Stroke or destroke?
Eugene Blanchard
Is it better to have a small engined stroked with a larger stroke or a
large engine destroked with a smaller stroke. Basically, which would be
a better engine: large bore with a short stroke or small bore with a
larger stroke? Doesn't a larger stroke give you more torque while a
shorter stroke allows higher revs?
An example would be destroking a sbc 400 to 354 cid with a 3.25" crank
from a 327 (if possible) versus stroking a 307 to 348 cid with a 3.75"
crank from a 400. The results would be:
354 cid - 4.125" bore x 3.25" stroke
348 cid - 3.875" x 3.75" stroke
Comments?
Bob Leggott
If money is no object, larger bore, longer stroke. eg: 705 ci aluminum
Merlin. Only in my dreams... ;-)
It is not the fact of allowing higher revs, but the fact that shorter stroke
will usually move the peak horsepower and torque to a higher RPM range than
a longer stroke. But not allways as cams and other mods can also change the
range of the powerband. The RPM limit of an engine is relative to the
intended use and quality of the build. As in nascar 9000+ rpm for 2 to 4
hours, or as in a daily driver GM truck 2800 rpm for 10 to 20 years, both
using 5.7's. The difference, the dollars spent to get the nascar to hold
together at higher rpm. As for which one is better, that depends on your
intended use and application. I could be wrong, but i seem to remember,
shorter strokes being able to handle the wear better if you are planning
high rpm use. I think what you need to do is decide if you want to pull
stumps, or run 10 flat in the 1/4 mile, or something inbetween. Then decide
if stroking something is worth the bucks as opposed to a straight build up
of a standard bore & stroke combo. I know it's a blast to build something
rare and unique, and the bragging rights that go along with it, but for me
it's usually the $$$ that decide it. I'm partial to 327's 350 block, 305
crank= 326.8 ci.
Bob Leggott,
Cloverdale, B.C.
Eugene Blanchard <blan...@cadvision.com> wrote in message
news:3A13F7BC...@cadvision.com...
Eugene Blanchard
choose. I'm interested in what others, with more experience than I,
would suggest as yays and nays for longer versus shorter strokes. BTW, I
believe that your 327 uses a 307 crank (3.25" stroke) not the 305
(3.48") which has the same stroke as a 350. This would give the 327
displacement.
Bob Leggott
You're correct about the 307 crank. I guess the gray mass is a little cloudy
at times. Personally, I am partial to small blocks. As for longer strokers
they seem to wear rod bearings & pins a little faster due to more lateral
movement per rev. Not really anything to worry about unless you plan to run
it above 6000. Above 6 you'd be wanting to magniflux everything, and find
forged rods and the like.I'm sure you already know about the cam and rod cap
bolt clearance issue. As well the piston skirt to crank thing. I'm sure
there's lots of other stuff to consider as well, but I'm getting near the
limits of my knowlege here, without crackin' open the books. Just remember
longer stroke = more bottom end torque. Shorter stroke = more top end
horsepower. As before, more or less depending on cam, intake etc etc ....
Different Strokes for Different Folks,
Have a Good one,
Bob.
Eugene Blanchard <blan...@cadvision.com> wrote in message
news:3A14BE28...@cadvision.com...
Massey
If the cylinder pressure remains the same, increasing the bore and
shortening the stroke maintain 350 will increase power across the entire RPM
range.
A 350 cubic inch engine with a 3" stroke will produce more power (any RPM)
than a 350 with a 4" stroke.
OK, let me have it! ( But do the math first, please. You'll see it works
out. :-)
An example was the 302 Chevy. Relatively large bore, 4". Short stroke, 3".
It had a very broad powerband.
Hot Rod or Popular Hottrodding built 2 - 350's a while back and the short
stroke engine had more power low to high in the RPM range.
Grape Ape
the longer stroke engine will make more torque. There will be the same
cylinder pressure pushing on the crank, but the rod journal will be further
from the crank centerline giving it more leverage.
The problem is that there will not be the same cylinder pressure. The
longer stroke engine will breath ok at lower rpm, but bore shrouding will be
a limiting factor up top. The shorter stroke engine will have less bore
shrouding and capable of higher rpm due to better breathing.
You can compare two engines, but you have to do it fairly, PHR did not. You
cannot simply change the stroke because then the engine will require a
different cam profile. They did not match the cam to the longer stroke.
Nor did they try the re time the cam on the dyno to see if that made a
difference. I would say the longer stroke 350 would need about 2 degrees
more lobe separation, 1 or 2 degrees more advance and probably a little less
duration. Put an optimum cam in both engines and the shorter stroke 350
will not be able to out torque the longer stroker.
--
Grape Ape www.ulster.net/~nubb/
"Massey" <dned...@willmar.com> wrote in message
news:9fiR5.134$_u1....@news7.onvoy.net...
Eugene Blanchard
one short stroke, put on exactly the same heads, cam, intake etc.. The
short stroke engine will produce more power.
Grape Ape says that you can compensate by retiming the cam on the longer
stroke engine. What would happen if you put the "retimed" cam into the
short stroke engine? Would it produce more power too?
P.S. I was waiting for Grape to join the fray, now we're getting
technical - yahoooo!
Pat_Teaford
>
>
> You can compare two engines, but you have to do it fairly, PHR did
> not. You
> cannot simply change the stroke because then the engine will require a
>
> different cam profile. They did not match the cam to the longer
> stroke.
