Electronic DV Control

[Ralph]

Hi Pete, thanks for the detailed response! You're absolutely right about the Evo wanting to "buck" during throttle lift due to the MAF setup, especially if it's cold outside and the DV isn't fully recirculated. Both will make things worse, but that's why I like the adjustable GFB valve so much - in the winter I can set it to full recirc to get smooth driving, and when it gets warmer I can VTA a bit to get my sound effects back .

The main reason I got thinking about TPS driven DV control is partial throttle flutter (the lift-off bucking is just something I've learned to work around by lifting completely and then getting back on it). I may be using the wrong terminology though: what's happening is (I think) that at steady partial throttle and positive boost, there is enough pressure differential across the throttle plate to drop the pressure in the DV signal line, and so it opens. That causes the boost to drop, which causes the pressure difference to drop, the DV closes, and boost builds up again, and then the cycle repeats. This happens very quickly (4-5 times a second maybe). So I'm thinking it's the DV that is fluttering, and not the turbo surging - although admittedly this is based solely on what I can hear, since I don't have separate pressure sensors for the manifold and the IC piping (upstream of the throttle).

While thinking about this, I came across this article on electronic DV control, and that made me curious about the whole thing:
http://autospeed.com/cms/A_2188/article.html