CA Smog Success!
#106
Rennlist Member
Thread Starter
I understand crank ventilation and how the AOS works.
But I don't think there's really that much vacuum (measured in inHg) going on even in front of the turbo; more of a passive pulling of air out of the AOS tube by the larger mass of air going into the turbo or NA throttle.
I think if you put a vacuum gauge on the crankcase itself and watched it on a stock 944 it would be running very close to "ambient" atmospheric pressure and just venting positive pressure.
A real PCV connects after the throttle to provide real vacuum.
But I don't think there's really that much vacuum (measured in inHg) going on even in front of the turbo; more of a passive pulling of air out of the AOS tube by the larger mass of air going into the turbo or NA throttle.
I think if you put a vacuum gauge on the crankcase itself and watched it on a stock 944 it would be running very close to "ambient" atmospheric pressure and just venting positive pressure.
A real PCV connects after the throttle to provide real vacuum.
#107
Rainman
Rennlist Member
Rennlist Member
Our 928 brothers have all kinds of issues with crankcase pressure but in my casual observation everybody (944 too) does it backwards...trying to vent out the cam tower etc.
Whereas again there are 60+ years of vacuum-based PCV systems working great in the rest of the auto world.
I'm about done playing with 944 engines but I think it'd be a worthwhile experiment for someone to try.
Whereas again there are 60+ years of vacuum-based PCV systems working great in the rest of the auto world.
I'm about done playing with 944 engines but I think it'd be a worthwhile experiment for someone to try.
#108
Intermediate
Hey all. I don't know if this thread is still active or not, but I just came by to give updates on the DEC PO82609B cat that was recommended to me by Tom 2 years ago. Thought i'd come by and post my results after two years for Cali smog.
Car is a 1988 Turbo S
2019 Smog results
2021 Smog results
Heads up that I only put 2000miles on the car between the two smogs. Didn't take it out much over covid. I'll come by again in 2years with the same cat if people would like to see how the cat holds up another 2 years.
Car is a 1988 Turbo S
2019 Smog results
2021 Smog results
Heads up that I only put 2000miles on the car between the two smogs. Didn't take it out much over covid. I'll come by again in 2years with the same cat if people would like to see how the cat holds up another 2 years.
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