[widetyres]

Originally Posted by David.m

I've had the BMS clutch stop in since day 1, 2 shims.
oem clutch as there isn't anything for rhd

I also had BMS clutch stop since day 1 (as I removed it from my previous car and put it straight on the M2 when I bought it - why BMW can't sort this straight from the factory is a mystery!)

I did not have the lag issue though, that appeared when I updated from the car's original ISTEP (dated 2015), to a post LCI ISTEP (dated 2018).

Funnily enough I did post about the issue back then, but it didn't really go anywhere - perhaps that is the post that Nezil is referring to in the very first post in this thread.

[lemetier]

Originally Posted by Nezil

Thanks widetyres for alerting me to the updates...

I have a copy of ISTA+ and E-Sys. I also have updated my I-Step myself a few months back (using E-Sys). My car is a 2018 LCI N55 and it had some updates shortly after purchase because of the dash recall. When I updated the I-Step, E-Sys calculates the modules that need updating and DME was not one of them. I can't remember what was now, but DME certainly wasn't.

I agree that this does sound like it's something that might work.

Technically the Wastegate doesn't stay open for 2 seconds, it actually stays at either 80% or at the point it was at before the shift. It also isn't open for 2 seconds following pedal tip-in, it's for 2 seconds following pedal lift off. Nevertheless it's certainly something to try.

The issue I'm having is that going all through ISTA+, I cannot find any information on this calibration ration. I searched the ISTA+ pages for information on manual gearbox and DME replacement and those don't mention it, and then did a text search for 'Teach In', which showed some results for DCT, but not for manual.

Can you elaborate on this? I have Euro MDM and M2GTS coding for DSC currently. I cannot say what difference each setting made because I did them both at the same time. I know that when I had M4GTS coded it would allow a lot of slip, but would also result in DSC activations around tight corners like freeway on ramps at pretty low speed. M2GTS doesn't have that issue, and just allows a nice amount of slip. I've not tried US MDM + M2GTS; are you suggesting that would be better?

Are you also suggesting that Euro MDM may allow more slip as we've found, but also has some other side effects?

Thanks for your help by the way lemetier.

I'll elaborate more but ask you to try something before I do.

If you don't mind giving this a shot:

- Code GHAS and anything else changed to M2GTS back to M2 Std.

- Scan for faults with ISTA, clear if any. Find and copy event log file to a familiar folder. This is über important. If you're unsure which one, locate the program data folder and search for the text file using these keywords (fault, implausible, ignored, test, bogus, cross, your, fingers, brick, car).

- Road Test and Log with:

- DSC off
- Throttle Sport and no pedal multiplier mapping added (pedal position equal to torque request)
- If burble map applied, disable.
- Speed 65 mph at start if possible but above 62mph and below 124mph
- Engine speed between 2500-5500
- WOT before and after gear change
- Gears 2-5 as needed to meet the conditions above.

- Share results

[Nick2016M2]

There's been some comments about behavior post-flashing. I bought my 2016 M2 brand new. It is stock and always has been. I have the lag.

[widetyres]

Originally Posted by lemetier

I'll elaborate more but ask you to try something before I do.

If you don't mind giving this a shot:

- Code GHAS and anything else changed to M2GTS back to M2 Std.

- Scan for faults with ISTA, clear if any. Find and copy event log file to a familiar folder. This is über important. If you're unsure which one, locate the program data folder and search for the text file using these keywords (fault, implausible, ignored, test, bogus, cross, your, fingers, brick, car).

- Road Test and Log with:

- DSC off
- Throttle Sport and no pedal multiplier mapping added (pedal position equal to torque request)
- If burble map applied, disable.
- Speed 65 mph at start if possible but above 62mph and below 124mph
- Engine speed between 2500-5500
- WOT before and after gear change
- Gears 2-5 as needed to meet the conditions above.

- Share results

Hi,
Re the logging, are you after logs from ISTA or Bootmod3?
Cheers.

[lemetier]

Originally Posted by widetyres

Hi,
Re the logging, are you after logs from ISTA or Bootmod3?
Cheers.

BM3 is fine for now. It's a PITA to datalog from Bootleg ISTA. Have you also been running M2GTS coding?

[lemetier]

Originally Posted by widetyres

I've been running F82GTS coding. But that was done quite a while after the lag w felt. I did however change the eps to F87CS around that time.

I cleared my fault logs the other day when doing the gear sensor service function. I'll put everything back to stock and report back.

Thanks.

What's visible is interesting, and I guarantee what's not shown on the back end is even more so.

F82GTS has its own set of issues but shares one thing in common with M2GTS (M2Racing Club Sport Variant):

DCT load-reversal dampening, which I suspected earlier.

[Nezil]

Originally Posted by lemetier

What's visible is interesting, and I guarantee what's not shown on the back end is even more so.

F82GTS has its own set of issues but shares one thing in common with M2GTS (M2Racing Club Sport Variant):

DCT load-reversal dampening, which I suspected earlier.

So would I be correct in understanding that if you set M2GTS, and don't have DCT, you'll get an implausibility error?

This error could be benign, or could have an impact on other things drivetrain related.

[widetyres]

Originally Posted by Nick2016M2

There's been some comments about behavior post-flashing. I bought my 2016 M2 brand new. It is stock and always has been. I have the lag.

I agree that it's always been there, it was just more pronounced/noticeable for me after an ISTEP update.

