Power lag during fast shifts (6 sp)

[91foxbody]

I'm fairly new to M3Post, but not to BMW's. I've owned 3 E36 M3's, an e92 328i, and a lot of old Mustangs. Coming from the Mustang world, I've learned to shift extremely quick, especially between 1-2 and 2-3. I've never had an issue in my E36's, but when doing quick shifts at WOT in my 6 speed E90, I often experience a significant drop in power. It's as if there is either A) clutch slip (not likely, the car only has 28k miles) or B) the car is intentionally retarding timing to drop power.

Has anyone else experienced anything like this?

[Joe S]

Maybe it's the traction control coming on to limit wheel spin during fast changes. Try to do this with DSC off ?? But be careful! Lol

[91foxbody]

Originally Posted by Joe S

Maybe it's the traction control coming on to limit wheel spin during fast changes. Try to do this with DSC off ?? But be careful! Lol

Not a bad idea. I'll give it a shot tonight on the way home and see what happens.

[dparm]

Does the E92 have a clutch-delay valve? I remember those from my Honda days.

[pshep138]

Originally Posted by dparm

Does the E92 have a clutch-delay valve? I remember those from my Honda days.

This was my idea. I believe the E46 M3 has one, because a lot of people delete it. Wouldn't be a stretch for the E9x to have one as well.

[RoundelObsession]

Originally Posted by dparm

Does the E92 have a clutch-delay valve? I remember those from my Honda days.

It has what looks like a clutch delay valve, but it is a non functioning piece.

[Lucrecio84]

I don't have that problem at all. Its most likely just your traction control kicking in

[IIAp3x]

Originally Posted by Lucrecio84

I don't have that problem at all. Its most likely just your traction control kicking in

That is exactly what it is for certain... And yes the e9x M3 has a clutch delay valve for sure, but I can still spin the wheels going from 1st to 2nd gear with the traction control off... With traction on, the 1st to 2nd shift at wot is very limited...

If you want a good intermediate that will allow you maintain full power with a nice little chirp into 2nd gear, rather than a full spin out, then use MDM mode...

This will let you maintain full power though the 1st to 2nd shift without getting too squirrely!!

I also find that a very calculated and precise shift is needed from 1st to 2nd at the red line point if you drive a manual like me... There is a split second of patience needed before pulling the knob back in order to get this right without missing second- and that is due to the clutch delay valve...

[kb9uwu]

I also have 6MT, it's the DSC!

[W///]

Originally Posted by IIAp3x

That is exactly what it is for certain... And yes the e9x M3 has a clutch delay valve for sure, but I can still spin the wheels going from 1st to 2nd gear with the traction control off... With traction on, the 1st to 2nd shift at wot is very limited...

If you want a good intermediate that will allow you maintain full power with a nice little chirp into 2nd gear, rather than a full spin out, then use MDM mode...

This will let you maintain full power though the 1st to 2nd shift without getting too squirrely!!

I also find that a very calculated and precise shift is needed from 1st to 2nd at the red line point if you drive a manual like me... There is a split second of patience needed before pulling the knob back in order to get this right without missing second- and that is due to the clutch delay valve...

Are you sure about that? I've always thought the E9x M did NOT.

[RoundelObsession]

Originally Posted by W///

Are you sure about that? I've always thought the E9x M did NOT.

It does not.

[pshep138]

Originally Posted by W///

Are you sure about that? I've always thought the E9x M did NOT.

Originally Posted by RoundelObsession

It does not.

Looks like you guys are right.

http://www.m3post.com/forums/showthread.php?t=153462

[IIAp3x]

Originally Posted by W///

Are you sure about that? I've always thought the E9x M did NOT.

I'm not 100% on that... I just assumed they maintained that because my e46 m3 had one, and I had it removed to help with rapid shifting on the track.. Sure feels like it though on the 1 to 2 shift at wot... I always rev match but the 1-2 shift is tricky at the redline.. No? Could be just the extremeness of 1st gear versus the synchro action that makes it feel that way... I always have to hesitate a split second before engaging into second because its very easy to miss at the redline..

Am I the only one who notices this?

For certain it is OP's traction control kicking in and causing his problem... Unless his clutch is slipping, which is unlikely at his miles...

[91foxbody]

I genuinely doubt it's the clutch slipping, and I do my absolute best to not "pop" the clutch enough to get wheel spin, but the Michelins are quite a bit more quiet than I'm used to....so undetected wheel spin could (and most likely is) the culprit.

Thanks for the opinions everyone!

[IIAp3x]

Originally Posted by 91foxbody

I genuinely doubt it's the clutch slipping, and I do my absolute best to not "pop" the clutch enough to get wheel spin, but the Michelins are quite a bit more quiet than I'm used to....so undetected wheel spin could (and most likely is) the culprit.

Thanks for the opinions everyone!

Try MDM mode and see how that feels... Should notice a huge difference...

[W///]

Originally Posted by IIAp3x

I'm not 100% on that... I just assumed they maintained that because my e46 m3 had one, and I had it removed to help with rapid shifting on the track.. Sure feels like it though on the 1 to 2 shift at wot... I always rev match but the 1-2 shift is tricky at the redline.. No? Could be just the extremeness of 1st gear versus the synchro action that makes it feel that way... I always have to hesitate a split second before engaging into second because its very easy to miss at the redline..

Am I the only one who notices this?

For certain it is OP's traction control kicking in and causing his problem... Unless his clutch is slipping, which is unlikely at his miles...

Correct, the E46 had it, but definitely not the E9x.

[IIAp3x]

Originally Posted by W///

Correct, the E46 had it, but definitely not the E9x.

Good to know... Cause I did not want one anyways...

[RoundelObsession]

Originally Posted by IIAp3x

Good to know... Cause I did not want one anyways...

You can remove the faux clutch delay valve if desired as well, you simply disconnect it and reconnect the lines, no additional parts needed.

[apecush]

what you are feeling is the dual mass flywheel compressing it's internal spring. it is the same reason you don't feel a harsh driveline shock when transitioning between accel and decel.

[Three Pedal Steve]

If you are truly power shifting (right foot does not lift during shift) you are probably hitting the rev limiter. Try the 1-2 power shift at 7900 to avoid hitting red line.

[M3Dimi]

Originally Posted by 91foxbody

I'm fairly new to M3Post, but not to BMW's. I've owned 3 E36 M3's, an e92 328i, and a lot of old Mustangs. Coming from the Mustang world, I've learned to shift extremely quick, especially between 1-2 and 2-3. I've never had an issue in my E36's, but when doing quick shifts at WOT in my 6 speed E90, I often experience a significant drop in power. It's as if there is either A) clutch slip (not likely, the car only has 28k miles) or B) the car is intentionally retarding timing to drop power.

Has anyone else experienced anything like this?

From what I noticed and I am new as well is that for it to get the full beans mode and not have it delay you have to rev first out all the way and shift at a very specific time on red line! (with traction control) I tried this with traction control on and the wheels still chirped but you definitely have to be more precise with traction control on otherwise you will loose power and have the delay.

[IIAp3x]

Originally Posted by Three Pedal Steve

If you are truly power shifting (right foot does not lift during shift) you are probably hitting the rev limiter. Try the 1-2 power shift at 7900 to avoid hitting red line.

May be on to something with this... I have noticed that the 1-2 is much easier around the 8k mark... I also notice that the power curve is flat after 7900 anyways so it does not really offer any gain shifting later, unless you are running a catless system with a tune... Mine is stock...