms as gears change.
--end quote--
http://www.carlist.com/newcars/2007/ncr1116.html
>>>> And yet, there is hardly a proliferation of CVTs on the market. Most
>>>> of them seem to be on hybrids in fact.
>>> that's consumer and mechanic inertia - nothing to do with benefits or
>>> reliability. trust me on that one - i've driven the daf for an extended
>>> period and it's a great system.
>>
>> Maybe. I would gladly trade the AT in my Ody for one if it was proven
>> reliable. Not all are. The on in the Saturn Vue was a disaster, but
>> I guess you have to expect that from GM. The Japanese units don't
>> seem to have any problems.
>
>i've never heard of problems with the civic hx.
Neither have I, but then there aren't a lot out there.
jim beam
> On Mon, 08 Jan 2007 21:25:13 -0800, jim beam
> <spamv...@bad.example.net> wrote:
>
>> Gordon McGrew wrote:
>>> On Sun, 07 Jan 2007 15:20:11 -0800, jim beam
>>> <spamv...@bad.example.net> wrote:
>>>
>>>>>>>>> The problem with most (virtually all) ATs is that they are biased
>>>>>>>>> toward automatic operation and discourage manual operation.
>>>>>>>> how? my auto has the shift in exactly the same place as where the stick
>>>>>>>> would be. i see no difference. the transmission even has a no-lock
>>>>>>>> gate between 3rd & 4th [commonest manual override] especially so you
>>>>>>>> /can/ flip up and down at will.
>>>>>>> If you put it in 4, will it ever downshift into 3 by itself?
>>>>>> yes, absolutely. it does it on "kickdown" acceleration /and/ it does it
>>>>>> on braking. not gentle braking, but harder braking.
>>>>> It is not a bad thing, I just don't care for it. If I want to
>>>>> downshift, I can do that. If I don't want to, I don't like the car
>>>>> doing it on its own.
>>>> why not? it's just like you'd have on a stick.
>>> Not sure I understand. My GS-R never downshifts on its own.
>> if it doesn't, then there's something wrong. how old is it?
>
> It is a '94 with a 5-speed manual transmission. What kind of MT cars
> have you driven that shift themselves???
i misunderstood you.
originally, you said "If I want to downshift, I can do that." well, you
can on an auto. on my car, the shifter is in the same place as a stick
would be too. and the auto replicates engine braking when you need it -
just like you'd do yourself. really, it's a good system.
you'd hate cvt. as i said before, there's zero relation between engine
speed and vehicle speed - if you drive on engine revs, and it sounds
like you do, you'll be suffering total loss of feedback.
> Like I said
> a the outside, it is a preference for MT. I like to drive cars and
> the MT is more enjoyable than the ATs I have driven. I don't like it
> shifting when I don't want it to and I don't like the slippy feel of
> the torque converter. The fact that the MT is usually faster and more
> fuel efficient is a bonus.
check the modern civics in that department.
>
>
>>>>> It is like a slipping clutch. As for more
>>>>> torque (horsepower really) a lot of that is eaten up by the
>>>>> inefficiency of the torque converter.
>>>> how is a slipping clutch more efficient? [it's not.]
>>> No, I understand that (unlike a slipping clutch) there is a benefit to
>>> the slip designed into the AT. I just don't like the feel of it and
>>> the benefit is more than eaten up by the inefficiencies that come with
>>> it.
>> you'd hate cvt. there's no "relationship" between revs and engine speed
>> at all.
>
> I think you are probably right. That is why I mentioned the fact that
> the CVT isn't very popular in the US (if anywhere) and I think it is
> because lots of people hate it. Why else would Honda sell a 7-speed
> CVT?
because they rely on dealer feedback, and dealers are morons? cvt was
pretty popular in europe iirc. volvo sold them as well as daf, and they
did quite well.
>
> OTOH, it probably appeals to - or at least doesn't repulse - the
> hybrid buyer because it befits the unconventional nature of the car. I
> realize there are technical benefits to the combination of hybrid and
> CVT, but I am saying that the unconventional nature of the CVT is less
> of a negative when you are already committed to buying an
> unconventional vehicle. If you are attracted to the hybrid because it
> is unconventional, the CVT is a plus.
nah, it's a pure engineering logic decision. cvt allows extremely good
engine efficiency. if you don't want that, you don't want a hybrid.
