TunerPro Rear Axle Ratio adjusting

  • Login or Register, members don't see Ads!
  • Tip: You can toggle the Dark Theme at the bottom of the page

General.Massacre

Specialist
May 14, 2018
59
Hi Guys.

i may be overshooting my experience and knowledge here.

But its known that the N54 DCT diff is 2.56.
the E92 M3 DCT diff is 3.15.

Im busy reading up on a IKM0S conversion, and one of the points was that the diff ratio must be updated to suit the desired application, due to the 1M only coming in Manual.
Rear Axle Ratio.png


I know fitting the M3 DCT Diff to the N54 335i DCT causes a world of issues with shifting and running, but if the Tuner Pro Table attached is assigned to read 3.15, wouldnt this then tell the ecu and TCU that the ratio will be acceptable, and allow us to fit the M3 DCT Diff into the 335i DCT and have LSD?

Forgive me if this has been discussed before, but couldnt find anything through searching.

Thank you
 

aus335iguy

Captain
Nov 18, 2017
1,040
Im pretty sure that that was tried before and didnt improve the shift behaviour. There’s wheelspeed information that goes from the DSC through to DME and other modules. It could be processed anywhere and then passed to the TCU which calculates how to engage clutches and what RPM needs to be demanded from the DME to match. It all needs to be taken into consideration so it works harmoniously. @NoQuarter ....
 
  • 1Like
Reactions: NoQuarter

General.Massacre

Specialist
May 14, 2018
59
interesting.
Thanks for the response Aus,
ive also just noted that the DCT tables for the Base Correction/Speed factors etc fromt he Throttle Sensitivity thread are in the negative values for the DCT parameters, then again, the XDF was for the IJE0S ROM, so im not sure it matches back to IKM0S?

Im pretty prepared now to flash my MSD81 via WinKFP in readiness to load IKM0S, but now im unsure about tables such as Base Correction - Vehicle Speed (DCT), as this reads cells showing -500.
and the Base Correction (DCT) table is also negative values.

So i still have a bit to read on this. i know youve done the IKM0S, but havent seen any info. did you encounter this, or will i be safe to just leave these tables.
 

aus335iguy

Captain
Nov 18, 2017
1,040
I’ve wanted to but haven’t attempted ikmos. @RSL has though, and per another thread encountered an issue. @PeterY was the one that published the throttle tables and the Ikmos stuff. These guys are best placed to help as well as @jyamona
 
Last edited:

General.Massacre

Specialist
May 14, 2018
59
Excellent thanks a mil.
I did start a private convo with JYamona, will see when he responds, hopefully here for all to see. but appreciate your response Aus.
 

RSL

Sergeant
Aug 11, 2017
398
Those tables are MT. There are undefined gears/FD tables separate for AT/DCT that effect things on the DME side. TCU side is TCU side and currently can't be altered from stock.

Getting IKM0S flashed in a 3 series DME is a whole other story. I've been asking Jake for some time. I'm almost positive you can swap in an MSD81 from a 135 (or directly from a 1M), rekey CAS, flash IKM0S, disable variant checks and go. Flashing to an MSD81 originally from a 3 is what seems problematic, I believe because non-volatile areas always indicate it's a 3 and will not recognize any 1 series bin as a proper rom. Those checks need to be disabled or the DME could potentially be told (written) that it's originally a 135 or 1M instead of a 335 to avoid DME swap/rekey.

Pete's is a good write up, but that factory ZB number on the DME is from a 135, which I believe is the only reason it works on his. Additionally, his must be an MT or those publicly defined tables wouldn't do anything. IKM0S does have DCT tables, gears, etc. in it already. You probably need a variable set to tell it there's a DCT in the car to read them since there's no factory option for DCT on 1M. I'm not sure where the tranny type variable is normally picked up from. I'd think VO, but that would be way too easy lol

IKM0S rom doesn't align with any other XDFs. -500 is some other value conversion from an incorrect address for the that table. Pedal factor tables might be -1 to 1 (or 0.996) IIRC. Those tables would need to be defined for their correct IKM0S addresses in the XDF if they're aren't already. Looking at IKM0S in anything other than an IKM0S specific XDF will not be the tables/values the XDF says they are.
 

General.Massacre

Specialist
May 14, 2018
59
Thank you so much for this key bit of info.
Funny enough I actually found and read your thread posts on other threads stating the same. And found myself trying to research the key differences that would define whether the MSD81 belongs to a 1 series or 3series but came up empty.

Short of looking for a second ECU I'll keep researching or at the very least got the INA0S route instead. But will keep my searching going.
 

