how much gear is too much gear?

[G_Body_Enthusiast]

its a simple question, really it is! you have an OD transmission (2004r), what rear gear do you choose? the application is a daily driver but i want excellent acceleration capability.

my current set up is a th-350 and a 2.41 gear, very pathetic in every way. acceleration sucks and i want it fixed without killing cruising RPM/fuel economy. i figure if i use a 4.1 gear in 4th gear it will act like more like a 2.73 gear and i can live with that. now if i went with a 4.56 it will act more like a 3.08 and i can live with that, at 70 MPH it only raises the RPM by only 300 over my current set up.

but with a 2.74 first gear that gives me over 12 and that's twice what my current first gear gives me with my current gear, 12.49 Vs 6.07. but is 12.49 too much for a street car? my concern is wheel spin in rain and other less than pleasant driving conditions. how high would you go with the gear? the wheels are 17x8 so they'd have wider than stock tires so i'd get a bit more grip on the road.

a 3.73 gear would act like a 2.49 gear with the 2004r in 4th gear and i could live with that but my car feels like a slug in 3rd gear with this 2.41 and 2.49 is not much different from the 2.41. if i stuck with the th-350 i could live with a 3.08 gear for it that why i'm thinking of matching the 2004r with a 4.56 gear or 4.1 gear. i hate going from 0-60 in 4 days. i hate laying into the pedal to get it moving and with the gearing in todays cars because of their OD their gearing is making my car look like it's in park and not drive. normally i go conservative and in the i wanted to use a 3.42 gear with a 2004r and i use to think 3.73 might have been too much but now i'm thinking it's a starting point rather than last choice for better acceleration.

you all with OD transmissions give me some insight here. i have driven but have never owned a car with OD and i always liked the better gearing in vehicles with OD. i know everything should match what the engine is doing and the engine should match what everything else is doing but i think i dont need to cam it all that much to match the engine's RPM range to the gearing of the drivetrain.

 

[monte olrac]

With a 4 speed transmission, man I'll go with the 3.42:1 plenty acceleration and still get pretty good milage

 

[-83MONTESS-]

I say 3.73s. Even with the 3.73s your rpms will still be pretty low on the highway but if it was my car I would have 3.90s or 4.10s. Mainly because mine doesnt see the highway much.

 

[pontiacgp]

2.92 or 3.08...it's a personal thing but I like the 3.08...

 

[G_Body_Enthusiast]

I say 3.73s. Even with the 3.73s your rpms will still be pretty low on the highway but if it was my car I would have 3.90s or 4.10s. Mainly because mine doesnt see the highway much.

my car most likely wouldnt see the highway much if at all. still, cruising at 2500 RPM at 70 with 4.10 gears isnt too bad. i cant wait to get a good 2004r to put in my car. then i'll really get to enjoy having a low gear.

if i stick with the th-350 i'd probably use nothing more than a 3.08 gear and that just doesnt give you the same oomph off the line as a 4.10 will. i cant complain about this transmission though. it has worked very well and hasnt let me down. it just doesnt have an OD gear and that makes a world of difference in rear gear selection. the 2004r even has a better first gear over the th-350, 2.74:1 Vs 2.52:1 which gives even better acceleration off the line. but really my only complaint about my current transmission is it doesnt have an OD gear and that makes it seem "behind the times" and it ruins the fun factor in driving the car. there is just no reason to stick with the th-350 when there are better transmission choices out there that not only will provide better performance but still provide good fuel economy at the same time which is a win win. especially in the times we live where gas is no longer cheap. so it's a necessity if you want a street driven car to have performance without constant fill ups on an all too regular basis. changing the transmission and gear will cost more over changing just the gear but it will provide better performance and the gas saved with the OD offsets the cost of the transmission making it all worth it in the long run. i've owned the car for 17 years, i'll probably own it till i die so its an investment in more ways than one.

now that i think about it since the 3.73 gear will act like a 2.49 gear with the .67 gear i might just go with that as anything lower would make the engine use more fuel than it does now and i really dont want that. since i still have the CCC system i can plug it in to the 2004r and use the lock up feature for better gas mileage. another win since my th-350 doesnt have lock up!

 

[DRIVEN]

It's generally accepted that a 10:1 compound 1st gear is ideal for a street car. That said, a 3.73 is almost a perfect match (mathematically) for a 200-4R's 2.74 low gear. I'm running a 3.42 behind mine and I'm happy. Play with this for a while:
http://www.angelfire.com/fl/procrastination/rear.html

 

[tc1959]

I run Richmond 3:24 gear with my 700 trans. Acceleration is very good, It will burn the rear tires off for as long as you want. It cruses the highway 75-80 all day, It is a very driveable combo. 8)

 

[rustyroger]

What engine do you have and is it stock or modified?.

If you have a torque monster like a BB Olds it will handle higher overall gearing better than a small block (or a V6) built to rev.
As a rule of thumb I would aim for the engine to be at its peak torque at your desired cruising speed, that might vary from 1500 to 4000 rpm.
Factor in your tire size as well, and don't forget the speedometer will also be affected.

Roger.

 

[84GP455]

Well I just installed the 2004r transmission and I love it!!! I have the GN 10 bolt posi with 3.42's and man my car screams! It's great off the line and even better on the highway with the lockup converter from the GN also. So my vote would be for 3.42 with the 2004r it makes a great combo. I can easily get 2nd gear chirps and still cruise on the highway going 75-80mph with the tach at around 2,000rpm!! This is also my fisrt O.D transmission in my GP and I love it!! I should have done the swap loooooong ago!

 

[G_Body_Enthusiast]

What engine do you have and is it stock or modified?.

If you have a torque monster like a BB Olds it will handle higher overall gearing better than a small block (or a V6) built to rev.
As a rule of thumb I would aim for the engine to be at its peak torque at your desired cruising speed, that might vary from 1500 to 400 rpm.
Factor in your tire size as well, and don't forget the speedometer will also be affected.

Roger.

i have the 3.8 buick V6 and i might stick with it since it's just a daily driver. they dont rev very high and the RPMs with the gearing i'm looking at wouldnt be any higher than it is now if i use a 3.73 gear with a 2004r. with a 4.10 it would be slightly higher but still within it's torque curve.

if i dont stay with the buick V6 at most it might be a very mild chevy with a cam that's at or barely above .400 lift so it would be a short duration cam. here's an example: http://www.summitracing.com/parts/SUM-1101/ it's operating RPM is idle to 4500 RPM, at most i MAY use the next one up: http://www.summitracing.com/parts/SUM-1102/ i think either would be fine for my application.

i'm just tired of having crappy acceleration (6.07=2.52 x 2.41) and i dont want to sacrifice fuel economy for better acceleration and the 2004r with a 3.73 or whatever would be a good way of getting what i want without compromising on fuel economy. also currently the engine is stock but may not stay that way in the future, i plan on putting in another engine, either to replace this worn out one or to just have a little more power with a V8, i think a buick 350 would be a good choice since it will bolt in place of the V6 and if i'm yanking the engine out i might as well make putting another one in worth my while so i may go with a buick 350. i'm considering a SBC simply because parts can be found just about anywhere and pretty cheaply compared to just about any other V8 i put in the car but i would prefer a BOP engine and the buick 350 would be the easiest to transplant.