>
>>>>> On cars where you can get a MT
>>>>> or AT with the same engine, the MT is almost always faster and gets
>>>>> better mileage.
>>>> not so with the modern autos. and that's one of the big things about
>>>> honda autos - it's basically a standard transmission with clutch packs
>>>> instead of synchros. inherently more efficient than planetary gears.
>>> Looking at the differences between the ATs in the econo cars tested by
>>> CR, Honda looks about as good as the other ATs (except for the CVT.)
>> you're looking at fuel economy, right?
>
> Fuel economy was significantly better for the MTs but the biggest
> difference was acceleration. The MTs blew the doors off the ATs. In
> terms of 0 - 60 time differences, the Yaris AT was the best - "only"
> 2.1 seconds slower than the MT version. Even the slowest MT car, the
> Kia Rio was faster than the Versa CVT. The fastest AT car, the Yaris,
> was 1.4 seconds slower than the Versa CVT.
dude, compare like with like - not different car to different car if
you're trying to compare trnasmissions, i.e. yaris with cvt, yaris with
stick, etc. yaris stick to versa cvt doesn't work.
>
>>>>>>> The ultimate "torque multiplier" is a CVT.
>>>>>> that's different - it's not a torque multiplier.
>>>>> Neither is the conventional AT, it just has a clever design to let the
>>>>> engine speed up ahead of the vehicle speed without shifting. It is
>>>>> basically like a limited range CVT.
>>>> no dude, they're totally different. "torque multiplier" is something a
>>>> torque converter can do - hence its name. everything else is ratio
>>>> control, be it continuously variable or discrete.
>>> OK, explain it to me. My understanding is that it is just a trick to
>>> get the engine running at a slightly higher rpm to produce more power.
>>> Kind of like a mini downshift. All car transmissions are torque
>>> multipliers.
>> ok, yes, but we're talking about different things. torque converters
>> can increase torque output from a little to a lot in a very limited rev
>> range. ratio change is something different and that's what the gears
>> are for.
>
> You understand that the ATs torque output at a certain rpm (i.e. power
> transmitted) is higher when the torque multiplication is active. There
> are only two way this can happen. The first is to increase the
> efficiency of the transmission. I think we can dismiss that. The
> other way is to increase the power input.
no, it depends on input/output speed differential. within certain rev
ranges, torque transmission is very high, even with a rev differential.
if it gets outside of that band, it drops right off.
> The only way to do that is
> to increase the throttle opening or increase the rpm. The throttle
> opening is determined by your foot (and it wouldn't be much of a trick
> for the torque multiplier to be just an extra jerk on the throttle and
> it wouldn't do much good if the throttle were already wide open.)
> However, rpm is largely controlled by the transmission. The
> transmission allows the engine to run a little faster and therefore
> produce more power which is transmitted to the wheels. This is what I
> meant by a mini downshift.
that's the lockup clutch releasing.
>
>>> They take high rpm/low torque and turn it into low rpm
>>> high torque. If it were perfectly efficient, the power output would
>>> be equal to input but of course it is always less. No way to get more
>>> power out unless you put more power in, i.e. run the engine at higher
>>> rpm.
>> see above.
>>
>>>>>> if is however a great
>>>>>> way of achieving absolute optimum gear for all conditions.
>>>>> I agree that it has a big theoretical advantage, especially compared
>>>>> to a conventional AT.
>>>> compared to /any/ transmission. there are mechanical efficiency issues
>>>> with the friction interface, but that is more than outweighed by ratio
>>>> flexibility and ability to keep the engine at its most efficient.
>>> The why doesn't the Versa with a CVT get better mileage or accelerate
>>> faster than the Versa with an MT? Unfortunately, there are few cars
>>> which allow you to directly compare CVT vs. MT.
>> civic hx was significantly more fuel efficient than the stick.
>
> I gather that was the CVT-equipped model. They don't sell it anymore.
> I guess people hated it more than high fuel costs.
my money's on dealer prejudice, not consumer. by the same token, the
hatchback has been all but dropped in the u.s. afaikt, that's more to
do with vehicles with the same utility selling for $30k rather than $15k
for a hatch, not consumer demand. try buying a used hatchback civic
here in the bay area - good luck! people just keep them - they never
sell.
not correct. when engine braking, fuel delivery is completely stopped.
