[aacabriolet]

Hi All

Would appreciate some help as I'm tearing my hair out.

Background:
Recently got BM3 Stage 2 tune with a FBO 435i. (Running Map 2 on Stage 2 Multimap).
Mileage: still low +-50,000km.
Mods: FBO (Charge pipe, IC, DP).

Test conditions:
Car in Sport+, Shifter in S, manually shifting with paddles.
WOT 3rd, 4th, 5th gear pulls from around 3k rpm.

Problem:
Everything was fine before, but more recently got xHP Stage 3 (the latest version v3.9), all settings left on default, but I experience intermittent shift bogs from gears 3-4, 4-5, 5-6 under higher load situations (i.e. not downhill etc)

When I shift from 3rd and up, a lot of the time I get a bog down where the car hesitates for 0.5 seconds before going again, almost like it lurches back a bit before carrying on, instead of lurching forward like I would expect it.

I then played around with the "Tq Reduction on upshift" setting and increased the Tq Reduction to +20% on shifts 3-4, 4-5, 5-6 etc. but it didn't help.

Then I flashed it again with Tq Reduction on -20% for those gear shifts, I initially thought this fixed it, but in fact it is still doing it after more testing.

xHP Adaptations/clutch charge times/pressures are all perfect.

Would appreciate it if you are able to shed any light on the situation.

I will also be flashing back to xHP stage 2 and doing some more testing over a longer term to see if this fixes it, but I would like to run the Stage 3.

See data logs below.

Data Logs:
I managed to get some data logs earlier of when this is occurring. Not sure if you can see anything there apart from some sub-par fuel we have here.

3-4 bog - https://www.bootmod3.net/log?id=64ae...90c6c2cc6ad980

3-4 bog 2 - https://www.bootmod3.net/log?id=64ae...729b2694efc18c

3-4 and 4-5 bog (came off gas shortly after the bog) - https://www.bootmod3.net/log?id=64ae...0b43aa72e64867

Do these Torque at Clutch (Actual) vs Target value normal to you?



Thanks for any advice.

[aacabriolet]

Could a sluggish wastegate actuator (EWG) cause this? Not reducing boost/tq quick enough on shifts. Reason I ask is I had a shadow code there before I tuned BM3 but didn’t take much notice of it. Code never came up again though.

Something along the lines of sluggish wastegate. Possibly this one - 123511 - Electric wastegate, wastegate flap: sluggish.

Anything in the logs suggest wastegate issues to you guys? Slow to build boost/slow to release boost when shifting?

[n55david]

#1 put the tq reduction back to the normal settings.. don't mess with that if you don't know what you're doing.. one way actually makes the car slower on shifts and the other while making it faster put huge stress on the trans.

I'll check out your logs when I get home.

[thejeremyman9]

I looked briefly at the logs for anything obvious, didnt see anything. boost holds, throttle stays open, and timing sucks overall but doesnt do anything strange that i saw.

You probably want to go to XHP stage 1 or 2 anyways - yunno the whole discussion from pure drivetrain - so i would try stage 2 XHP with completely OTS settings as a first step. If it still happens then stage 1. If it still happens then remove XHP.

[aacabriolet]

Originally Posted by thejeremyman9

I looked briefly at the logs for anything obvious, didnt see anything. boost holds, throttle stays open, and timing sucks overall but doesnt do anything strange that i saw.

You probably want to go to XHP stage 1 or 2 anyways - yunno the whole discussion from pure drivetrain - so i would try stage 2 XHP with completely OTS settings as a first step. If it still happens then stage 1. If it still happens then remove XHP.

thejeremyman9 n55david

Thanks guys, appreciate the time to look into it and the advice.

I was only changing those settings based on advice from xHP themselves to try - and + and see if it helped.

They also advised me to test with Stage 2 which I will do. Have a dealer license so have to wait to get it done at my dealer and flash it and test it properly.

Thanks

[AmuroRay]

Could be transmission/throttle adaptations. Based on how you drove since it was flashed last.

It happened to me in my E90 when I tuned the car (it was a 6mt) If I drove it erratically (WOT to sudden slowdown) the car learned the throttle behavior and drove wonky.

[aacabriolet]

Had a couple of people tell me this is normal Tq Reduction what I’m feeling. And if I shift at redline (more like 6500rpm) then I won’t feel it.. will give it a shot. If this is true I guess the only explanation is because xHP Stage 3 is shifting so much quicker, the tq reduction is much more noticeable.

[thejeremyman9]

Originally Posted by aacabriolet

Had a couple of people tell me this is normal Tq Reduction what I’m feeling. And if I shift at redline (more like 6500rpm) then I won’t feel it.. will give it a shot. If this is true I guess the only explanation is because xHP Stage 3 is shifting so much quicker, the tq reduction is much more noticeable.

I drove stage 3 for like 2 years before i went down to stage 2 and never had any problems, if anything the car maintained power better on shift because the shift was improved. But anyways just try stage 2 tune and see what happens

[aacabriolet]

Originally Posted by thejeremyman9

I drove stage 3 for like 2 years before i went down to stage 2 and never had any problems, if anything the car maintained power better on shift because the shift was improved. But anyways just try stage 2 tune and see what happens

Great will do so, probably end up sticking on stage 2 then!

But will test and update