> Nor did they try the re time the cam on the dyno to see if that made a
>
> difference. I would say the longer stroke 350 would need about 2
> degrees
> more lobe separation, 1 or 2 degrees more advance and probably a
> little less
> duration. Put an optimum cam in both engines and the shorter stroke
> 350
> will not be able to out torque the longer stroker.
> --
> Grape Ape www.ulster.net/~nubb/
>
Grape's right, you should never take PHR or any of the magazine's
articles as any kind
of factual information. I've seen Aluminum headed small blocks compared
to stock cast iron
headed big blocks, B&M blowers compared to extremely underdriven 6-71
blowers, it's pretty
humorous how they screw with some of the readers with junk like that.
And you can't just swap cranks in a motor without optimizing the
combination and compare them
As far as the question goes on the stroke or destroke, that would be a
hard question to answer
without a lot of research, the easiest way I know to compare them would
be to find a drag racing
class that has a certain C.I.D. limit and see what the winning cars are
running for bore and stroke.
(If you can get them to tell you)
Personally I would take the longer stroke over the shorter, it would
make a higher lower end torque
motor and would give you that little jump off the line that is always
harder to catch in the big end.
I would also like to note that when Chevrolet designed their new LS-1
small block from a clean
sheet of paper they opted for a longer stroke and a smaller bore; the
new LS-6 Corvette version
of that at 346 cubes (3.8976 bore and 3.662 stroke) is making 10 more HP
(385 HP) than the 4 valve ZR-1
350 Vette motor of a few years ago.
> "Massey" <dned...@willmar.com> wrote in message
> news:9fiR5.134$_u1....@news7.onvoy.net...
> > Take an engine of a given cubic inch, say 350.
> > If the cylinder pressure remains the same, increasing the bore and
> > shortening the stroke maintain 350 will increase power across the
> entire
> RPM
> > range.
> > A 350 cubic inch engine with a 3" stroke will produce more power
> (any RPM)
> > than a 350 with a 4" stroke.
> >
> >
> > OK, let me have it! ( But do the math first, please. You'll see it
> works
> > out. :-)
> >
> > An example was the 302 Chevy. Relatively large bore, 4". Short
> stroke,
> 3".
> > It had a very broad powerband.
> > Hot Rod or Popular Hottrodding built 2 - 350's a while back and the
> short
> > stroke engine had more power low to high in the RPM range.
> >
> > Eugene Blanchard <blan...@cadvision.com> wrote in message
> > news:3A14BE28...@cadvision.com...
--
Pat_Teaford
http://home.swbell.net/nitro57/FORSALE.HTM
Massey
Grape Ape <Grap...@grapeape.net> wrote in message
news:JLiR5.5207$a5.24...@newsfeed1.thebiz.net...
> Ok, I'm going to let you have it. If cylinder pressure remains the same,
> the longer stroke engine will make more torque. There will be the same
> cylinder pressure pushing on the crank, but the rod journal will be
further
> from the crank centerline giving it more leverage.
That would be true if the area the pressure was acting on remained constant.
But the increased bore diameter gives you much more area for the PSI to push
on.
example:
4.01" bore pushing on a 3.5" stroke at a 90 deg. angle. (to make it easy :)
353.6 ci
Let's say 200 PSI above piston.
4" bore = 12.63 sq. in.
12.63 x 200 PSI = 2525.86 lbs downforce. acting on 1.75 in. lever. = 368.35
ft. lbs
4.25" bore pushing on a 3.12" stroke 354.09 ci
2837.25 lbs acting on 1.56 in. lever = 368.84 ft. lbs
Ok let's get crazy.
6" bore and 1.57" stroke 355.13ci
5654.86 lbs! on .785 lever = 369.9 ft lbs.
3" bore and 6.25 stroke (heh heh) 353.43ci = 368.16 ft. lbs
These numbers don't show any dramatic difference. I agree that the popular
magazine articles never do quality comparisons. But they do exagerate the
bonuses implied by a "stroking an engine" they make the increased stroke
seem magical. It is the increased cid that gave the power. When working
with a given cid, a large bore short stroke combination will tend to be a
more efficient engine.
I also think they give readers the incorrect notion about the torque vs.
horsepower thing. It is horsepower that does all the work. Torque by
itself is meaningless. It is a static number. You can easily produce 500
ft. lbs of torque pulling on a long bar. But that wouldn't move your
vehicle down the road very fast :) You must know the time in which the
action happens. This happens to be noted as RPM . Once you throw time in
the equation your dealing with horsepower.
I think my soapbox is collapsing. I better get down.
>
> The problem is that there will not be the same cylinder pressure. The
> longer stroke engine will breath ok at lower rpm, but bore shrouding will
be
> a limiting factor up top. The shorter stroke engine will have less bore
> shrouding and capable of higher rpm due to better breathing.
>
> You can compare two engines, but you have to do it fairly, PHR did not.
You
> cannot simply change the stroke because then the engine will require a
> different cam profile. They did not match the cam to the longer stroke.
> Nor did they try the re time the cam on the dyno to see if that made a
> difference. I would say the longer stroke 350 would need about 2 degrees
> more lobe separation, 1 or 2 degrees more advance and probably a little
less
> duration. Put an optimum cam in both engines and the shorter stroke 350
> will not be able to out torque the longer stroker.