[widetyres]

Originally Posted by Nezil

So would I be correct in understanding that if you set M2GTS, and don't have DCT, you'll get an implausibility error?

This error could be benign, or could have an impact on other things drivetrain related.

I went for a drive the day after the previous fault code reset (whilst the car was still running F82GTS coding). Overall, it was a bit better, but the lag was still felt in some gear changes, but less so in others, but overall I perceived it was less laggy, so I believe the error codes were having some impact, but lemetier will be able to confirm. The log for that journey (which I won’t bore you with as it’s quite long) showed the same, with the wastegate closing quickly sometimes, but more slowly on other shifts (more commonly).

After this drive (which I really enjoyed BTW down some great roads), the error log was empty.

@Lemetier: Please can you let us know the situation that causes the load reversal dampening, and which module is responsible for this protection function? (we can then avoid coding that in future). Thanks.

[widetyres]

Originally Posted by lemetier

- Share results

Just went and did the logs.

I put my car back completely back to standard M2/F087 coding. After doing this, I immediately (without driving) got the two “regulated differential lock” errors, which I cleared.

From what I can see from the logsm they confirm Nezil’s findings. Apart from the time that I overcooked the revs (and the engine held boost between shifts), the pattern when shifting below 5.5K seems to be:

1) On gear change, DV dumps boost.
2) On release of clutch, the wastegate closes completely, but only momentarily.
3) The wastegate then opens as the throttle goes down, even though the boost is below target, thereby delaying boost build up.

lemetier: I will send you the logs directly.

What do you reckon is happening?

Thanks.

[Dasnub]

Noticed this comment in another thread and curious what effect it would have for this application. Any thoughts?

“ Coding, "Start engine without clutch" switches off auto rev-matching in all modes..

Be aware, it kills the clutch position sensor and any related features that depends on this sensor for data, which includes but is not limited to; anti-stall, hill hold (to cancel with the clutch pedal), one push start button, ect..”

[DroneandDone]

I'm still hoping for an answer to what Euro MDM does.

[lemetier]

Originally Posted by DroneandDone

I'm still hoping for an answer to what Euro MDM does.

Changes the TPMS settings for indicating when to activate the tell-tale warning for low tire pressure.

[lemetier]

Originally Posted by widetyres

Just went and did the logs.

I put my car back completely back to standard M2/F087 coding. After doing this, I immediately (without driving) got the two "regulated differential lock" errors, which I cleared.

From what I can see from the logsm they confirm Nezil's findings. Apart from the time that I overcooked the revs (and the engine held boost between shifts), the pattern when shifting below 5.5K seems to be:

1) On gear change, DV dumps boost.
2) On release of clutch, the wastegate closes completely, but only momentarily.
3) The wastegate then opens as the throttle goes down, even though the boost is below target, thereby delaying boost build up.

lemetier: I will send you the logs directly.

What do you reckon is happening?

Thanks.

We'll discuss. I'm seeing something consistent from the BM3 logs. From the ISTA event logs, to put things in perspective:

- 9 indexed faults are displayed
- 3 indexed faults are not displayed
- I stopped counting at 100 un-indexed faults that are not displayed.

[widetyres]

Originally Posted by lemetier

We'll discuss. I'm seeing something consistent from the BM3 logs. From the ISTA event logs, to put things in perspective:

- 9 indexed faults are displayed
- 3 indexed faults are not displayed
- I stopped counting at 100 un-indexed faults that are not displayed.

For the benefit of others, here is an extract from the log in question:

[Bee Pee]

Vlogger with MT M2 commented lag felt much less post install of TS DV & MST inlet pipe and FTP rigid TIP.....

[mr_lab_rat]

Originally Posted by Bee Pee

Vlogger with MT M2 commented lag felt much less post install of TS DV & MST inlet pipe and FTP rigid TIP.....

That's pretty cool but it's a heavily modified car. Nezil has an upgraded DV and is experiencing the issue. I'm completely stock and sometimes I feel it too. I'm currently working on improving shifting. So far I did the UCP, next is CDV removal, Turner rear bushing, and possibly whole different shifter.

After that I'll look into DV. I already bought GFB DV+ but I'll look at Turbo Smart before going through the trouble of installing it.

Thanks for sharing this.

[Nezil]

I think I also reported less lag after installing the GFB diverter valve. Having said that, it wasn’t less lag between shifts, it was less lag when going on and off throttle in the same gear.

The software induced lag is only between shifts, and diverter valve upgrade cannot fix that I don’t think.

[lemetier]

Poll time:

How many of you experiencing excessive "lag" have disabled/removed exhaust flaps?

[Dasnub]

Originally Posted by lemetier

Poll time:

How many of you experiencing excessive "lag" have disabled/removed exhaust flaps?

I have lag, no changes to flaps.

[Nezil]

Originally Posted by Dasnub

I have lag, no changes to flaps.

I have lag, no changes to flaps that I'm aware of... tune might have software changes but I had lag with the stock map as well.

[David.m]

I have the exhaust flap fuse removed (so flap locked open). I've had 3 track days in the last 6 weeks, the most recent after getting a BM3 custom tune which didn't affect this issue. Whether I get the lag or not on wot shifts seems to be consistently related to shift speed.

Deliberate/quick shifts (Auto Solutions SSK 20%, stock clutch) never result in lag but if I'm just a little casual the lag returns. It's not the perfect situation though does make me more focussed when going hard!