> What it needs in a
> powerful computer with optical sensors to look ahead, evaluate the
> situation and decide whether engine braking is advantageous
why? i don't want my car making /that/ kind of decision. seriously,
auto engine braking only happens when you're foot braking - just like on
a stick. you can't criticize what you've not used dude.
/all/ the 96-2000 hx autos are cvt.
Gordon McGrew
<spamv...@bad.example.net> wrote:
The AT Civic gets slightly better highway mileage than the MT - I am
guessing it may have a higher final ratio. The Accord 4 and V6 and
the Fit all get better mileage with the MT. I don't have any test
results, but I bet the MTs are universally faster (see below.)
>>>>>> It is like a slipping clutch. As for more
>>>>>> torque (horsepower really) a lot of that is eaten up by the
>>>>>> inefficiency of the torque converter.
>>>>> how is a slipping clutch more efficient? [it's not.]
>>>> No, I understand that (unlike a slipping clutch) there is a benefit to
>>>> the slip designed into the AT. I just don't like the feel of it and
>>>> the benefit is more than eaten up by the inefficiencies that come with
>>>> it.
>>> you'd hate cvt. there's no "relationship" between revs and engine speed
>>> at all.
>>
>> I think you are probably right. That is why I mentioned the fact that
>> the CVT isn't very popular in the US (if anywhere) and I think it is
>> because lots of people hate it. Why else would Honda sell a 7-speed
>> CVT?
>
>because they rely on dealer feedback, and dealers are morons? cvt was
>pretty popular in europe iirc. volvo sold them as well as daf, and they
>did quite well.
Why is that in the past tense? We agree they are more efficient than
conventional ATs and if they were popular, why didn't they drive
conventional ATs off the market? Reliability could have been an issue
but shouldn't be now (as long as you stay away form GM.)
>>
>> OTOH, it probably appeals to - or at least doesn't repulse - the
>> hybrid buyer because it befits the unconventional nature of the car. I
>> realize there are technical benefits to the combination of hybrid and
>> CVT, but I am saying that the unconventional nature of the CVT is less
>> of a negative when you are already committed to buying an
>> unconventional vehicle. If you are attracted to the hybrid because it
>> is unconventional, the CVT is a plus.
>
>nah, it's a pure engineering logic decision. cvt allows extremely good
>engine efficiency. if you don't want that, you don't want a hybrid.
Exactly right. The converse of that statement is that, if you want
increased efficiency, you will tolerate or even embrace the CVT. And
if you like the hybrid because it is odd or technologically advanced,
then you will love the CVT.
>>>>>> On cars where you can get a MT
>>>>>> or AT with the same engine, the MT is almost always faster and gets
>>>>>> better mileage.
>>>>> not so with the modern autos. and that's one of the big things about
>>>>> honda autos - it's basically a standard transmission with clutch packs
>>>>> instead of synchros. inherently more efficient than planetary gears.
>>>> Looking at the differences between the ATs in the econo cars tested by
>>>> CR, Honda looks about as good as the other ATs (except for the CVT.)
>>> you're looking at fuel economy, right?
>>
>> Fuel economy was significantly better for the MTs but the biggest
>> difference was acceleration. The MTs blew the doors off the ATs. In
>> terms of 0 - 60 time differences, the Yaris AT was the best - "only"
>> 2.1 seconds slower than the MT version. Even the slowest MT car, the
>> Kia Rio was faster than the Versa CVT. The fastest AT car, the Yaris,
>> was 1.4 seconds slower than the Versa CVT.
>
>dude, compare like with like - not different car to different car if
>you're trying to compare trnasmissions, i.e. yaris with cvt, yaris with
>stick, etc. yaris stick to versa cvt doesn't work.
It doesn't matter whether you compare like to like or unlike to like.
All of the MTs are faster than all of the ATs and the CVT. Let me
tabulate it for you:
0-60 45-65 1/4 mi
Fit AT 12.4 8.4 19.0
Fit MT 9.9 6.5 17.4
Versa CVT 10.1 6.4 17.8
Versa MT 9.5 5.9 17.2
Rio AT 12.8 8.1 19.3
Rio MT 10.0 7.1 17.5
Accent AT 12.5 7.7 19.1
Accent MT 9.5 6.5 17.2
Yaris AT 11.4 6.9 18.6
Yaris MT 9.3 6.0 17.3
As I said, "The MTs blew the doors off the ATs."
>
>>
>>>>>>>> The ultimate "torque multiplier" is a CVT.