> --
> Grape Ape www.ulster.net/~nubb/
>
Stan Weiss
the rod and crank are at 90 degrees changes (piston depth in the bore) and so
the gas pressure can not be constant as in your examples
Stan
Grape Ape
comparison.
--
Grape Ape www.ulster.net/~nubb/
"Stan Weiss" <srw...@erols.com> wrote in message
news:3A16A9B5...@erols.com...
Grape Ape
general, if your looking for low-end grunt, a longer stroke is the way to
get it easier. If you want high revs and top-end horsepower, the shorter
stroke will work better.
We can stroke a 350 to a 383 and if you're using the same heads and stuff,
the 383 places a larger flow demand on the heads at high rpm. You have the
same flow restriction, but more cubic inches trying to flow through it. At
low speeds, the longer stroke makes better leverage and more power, but once
the flow begins to be restricted, the power will fall. So in that case a
350 will have more rpm potential and more HP per cubic inch potential.
On the other hand you can destroke a 400 to the same cubic inches and the
heads will flow better due to less bore shrouding. At low rpm there will be
less leverage on the crank, but top-end will make up for it. The destroked
engine will need more gear also to keep the engine in the power band at the
same speeds.
There are just too many things that affect everything, to make a perfectly
fair comparison. But we have to do better than simply swapping stroke and
bore diameter. Doing that changes the rpm range, and well all know that if
the rest of the combo is not matched to an rpm range the engine will not
make it's power potential.
--
Grape Ape www.ulster.net/~nubb/
"Eugene Blanchard" <blan...@cadvision.com> wrote in message
news:3A161FEF...@cadvision.com...
Bob
Eugene Blanchard wrote:
> So if I understand correct, if you take two 350 engines, one long and
> one short stroke, put on exactly the same heads, cam, intake etc.. The
> short stroke engine will produce more power.
Only if the cam and heads etc. suited that bore/stroke. If you optimize both
engines, the short stroke will produce more HP because you can fit larger valves.
It all comes down to how much air you can flow through the engine. Bob
Grape Ape
the same or does the shorter stroke engine have a longer rod?. To do it
correctly, you must know cylinder pressure at several points in the stroke
and what rods angle it was. It probably going to end up with the longer
stroke engine have a shorter rod and less rod/stroke ratio. Now this brings
us back to cylinder pressure, it's not going to be the same. Shorter rods
increase piston speeds at TDC which help scavenging at low-rpm. Now
consider than with the longer stoke the piston speeds are even higher, so
than means even faster speeds yet to help scavenge. Piston speed has
nothing to do with over all volume since it's the same for both engines, but
where the speed is makes a difference. As rpm goes up the better flowing
large bore and better rod angle engine catch up and pass the power potential
of the longer stroke engine.
I agree with you on the HP and torque. It's always better to get as much
horsepower as you can, and gear the car to gain back the torque plus some,
but sometimes that puts the rpm range in an impractical place for a street
car. It all depends on what rpm range you want the power, but no matter
what, if you build HP the torque will be there.
--
Grape Ape www.ulster.net/~nubb/
"Massey" <dned...@willmar.com> wrote in message
news:djxR5.151$_u1....@news7.onvoy.net...
Bob
Massey wrote:
> I also think they give readers the incorrect notion about the torque vs.
> horsepower thing. It is horsepower that does all the work. Torque by
> itself is meaningless. It is a static number. You can easily produce 500
> ft. lbs of torque pulling on a long bar. But that wouldn't move your
> vehicle down the road very fast :) You must know the time in which the
> action happens. This happens to be noted as RPM . Once you throw time in
> the equation your dealing with horsepower.
>
> I think my soapbox is collapsing. I better get down.
Now I always have thought the other way round, i.e. that HP is the calculated
number and that torque is what gets the job done. It's torque over a period of
time that accelerates you, it takes torque to get that engine [and car] up to
top speed. I've seen engines with lots of HP that lacked enough torque to to
obtain max RPM in top gear, then shorten the gear and lower the top speed. Later
change the cam [optimize it] go back to the original gear and pull max RPM thus
raising the top speed. In my book, torque is all important. For a given engine
with a fixed bore/stroke I 'd go for max torque. Right? Wrong? Bob
Massey
with these short blurbs. But it's interesting nonetheless!
Thanks again for the great replies all!
Grape Ape <Grap...@grapeape.net> wrote in message
news:hRyR5.5289$a5.25...@newsfeed1.thebiz.net...
> There are so may factors that this thread could go on forever. But in
> general, if your looking for low-end grunt, a longer stroke is the way to
> get it easier. If you want high revs and top-end horsepower, the shorter
> stroke will work better.
Not necessarily. A short stroke, large bore engine would still make as much
torque at low RPM's as the small bore long stroke. A shorter rod would help
at low RPM also. Start lengthening the rod stroke ratio as you want to move
the RPM range up.
>
> We can stroke a 350 to a 383 and if you're using the same heads and stuff,
> the 383 places a larger flow demand on the heads at high rpm. You have
the
> same flow restriction, but more cubic inches trying to flow through it.
At
> low speeds, the longer stroke makes better leverage and more power, but
once
> the flow begins to be restricted, the power will fall. So in that case a
> 350 will have more rpm potential and more HP per cubic inch potential.
