Originally Posted by Rob Strelecki
Originally Posted by Jay Stacey
I always thought that the vacuum from the intake pipe wasnt strong enough to over power the crank case pressure.


I was curious about that myself and planned to hook my boost gauge up to the catch can to see how much vacuum it might pull. Someday!

..and also to see how much boost i.e. how bad the blow-by might be :|

I think we also need to consider it one of those "any bit that helps" kinda things. If you relieve some pressure, it's not pushing as much the wrong way.


I believe there was a tuners member who put a MAP sensor on his intake and there was a fairly decent amount of vacuum.

I don't think it's all about the absolute vacuum amount but rather the way the air passes the port, just the way a siphon feed air gun works, by passing air over the opening of the port, it creates a quite a lot of vacuum and can lift liquids up through many feet of hose.

1997 Eclipse GST - AWD swapped - TPC - GT Spec powered
2023 - 9.63 - 145mph