Discussion about issues encountered whilst converting to M3 Flash and GWS

[aus335iguy]

How much did you spend on m3 components? Did you pick up entire rear end (subframe, axles, diff, hubs, etc?).


@aus335iguy thank you for all the research! I am still confused why DSC is our suspect; is transmission thinking it is slipping and triggering traction issues?



I drove the car 20 or so miles. If I am light on throttle it seems to do OK but does not like shifting at all. I might be able to drive to work in it, really don’t want to go to stock IS GWS.

I’m thinking that the wheelspeed is what the TCU uses to calculate/ derive (I have another theory) output shaft speed and so there may be some work to be done in that regard when you change final drive. Also m drive is likely dependant on the DSC from m3

 

[LMB335is]

Looked through the DSC trace from the M3 and one setting "M3 Construction"would be interesting to look at in 'Dummy to see what the variants are...
RPA
not active
MSA
active
M3_ CONSTRUCTION
wert_05
M3_ GEARBOX
wert_01
M3_UEBER TAX_MUE_0
wert_01
M3_UEBER TAX_MUE_1_2
wert_01
MDYNAMIC_MODE_USA
active
M3_PRE_MSR
not active
STEERING ANGLE CHANNEL
wert_00
LAT_EBD
active
US_VEHICLE
not active
POHO
not active
DDS_PLUS
not active
TURN OFF BARENCE _DSC
active
PRINT MODEL_HA
wert_00
PRINT MODEL_VA
wert_00

Use Dummy with MK60_M3.C08 and the TRC I posted. It's pretty easy to figure out what all the parameters mean, especially since there's so few of them in these modules. RPA is tire pressure. US VEHICLE and MDYNAMIC MODE are for Euro MDM, all the steering settings relate to E90, 92, 93 and if it's US or not and Comp/GTS. There's only a couple I'm not sure about,

 

[LMB335is]

So to be clear the reason your choosing that ratio is because it’s been known to be tolerated by both m3 and 335is?

That, and it's a happy medium speed/rpm wise. The last thing I need is a lower gear coming off the line. I can light them up in third now, I can't imagine what effect a 3.15 would have. I don't mind a little lower gear and a 2.65 would be another possibility but I think it's harder to source. I've spent hrs lately on realOEM and researching diff case size and gearing to find out exactly what cars these ratios were on. Lets just say all are at least 15 yrs ago and most of them 20 or more.

 

[derekgates]

That, and it's a happy medium speed/rpm wise. The last thing I need is a lower gear coming off the line. I can light them up in third now, I can't imagine what effect a 3.15 would have. I don't mind a little lower gear and a 2.65 would be another possibility but I think it's harder to source. I've spent hrs lately on realOEM and researching diff case size and gearing to find out exactly what cars these ratios were on. Lets just say all are at least 15 yrs ago and most of them 20 or more.

Wow. I looked up the E31 confused what that was; the 8 series?!!! That’s a pretty rare care to find parts from.

I’m very interested in fixing my FD ratio, the M GWS makes the car amazing. I haven’t found much in the way of used M3 drivetrain though. What I’ve found is a subframe for $300, diff for $999 and that leaves many more components to replace.

 

[RSL]

I'll be anxious to see what the DSC swap does, I'm banking on that being a key factor.

@LMB335is, still running with e-diff and other nannies disabled (just to rule them out)?

You can more or less throw an M around more with DTC fully on than you can a non-M with it "fully" off. It's much less intrusive, so I'm hoping it's just seeing off sensor inputs (or calculated outputs) and the non-M DSC is triggering reductions where they might fly under the radar on the M DSC.

I ordered connectors today since I had to grab some other stuff, but kinda slowed my pace with jumping on this until it's been verified things work smoothly without a diff swap.

 

[LMB335is]

Wow. I looked up the E31 confused what that was; the 8 series?!!! That’s a pretty rare care to find parts from.

I’m very interested in fixing my FD ratio, the M GWS makes the car amazing. I haven’t found much in the way of used M3 drivetrain though. What I’ve found is a subframe for $300, diff for $999 and that leaves many more components to replace.

Wow. I looked up the E31 confused what that was; the 8 series?!!! That’s a pretty rare care to find parts from.

I’m very interested in fixing my FD ratio, the M GWS makes the car amazing. I haven’t found much in the way of used M3 drivetrain though. What I’ve found is a subframe for $300, diff for $999 and that leaves many more components to replace.

You can find a 2.81 in E34 540 diffs as well, pretty common and cheap.

I got lucky and was able to piece mine together from 13k and 30k mile M3's for under $1k total about a month ago. Parts seem scarce on Ebay right now. You just need the DCT driveshaft, diff, and axles. I went ahead and bought all the hardware I might need and the M3 trans output flange so I wouldn't need to chop up my 335is drivetrain as well.

 

[aus335iguy]

Got a text from @juld0zer. He suggested that we could try disconnecting wheel speed sensors. This will of course get the DSC knickers in a twist BUT it will still rive and will take shaft speed calculation out the equation as well. It may require all 4 sensors to be disconnected as road speed and therefore expected shaft speed could be calculated from just one valid sensor.

Thoughts ?

 

[LMB335is]

I'll be anxious to see what the DSC swap does, I'm banking on that being a key factor.

@LMB335is, still running with e-diff and other nannies disabled (just to rule them out)?

You can more or less throw an M around more with DTC fully on than you can a non-M with it "fully" off. It's much less intrusive, so I'm hoping it's just seeing off sensor inputs (or calculated outputs) and the non-M DSC is triggering reductions where they might fly under the radar on the M DSC.