Same paradigm. Think of how to make the best use of what cylinder pressure
there is. Remember I'm thinking no change in cid for the comparisons.
>
> On the other hand you can destroke a 400 to the same cubic inches and the
> heads will flow better due to less bore shrouding. At low rpm there will
be
> less leverage on the crank, but top-end will make up for it. The
destroked
> engine will need more gear also to keep the engine in the power band at
the
> same speeds.
More leverage on the crank, but less crank length! Much more down pressure
from the additional area for the pressure to push on. (Assuming no loss in
cid.) This makes the Torque nearly even for the two combinations. With the
short stroke/large bore advantages you mention also.
>
> There are just too many things that affect everything, to make a perfectly
> fair comparison. But we have to do better than simply swapping stroke and
> bore diameter. Doing that changes the rpm range, and well all know that
if
> the rest of the combo is not matched to an rpm range the engine will not
> make it's power potential.
Same paradigm. The cam and heads generally determine the RPM ranges.
The new motors from GM do have a longer stroke. That was for emissions, not
efficiency or power. A long stroke is a bit cleaner at road speeds.
Massey
>
> --
> Grape Ape www.ulster.net/~nubb/
> "Eugene Blanchard" <blan...@cadvision.com> wrote in message
> news:3A161FEF...@cadvision.com...
> > So if I understand correct, if you take two 350 engines, one long and
> > one short stroke, put on exactly the same heads, cam, intake etc.. The
> > short stroke engine will produce more power.
> >
Massey
> One more thing we have to add to this equation is the rod angles, are they
> the same or does the shorter stroke engine have a longer rod?. To do it
> correctly, you must know cylinder pressure at several points in the stroke
> and what rods angle it was. It probably going to end up with the longer
> stroke engine have a shorter rod and less rod/stroke ratio. Now this
brings
> us back to cylinder pressure, it's not going to be the same. Shorter rods
> increase piston speeds at TDC which help scavenging at low-rpm. Now
> consider than with the longer stoke the piston speeds are even higher, so
> than means even faster speeds yet to help scavenge. Piston speed has
> nothing to do with over all volume since it's the same for both engines,
but
> where the speed is makes a difference. As rpm goes up the better flowing
> large bore and better rod angle engine catch up and pass the power
potential
> of the longer stroke engine.
Yes, I agree. My thinking is coming from the standpoint of using whatever
rod length we want to determine the RPM range. Matched, of course, with the
heads and cam. The engines I build in my shop generally use no factory
parts as I am not limited to any certain lengths (until we come the top of
the piston!) However I am limited to 362 cid. (Modified circle track
classes) But I use some of the same combinations in my tow vehicles.
Yes, the short rod develops more pressure on the crank while still higher in
the bore (versus long rod) so can make use of the higher cylinder pressure.
>
> I agree with you on the HP and torque. It's always better to get as much
> horsepower as you can, and gear the car to gain back the torque plus some,
> but sometimes that puts the rpm range in an impractical place for a street
> car. It all depends on what rpm range you want the power, but no matter
> what, if you build HP the torque will be there.
YEP! But you still see all these articles "Build this TORQUE MONSTER" heh
heh. But I still keep buying 'em.
later,
Massey
> --
> Grape Ape www.ulster.net/~nubb/
> "Massey" <dned...@willmar.com> wrote in message
> news:djxR5.151$_u1....@news7.onvoy.net...
> > Thank you GrapeApe for the thoughtful reply.
> >
> > Grape Ape <Grap...@grapeape.net> wrote in message
Grape Ape
the best I can. HP and Torque are directly related to each other. In
reality, torque is what moves the car, HP is how fast that torque can be
used. Hp is simply a measurement of torque over a time period. That time
period is measured in rpm.
Lets say it were possible to build an engine with a perfectly flat torque
curve of 500 ft. lbs. (far fetched but lets pretend). At any rpm the engine
always has 500 ft.lbs. As rpm increases, so would HP and the engine would
be getting more powerful (per minute). Having 500 ft.lbs at 6000 rpm will
have twice as much HP as 500 ft.lbs at 3000 rpm. This is because at twice
the rpm, there is twice as many fires of the same power (more speed).
Now in the real world, once torque peaks the volumetric efficiency starts to
drop off and torque starts falling due to less cylinder filling. RPM will
still increase horsepower to the point that the engine can no longer breath
enough to support the power. Then hp will start falling. At this point it
is time to shift a gear and get the engine back into the power band:)
--
Grape Ape www.ulster.net/~nubb/
"Bob" <gold...@rosenet.net> wrote in message
news:3A16C6E9...@rosenet.net...
Grape Ape
everything else. I 100% believe you on the piston area and calculations
that you made. The thing that we would have to figure is what the real rod
to crank angles are and where the best leverage is. If the rod / stroke
ratios are the same, that is not a problem, but the rod length/stroke ratio
will usually not be the same for both engines. Chances are you'll shorten
the stroke and make up for it by lengthening the rod. Even if you use the
same length rod, the rod length/stroke ratio will change. Now we would need
to know at each crank degree what leverage the rod had on the crank because
it is not 90 degrees for a very long time and even when it is 90 degrees the
piston is not pushing at 90 degrees from the crank throw. From the best I
can figure, peak cylinder pressure should come on before peak rod leverage
or you'll loose most of the charge out of the exhaust. A shorter rod will
have best leverage sooner than a longer rod (closer to peak cylinder
pressure). It has been proven in prostocks that a1.72:1 rod ratio is best
for power output, why could be a lot of reasons. Endurance engines go
higher, but for other reasons. If a longer stoke engine has a higher rod
ratio than the short stroke, what's the leverage like then? If I try a
figure that out now I might get a nose bleed.
