CamaroSS

iTrader: (2)

OK so what am I gaining and what am I losing?

What will my top speed be?
What will I experience going from a 3.23 to a 3.73?

Please inform me, I know very little about gears, and I just bought 3.73s and they go in this Friday.

Colonel

You top speed will be dictated by the power you make at the RPMs where your power becomes limited by aerodynamics. You'll be able to get into your power in 4th gear better with the 3.73s than with 3.23s so your top speed will increase.

Gains in the 1/4 mile? Not much if you have a good converter already. Possibly a half second if you have a stock converter. Expect to drop a couple MPG.

FenixSS

iTrader: (3)

Oh, I was under the impression (from reading some posts via search button)that Gears and Verter/TransGO help in gas mileage especially on daily drivers with about a 10-15% loss on Horsepower. Or did I get it wrong?

Also, is TransGO the way to go, or would the B&M Shift kit be sufficient. It's what's available in Hawaii, I'd have to pay for the TransGO to be shipped here

1999Z28

a guy i race with put 3.73s in a ls1 formula, he saw .3 gains tho. he had minor things done to his car too.

Colonel

Your RPMs will be turning about 15% higher with 3.73s than 3.23s when cruising. You tell me if it sounds like you'll get better MPG while spinning the engine faster. If you went from 3.23s to 4.10s (27% change) it would be almost as if you were driving around in D rather than in OD.

Again, if you have a good converter (say, 3500 stall or better) then you should expect only small gains in 1/4 mile acceleration from a gear swap. I've raced 2.73s, 3.23s, 3.42s, 3.73s, 3.90s, and 4.10s with a variety of engines and converters. For a street/strip setup I recommend a good stall converter with stock gears.

My pick for a shiftkit is TCI's. I've used a TransGo before too. It's probably just as good but it's a much more involved installation with more room for installation error.

CamaroSS

iTrader: (2)

Thanks for the info. SO you are saying I will see a higher top speed with a 3.73 over my 3.23?

Also what kind of top end power am I looking at here? I mean I like to race from *cough*rolls on ocasion. Like will I see more or less umph at 60 or 65mph? basicly give me a tutorial on what I will see.

~Thanks
Kevin

MNR-0

No. Colonel is saying your RPMs will climb 15% faster. Your top speed will decrease as you are increasing the number of tyre rotations per minute to cover the same distance. Your ET will increase because you can reach your peak power quicker therefore keeping your car in that range longer. You will never reach your top speed drag racing the QTR unless your gearing is way high. Effective torque will increase as it takes less effort to spin those wheels.

As torque converters are designed to reach your peak power and keep you there longer they negate some of the benefits of a diff change. The only real advantage with higher gears in a converter is that you can reach peak power RPM quicker after torque converted lockup. Once complements the other.

For the street you want the converter to feel tight. Higher gear ratios help this. For the strip you want max. shift extension so you want the converter to feel loose. A loose converter also helps with the traction.

There is never the perfect combo. There is, however, the perfect compromise. You determine that compromise.

Colonel

Sure your engine RPMs will climb faster with numerically higher gears. However...

"Your top speed will decrease as you are increasing the number of tyre rotations per minute to cover the same distance."

I do not follow what you're saying here. If you were referring to trap speed rather than top speed then 3.73s will also give you a higher trap speed. You'll get out of the hole a little quicker and you'll cross the finish line closer to your HP peak than you would with 3.23s. It takes ALOT of power to pull 3.23s out even close to the HP peak in the 1/4 mile.

I WAS in fact saying that your top speed will be a little higher with 3.73s than with 3.23s. Why? Because in either case your top speed will come in OD but you'll be able to get closer to your HP peak with 3.73s before wind drag puts the stop on speed increase. You'll have more HP available to fight wind resistance at top speed, in other words. Example...165 MPH would come at only about 5100 RPM (counting converter slippage) with 3.23s but would come at 5900 with 3.73s.

"Your ET will increase"

I think you meant to say that your ET will decrease (you'll go quicker) with numerically higher gearing.