Originally Posted by ace996
At this point, your conclusion makes good sense.
As for the flap and a hot day in traffic...well, I wouldn't be beating on it in traffic...I usually save my "fun" for the track or roads I know well and only when they are quite empty. It usually only takes a short time for the movement of warm air to be replaced by cooler air. My thought was that the flapper may help with higher pressure intake air at high speed on the track, but based on your experience with the string...the flapper would not seal= no benefit of positive pressure.
I'm going to Limerock on Nov1st...I'll do the string thing as well and should be able to get it on video as well.
I actually did the string experiment because I was wondering if a piece of saran wrap on the top of the snorkel under the hood (open the hood, put on saran, close the hood) would be a cheap way to get more power. The string experiment convinced me otherwise.
As for heat soak, I had an E39 M5 before and there are lots of threads on the M5 board about heat soak on the intake robbing power. I agree with you, though - when I'm going fast it's not a problem and when I'm going slow I don't care. Whether any of it was really a factor, I don't know, but I think it's safe to say that the E92 M3 won't have a heat soak problem because of the intake design.