I have installed a 3.27-diff on a C36-engine/tranny, and I think the ratio is too much for autocrossing.

Has anyone else tried it?

While the accelleration is great, it seems to have too much drag to top speed.

Should I go back to 2.87 or try a 3.07 ?

BTW: this is a fast autocross course . . .

Thanks,
:-) neil

I can not comment about usability of the 3.27:1 on the C36 but on my W201, I went from a 2.87:1 non-LSD to a a 3.27:1 LSD and it made a great improvement in 0-60 times. I would think for autocrossing, this is what you would want. The trade off being the top end, although the auto trans 16 valve W201's also came with the 3.27:1 (all W201 manuals have non-lsd 3.27:1 diffs) and that particular cars top speed (with auto) was rated very close to the manual trans top speed.

I would keep it as it is IMO

__________________
1993 500E
http://2phast.com/500e/500e-sig.jpg

Where did you get different ratio differentials? Were they custom built? I am trying to source a shorter ratio differential for my R129 SL500 so any help would be appreciated.

Marek

Via friends in Europe.

What ratio are you looking for? What's your budget?

:-) neil

Budget is less of an issue but quality of work is. What I am looking for is a differential with the ratio of 3.27 instead 2.65. However, I understand that the software has to be modified as well. I spoke to different tuners but nobody wanted to touch it.

Marek

I think a 3.27 is too much for everyday driving. How about a 3.07 ?

Is your R129 a 4-speed or 5-speed? Model year? I don't think you need to change chips/computers, only speedo.

I think you have ASR, correct?

:-) neil

My car is 1998 SL500 with the 4-valve engine (119). Yes, I do have ASR.


3.27 might seem like a radical change but it is not. The top gear ratio with 3.27 differential with 5-speed automatic would be very close to R129 500SL with 4-speed automatic from 1990-1994.
I would also accept 3.07 differential if it were as strong as the factory one.

I was told that I would need a software change since the computer looks at speeds on all 4 wheels. If let’s say we change the differential ratio, the computer would think the rear wheels are turning faster that the front wheels and it would activate ASR and switch the tranny to the limp mode.

Marek

Good question, esp. since the ASR pickup is at the diff, not the rear wheels (ASR & ABS looks at the front wheels).

I'd call RennTech or Brabus and tell them you're interested in one of the peformance differential upgrades and ask them if you need a computer change, or if one is included.

:-) neil

i did already. they gave me different answers but they agree in one repect - they do not want to touch it.