>>>>>>> that's different - it's not a torque multiplier.
>>>>>> Neither is the conventional AT, it just has a clever design to let the
>>>>>> engine speed up ahead of the vehicle speed without shifting. It is
>>>>>> basically like a limited range CVT.
>>>>> no dude, they're totally different. "torque multiplier" is something a
>>>>> torque converter can do - hence its name. everything else is ratio
>>>>> control, be it continuously variable or discrete.
>>>> OK, explain it to me. My understanding is that it is just a trick to
>>>> get the engine running at a slightly higher rpm to produce more power.
>>>> Kind of like a mini downshift. All car transmissions are torque
>>>> multipliers.
>>> ok, yes, but we're talking about different things. torque converters
>>> can increase torque output from a little to a lot in a very limited rev
>>> range. ratio change is something different and that's what the gears
>>> are for.
>>
>> You understand that the ATs torque output at a certain rpm (i.e. power
>> transmitted) is higher when the torque multiplication is active. There
>> are only two way this can happen. The first is to increase the
>> efficiency of the transmission. I think we can dismiss that. The
>> other way is to increase the power input.
>
>no, it depends on input/output speed differential. within certain rev
>ranges, torque transmission is very high, even with a rev differential.
> if it gets outside of that band, it drops right off.
http://en.wikipedia.org/wiki/Torque_converter#Efficiency_and_Torque_Multiplication
--quotes-- [my comments in brackets]
Unlike a fluid coupling, however, a torque converter is able to
multiply torque when there is a substantial difference between input
and output rotational speed, thus providing the equivalent of a
reduction gear. [IOW, a mini-downshift, a slightly lower gear that
allows the engine to run faster and produce more power.]
The principal difference is that whereas a fluid coupling is a two
element drive that is incapable of multiplying torque [IOW, it has a
1:1 ratio of input to output] , a torque converter has at least one
extra element - the stator - which alters the drive's characteristics
during periods of high slippage, producing an increase in output
torque. [IOW, it allows the engine to run faster and produce more
power, just like a lower gear.]
The Buick Dynaflow automatic transmission was a non-shifting design
and, under normal conditions, relied solely upon the converter to
multiply torque. [IOW, there was no gear transmission, all ratio
change was due to slippage of the TC - an early CVT!] The Dynaflow
used a five element converter to produce the wide range of torque
multiplication [i.e. wide range of drive ratios] needed to propel a
heavy vehicle.
* Acceleration. The load is accelerating but there still is a
relatively large difference between pump and turbine speed. [i.e. low
gear] ...The amount of multiplication will depend upon the actual
difference between pump and turbine speed, [i.e. the effective drive
ratio] as well as various other design factors. [efficiency]
* Coupling. The turbine has reached approximately 90 percent of
the speed of the pump. Torque multiplication has ceased [i.e. gear
ratio is slightly less than 1:1 but the slight power increase from
higher engine rpm is lost to inefficiency] and the torque converter is
behaving in a manner similar to a fluid coupling. In modern automotive
applications, it is usually at this stage of operation where the
lock-up clutch is applied, a procedure that tends to improve fuel
efficiency.
--end quotes--
When they say "torque multiplication" what they really mean is a drive
ratio less than 1:1. IOW, every transmission is a torque multiplier,
at least in the lower gears.
>
>> The only way to do that is
>> to increase the throttle opening or increase the rpm. The throttle
>> opening is determined by your foot (and it wouldn't be much of a trick
>> for the torque multiplier to be just an extra jerk on the throttle and
>> it wouldn't do much good if the throttle were already wide open.)
>> However, rpm is largely controlled by the transmission. The
>> transmission allows the engine to run a little faster and therefore
>> produce more power which is transmitted to the wheels. This is what I
>> meant by a mini downshift.
>
>that's the lockup clutch releasing.
Right, there is no torque multiplication in the TC unless it is
slipping.
I personally like hatchbacks and I know they have a following. I too
am surprised and disappointed that they have all but disappeared. I
don't know I am ready to sign on to the conspiracy theory though. If
there were a strong market, Someone like Mazda or Nissan would jump to
serve it to increase their sales. apparently there isn't enough
demand to justify the high expense of two body styles and the sedan is
more popular.
I suppose I could blame the shortage of MTs on greedy dealers and
manufacturers who want to force me to buy a more expensive AT.
However, I am more inclined to blame Starbucks.
