PCV on a boosted car?

[Mr_Efficiency]

What has to be done with the pcv and other vent systems like that on a boosted motor?

I remember reading somewere once that it had to be re routed some how but I cant remember what had to be done. I just remember something about if not done properly it would create positive pressure in the crank case??? Anyone have any ideas as to what im getting at?

[Joseph Upson]

You have to connect the PCV tube from the valve cover ahead of the turbo to insure no pressure is blown through it back into the crank case. The crank case vent system is apparently different on later engines at least in my case because I was able to blow air into it confirming that I would have lost boost pressure as well as pressurized the crank case.

I don't like the idea of oil in the intake so when I make the above correction I may use a catch can although I understand water injection keeps the combustion chambers pretty clean. Having the system connected helps with ring sealing or oil control and reduces contaminants in the oil by removing combustion gases.

[Mr_Efficiency]

I plan on running water injection just for a saftey measure to help prevent detonation. Still havent really thought it through yet how I'm going to go about doing it tho.

I was just worried about the rings sealing, but i guess relocating the line to befor the turbo makes perfect sence, lol

What about all the vacume lines off the intake manifold and throttle body, are those ok? I'm not sure what most of them run but if they need vacume and I apply boost then whats going to happen?

[Joseph Upson]

Boost pressure at the regulator is a good thing as it raises fuel pressure and fuel flow to the engine. The brake booster has a check valve that only allows vacuum. You may or may not get boost pressure in your fuel tank depending on the vacuum line setup. The only time I had a problem with that is when one of the lines from the tank to the charcoal canister got clogged very likely as a result of my having turned the canister upside down at some point while there was vacuum on the system while the engine was running. The canister has a check valve also so either the pressure was from boost or blockage of the vacuum line preventing ventilation through the canister as fuel vapors built up from the warm fuel returned from the fuel rail.

[WrathOfSocrus]

I would make certain the brake booster check valve is functioning properly. I have also read on here somewhere that wastegates are NOT designed to handle vacuum, and must have a check valve to only allow boost pressure to prevent damage.

[RedZMonte]

i just have mine sitting out in the open. I want to get a ketch can and build an intake and attach it to the intake pipe. Im just running a screen for a intake now.

S

[Joseph Upson]

I have also read on here somewhere that wastegates are NOT designed to handle vacuum, and must have a check valve to only allow boost pressure to prevent damage.

First time I've heard that and I find it quite surprising given the amount of heat they often tolerate whether internal or external. I've never had a problem and if you look at some of the integral wastegates you'll note that some new units are plumbed directly into the compressor housing signal.

[ForcedFirebird]

I would suggest a catch if you route the PCV before the turbo to keep comtaminants out it.

I made some catch cans, but they are small. They were designed by a guy driving an LS1, so room is limited. I have a couple more left if anyone is interested...

[powerdoctor]

I usually put a fuel "anti flow back" valve inline on the main vac lead.
What I mean by "main" ...

I have found that if I take the main vac lead, usually 3/8 or .5 inch, and then run it to the A F B valve then to an old ford vacuum distibution block it works well.
Then at idle or when vacuum is present the system works, and when you go to boost, the system closes due to the valve and the brakes hold their vacuum and don't bleed off leaving a hard pedal.

The boost cant get past the valve and won't pressurize the crankcase throught the P.C.V.

Then just tie in your wastegate to the manifold.

Any thoughts on this?