I was looking at xtremepc's oil catch can set-up and have a question. Xtremepc if your on this site could you please respond to this post. I am sure you guys can help me understand his setup aswell.

I noticed that he has the the vacum line from the PVC valve that use to go into the Intake manifold ran to hit catch can.

My question is how come he/you didn't just block off the vacum port on the Intake manifold?

Next question, Where do you/he have the vacum line ran to from the Port on the Intake manifold.

Should it be blocked off??

http://home.comcast.net/~xtremetib/turbo2.JPG

 

On a stock Tib you have two lines connecting to the back of your Valve Cover. One goes to the IM from the PCV valve and the second goes to the elbow right before the TB. With a ctach can you put it between the elbow and the valve cover. You MUST have the IM connected through the PCV valve. This is how the valve cover is cooled. The higher pressure in the IM the more air is pulled through the valve cover.

 

If you don't want to go this route, you could always get a crank filter but it'll leak a tiny amount of oil.

 

Crank filter? Do you mean those little filters? They work well as long as your car is MAP not MAF.

 

If you look at his setup this is what he's doing.

Both the PCV valve and the 2 way are connected to the catch can. The Catch can has a breather filter on top of it to allow it to vent air, or suck in air as the engine needs to. That setup is perfectly OK. On a boosted motor, you don't want to leave the PCV/Valvetrain vent connected up to the incoming charge air. You will litterlly be pressurizing your crank case/valve train with the incoming boost pressure (not good). That's why you allow it to suck in outside air, and vent to the outside air.

The Fitting on the intake manifold he is using to trigger his BOV. IMHO, this is a big mistake. The trigger for the BOV (vacuum/boost line) should be between the Throttle body and the turbocharger, not AFTER the throttle body in/on the intake manifold. This setup he has will allow a boost/pressure spike to bounce off the closed throttle body and go back to the turbo, and the BOV will never open. That is a BAD THING boys and girls. VERY BAD.

You should put a fitting for the BOV just before the throttle body, or somewhere between the TB and the intercooler. Preferably within 6" of the Throttle body. I sure hope he's moved it since this photo was taken.

Some folks use a reference off the compressor discharge to actuatle the wastegate and BOV, but I prefer to use that for the wastegate only. If the pressure wave has gotten back to the discharge outlet, it's too late to vent it via the BOV to prevent the pressure wave from hitting the compressor.

 

I have a similar setup, but I remove the PCV valve. I replaced it with a fitting and connected it to the catch can. Since it is not connected to the IM, there is no vacuum to open it. It only opens upon internal pressure. By removing it, it is constantly open.

 

The best place to feed the BOV is from the wastegate. Put a T in between the turbo and wastegate and youll be alright.

 

NO, you SHOULD NOT have the 2 operate off the same hose. You should NOT operate a BOV off the Intake manifold.

If you feed the BOV a pressure/vac signal from the intake manifold, it will only open based off vacuum, not based off boost (or excess boost). You'll be discharging your BOV every time you close the throttle and get intake vacuum. This needlessly wastes built up boost pressure. Set your BOV to go off at 2-3 PSI over whatever boost you are running, and connect it to the charge piping between the TB and the BOV.

You won't get that "wuffle" or "woosh" every time you shift, but you car will be MUCH MUCH MUCH more responsive.