I ordered connectors today since I had to grab some other stuff, but kinda slowed my pace with jumping on this until it's been verified things work smoothly without a diff swap.

I turned all the nannies back on a while ago. I wasn't tracking the car so I was probably better off with them on. I agree with you on the M DSC especially in comparison to the non M DSC. Just a look at the parameters between the two and you can see at least twice as many controls or functions in the non M module. I just coded Euro MDM in for a guy last week and he said it made a huge difference in being to hang out the car and that's just a simple MDYNAMIC_MODE_US and US_VEHICLE changed to nicht aktiv.

 

[RSL]

I turned all the nannies back on a while ago. I wasn't tracking the car so I was probably better off with them on. I agree with you on the M DSC especially in comparison to the non M DSC. Just a look at the parameters between the two and you can see at least twice as many controls or functions in the non M module. I just coded Euro MDM in for a guy last week and he said it made a huge difference in being to hang out the car and that's just a simple MDYNAMIC_MODE_US and US_VEHICLE changed to nicht aktiv.

M DSC also has 3 operating modes IIRC (0,1,2) where non-M has 2 (0,1). I remember the data/equations in the M DSC module were significantly different for calculating slip.

I know someone here mentioned trying an M DSC bin on the non-M DSC (you?), was that ever done? Different P/Ns on the units themselves, but they use the same speed sensors.

335is DSC: http://www.realoem.com/bmw/enUS/showparts?id=KG13-USA-06-2013-E92N-BMW-335is&diagId=34_1695
M3 DSC: http://www.realoem.com/bmw/enUS/showparts?id=KG93-USA-05-2010-E92N-BMW-M3&diagId=34_1695

 

[dyezak]

I was going to do the flashy thingy. But I haven't been able to find the M3 DSC ZB # so I haven't tried it. If someone was to give it to me I'd give it a shot.

 

[LMB335is]

I was going to do the flashy thingy. But I haven't been able to find the M3 DSC ZB # so I haven't tried it. If someone was to give it to me I'd give it a shot.

It's 7846816 and the 1M is 7846411. The problem is when you pull up your module, DSC90, neither one is there to chose from. You might be able to do it in Expert mode but I don't know enough about WinKFP to say for sure. You could try flashing it by choosing DSCM90 as your module and see if WinKFP has a meltdown.

 

[RSL]

I was going to do the flashy thingy. But I haven't been able to find the M3 DSC ZB # so I haven't tried it. If someone was to give it to me I'd give it a shot.

Heading to work in a minute, but if no one has located one by then, I'll dig when I get home tonight. Thanks for offering to test it.

EDIT: ninja post. With WinKFP, you can enter or select the ZB manually. If there is different firmware on the M DSC or something, it may outright decline installing. If it does flash, reset to defaults after and then see what we've got.

 

[dyezak]

I'll look into the DSC flash in a bit.

On a different note I did find a driveshaft shop locally that will shorten my driveshaft with a 1d turnaround. I'll do the diff swap on Saturday and take them the driveshaft on Monday. I'll pick it up on Tuesday and finish the install the following weekend. So I should have a working M3 Diff swap in 10d or so.

 

[dyezak]

Just an interim step. My current ZB on my DSC is so old it's not even in my Daten files. I'm just updating it right now to the newest correct ZB and will test everything out, then I'll try the M3 ZB.

 

[dyezak]

Good news and bad news:

Bad: I just tried to update the ZB to the most recent version. Nothing fancy. Now my DSC module is completely non-operative. It responds to WinKFP still, NCS Expert, etc, no problem. The flash was successful...but I have all functions non-operable. Sigh...

The Good: I decided to take it for a test drive. Let me tell you this. DSC = OFF isn't nearly the same thing as no DSC at all. Holy shit. The car isn't fast...it's just scary. BUT! I wanted to check out the shifts and.......no change.

I don't think the DSC is contributing to the poor shifts after this test. I mean it wasn't how I planned to test things, but with a fully inoperable DSC it can't be telling the trans to do anything funky and slow down the 3+ shifts. It is something else.

Now off to try and fix my damn DSC....

EDIT: Looks like I need to calibrate it....hrmmm

 

[aus335iguy]

The part of the DSC that may be contributing to our problem is the wheel speed sensors. Wheelspeed data may still be getting through to the TCU and therefore anticipated output shaft speed derived. The only way to be completely sure and count out DSC is to disconnect all four sensors and see what it does.

 

[RSL]

Yeah, I did steering, lateral, etc. calibrations and then finally had to default code the module when I updated mine.

No telling if a missing parameter isn'the the same as a capped parameter and still not allowing it to shift right, but if you don't want to mess with it anymore, I don't blame you. If you ever hit the top torque limit cap on torque output, you'd see it just sits on torque limiter 1, kinda wondering if something similar is going on with DSC/TCU that we can't see.

 

[dyezak]

Well, I know for a fact that the DSC is limiting trans behavior now. I took it for another test drive and couldn't go into S6 mode and while in M mode the car auto shifts from 1st to 2nd at 2700rpm no matter what.

All this is with the DSC all fudged up. So the DSC is integral in the transmission operation....

 

[RSL]

Good deal, that's an indicator at least and I was so sure DSC was going to be huge part or all of it. Question now will still be just bin or whole unit + bin.

 

[dyezak]

I've never had luck with my INPA install. It's v5.000 and there were significant changes to 5.002 and 5.006. Instead of fudging with something I don't like (INPA) I'm getting ISTA+D installed to start using that. I have never had an issue with NCS Expert or WinFKP.