3.92 and 3.55 what is really the dif?
Kristopher L. Broberg
I understand they are both gear ratios, and I read the discussion earlier
on this subject. I am about to order a 2000 Dakota Quad Cab 4x4 as soon
as I can.
I have heard conflicting things about the affect of the different gear ratios?
I am still deciding between the 4.7 liter and the 5.9 liter V8. But I am
leaning toward the 4.7L. If I get the 5.9 I will get the 3.55, but with
the 4.7l I am not sure.
I asked the dealer about the gear ratios, he seemed to really be pushing
the 3.55 gear ratio to the point that I almost don't trust what he is
telling me. He told me with the 3.92 setting I will get less pep, less
acceleration. On hear I read different. I drove a4.7l with 3.55 gears
and it seemed very peppy and powerful, but that was just a short little
drive.
I really don't know.
What really are the differences in gear ratios plusses and minuses?
An explanation of what they mean would be useful? I know 3.55 is a higher
gear ratio then the 3.92. But how much difference does that really make?
I admit I am ignorant, that is why I am asking, so no comments on that,
please...
Thanks
Light, Ed
travel trailer or whatever in the mountains, in which case it may be a good
idea.
I'm sure some of the new 4.7 owners will take it up for you.
APelouze
that there is much lacking in the acceleration department. Living at 6000+
feet getting on the freeway at 75 mph is a snap. I figure about 2-3 mpg lose
over the 3.55. Going off road in 4 lo the 3.92 makes the trek a breeze. The
3.92 will make towing easier on the engine.
--
Aaron
Sent via Deja.com http://www.deja.com/
Before you buy.
APelouze
Christopher H.
acceleration off the line but at 60 MPH you'll be turning 3000 rpm. The
lower ratio is best for all around driving. But unless you are going to tow
heavy loads (6,200 lbs) go with the lower number.
Kristopher L. Broberg <kr...@real-pros.com> wrote in message
news:kris-30099...@klb-2.dsl.visi.com...
mrdancer
effectively increasing my gear ratio to around 3.90 gears. Mileage is the
same around town, suffers by 1-2 MPG on the highway. Acceleration is brisk,
but not significantly greater than with 3.55's. Also, high-speed passing
maneuvers seem to be a little less peppy with the 3.9's (unless you really
kick it down) - this may be what your dealer is referring to. The problem
is that the engine has to move across a wider rpm band to accelerate to the
same speed with the shorter gears. This is not a problem on engines that
like to rev, which is another reason smaller engines have short gears.
The dealer wants you to buy the 3.55 because it helps the CAFE (and also
because that's probably what he has most of on the lot - his supplier also
wants him to sell more 3.55's than 3.92's). Were it my choice, I'd pick the
3.55 unless I was doing either lots of towing or most of my driving was
around town. Besides, you can always change tire diameters if you want to
'play' around with different 'effective' gear ratios after the fact.
--
'92 Dak CC 2wd 318 3.55
'84 GoldWing Interstate
APelouze
My econo box car makes more noise at the same speed about 3200 RPMs. A very
nice ride on the freeway.
Light, Ed
mrdancer <mrdanceratcamalottdotcom>
> wants him to sell more 3.55's than 3.92's). Were it my choice, I'd pick
the
> 3.55 unless I was doing either lots of towing or most of my driving was
> around town. Besides, you can always change tire diameters if you want
to
> 'play' around with different 'effective' gear ratios after the fact.
I got some good insights from your post.
As to a 3.90 being best in town, I have a 3.2 and it's really ok in town.
You don't need acceleration and it just kind of seems to idle along. With
an old carbureted 318. The fuel-injected modern ones would have much more
power.
As for counting on being able to change tire diameters, research it first.
On my 15" tires 235/75 15, I can't go down in diameter without taking a
serious hit in load carrying.
.boB
> I understand they are both gear ratios, and I read the discussion earlier
> on this subject. I am about to order a 2000 Dakota Quad Cab 4x4 as soon
> as I can.
>
> I have heard conflicting things about the affect of the different gear ratios?
>
> I am still deciding between the 4.7 liter and the 5.9 liter V8. But I am
> leaning toward the 4.7L. If I get the 5.9 I will get the 3.55, but with
> the 4.7l I am not sure.
>
I hat to disappoint you. But you can't get the 5.9 in 4WD. Only available
in the 2WD Sport R/T package, and only with auto tranny.
--
.boB
97 H-D 1200S
97 H-D FXDWG
95 Ram 1500 CC/LWB
83 GMC Jimmy (beater)
65 427SC Cobra (project)
Dale
in my '97 Dak, automatic tranny.
I tow a 5000 lb. travel trailer and the 3.55 gearing felt too high (31"
tires on the 4x4). At 25k miles, I pulled the gears and changed to
3.92. My truck is much happier with heavy loads now. I concur with the
previous poster, mileage around town is nearly identical, but you give
up about 1-2 mpg in highway mileage. At 60 mph, AT OD, 3.55 was ~1630
rpm, 3.92 is about ~1800 rpm. Basically, 3.92's are 10% lower gears,
yielding a 10% higher RPM for a given speed, and (roughly) 10% lower
highway mileage.
Go with the 3.92s if you're towing heavy loads in the hills, go with the
3.55 if you're looking for max mileage.