It's nice to get a technical discussion without flames. I'm impressed with
this thread.
--
Grape Ape www.ulster.net/~nubb/
Massey
> I'm thinking that the only confusion left is below. We seem to agree on
> everything else. I 100% believe you on the piston area and calculations
> that you made. The thing that we would have to figure is what the real
rod
> to crank angles are and where the best leverage is. If the rod / stroke
> ratios are the same, that is not a problem, but the rod length/stroke
ratio
> will usually not be the same for both engines. Chances are you'll shorten
> the stroke and make up for it by lengthening the rod. Even if you use the
> same length rod, the rod length/stroke ratio will change. Now we would
need
> to know at each crank degree what leverage the rod had on the crank
because
> it is not 90 degrees for a very long time and even when it is 90 degrees
the
> piston is not pushing at 90 degrees from the crank throw. From the best I
> can figure, peak cylinder pressure should come on before peak rod leverage
> or you'll loose most of the charge out of the exhaust. A shorter rod will
> have best leverage sooner than a longer rod (closer to peak cylinder
> pressure). It has been proven in prostocks that a1.72:1 rod ratio is best
> for power output, why could be a lot of reasons. Endurance engines go
> higher, but for other reasons. If a longer stoke engine has a higher rod
> ratio than the short stroke, what's the leverage like then? If I try a
> figure that out now I might get a nose bleed.
My circle track motor uses 6.125 rods and 3.5 stroke in a 360 cid sb. (1.75
ratio)
But seldom do my RPM's fall below 4000 and I hit my rev limiter at 7400.
I think a tow rig motor could use a smaller ratio and it would be beneficial
below 2000.
My 4x4 has a 406 with the short rods. 1.48 ratio! yikes, I haven't figured
that one for awhile. :-)
But of course I have it set up for that. It pulls like crazy up to about
3800 then starts to fall off.
I did develop a spreadsheet that gave me a bunch of that info for whatever
combination I could dream up. It was a nightmare to get the calculations
figured out. I had to dig out some of my old Statics and calculus books. I
have forgotten more than I could use I found out!
Not only did the rod/stroke/bore ratios give different results, moving bore
centerlines off center had simialr results. And they very a bit from the
factory too!
>
> It's nice to get a technical discussion without flames. I'm impressed
with
> this thread.
I was a little worried what I was getting into here. I've followed this
newsgroup off and on, but too often a good discussion, that might give some
insight into an area of interest, turns into two people playing games with
their words and smart remarks. A while back it got so bad around here I
just quit reading for awhile. Thanks to all who contributed with their
thoughtful input. I might hang around for awhile again. I'll let the
little grey cells chew on what we've discussed.
Massey
Stan Weiss
pin offset in the piston. With the pin offset clock wise looking from the front
of the engine, atdc you had a crank rod angle of less than zero. If the pin was
offset the other way the piston was on the way up the cyclinder when the crank
rod angle was zero.
Stan
Locke
> > One more thing we have to add to this equation is the rod angles, are
they
> > news:djxR5.151$_u1....@news7.onvoy.net...
> > > Thank you GrapeApe for the thoughtful reply.
> > >
Dogbite
In addition, it was pointed out to me in a discussion of Harley "monster
torque" vs rice rocket horsepower, that even if I am riding a HD with 95
ft.lbs of torque at 4000 and my friend is riding a heavily laden rocket(to
equalize the weight) with 90 ft.lbs at 8000 rpm he will just stomp the crap
out of me. The reason, I suppose is twofold. First he is making much more
HP due to the rpm, and he has double the mechanical advantage in overall
gear ratio since he can go to twice the rpms at the same ground speed.
We've tried this and it is true. I can launch faster and get across the
intersection but after that all I see are taillights. I still look cooler
when we get there though.:-)
Bob
--
"Bigger, Better, Faster, More!"
To email, replace nospam with dogbite.
"Grape Ape" <Grap...@grapeape.net> wrote in message
news:1dCR5.5301$a5.25...@newsfeed1.thebiz.net...
'snip'
> Lets say it were possible to build an engine with a perfectly flat torque
> curve of 500 ft. lbs. (far fetched but lets pretend). At any rpm the
engine
> always has 500 ft.lbs. As rpm increases, so would HP and the engine would
> be getting more powerful (per minute). Having 500 ft.lbs at 6000 rpm will
> have twice as much HP as 500 ft.lbs at 3000 rpm. This is because at twice
> the rpm, there is twice as many fires of the same power (more speed).
>
> --
'snip'
Grape Ape
just look at torque. Lets say the Harley has 95 ft/lbs at 4000 rpm and a
final drive ratio of 1:1 (just to make it simple). That would be 95 ft/lbs
at the rear wheel (assuming no losses). Now the rice rocket has 90 ft.lbs
at 8000 rpm, but is geared at 2:1 to make the same rear wheel speed. It
then has 180 ft/lbs at the rear wheels
Now if you look at the HP, it makes a little more sense. 95 ft/lbs at 4000
rpm is 72.4 HP and 90 at 8000 rpm is 137.1 HP. Both engines make close to
the same torque, but the one spinning twice as fast can use it twice as fast
(which is what HP is all about). Now if it were feasible to get 180 ft/lbs
out of the Harley at 4000 rpm, it would have the same power at the rear
wheel, 180 ft/lbs at 4000 rpm = 131.1 hp.
