As best as I can tell from the write-ups, the installation of the Stillen SC retains the functionality of the positive crankcase ventilation system (as I suspect would be required to gain CARB approval). I'm assuming that the check valves for the PCV keep (reasonable) boost from pressurizing the crankcase. What is the reasonable boost limit for that to continue to function as such? And other than defeating the purpose of PCV entirely, what are the options?

 

PCV still works with a boosted setup. When you go into boost, your PCV valve completly seals up and doenst allow boost into the Valve covers...pretty much the same as ZERO Vaccum. When you go out of boost and into Vaccum, your PCV opens up and functions properly.

Ive seen a few people take out the PCV valve compltely, and just filter both valve covers. Im pretty close to doing that same thing, just havent taken that step. Either way, the front valve cover will need to be switched over to a Filter ONLY.

-matt

 

Yea, I'd like to discuss this a little more in detail.

My last motor, smoked to **** from the Crankcase ventilation hose. I didn't have a filter setup, so that may be why.

The motor I'm currently building is going in soon, and want to know what the best route, as far as boost and Crankcase Ventilation is. I was going to run the stock pcv/vent system, and route the front valve cover breather, to the air filter on the front of the blower. Is that my best option? Again, I'm running a VQ35. Would be of greater benefit to remove the PCV and hose (that connects both valve covers), and just put a small filter on both? Any help is appreciated.

 

Just my 2¢ (and I've been known to be wrong before), but if you route the PCV fumes updtream of the MAF, I suspect that you'll have to clean your MAF pretty often.

Matt - any idea what kind of boost the PCV check valves can live with?

 

Not getting an answer to my basic question: What is the reasonable boost limit for PCV check valve to continue to function as it's supposed to?

 

for pcv system, i suggest having it vented. I never understood how it boosted applications worked with pcv system. specially if its aftermarket boost such as our cars. here is why, the pcv system is meant to releave pressure from inside the crankcase, in vacum this cracase pressure is being sucked out which yea the idle is smoother and driving within vacum is smoother as well, but now if you go into boost and the pcv valve closes, where does the pressure go under boost?! does the pressure stay inside the crankcase while the intake manifold is under positive pressure? i dont like that, so i vented my system, i plan to further improve how i have mine vented, but basically, i have my return from my scavange pump going into one of the barbs that's on the front vavel cover, then used the other barb to connect it to the rear, and then the rear remaining barb has a hose thats exposed to atmoshphere, iv been running it like this since i did my rear mount turbo setup about 7months ago, no problems. Only complaint i have is the fumes coming out STINK! and also a bit of oil comes out as well but i think thats due to my oil return being into the valve cover and not the upper oil pan.

 

No disrespect intended, but I am seeking input from someone who does understand.
Point 1. I know I can always resort to venting.
Point 2. I have a fair amount of respect for the engineers at Stillen who designed the system and, for whatever reason, chose to retain the functionality of the PCV system. Most likely required to get CARB approval, but it apparently works on a boosted engine.
So, for those who did retain and not vent their PCV, did that lead to any problems? And for those who retained it and moved to smaller pulleys (and higher boost), did you run into problems that pushed you to vent?
Matt, you say you're pretty close to doing that and I assume by that you mean with progressively smaller pulleys you've gotten closer and closer to doing that. Expand on that if you would.
Thanks.

 

I'm seeing some oil blowing from around my timing chains and intake. But I'm not 100% sure my pcv is working correctly.

 

If it's coming from near the timing cover, chances are you installed the bolts for the blower incorrectly. There is a thread regarding this....I'll see if I can find it. I think it was called "Timing Cover Leak"....

But make sure that all your blower bolts are properly torqued. Hope this helps.

 

it not coming out near the bolts . it's just like a thin coating around the seals it's not dripping or anything I was chalking it up to 160,000 miles

 

The ability of your PCV to retain pressure from the intake is dependant upon the style and manufacturer of the PCV. Cheaper units will allow boost pressure to leak by, even at lower pressures. I've ran into these issues as well. I chose to install an electric vacuum pump which kicks on about 1/4 throttle (via micro switch). I still use my PCV at this time to pull vacuum at idle. There is another option that was suggested:

http://www.et-performance.com/turbo.html