E92 6 Speed - sometimes feels "flat" at wide open throttle

[tomfraser]

Hi Guys,

Got an odd periodic issue with the M3 (6 speed, LCI)

Mostly it is fine, but sometimes if I am cruising along, usually in a lower gear like 3rd and punch it, the car feels flat, almost like the throttle butterflies are not opening fully (and definitely has less induction noise), then if I back off the accelerator and punch it again it is fine, accelerates normally (and has full induction noise)

Car is showing no codes, and I have lubricated the throttle linkages with PTFE lube.

Any ideas - early TA degradation or something else?

Cheers
Tom

[roastbeef]

When was the last time you changed your spark plugs and checked your air filter?

[Evolve Automotive]

Originally Posted by roastbeef

When was the last time you changed your spark plugs and checked your air filter?

+2

[tomfraser]

Air filter is new, spark plugs - not sure, have ordered some new ones for good measure and will swap them out. Will see if that fixes it.

[tomfraser]

Update - I have had the software flashed to latest integration level (was still at original 2010 ship integration) , and last weekend changed the spark plugs - so far all seems well!

[MMM3PWR]

higher miles I suggest new ignition coils , they won't throw codes if under threshold

[Powashiftin]

Originally Posted by tomfraser

Update - I have had the software flashed to latest integration level (was still at original 2010 ship integration) , and last weekend changed the spark plugs - so far all seems well!

Where did you get this done?

[tomfraser]

Originally Posted by MMM3PWR

higher miles I suggest new ignition coils , they won't throw codes if under threshold

Car has 56k miles - wouldn't think that would be high enough for new coils?

[tomfraser]

Originally Posted by Powashiftin

Where did you get this done?

Software - paid the dealer to do it, plugs, did it myself.

[Redd]

Get a BPM tune, then you'll really see what the S65 can do.

[BGBF18]

Originally Posted by Redd

Get a BPM tune, then you'll really see what the S65 can do.

Concur, BPM tune is a must, imho. Brings the car to life.

[loveskiing]

This problem seems to occur periodically with some cars...it's most likely a case of MTitis...and the only known remedy is DCT...

[Rajmun340]

You're getting a lot of bs answers. IMO, there's no need for a bpm tune -waste of money if you can drive the m3 which most 6MT owners can, different story for automatic dct owners. Seems either a TB problem, O2 sensor, or stupid adaptation part of the ECU. Is the engine running too rich AFR ? how do your tail pipes look like, are they very sooty ?
If it's not a part issue, the M3 engine definitively is not very consistent due to ECU adaptation. Unless you push it almost every drive, it will become lethargic it's all adaptation. I noticed it too, just run your lower gears longer and higher rpm without trying to accelerate too much. Doing that seems to wake up the ECU. If you never run your gears up and long, adaptation puts the response to sleep.

[Redd]

Why is a tune a waste of time 6MT but not DCT?

[Rajmun340]

Originally Posted by Redd

Why is a tune a waste of time 6MT but not DCT?

misquoted, not what i said. I compared 6MT owners / dct owners. Due to extra skills required to drive 6MT owners are usually better on average at extracting power and enjoying the car. dct owners are on average more 'challenged' and may need the tune to enjoy the car with their more limited and passive driving skills. That's a general trend, there are skilled dct drivers of course.

[tomfraser]

Ok, how did my thread get derailed to a DCT vs 6 Speed and then get a tune - anyway, took the car for a very spirited drive today, no issues at all (it was very noticeable) either the plugs or the software update definitely sorted it.