For anyone who doesn't know, the formulas go like this:
HP = (rpm * torque) / 5252
Torque = (5252 * HP) / rpm
I have a little more info on this topic on my site at
http://www.ulster.net/~nubb/tech/miscpower.htm if anyone wants to check it
out.
--
Grape Ape www.ulster.net/~nubb/
"Dogbite" <nos...@sasquatch.com> wrote in message
news:8v90a5$grg$1...@news.sasquatch.com...
Carron
look at the Harley. They don't care how much torque or Hp either makes.
Another way to look at it is Hp-years. the average life of the RR is less than
3 years, the Harley nearly 20 years. So, 95 X 20 = 1900 Hp-yr. 180 X 3 = 540
Hp-yr. Dang, those RR are puny :-)
Cheers/Carron
Seek liberty and gracefulness in your lives. Peace and security are proper
concerns for children and slaves.
Grape Ape
as well, but I would want to build it up to beat the RR's. Then I can get
the attention and have the speed :-).
--
Grape Ape www.ulster.net/~nubb/
"Carron" <step...@aol.comNOJNK> wrote in message
news:20001119160132...@ng-cn1.aol.com...
John Kunkel
>
> In addition, it was pointed out to me in a discussion of Harley "monster
> torque" vs rice rocket horsepower, that even if I am riding a HD with 95
> ft.lbs of torque at 4000 and my friend is riding a heavily laden rocket(to
> equalize the weight) with 90 ft.lbs at 8000 rpm he will just stomp the crap
> out of me. The reason, I suppose is twofold.
The reason is very simple, the Harley is based on an archaic design that
hasn't changed since 1936. The rice grinder is state of the art.
John
Roger Mauck
>
> Dogbite wrote:
> >
> > In addition, it was pointed out to me in a discussion of Harley "monster
> > torque" vs rice rocket horsepower, that even if I am riding a HD with 95
> > ft.lbs of torque at 4000 and my friend is riding a heavily laden rocket(to
> > equalize the weight) with 90 ft.lbs at 8000 rpm he will just stomp the crap
> > out of me. The reason, I suppose is twofold.
And if you pull down on the throttles of both of them in high gear at
30, 40, 50, 60, and possibly 70, 80, 90 mph the Harley will walk away
torque does have it's advantages.
>
> The reason is very simple, the Harley is based on an archaic design that
> hasn't changed since 1936. The rice grinder is state of the art.
> John
As long as you keep in mind that a top fuel Harley will run in the mid
sixes at 220mph or so. All that with two cylinders, two valves per
cylinder and pushrods. The "archaic" design you speak of is also the
reason Harley Davidson sells more bikes than any other manufacturer
(maybe just heavyweight bikes, not sure). Their sales figures are
impressive. They were designed for cruising not for high performance and
readily lend themselves to traditional high performance modifications.
Maybe you should go to an all Harley drag race and see for yourself. I
rode my nineteen year old Harley (90 "archaic" horsepower)(not stock)to
work twice last week (it was 34 degrees, and yes I am stupid). Didn't
see a damn "riceburner" anywhere, although I did see several Harleys.
Torque is a hard thing to resist.
Roger
Roger Mauck
>
> That's a good way to look at :-). Actually I would like to have the Harley
> as well, but I would want to build it up to beat the RR's. Then I can get
> the attention and have the speed :-).
> --
> Grape Ape www.ulster.net/~nubb/
Hey Grape you could by a basic assembly from Merch Performance. A Harley
clone engine with 140 horsepower and 150 ft bls torque. The horsepower
peaks at 5400 rpms. If you have ever seen A Harley's intake ports you'd
know why, they are puny. Just wave you wand over the heads, spruce up
the valve timing and caruretion and you could have monster on two
wheels.
Roger
Pat_Teaford
> Dogbite wrote:
> >
> > In addition, it was pointed out to me in a discussion of Harley
> "monster
> > torque" vs rice rocket horsepower, that even if I am riding a HD
> with 95
> > ft.lbs of torque at 4000 and my friend is riding a heavily laden
> rocket(to
> > equalize the weight) with 90 ft.lbs at 8000 rpm he will just stomp
> the crap
> > out of me. The reason, I suppose is twofold.
>
> The reason is very simple, the Harley is based on an archaic design
> that
> hasn't changed since 1936. The rice grinder is state of the art.
> John
But that's the whole point, that's why there's a 2 to 3 year waiting
list for the Harley.......HD has spent tons of money on the old archaic
V-twin just so it will still look like the old archaic V-Twin.
I had a '98 Softail Custom, loved it, other than wanting to put a 230
mm tire on the back there was
nothing about it I would have changed.
My only regret is that I had to let it go so I could afford a 30' by
40' garage at my new house.
I'd say since the rice grinder builders are building clones of it
Harley must be on the right trail, but like a told a
friend who was thinking about buying a clone, It only looks like a
Harley until you try to sell it then it don't look like a Harley no
more.
You can have the speed, I'll just get me another Harley.