Dale
mrdancer wrote:
>
> I have a 5.2 w/ 3.55 gears. I recently swapped to shorter tires,
> effectively increasing my gear ratio to around 3.90 gears. Mileage is the
> same around town, suffers by 1-2 MPG on the highway. Acceleration is brisk,
> but not significantly greater than with 3.55's. Also, high-speed passing
> maneuvers seem to be a little less peppy with the 3.9's (unless you really
> kick it down) - this may be what your dealer is referring to. The problem
> is that the engine has to move across a wider rpm band to accelerate to the
> same speed with the shorter gears. This is not a problem on engines that
> like to rev, which is another reason smaller engines have short gears.
>
> The dealer wants you to buy the 3.55 because it helps the CAFE (and also
> because that's probably what he has most of on the lot - his supplier also
> wants him to sell more 3.55's than 3.92's). Were it my choice, I'd pick the
> 3.55 unless I was doing either lots of towing or most of my driving was
> around town. Besides, you can always change tire diameters if you want to
> 'play' around with different 'effective' gear ratios after the fact.
Kristopher L. Broberg
You can't disapoint me. I will probably not get the 5.9L but you can get
it with 4WD on the new Dakota Quad Cab unless something has changed since
they wrote there litereature and since I talked to the dealer last week.
Jim Bryner
"Kristopher L. Broberg" wrote:
> I understand they are both gear ratios, and I read the discussion earlier
> on this subject. I am about to order a 2000 Dakota Quad Cab 4x4 as soon
> as I can.
>
> I have heard conflicting things about the affect of the different gear ratios?
>
> I am still deciding between the 4.7 liter and the 5.9 liter V8. But I am
> leaning toward the 4.7L. If I get the 5.9 I will get the 3.55, but with
> the 4.7l I am not sure.
>
Brooke Clyde
give a nice torque boost in the lower RPM range, which is nice since the 4.7
doesn't really pick up until 2000+ RPM. However, the 4.7 does rev quickly,
so even with the 3.55 you won't be disappointed.
I drove the 4.7 with 3.55 gears in a Dakota. Very nice. As I said, it revs
quickly, pulls nicely once the RPM is 2000+, and sounds good. The
well-reviewed Jeep that introduced this engine is heavier than the Dakota
and has a 3.73 ratio. I found it great to drive. On that comparison, the
lighter Dakota should be more than OK with the 3.55.
I drove the 3.92 gears in a Durango. What an improvement! Now this isn't a
scientific test, since these test drives were days apart and I'm certainly
no expert, but the 3.92 felt significantly peppier to me all over the RPM
band. And this was in a vehicle 500# heavier than the Dakota.
The 3.92 should = 10% increase in RPM over the 3.55, but that's no problem.
The 4.7 cruises between 40-70 mph at 1800-2100 RPM with the 3.55 ratio.
The downsides to the 3.92 given by your salesman don't sound right to me,
but what do I know?
On the 5.9 vs. 4.7 issue, all I can say is that I got the 4.7 liter. Drive
'em both. The 4.7 seems to me somehow quicker to respond than the 5.9;
whether that makes the vehicle move faster, I don't know. Also, being a bit
of a techie, I couldn't see myself in a pushrod engine. ;)
Have fun!
---
Brooke Clyde
bro...@sonic.net
<snip>
CERES...@aol.com
equal, the engine will rev about 10% higher at any given speed. That won't
quite equate to a 10% drop in gas mileage because throttle openings won't be
the same but gas mileage will suffer.
You will have (at the drive wheels) about 10% greater torque available. If
you like to peel rubber, this will help but if you are considering the
smaller engine, that's probably not the case.
With the automatic transmission it may shift at lower speeds because it gets
to the shift rpm quicker.
You will lose about 10% of your top speed.
Finally, it will tow better than the 3.55 if that is an concern. If you live
in hilly country, the 3.92 will help.
If you are just running around town, some interstate travel and lightly
loaded all of the time and the 3.55 is satisfactory, then go with it.
If you intend to special order, the dealer shouldn't give a rap about what
you want but most vehicles are ordered with the "economy" rear end which is
the 3.55.
I suspect he is hoping that he will be able to find one at another dealer
somewhere and transfer it rather than a direct factory order. A 3.92 rear end
would make that just about impossible.
Dealers have all sorts of reasons for not giving you the options you want.
Most of it has to do with stock availability. They will disparately try to
talk you out of limited slip rear ends, heavy duty alternators and some of
the more obscure options. WHY DO YOU WANT THAT is the recurring theme. The
answer should always be if you are certain..it's my money, that's what I want
and if you are incapable of ordering or finding it for me I will go somewhere
else to a dealer that will.
For example:
I've been told that the split bench seats (40/20/40 seats are not avaiable in
vinyl. Salesman swore up and down that it was not available. Guess what?
last page on the 2000 catalog, picture of seats item D. Yes, not available
in the WS but it's standard in the ST. I suspect the reason is that they
really don't look that bad and they would like to push you up to the SLT trim
or get the option sale. I'm obviously trading a lot of the interior goodies
to get the running gear mechanicals at the price I want to pay.
Good luck on your purchase,
John G
Sent via Deja.com http://www.deja.com/
Share what you know. Learn what you don't.
Light, Ed
<CERES...@aol.com> wrote in message news:a5ea045e...@aol.com...
> You are looking at about a 10 percent difference in ratio
Do you suppose a 3.2 would get better mileage than a 3.55 ?
My '86 318 has a 3.2. I wonder if it hurts or helps the mileage over stock.
Joe
> My '86 318 has a 3.2. I wonder if it hurts or helps the mileage over
stock.
>
>
acceleration.