Lets talk gears.....

[shadyphi]

Ok, again you must pardon my knowledge on alot of this stuff... it is all brand new to me ... (gotta start somewhere I guess!)

1) Could someone explain the basic jist of gears to me... for instance ... what exactly is 3.73 gears... 4:10 .... etc....

2) I have a 97 LT1 M6 ... what gear ratio do I have stock?

3) If I upgrade to a new gear ratio, is it still drivable everyday on the street, or is it strictly for the track??

Thanks all... !!!

[Dave M]

1. The ratio describes how many revolutions the rear axle makes for every turn of the driveshaft. 3.73's turn the rear axle 3.73 tunrs for every turn of the driveshaft. 4.10's turn it 4.1 times for every driveshaft turns. Hence, you'll accelerate quicker with 4.10's, but you'll be spinning the engine at a higher rpm for the same speed. Hence worse gas mileage and lower top speed.

2. you have 3.42's stock

3. Upgraded gears are not for the track only. You can drive every day provided you're willing to forego some gas mileage. 4.10's are the generally accepted best gears for an M6, and some people actually get better mileage with them because 6th gear becomes more useable.

[shadyphi]

1. The ratio describes how many revolutions the rear axle makes for every turn of the driveshaft. 3.73's turn the rear axle 3.73 tunrs for every turn of the driveshaft. 4.10's turn it 4.1 times for every driveshaft turns. Hence, you'll accelerate quicker with 4.10's, but you'll be spinning the engine at a higher rpm for the same speed. Hence worse gas mileage and lower top speed.

2. you have 3.42's stock

3. Upgraded gears are not for the track only. You can drive every day provided you're willing to forego some gas mileage. 4.10's are the generally accepted best gears for an M6, and some people actually get better mileage with them because 6th gear becomes more useable.

Gotcha... thank you!

So, in a nutshell, if I'm going to get some gears, 4:10 is the way to go ... hands down... right??

[Dave M]

3.73's really wouldn't be much of an improvement over 3.42's. The difference would be negligible. 4.10's would be the way to go for an M6.

[Jeff95TA]

1. The ratio describes how many revolutions the rear axle makes for every turn of the driveshaft. 3.73's turn the rear axle 3.73 tunrs for every turn of the driveshaft. 4.10's turn it 4.1 times for every driveshaft turns.

I think you have it backwards.

[95TransAm]

3.73's really wouldn't be much of an improvement over 3.42's. The difference would be negligible. 4.10's would be the way to go for an M6.

I second this...definitely get 4.10's.

[95TransAm]

A good read to understanding a differential and rear end gears is here.

[94Z/28]

You have the gear thing backwards, ex 4.10 gears would have the driveshaft turn 4.10 to 1 turn of the axle

[Injuneer]

Think of the gears as a "torque multiplier". Going from your current 3.42 --> 3.73 would increase the torque at the rear wheels by 9%. You will "feel" it, and IMHO its more than negligible. Going from 3.42 --> 4.11 will increase the torque at the rear wheels by 20%. Definitely going to feel that, and definitely more significant than the 3.73's.

As noted in a couple posts above, the gear ratio reflects the number of revolutions of the driveshaft, for each revolution of the rear wheels.

Since you are increasing the torque at the rear wheels, you will definitely accelerate faster in any given gear. You will just hit "redline" (max allowable engine RPM) a little sooner in each gear. And, for any given cruising speed, in any given gear, the engine will be turning that much faster.

Some examples, assuming you are shifting at 5,600RPM:

GEAR - 3.42 - 4.11
---- - ----- - -----
1 - - - -47 - - 39 MPH
2 - - - -70 - - 58 MPH
3 - - - -96 - - 80 MPH
4 - - - 125 - -104 MPH

When cruising at 70 MPH in 6th gear:

3.42 - 1,600 RPM
4.11 - 1,920 RPM

The actual number will vary a bit based on actual tire diameter, but you get the idea.

When you change the rear axle ratio, you need to have your PCM reprogrammed with the correct rear axle ratio, or your speedometer will read incorrectly.

[Dave M]

I knew I had it backwards when I posted it!! I always get it backwards. It's the driveshaft that turns faster, hence the reason why you rev higher with the higher gears.

[wrd1972]

I have been toying with the idea of putting 4.10's in my nearly stock Z28 6 speed.
Some people have said it is beneficial and others said its not worth it.
Looking at it from a logical standpoint I believe it has to help exactly the way injuneer said.
Personally I dont care about top-end speed, my 150MPH days are long gone but I just want more accelaration especially after gentle take-off's when I floor it. My LT1 wont pull hard till about 2500 RPM.
If one were to take a bone stock Z28 and slap the 4.10's in it what could you expect with respect to 0-60 and 1/4 with the mod.
And is it true that 4.10's dont hold up well cause of the small pinion?
Thanks all

[Dave M]

I think you could expect 2 - 4 tenths in the quarter. You've already got the HPP so you could adjust the speedo for the gears. I'd say it would be worth it.

As for strength, if you stick with the stock 10 bolt, anything can break, but 4.10s aren't inherently more weak than stock gears, AFAIK.

[jessica2112]

What about an a4 going from 3.42's to 3.73 or 4.10?

[Dave M]

Highest recommended gear for an a4 is 3.73. Going from 3.42 to 3.73 would not be much. I think Injuneer said 9% gain. On a V6, you might see a tenth or 2 in the quarter. I'm not sure it would be worth the cost. I've always thought 3.42 is just about the perfect ratio for an A4. It's better than the 2.73 or 3.23 the car came with, but isn't steep enough to really impact mileage. Although, being a V6, you need more help getting the same performance a V8 naturally has. If you've got the money, and you want every tenth you can get, don't stop at 3.42's.

[wrd1972]

What is the best quality R&P with respect to strength and low noise.
Whats the deal with the 4.10 vs. the 4.11. Some say the 4.11 is much stronger!