Thread: Boost Blow By Issue

i have an SR20DE+T, well when i changed from S3 to S4HL cams i lost power(20hp) also due to some boost leaks which are now fixed but during the time i waited for my Chip i drove my car N/A for a mth, also my compression went from 175psi to 165psi with new Cam's, now i have already checked PCV and its good. Ok now when i was doing a boost leak test we notice that the oil dip stick popped and released psi, so we held it down and then took off the oil valve cap and it flew up and hit hood, now my car before had blow by issues but not that bad. We think it might be piston rings due to engine ware since the engine has about 115 thousand miles on it or also worn valves guides or even head gasket, if anyone might know what the blow by issue might be coming from let me know or let me now what other things to check out :-P

do a leak down test.

yeah i have to do that aswell :-P

ok i will have to save the leak down test later since i blew 3rd gear on my tranny :-P

What manifold are you running btw?

you said you checked your pcv... why not change it regardless.

Any word on the manifold? There is a reason on why I ask this. If you are running a very restrictive setup like a T25, or a log manifold, you lost your power due to reversion. Cam overlap is killing it basically.

S3 - .442" (11.2) LIFT / 260º DUR. - OVERLAP - 20º
S4 - .464" (11.8) LIFT / 266º DUR. - OVERLAP - 28º
S4HL -.484" (12.4) LIFT / 266º DUR.

I can't find any overlap numbers for High Lift S4's, but it's at least 28º, which on a T25 or a log manifold is too much as is and would be robbing power. S3's still have a manageable 20º of overlap.

check dipstick & pcv. cheap enough. fixed mine. i can dig up part nos if needed