--
Pat_Teaford
http://home.swbell.net/nitro57/FORSALE.HTM
Donnie Barnes
In this case you could define "speed" as not having to stop all the time
and pick up the spare parts the Harley shook off.
I'd just like to point out that many "rice grinder" riders aren't all
about "speed" anyway. Many of us love to sling the bike side to side
through corners repeatedly for the fun of *that*. You can't do that
with all that damned chrome hanging off your ass.
I'll take my very torquey and fast v-four Honda any day over one of
those paint shakers. It's a matter of personal preference. Sure, if
you just want to cruise and have the money to spend, get a late model
Harley. If you want to have fun *riding* the bike (vs sitting back
and taking in the people looking at you), get a "rice grinder" (or a
Buell, which is sort of a Harley spin off but a real sport bike).
--Donnie
--
Donnie Barnes http://www.donniebarnes.com d...@donniebarnes.com "Bah."
Challenge Diversity. Ignore People. Live Life. Use Linux. 879. V.
Bats, when dipped in batter and deep fried, still taste pretty bad.
rmauck
Donnie Barnes wrote:
> > You can have the speed, I'll just get me another Harley.
>
> In this case you could define "speed" as not having to stop all the time
> and pick up the spare parts the Harley shook off.
>
Done that, nick named my bike "Litterbug".
> I'd just like to point out that many "rice grinder" riders aren't all
> about "speed" anyway. Many of us love to sling the bike side to side
> through corners repeatedly for the fun of *that*. You can't do that
> with all that damned chrome hanging off your ass.
Proof that you've never ridden a Harley. You *can* do that. Plus it takes a
real man to run the twisties on a bike with no ground clearance, poor brakes
and bad handling characteristics. Anyone can do it on a purpose built machine.
>
>
> I'll take my very torquey and fast v-four Honda any day over one of
> those paint shakers.
My paint shaker has 90 horsepower, maybe not on par with your sport bike but
still respectable.
> It's a matter of personal preference.
Exactly, It sounds as if you've never ridden a Harley. Do knock what you
haven't tried.
> Sure, if you just want to cruise and have the money to spend, get a late
> model
> Harley. If you want to have fun *riding* the bike
I just checked and you know I rode my bike 15,000 in two years. So I guess I
did some "riding" too. It was fun too.
> (vs sitting back
> and taking in the people looking at you), get a "rice grinder" (or a
> Buell, which is sort of a Harley spin off but a real sport bike).
>
Your right about that, a lot of the people that ride Harleys today are
*posers*. I myself ride for the fun of it and also as an everyday thing. I
could care less about people "looking" at me. Just as a note, I've surprised a
few sport bike riders with my shakin', chrome monster. I've got no illusions
about my bikes performance but a few of the "rice burner" riders have done a
double take when they blow by me and look over to see me right back up there
with them at 110 mph.
Remember the next time you see someone on a Harley "shaker" that just because
they think your an idiot doesn't mean you really are.
Roger
John Kunkel
>
> > You can have the speed, I'll just get me another Harley.
>
> In this case you could define "speed" as not having to stop all the time
> and pick up the spare parts the Harley shook off.
Yep, that's why I made the change to "rice", and my throttle hand
doesn't go to sleep anymore.
John
Donnie Barnes
>> and pick up the spare parts the Harley shook off.
>
Heh.
>> I'd just like to point out that many "rice grinder" riders aren't all
>> about "speed" anyway. Many of us love to sling the bike side to side
>> through corners repeatedly for the fun of *that*. You can't do that
>> with all that damned chrome hanging off your ass.
>
>Proof that you've never ridden a Harley. You *can* do that. Plus it takes a
>real man to run the twisties on a bike with no ground clearance, poor brakes
>and bad handling characteristics. Anyone can do it on a purpose built machine.
Sorry, I didn't mean that you "can't", but rather that *most* riders
probably wouldn't. *Most* Harley owners have more money invested in
add-on chrome than they do in the rest of the bike, so taking a chance
on scraping it up isn't high on their list of fun things to do.
>> I'll take my very torquey and fast v-four Honda any day over one of
>> those paint shakers.
>
>My paint shaker has 90 horsepower, maybe not on par with your sport bike but
>still respectable.
Yeah. And your bike sounds better, too. Mine still sounds good for a
"rice grinder" (people often comment that the v-four is a "baby V8"), though.
>> It's a matter of personal preference.
>
>Exactly, It sounds as if you've never ridden a Harley. Do knock what you
>haven't tried.
I owned an '85 Honda Shadow as my first bike. No, not a Harley by any
stretch, but not what I wanted, either. I don't care for the laid back
seating position, nor the fact that the first thing to scrape was a tail
pipe (instead of a peg, as it should be).
>> Sure, if you just want to cruise and have the money to spend, get a late
>> model
>> Harley. If you want to have fun *riding* the bike
>
>I just checked and you know I rode my bike 15,000 in two years. So I guess I
>did some "riding" too. It was fun too.
You sound as though you do "ride" your bike. Most don't. There are always
exceptions. :-)
>> (vs sitting back
>> and taking in the people looking at you), get a "rice grinder" (or a
>> Buell, which is sort of a Harley spin off but a real sport bike).