[Redd]

Originally Posted by JoeM3SSII

misquoted, not what i said. I compared 6MT owners / dct owners. Due to extra skills required to drive 6MT owners are usually better on average at extracting power and enjoying the car. dct owners are on average more 'challenged' and may need the tune to enjoy the car with their more limited and passive driving skills. That's a general trend, there are skilled dct drivers of course.

not trying to start an argument but with 6MT you have fewer gears, and the gaps between the gears are larger (fact, just check the ratios). this means that 6MT benefits more from a tune like BPM, which raises low and midrange torque figures, more so than DCT which has more gears to play with.

just my opinion. more power/torque never hurt anyone.

redd

[Rajmun340]

Originally Posted by Redd

not trying to start an argument but with 6MT you have fewer gears, and the gaps between the gears are larger (fact, just check the ratios). this means that 6MT benefits more from a tune like BPM, which raises low and midrange torque figures, more so than DCT which has more gears to play with.

just my opinion. more power/torque never hurt anyone.

redd

And your are simply wrong and late on the topic. Some of us went through that in 2008 to run full simulations for torque / acceleration curves / 0-60 time. The 6MT' 1st gear*FD is 3.3% shorter than the DCT 1st gear*FD Meaning, stock vs. stock the 6MT will pull with +3.3% more torque than the DCT in 1st gear, that's just facts. The high revving S65 8300 RPM can get you to 40 mph in 1st gear before upshifting. The 6MT will reach that speed first due to the extra torque at the wheels. On the 2nd gear*FD, the dct ratio is shorter than 6MT by 2% so it'll start evening out, but 2nd gear reaches 65 mph. So that on a 0-60 mph run 6MT is mechanically faster than the dct, the only way dct gets to be faster is by the 6MT loosing time over manual 2nd gear shifting.

That's a strict mechanical analysis. From the human perspective, The faster automated dualclutch shifts takes away driver involvement and suppresses the reward/penalty of doing 6MT manual gear shifts. 6MT drivers are forced to learn how to extract power because RPM can drop fast between gears if you don't learn which brings the fun to another level. dct naturally leads to passivity and you are more at risk to become jaded with the car and that is where the tune comes in for dct cars. So again, on average 6MT drivers are naturally expert at extracting top range power and having fun doing it they are less likely to feel the need for a tune.

Ultimately it's the fun factor that matters not which car is faster. Just like the F8x is faster but it's less fun IMO.

6MTFTW

[BGBF18]

Originally Posted by JoeM3SSII

You're getting a lot of bs answers. IMO, there's no need for a bpm tune -waste of money if you can drive the m3 which most 6MT owners can, different story for automatic dct owners. Seems either a TB problem, O2 sensor, or stupid adaptation part of the ECU. Is the engine running too rich AFR ? how do your tail pipes look like, are they very sooty ?
If it's not a part issue, the M3 engine definitively is not very consistent due to ECU adaptation. Unless you push it almost every drive, it will become lethargic it's all adaptation. I noticed it too, just run your lower gears longer and higher rpm without trying to accelerate too much. Doing that seems to wake up the ECU. If you never run your gears up and long, adaptation puts the response to sleep.

Interesting comment about adaptation. My experience with a tune was fairly black and white.

It certainly is personal preference regarding whether to tune or not. My particular M3 had a pronounced and unacceptable flat spot in perceivable torque from about 2000-2800 that made my 44 mile round trip urban commute painful with a manual tyranny.

I was constantly finding myself in a dead zone of low rpm and having to downshift excessively - the tune added a torque bump right in that range that allowed me acceptable acceleration in one higher gear in most cases. Overall, my commute became far more enjoyable, but it also allowed me to tweak the throttle to a sharper response which permits a more shallow and more natural depression of the throttle to nail smooth up and down shifts. In addition, it returns slightly better gas mileage, raised redline to 8600 and now pulls slightly harder top end.

Once, post tune, the dealer squirted OEM software (240E, I believe) without telling me and I noticed the difference immediately - and I was furious the entire drive home.

Is the tune worth $1000? Probably not, but for me it has returned measurable satisfaction. As an aside, I've driven 2 other 6MT M3s of varying years and they both felt the same and not as good as my tuned 2008 FWIW (which isn't much!).