V8 Torsen Diff

[Masterblaster]

Hi

i want to replace my back diff from my UrS4 with on from an Audi V8.
Which diff do i need to get, and what do i need to modify or change in order to get it in?
I am thankful for any info..

cheers
Kai

[Error404]

http://www.s2forum.com/forum/showthread.php?t=9680

[goodall]

For an s4 would be best just use the whole diff, including casing, as the rear suspension/drivetrain is same between the V8 and S4 and all other large chassis quattros of the era

[Error404]

Super easy then

[UrS4boy]

Just make sure that the V8 torsen that you get is a) in good condition (not too much play) and b) that it is 4.11 to 1. (There was a 3.89 or something out there as well).

[Masterblaster]

thx for the info.
What is the Audi Code for the 4,11 diff?

[UrS4boy]

thx for the info.
What is the Audi Code for the 4,11 diff?

Now I can not find any trace of the the 3.89 rear diff. As far as I can tell (now), from 1989 to 1994 the V8 rear diffs were either AFV or AXZ code with a 37:9 (crown teeth to pinion teeth) ratio, i.e. 4.11 to 1. Nevertheless, check the diff by turning the input shaft flange by hand and counting how many turns it takes to make an output flange turn one turn. Should be just more than 4 turns on the input shaft.

[JP]

Just be aware to not put it on a car pushing over 420hp as they will smash themselves to pieces as they aren't very strong. I know of two that have let go on cars less than 450 now.

[Error404]

yup definately no launches!

[Masterblaster]

Ok ,to bad its only good for around 450hp since i am running around 600HP

[URSIMPO]

Are the TORSEN diffs weak for just standing starts, or would they blow up if I gave it the beans going round a corner - on a track for instance?

[Error404]

They struggle with launches and hard use with torque much over high 300s AFAIK
They generate a lot of heat so need a diff oil cooler on track IMHO.

[URSIMPO]

Does anyone know if the rear diff in the s6 is similar to diff in the Audi A4 B5?

Quaife makes a rear LSD for the A4 rear diff, so if they're similar it should bolt in to the s6 casing. Right?

[caterpillar]

some of the s4 diff ( cron and pinion) are 3,889( spec the autotranny ones; but if you use ONLY the diff unit, the diff code doesn't matter... the v8diff( thorsen unit will fit the mostly audi casing, short housing, the audi 100/200/s4/s6 and others...!)

[URSIMPO]

Caterpillar - thanks for the advice. Do you know if the A4 B5 diff is compatible with the diff on the S6.

Could I put this http://www.quaife.co.uk/catalogue/products/qdf4q-3 in to the s6 diff case?