DCT(dkg) errors after m3 differential swap

johnybravo

New Member
Apr 17, 2018
2
0
0
Poland, Warsaw
Ride
BMW E92 335i n55 DCT
Hello guys!

In 2 words:
We swapped to 335i (n55 dct 2.56 differential) differential from m3 with 3.15. And now have errors with ABS and DCT.
Did anyone found the solution for ratios in m3 diff or in DCT(DKG) software? Ore maybe you know Where we could find custom diff ratios for E92 M3?

Unfortunately I can’t find anything similar here :(
 

LMB335is

Sergeant
Apr 12, 2017
286
186
0
FOB FL
Ride
13 335is
Hello guys!

In 2 words:
We swapped to 335i (n55 dct 2.56 differential) differential from m3 with 3.15. And now have errors with ABS and DCT.
Did anyone found the solution for ratios in m3 diff or in DCT(DKG) software? Ore maybe you know Where we could find custom diff ratios for E92 M3?

Unfortunately I can’t find anything similar here :(

Do you mean you swapped to the M3 3.15 diff from the stock DCT 2.56 diff?
 

LMB335is

Sergeant
Apr 12, 2017
286
186
0
FOB FL
Ride
13 335is
You're going to get those errors on the non M DCT. The percent difference between the 2.56 and 3.15 is too large and is interpreted as clutch slippage by the DME/TCU. There are other ratios available you just have to do some hunting. I'm having a 2.81 installed in my M3 diff as I type this. A 2.65 (super rare) and 2.93 are also available. These all come from 90's era V8 BMWs generally, like the 2.81 I found is from a 850ci manual car. Any ring gear from a large case 210mm diff will work in the M3 diff. Try this place http://racingdiffs.com/index.php/en/ and there's a couple more in the UK I believe.
https://www.ebay.com/itm/Used-E-BMW...ash=item3d1cf01af8:g:B7cAAOSwuhhXWv0G&vxp=mtr
 
Last edited:

BMWJunkie

Private
Dec 25, 2016
37
30
0
Finally someone else the support my finding.

I had this issue in 2013 and we had to swap the final drive ratio on the m3 diff down to a 2.81 gearset to get the car to drive correctly.

You can use this to "yellow box" spoof the correct wheel speed per gear and the car should drive correctly
https://yellr.com/

The other option is to convert to the m3 gws and dct software.

I must say though that the 3.15 ratio is too aggressive for anything over 450-500hp