I am trying to debate between 4.11 and 4.56 gears. Can someone tell me what the top speed would be in each gear (M6), at say 6800rpms? Thanks

 

Roughly 130 mph with 4.11 and 115 mph with 4.56, with a tire radius of 13".

 

What gear is that in?

 

ive been at 150mph in 5th at a tad over 6krpms. I think top speed would be 160ish unless you want to rev it to 7k.

With 4.56s you may reach top speed in 6th if you have enough power.

 

I was going by 5th gear ratio of 1, 6th will get you higher.

 

With 4.11's in 5th gear you should reach 171mph-4.56's should get you to 156.

 

A T56 does not have a 1:1 5th gear. 4th gear is 1:1. 5th gear (0.74:1) and 6th gear (0.50:1) are both overdrives.

With 4.11's, at 6,800RPM, the theoretical speed is:

5th - 170
6th - 252

With 4.56's, at 6,800RPM, the theoretical speed is:

5th - 153
6th - 227

Whether you can reach those speeds depends on how mugh HP you are putting down. Its not likely you could get anywhere near 200mph without huge HP.

 

Assuming stock sized 245/50R16 tires and stock M6 tranny ratios (these are the ratios of my '02 Z... most LT1's are the same, but I think 93's had a different first gear ratio).

4.11:1 rear end @ 6800 rpm:
1 - 47mph
2 - 70
3 - 97
4 - 126
5 - 170
6 - 252

4.56:1 rear end @ 6800 rpm:
1 - 42
2 - 63
3 - 87
4 - 113
5 - 153
6 - 227

That is, of course, assuming you have the power to reach 6800rpm in each of those gears, which is extremely unlikely.

 

Bah! Fred beat me by three minutes. I was more thorough though!

 

Don't feel bad about the three minutes, that's what his car would beat mine in, in the quarter mile!

 

Hey thats exactly what I was looking for, I think I will go with the 4.56s. They should turn good times at the track with the 383, LE ported trickflows and intake, and the HEALTHY bauer cam. Plus the CSR Waterpump etc.

 

Just in case this is a street car, you may be interested to know that the 4.56 setup will have you at about 1800rpm at 60mph. In general, your RPM will be 33% higher than it was with stock 3.42's.

 

I didn't know 4th was 1:1, shows how much I know about manuals...

 

Thats okay man, just the other day I figured out I drove a Firebird and not a Camaro.

 

Just so you know, with that setup and 4.56's, you're going to be shifting into 5th before the end of the 1/4 mile. Depending on how fast you shift, you might actually not gain anything over the 4.11's. Just my 2cents.