But kinetic energy is being lost. Doesn't matter if the car has to be
brought to a stop anyway, but if the driving situation requires little
or no compression braking and the computer orders a lot, the car will
slow unnecessarily and fuel will be consumed bringing it back up to
speed.
I use compression braking a lot. Sometimes I use a little, sometimes
I use a lot. Sometimes I coast with the clutch disengaged for maximum
distance. A transmission that always applies medium compression
braking is not as going to achieve the same thing.
>> What it needs in a
>> powerful computer with optical sensors to look ahead, evaluate the
>> situation and decide whether engine braking is advantageous
>
>why? i don't want my car making /that/ kind of decision. seriously,
But you are satisfied with it making the decision mindlessly. I agree
I do not want the car making that decision. I want to make it myself
and shift the transmission accordingly. My brain is the powerful
computer and my eyes are the optical sensors.
>auto engine braking only happens when you're foot braking - just like on
>a stick.
Not true. I use compression braking all the time with my foot off the
brake. Descending grades would be a prime example except that I live
in Chicago and there are no hills. Instead, I am the only guy in
crawling rush hour traffic not flashing his brake lights every 20
feet. It is way more fun than an AT if you play the game.
>you can't criticize what you've not used dude.
I am only pointing out that this feature has a down side. It might
not bother 95% of drivers, but it would bother me.
Yes, but how many is that? If they had sold that many, it would still
be on the market. Don't get me wrong, I don't think they are any less
reliable than a conventional Civic AT, but I don't think there are
enough out there to really know for sure. They certainly aren't
terrible like the GM CVT.
jim beam
<snip>
>
> I use compression braking a lot. Sometimes I use a little, sometimes
> I use a lot. Sometimes I coast with the clutch disengaged for maximum
> distance.
that's unsafe btw.
> A transmission that always applies medium compression
> braking is not as going to achieve the same thing.
>
>>> What it needs in a
>>> powerful computer with optical sensors to look ahead, evaluate the
>>> situation and decide whether engine braking is advantageous
>> why? i don't want my car making /that/ kind of decision. seriously,
>
> But you are satisfied with it making the decision mindlessly.
no i'm not. i am satisfied from extensive experience over many years in
all conditions and many many miles, clearly based on extensive research
on driver usage and testing of driveability, that programmed engine
braking algorithms used in electronically controlled automatics are
highly proficient and effective. as you would know if you'd driven one.
> I agree
> I do not want the car making that decision.
i don't want it making an independent decision. they're programed to
make *dependent* decisions based on how the driver is asking the vehicle
to behave. which is what you want.
> I want to make it myself
> and shift the transmission accordingly.
you can - use the shift lever.
> My brain is the powerful
> computer and my eyes are the optical sensors.
but the two are apparently unable to work together to get the ass on
into a dealer to test out the new fangled machine the mouth is criticizing.
>
>> auto engine braking only happens when you're foot braking - just like on
>> a stick.
>
> Not true. I use compression braking all the time with my foot off the
> brake.
no, it's true. autos engine brake, just like a stick. and you can
engine brake without the foot brake too. we've discussed that repeatedly.
> Descending grades would be a prime example except that I live
> in Chicago and there are no hills. Instead, I am the only guy in
> crawling rush hour traffic not flashing his brake lights every 20
> feet. It is way more fun than an AT if you play the game.
see above.
>
>> you can't criticize what you've not used dude.
>
> I am only pointing out that this feature has a down side. It might
> not bother 95% of drivers, but it would bother me.
but your assessment of the whole situation is flawed - it's assumption
and speculation /not/ based on either experience or sufficient
knowledge. modern autos shift to engine brake. they do it flawlessly
and just as a normal driver would shift a stick. and the degree of
braking depends on how hard the driver's braking - /that/ is /more/
sophisticated than the average stick driver.
Gordon McGrew
<spamv...@bad.example.net> wrote:
>Gordon McGrew wrote:
><snip>
>>
>> I use compression braking a lot. Sometimes I use a little, sometimes
>> I use a lot. Sometimes I coast with the clutch disengaged for maximum
>> distance.
>
>that's unsafe btw.
Why?
>> A transmission that always applies medium compression
>> braking is not as going to achieve the same thing.
