jpkalas

1996 Z28 M6
LT headers
Hi-flow cats
SLP Loudmouth 1
Moroso CAI
B&M Short Throw shifter

I have stock gearing, 3.42 I believe. I'm looking to change that, but don't know the first thing about which ones to select. I've read that 4.10's are better with the M6.

What are the advantages/disadvantages of having this particular gearing? I'm looking to simply increase my acceleration rate. Any suggestions for new gearing welcomed. Thanks!!

Z28SORR

The 4.10's are probably the most common suggested gear for a street M6 because they are relatively inexpensive, easy to install, and give you a good boost of accelleration with almost no loss of gas mileage. You'll just find youself in 5th or 6th more often.
You can go high gear ratio's 4.56, 4,88, etc. but you begin to loose the use of 1st gear unless you get a different trans., which is expensive. Also these higher gears may require the use of a different carrier, which adds to the cost.
Traction with the 4.10's and street tires can also be a problem, so higher gear ratio's would increase this problem, on the street.

P.S. Personally I regret not going to the 4.10's in my "heavy *** vert."

jlew69

I have 4:10's in my 95 Z M-6. With stock size tires at 55mph in 6th gear I'm running 1700 rpm's. It really is a good gear for the street.

Nickw059

Where's the best place too buy some of the gears at??

jpkalas

What if I were to go DOWN a gear ratio? Wouldn't it stand to reason that the longer you can make each gear last, the faster you go? Is it possible to get my M6 to be similar to an A4 in terms of length of time in each gear?

Z28SORR

NO! If you go to a lower numerical gear your acceleration times will get slower. Say your running the 3.42 gear and you go to a 3.23 gear your acceleration will get slower. So if you were running a 14.00 1/4 mile time with the 3.42 gear you may only run a 14.40 1/4 mile time with the 3.23 gear.

higher numerical gear(4.10) - quicker acceleration.......but, slower top speed.
lower numerical gear(3.43) - slower acceleration......higher top speed.

This is very general and only applies to gears in the "normal" ranges. Once you get to the extremes at either end other factor come into play.

jpkalas

Ah alright. Makes sense. Can I just get the ring and pinion with the 4.10 ratio? Or do I need a whole new rear end? What kind of tuning is involved?

Injuneer

You need a set of gears that fits your 3-series carrier, a rebuild/install kit and someone that knows how to install it. Gears run about $200. Install kit can be $75-125, depending on how complete, crush sleeve or solid spacer. Install will probably run $250-300. You could do it yourself with the correct tools, including a dial indicator to measure backlash and a pinion depth checker. But this is a job that is best left to someone that knows exactly what they are doing. A small error on the setup, and the gears will whine so loud you can't hear yourself think, and destroy the gears.

You will need the new gear ratio programmed into your PCM, or the speedo will read 20% higher than actual speed.

When looking for a source of parts, its always a good idea to start with one of our supporting vendors:

http://www.thunderracing.com/shop-by...s-and-Gaskets/

jpkalas

Thanks very much all! You've been a big help!