[Nezil]

Hi all. I've got quite a bit more information, but not much of an update I'm afraid.

I have been working with Halim @proTUNING Freaks, and initially things looked good. I do have a firmware that appeared to reduce the waste gate delay, but further testing shows that this might not have been the case.

To be clear, the issue that I'm trying to fix, is the ~1.0 seconds of additional lag after a shift if you're not really 100% 'on it'. One of the things that has pissed me off about the M2 since buying it, is that if you drive it at 10/10ths, really hard, red-lining and slamming shifts, there is no question that it's fast and there are few problems. As soon as you drive it at 7/10ths, maybe shifting at 5,500 rpm, or taking just over a second for a shift, all sorts of strange and undesirable behaviour occurs.

I've said it many times already, but just to re-iterate, I'm not expecting boost to be held between shifts, I'm not expecting 6MT to be able to shift as fast as DCT, and I'm not expecting no lag at all.

In my most recent email discussion with Halim, he mentioned something very interesting. He said that the DME has a 'feature' where if you're WOT and you let off briefly, either to tap the breaks, or to shift gear, you then only need 25% pedal travel for the motor to go back into WOT state again. I assume that there is some check to make sure that you actually did go back to 100% pedal travel, but I think the purpose is to improve perceived throttle response by anticipating your intent.

Anyway, Halim's point was that if you take a long time over a shift, you may drop out of this window while you're off throttle. He therefore suggested that I try shifting quicker. As stated earlier, this goes against what I was hoping to achieve. My normal fast shift speed is pretty consistently 1.4s off the pedal, but I can do shifts consistently at about 0.7s if needed. This wouldn't be a solution in my mind, but I captured some logs this way anyway.

What I found was that if the shift is quicker, the delay before the waste gate closes is longer, by almost exactly the same amount of time. If I make my shift 0.5s shorter, the waste gate closes 0.5s later! To state this another way, the waste gate closing delay is not changed or improved at all by shifting quicker.

It seems like the waste gate behaviour is gets disrupted for a fixed period of time which starts from when you come off the pedal for any reason. Once you're back on the pedal again, the waste gate goes to about 80% and stays there until this fixed period ends before resuming regular behaviour.

In the past, I had felt that the delayed waste gate closing might be in response to the DME seeing the clutch position change. I therefore took some logs with the clutch position sensor disconnected. You need it connected to start the car, but can then disconnect before logging. The results were identical - the clutch position is not what the DME is responding to.

My theory at this point, is based on what Halim said. I think that the DME behaviour that allows the motor to go back to WOT with only 25% pedal may be the cause. This 'anticipation' behaviour puts all of the motor controls back in a WOT state very quickly, but part of this is putting the waste gate either at the same position as it was before the lift, or at a pre-determined position, rather than 100% closed. After a period of time, the DME goes back to regular control, and the waste gate acts normally again.