>
>Your right about that, a lot of the people that ride Harleys today are
>*posers*. I myself ride for the fun of it and also as an everyday thing. I
>could care less about people "looking" at me. Just as a note, I've surprised a
>few sport bike riders with my shakin', chrome monster. I've got no illusions
>about my bikes performance but a few of the "rice burner" riders have done a
>double take when they blow by me and look over to see me right back up there
>with them at 110 mph.
Cool. I'd love to ride with someone like you.
>Remember the next time you see someone on a Harley "shaker" that just because
>they think your an idiot doesn't mean you really are.
That was my point! ;-)
Pat_Teaford
> > You can have the speed, I'll just get me another Harley.
>
> In this case you could define "speed" as not having to stop all the
> time
> and pick up the spare parts the Harley shook off.
>
> I'd just like to point out that many "rice grinder" riders aren't all
> about "speed" anyway. Many of us love to sling the bike side to side
> through corners repeatedly for the fun of *that*. You can't do that
> with all that damned chrome hanging off your ass.
>
> I'll take my very torquey and fast v-four Honda any day over one of
> those paint shakers. It's a matter of personal preference. Sure, if
> you just want to cruise and have the money to spend, get a late model
> Harley. If you want to have fun *riding* the bike (vs sitting back
> and taking in the people looking at you), get a "rice grinder" (or a
> Buell, which is sort of a Harley spin off but a real sport bike).
>
> --Donnie
Like I said, you can have the speed, I'll just get another
Harley......we'll see who lives longer....
I had my share of speed, even the grinders knew better than to mess with
my last street car. (My '57 Chevy)
I sure did like smokin' 'em -
It was somewhat torquey and fast, too.....
(8.98 at 150 mph 1/4 mile; 5.72 at 122 mph 1/8 mile; zero to 60 in 1.68
seconds)
--
Pat_Teaford
http://home.swbell.net/nitro57/DRAG.HTM
http://home.swbell.net/nitro57/FORSALE.HTM
Bob Leggott
Bob Leggott,
Cloverdale, B.C.
Eugene Blanchard <blan...@cadvision.com> wrote in message
news:3A170AD5...@cadvision.com...
> Thanks to all who replied to my initial post. What an absolutely great
> thread! Kudos to all who participated.
>
> Thanks again.
>
>
> Grape Ape wrote:
> >
> > This seems to get confusing for a lot of people. I'll try to explain
this
> > the best I can. HP and Torque are directly related to each other. In
> > reality, torque is what moves the car, HP is how fast that torque can be
> > used. Hp is simply a measurement of torque over a time period. That
time
> > period is measured in rpm.
> >
> > Lets say it were possible to build an engine with a perfectly flat
torque
> > curve of 500 ft. lbs. (far fetched but lets pretend). At any rpm the
engine
> > always has 500 ft.lbs. As rpm increases, so would HP and the engine
would
> > be getting more powerful (per minute). Having 500 ft.lbs at 6000 rpm
will
> > have twice as much HP as 500 ft.lbs at 3000 rpm. This is because at
twice
> > the rpm, there is twice as many fires of the same power (more speed).
> >
Donnie Barnes
>Harley......we'll see who lives longer....
I never said I craved speed. I crave handling and "fun" riding (yes, by
my own definition, which rarely includes going over 110 mph and never over
about 90 mph for any real duration). I've taken both MSF courses and
refuse to ride in situations that would put me in serious traffic (I
trailer to the mountains or ride locally on Sunday).
Not to say that I'm doing anything different or "better" than you. But
I'd bet that both of our riding styles probably lend more to dumb luck
killing one of us rather than the fact that I ride a sport bike and you
ride a cruiser.
Sure, there are more "squids" out there on sport bikes than sane riders
who probably do have a much higher chance of killing themselves on their
bike than you do. I'm just pointing out that not all sport bike riders
fit your mold (and glad to see someone else point out that not all
Harley riders fit the Harley stereotype).
Dogbite
difference between HP and torque. As I have both kinds of bike I can assure
you they are completely different animals with totally different purposes.
I enjoy both in different ways. Never meant to start a my bike is better
than your bike thread, I'm almost sorry I used that particular example
except for the mild entertainment value of the resulting "discussion".
Donnie Barnes
>Just in case anyone cares, I brought up the HD vs RR just to exemplify the
>difference between HP and torque. As I have both kinds of bike I can assure
>you they are completely different animals with totally different purposes.
>I enjoy both in different ways. Never meant to start a my bike is better
>than your bike thread, I'm almost sorry I used that particular example
>except for the mild entertainment value of the resulting "discussion".
Well, I don't think there's been much unreasonable discussion of the
topic (though it is mostly off topic ;-). But I'll also point out that
your analogy would have been better served by better qualification of
the "rice grinder" theory. I think what you meant was "inline four
cylinder rice grinder" for your horsepower comparison to the Harley.
There are plenty of V-twin rice grinders as well as a handful of v-four
grinders out there that do have lots of torque, too.
Dogbite
are V-twins which further makes the point of Hp vs torque as even the basic
engine design is similar. The inline fours are even scarier in the power
department. Not really sweating the deviation of the thread, it just seemed
like it might turn into a pissing contest as I have seen on many bike
related newsgroups.
All in all, you're right though, the thread has been pretty civil and on
topic.
--
"Bigger, Better, Faster, More!"
To email, replace nospam with dogbite.
"Donnie Barnes" <d...@laptop.donniebarnes.com> wrote in message
news:slrn91lv8...@laptop.donniebarnes.com...