West Coast Corvette

I have posted this link to help with this issue. I have driven an A4/Auto C5 equipped with the 3.90 gears at various speeds, and have determined this, Gear Ratio / MPH Calculator to be very accurate.
I will post the transmission gears for the A4 Auto, Std. 6 Speed and the Z06 6 Speed to make your calculating a little easier. All you need to do is input the tire size 275/40-18 (Stock Rear), the gear ratio (3.90) and the trans. gears. As an example with an A4/Auto, at 70 MPH, you will only be at 2400 RPM, a very drivable RPM range.
http://www.f-body.org/gears/

A4 / Auto

1st - 3.06
2nd - 1.62
3rd - 1.00
4th - 0.70

Std. 6 Speed

1st - 2.66
2nd - 1.78
3rd - 1.30
4th - 1.00
5th - 0.74
6th - 0.50

Z06 6 Speed

1st - 2.97
2nd - 2.07
3rd - 1.43
4th - 1.00
5th - 0.84
6th - 0.56

Todd :flag

BA2

Just when I thought 3.42 was the answer, along comes 3.90. I drove a 69 Mach 1 with 4.57 gears for years in LA traffic on the 405. I wish it was as efficient as my C5. I don't even think 4.10s would be a problem.

I've been clocked at 159 by radar during a recent Silver State Classic Challenge. Now I don't need to go that fast anymore. Now it's time to go QUICK.

I'll keep watching the threads. Durability is my concern and it looks like that is not a problem.

Thanks,

:flag

vetterdstr

That website you have linked is one of the best sites I have ever found for setting up a drivetrain. I used it extensively to plan the gearing & tire size on my car and found it to be invaluable.

vetterdstr :cheers:

MelloYellow

What is the Warranty on the 3.90's again?

West Coast Corvette

MelloYellow,

They have a 1 yr. / 12,000 mile warranty against manufactures defects,
and I might add, Getrag offers us, NO warranty on the 3.73 gears we buy from them.
:flag

AnteVenom

The warranty is an interesting issue and one would think it would be better to buy a 3.90 with at least a manufacturers defect warranty rather than a 3.73 with no warranty.

After thinking about this I was wondering what the 3.90 gear manufacturer would require from the gear set purchaser to prove it was indeed manufacturers defect?

If I am at the track and the rear breaks how would anyone know at that point where the problem lies?

If the 3.90 gear manufacturer had a set of criteria they would set out ahead of time to address this issue I would feel like there was some teeth to the warranty they are offering, otherwise it is an advertisement catch phrase that really means nothing to the consumer looking for an additional reason to buy a 3.90 over a 3.73.

Just my .02

Chuck