SMG control unit & differential HELP PLEASE :-(

Sorry to post it here since I have the Z4, but there isn't any Z4 forum where I can get specific technical help like in this case.

- I have Z4 3.0 SMG; with stock final drive ratio 3.07
- I swapped to a 3.46 differential yesterday
- Now the computer seems confused and isn't adapting to the new differential at all. Shifting becomes jerky, and downshifting/rev-matching is pratically useless.

Now I know that
-Z4 2.5 SMG has a stock final drive ratio of ALSO 3.46.
- the transmission parts are exactly the same as 3.0
- programming is different. Computer is likely set to worth with a 3.46 gear (shifting points, etc)

If I just get the 2.5 SMG control unit? Will that work with me car at all?? In theory it sounds like it might, but I'm worried about the communication between the ECU. And I really don't wanna spend $1000 just to find out :-(

If anyone know, please help me!!!

Reply » SMG control unit & differential HELP PLEASE :-(

First of all, welcome to the Bimmerfest.

I'll move this thread to the Z forum.

Also please do not cross post the same thread on different forums.

Cheers
Alex

Reply » SMG control unit & differential HELP PLEASE :-(

Hi,

Sorry, moderator.

But can I at least post it in the E46 forum? Cos I know there are more people with E46 3-series SMG then there are people with Z4 SMG. And E46 and Z4 uses the same SMG technology.

Thanks!

Reply » SMG control unit & differential HELP PLEASE :-(

And I'm definitely sure a lot more 3-series owners swapped their differentials than Z4-ers.

Reply » SMG control unit & differential HELP PLEASE :-(

You'll be surprised to know how knowledgeable our resident Z gurus are.

Reply » SMG control unit & differential HELP PLEASE :-(

I bet there are more differential swaps in this Z section than on all the other forums put together... LOL. Heck, I have done mine twice and I just got another diff to put in...

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