RT930turbo

Hey guys,

It seems my somewhat new to me 88 S4 has 2.54 gears in it. This car is certainly a US spec car, as I have the original bill of sale. I also have just about all the maintenance records, however there is a gap from about 94-97.

Is it possible this car came from the factory with this ratio? Otherwise, where are the transmission / final drive numbers on the case?


....or am I just missing something painfully obvious

RT930turbo

RT930turbo

This is also the first car I've ever had with a slush-o-matic... am I not taking converter slip into account properly?

soontobered84

If you post your VIN# on this thread:

https://rennlist.com/forums/928-foru...8-79-a-53.html

and ask nicely, Rob Edwards or one of the other VIN gurus will run it and give you a list of the options associated with your car. It might have been an option from the factory or maybe your car came with an '89 transmission?

Imo000

Your car has an OD.

Rob Edwards

Operators are standing by.

RT930turbo

Thanks guys, Rob has decoded my VIN already

And 4th gear is not OD as far as I know. Should be 1:1, right?

RT930turbo

For reference...

Speedtoys

That is the special fun gearset in the 88 auto transmissions.

Much sought after.

3 is 1:1, 4th is OD.

RT930turbo

http://members.rennlist.com/pirtle/s4atrans.htm

General Data
A 28.04/07/12
A 28.05/06/09/11/14/16

Design

Fully automatic 4-speed sun-and-planet transmission

Ratios

1st gear
2nd gear
3rd gear
4th gear
Reverse gear

A 28.04/05/06/06/08/09/11/12/14

3.6760
2.4120
1.4360
1.0000
5.1390

A 28.16

3.87
2.25
1.44
1.00
5.59

Speedtoys

Which is odd, we don't dyno in 4th, we force it to stop in 3rd.

Ok.

RT930turbo

Also as a data point, the speedo is within 2-3 MPH GPS

dr bob

My amateur eyeball of the speedo and tach readings says you have the longer-legged 2.20:1 final drive ratio.

I thoroughly enjoy the 2.54:1 in my 1989 car, especially when in traffic. For any serious touring though, I'd prefer the 2.20:1 you have in your car. I'm not ready to swap permanently, but would have no trouble putting a 1988 gearbox in while I had GB refresh the original 1989 box.

Richard S

"2.54 gear ratio doesn't make the car any quicker than 2.20 gear ratio because blah blah blah blah blahl blah blah blah blah blah blah blah infinity." Mark Kibort

Imo000

I'm confused now! What ratio is your dif?