Originally Posted by JjCoDeX75
Basically, if I understand it correctly, where the cam separation is increased I guess the overall flow of the engine is reduced, which would lead to increased likleyhood of surge?
JJ
Thats my understanding of it too mate
Remove all the overlap, and increase the duration its open for after BDC and you effectively cap the flow through the engine, and hence move yourself to the left on the compressor map for that amount of boost, by flowing less, which in turn increases the chance of surge.
I suspect there is far more to it than us mere mortals realise though, but its the one subject no tuner on here ever seems prepared to go into depth on from what ive seen!