>>
>>>> What it needs in a
>>>> powerful computer with optical sensors to look ahead, evaluate the
>>>> situation and decide whether engine braking is advantageous
>>> why? i don't want my car making /that/ kind of decision. seriously,
>>
>> But you are satisfied with it making the decision mindlessly.
>
>no i'm not. i am satisfied from extensive experience over many years in
>all conditions and many many miles, clearly based on extensive research
>on driver usage and testing of driveability, that programmed engine
>braking algorithms used in electronically controlled automatics are
>highly proficient and effective. as you would know if you'd driven one.
It can have all the algorithms it wants but it doesn't know whether
the hill is long or short. It doesn't know whether, at the bottom of
the hill, there will be the beginning of a steep ascent or a freight
train crossing. It just goes for some predetermined drive ratio,
oblivious to what is outside the window. I chose the level of
compression braking based on information the computer just doesn't
have.
>> I agree
>> I do not want the car making that decision.
>
>i don't want it making an independent decision. they're programed to
>make *dependent* decisions based on how the driver is asking the vehicle
>to behave. which is what you want.
No, I want to tell it what to do. I don't want it to infer what I
might want the transmission to do based on what I am doing with the
throttle and brake. At least a conventional AT gives you some direct
control over this. I would like to believe that the CVT does also,
but I don't really know. It should assume that I want minimal
compression braking unless I specifically signal otherwise. If it
wants to assume I want more compression braking if I am at least
moderately on the service brake, that is OK. But if I take my foot
off the brake, it should resume minimum compression.
>> I want to make it myself
>> and shift the transmission accordingly.
>
>you can - use the shift lever.
Not clear on how you control the CVT, but the article implied that it
automatically went to some medium level of compression braking. It
wasn't clear that you could over-ride this and force less or more
compression braking.
>> My brain is the powerful
>> computer and my eyes are the optical sensors.
>
>but the two are apparently unable to work together to get the ass on
>into a dealer to test out the new fangled machine the mouth is criticizing.
That's just it. I don't test drive cars unless I am considering
buying one. If I get the opportunity, I would gladly take it. But I
don't think I would ever consider buying one if an MT were an option.
>>> auto engine braking only happens when you're foot braking - just like on
>>> a stick.
>>
>> Not true. I use compression braking all the time with my foot off the
>> brake.
>
>no, it's true. autos engine brake, just like a stick. and you can
>engine brake without the foot brake too. we've discussed that repeatedly.
But you said it happens *only* when you are foot braking. I thought
you were referring to the CVT. I know how a conventional AT works.
>
>> Descending grades would be a prime example except that I live
>> in Chicago and there are no hills. Instead, I am the only guy in
>> crawling rush hour traffic not flashing his brake lights every 20
>> feet. It is way more fun than an AT if you play the game.
>
>see above.
>
>>
>>> you can't criticize what you've not used dude.
>>
>> I am only pointing out that this feature has a down side. It might
>> not bother 95% of drivers, but it would bother me.
>
>but your assessment of the whole situation is flawed - it's assumption
>and speculation /not/ based on either experience or sufficient
>knowledge. modern autos shift to engine brake. they do it flawlessly
>and just as a normal driver would shift a stick. and the degree of
>braking depends on how hard the driver's braking - /that/ is /more/
>sophisticated than the average stick driver.
It may or may not be more sophisticated than the *average* stick
driver but it is no way more sophisticated than what *I* do. I can't
decide what gear to be in without assessing the situation outside the
windshield. No matter how powerful the computer and elegant the
software, it is a blind driver. I use engine braking instead of the
service brake. To have it mindlessly aping what I do with the service
brake is hardly sophisticated.
Brian Smith
"Gordon McGrew" <RgEmMc...@mindspring.com> wrote in message
news:m9hjq29983l6m2cv1...@4ax.com...
>>
>>that's unsafe btw.
>
> Why?
It doesn't allow engine braking for one thing and it's illegal for
another.
Dave Kelsen
FWIW, neither of those responses have anything to do with safety,
although I suppose you could make a tenuous case for the first, given
some not-obvious assumptions about manufacturer's intent to provide and
buyer's intent to use engine braking.
RFT!!!
Dave Kelsen
--
"Government is not reason, it is not eloquence, it is force; like fire,
a troublesome servant and a fearful master. Never for a moment should
it be left to irresponsible action." -- George Washington
Brian Smith
"Dave Kelsen" <inv...@invalid.invalid> wrote in message
news:45aa3da7$0$9646$4c36...@roadrunner.com...