General.Massacre

Specialist
May 14, 2018
59
Im pretty sure that that was tried before and didnt improve the shift behaviour. There’s wheelspeed information that goes from the DSC through to DME and other modules. It could be processed anywhere and then passed to the TCU which calculates how to engage clutches and what RPM needs to be demanded from the DME to match. It all needs to be taken into consideration so it works harmoniously. @NoQuarter ....
Aus, your application of the custom IKM0S ROM, I assume jyamona assisted in porting over the relevant requirements?

My route will be to load the IKM0S BEF with JB4 soon as i have the WinKFP flash done.
I have already pre-prepared my IKM0S BEF from the BMS packages with regards to the Rear axle ratio and the required check toggles as pointed out by PeteY.

Do you reckon it would still be the same principle?
 

General.Massacre

Specialist
May 14, 2018
59
I got this bit of info from another person in SA that does ECU repairs and coding. He unfortunately says he cant assist as he doesnt do work for the private sector he says.

But here is what he says.
"Morning. Theres an FSC code loaded on the 1M dme as well in order to enable the map to run. Thats always been the biggest challenge in swopping out 1M dmes, as the repair FSC code needs to be loaded as well. Its not just a power class thing
FSC codes are linked to the VIN of the car. Youre better off just doing a tune on the existing software, than trying to get a 1M flash to work on a non 1M."

Any of you gents can add to this or provide anything back on what I was told here?
 

doublespaces

Administrator
Oct 18, 2016
8,009
AZ
I know fitting the M3 DCT Diff to the N54 335i DCT causes a world of issues with shifting and running, but if the Tuner Pro Table attached is assigned to read 3.15, wouldnt this then tell the ecu and TCU that the ratio will be acceptable, and allow us to fit the M3 DCT Diff into the 335i DCT and have LSD?
I know a little bit of information about this actually. Not really my place to say but I can tell you that @aus335iguy is right, more is needed to make this work.
 

General.Massacre

Specialist
May 14, 2018
59
I know a little bit of information about this actually. Not really my place to say but I can tell you that @aus335iguy is right, more is needed to make this work.
Thanks bud.
I know alot of info has been recently asked about this. But I'm trying to learn as much as I can.
In south africa we dont have alot of people that know this stuff, so I'm teaching myself. And just need a few nudges in the right direction.

Another thing @aus335iguy, did you feel any positive difference moving over to IKM0S?

I'm still with JB4, so as stated above I'd be using the IKM0S BEF once coded up and upgraded
 

aus335iguy

Captain
Nov 18, 2017
1,040
As i said before I haven’t got an IKMOS rom. Never have and unless something changes probably never will.
I run IJAOS. I wouldn’t use a JB4 on a DCT car either. Not that it wont work its just harder.
We’re talking at crossed purposes here anyway. final drive change on a DCT car is more involved than just the DME its only part of it. Read through the recent discussion with NoQuarter for more information but the DSC, KOMBI, TCU and others may or may not have something to contribute how wheel speed and the clutch packs interrelate.
 

General.Massacre

Specialist
May 14, 2018
59
Thank you guys.
You can close off this thread, or maybe split the IKM0S posts to an IKM0S related thread if possible, or should i start a new one?
 

jyamona

Captain
Platinum Vendor
Nov 7, 2016
1,079
Philly
Rear axle ratio tables in the DME are only used to calculate when the shift indicator should appear on the dash. There is no fix on the TCU side unless it is flashed or you spoof the wheel speed CAN msgs going to it in order to make it line up with it's expected values.

As for running IKM0S bin on ANY msd81 DME, this is a service I offer. I make a custom MHd build which patches the required bits automatically at flash time. It does not matter if the DME is from a 1 or 3 series vehicle.

@RSL I apologize I never got that for you. I can do it today. PM me last 7 of your VIN and email.
 
  • 1Like
Reactions: RSL

General.Massacre

Specialist
May 14, 2018
59
Rear axle ratio tables in the DME are only used to calculate when the shift indicator should appear on the dash. There is no fix on the TCU side unless it is flashed or you spoof the wheel speed CAN msgs going to it in order to make it line up with it's expected values.

As for running IKM0S bin on ANY msd81 DME, this is a service I offer. I make a custom MHd build which patches the required bits automatically at flash time. It does not matter if the DME is from a 1 or 3 series vehicle.

@RSL I apologize I never got that for you. I can do it today. PM me last 7 of your VIN and email.
Hi jyamona,
Thank you thats great info, i have started a conversation with you via PM, would be great to know more if we can get to it, i know you're a very busy man right now.

Look forward to chatting further.
 

Create an account or login to comment

You must be a member in order to leave a comment

Create account

Create an account on our community. It's easy!

Log in

Already have an account? Log in here.

Top