>
> FWIW, neither of those responses have anything to do with safety, although
> I suppose you could make a tenuous case for the first, given some
> not-obvious assumptions about manufacturer's intent to provide and buyer's
> intent to use engine braking.
For one thing, the fact that coasting doesn't allow for engine braking
is a safety issue. For the second, the fact that it is illegal makes it a
valid point.
jim beam
<snip>
you just want to express your opinion, not discuss merits of either
system. that's fine if the opinion is informed, but since you have no
experience and apparently don't wish to pay any attention to fact, then
your opinion isn't opinion, it's mere prejudice.
i'm sorry i wasted my time.
Gordon McGrew
Saying that coasting is unsafe because it doesn't allow engine braking
is like saying that not pushing on the brake pedal is unsafe because
it doesn't allow frictional braking. Engine braking is available if I
want it, just like frictional braking. When and where each is used is
a decision to be made by the driver based on the situation. For
example, coasting on glare ice is a lot safer than compression
braking, especially on a rear wheel drive car. Even more so with the
advent of ABS.
As for laws against coasting; they may vary from state to state. Here
is one form Maine:
An operator, when traveling on a downgrade, may not coast with the
gears of the vehicle in neutral. [1993, c. 683, Pt. A, §2 (new); Pt.
B, §5 (aff).]
Now notice that it specifies coasting *on a downgrade* *in neutral*.
Coasting on level ground or coasting down a hill with the clutch
disengaged but the transmission in gear is legal. I would agree that
this is generally a bad idea and certainly bad if you are riding the
foot brake. However, if you are coasting down the hill with the
clutch in, not using the foot brake, and you are satisfied that your
speed is not excessive, what is the problem?
The only purpose of such a law is to give them another charge to throw
as some idiot who causes a wreck because he doesn't know how to
control his vehicle. Can you imagine being pulled over because you
were coasting down a hill?
And just to be sure we are perfectly clear on this point, I use more
compression braking and less frictional braking than about 95% of
drivers in the same situation. But I don't use any braking where it
is not needed.
Gordon McGrew
I stand by my original position; if it doesn't know what is happening
on the road ahead, it cannot possibly make the best decision regarding
operation of the transmission.
jim beam
jeepers, engage brain before opening mouth will ya? if it had that kind
of autonomy, it wouldn't even need a steering wheel!!! way you talk,
having 1930's style manual ignition timing controls in the middle of the
steering wheel are the way to go too.
Gordon McGrew
<spamv...@bad.example.net> wrote:
>Gordon McGrew wrote:
>> On Sun, 14 Jan 2007 08:17:02 -0800, jim beam
>> <spamv...@bad.example.net> wrote:
>>
>>> Gordon McGrew wrote:
>>> <snip>
>>> you just want to express your opinion, not discuss merits of either
>>> system. that's fine if the opinion is informed, but since you have no
>>> experience and apparently don't wish to pay any attention to fact, then
>>> your opinion isn't opinion, it's mere prejudice.
>>>
>>> i'm sorry i wasted my time.
>>
>> I stand by my original position; if it doesn't know what is happening
>> on the road ahead, it cannot possibly make the best decision regarding
>> operation of the transmission.
>
>jeepers, engage brain before opening mouth will ya? if it had that kind
>of autonomy, it wouldn't even need a steering wheel!!!
I don't expect anywhere near that level of autonomy in the foreseeable
future. Nor am I looking for it. I like to drive the car.
> way you talk,
>having 1930's style manual ignition timing controls in the middle of the
>steering wheel are the way to go too.
I am hardly a Luddite. I like technology when it is well applied. My
first Honda had a manual choke. It was fun, but I never hesitated to
exchange it for an automatic choke and later FI. These systems manage
the engine so that it gives me what I want as a driver; smooth,
predictable throttle response. That increases my control over the
power.
I remember being in 3rd grade (1964) and reading how in the future (by
the year 2000?) you would just hop in the back seat of the car and
tell it where you wanted to go. I hope they have that perfected by
the time I am too old to drive. Until then, I have no use for it. And
as long as I am driving, there are certain things I want to control.
If new technology increases my control, I am all for it. If it makes
driving easier while decreasing driver control, I have no interest in
it and I resent having to pay for it. That is how I feel about every
AT I have ever driven. I is the fundamental way in which they work
which I object to. Refining that operation does not address my
primary objection.