Thread: Crank Case Ventilation fully explained. (Turbocharged edition.)

I see no issues with drill/tap/Ultra Grey RTV.

Hey Ben, great read...and it's got me wondering about mine now.



PCV hose is stock so that's good.
I'm hoping the pic is not too dark to see but one side of the VC vent tee goes to the catch can then to a barb fitting on the intake that's between the Cobra MAF and the turbo. The other hose from the VC vent tee goes back to the block, just below the #4 exh. It's reddish orange b/c it's 'high temp'... I figured I needed this cause it's so close to the exh.mani.

Other info: Greedy Catch is not vented to atmosphere. Setup is an FMAX stage 2 w/ a T3/T04e 60trim, stage V wheel, .82 a/r. JWT ecu tuned for S3s, Cobra MAF, & 72 lb'rs.

Thank you...Jody

ben, can I dump the pcv output to before the turbo safely?

essentially both my valve cover exits would go to the turbine wheel rather than the intake manifold....

Jody, your setup is basically and effectively almost identical to a stock turbo setup. Instead of having the catch can between the block and the "T" on the valve cover, you've now basically moved the catch can to be after the "T" on the valve cover. No big deal. Except I guess you've lost the auto-drain-back feature of the stock catch can setup. So there's that...

But obviously you had to do something because of where your turbo is, so you've done a good job.

Something tells me you've probably also removed the WOT section restrictor. It might be good to put that back if you've removed it.

Safely? No? It depends what you call safe? You can run the smaller PCV line to before the turbo, but that defeats the purpose of the small PCV line. You might as well just cap it off if you're going to do that.
You will have no vacuum in the crank case at idle, or small and medium loads. This is a very bad idea for all the common lack-of-ring-seal reasons.

ok so that line is best to run a catch can between the small PCV and the IM to prevent oil getting to the spark plugs...

also im running the 20v valve cover... that plastic PCVvalve, what do you think of the quality... will it be fine? should I upgrade it to a metal one?

Correct.

First off, if you're running a 20V valve cover, then your small PCV section already has tons of oil separation, much better than a DE, better than the RR, and I think maybe even better than the normal VE. I'm not sure adding a catch-can on that line is necessary. Remember, when that line is providing good suction, you are at idle, low or medium loads with almost perfect ring seal so really you get basically no blow-by to begin with. Almost no oil or no oil at all really goes through this line. In my opinion and extra catch can there is just a waste.

However, about the plastic PCV valve... I'm not sure how well they will handle boost. I hope they will handle it well, because I have a plastic one from an N/A Toyota engine going on my car.

Here's the thing. These valves are designed to shut in the event of a back-fire (in the intake) preventing that from entering the crank-case and potentially causing an explosion of the engine. If the valve can handle a back-fire, I'd hope it could handle a some boost, right?

Would you be kind enough to post pics of your set up or how you would run your set up

When I'm done with mine, I can post pics... But it is easy to describe.

My setup is a 20V valve cover with no additional catch-cans. Both factory restrictors will be in place, an OEM PCV valve (any manufacturer will do, get whatever fits for you) will be in place, and the outlet from the valve cover is routed to the intake before the turbo (and after the MAF if you have one). You want the bung on the intake to enter at a 45 degree angle to maximize the suction effect.

That's it. That is all I would do for a small or medium turbo build. Serious track cars or large turbo setups might benefit from additional attention to the system.

Feel free to substitute the 20V valve cover for a normal VE valve cover. That will absolutely suffice. The 20V valve cover is what I went with because I'm using 20V coils as well. A VE valve cover is really just as good.

Keep in mind if you have a lowport head and intake manifold the VE and 20V (and RR) valve covers don't fit well. They run into the throttle body drum section where the cruise control drum is. If you don't have a cruise control throttle body, then you should be fine. Otherwise, you may need a throttle body spacer or to do some other modifications to make the valve cover fit properly.

I ended up taking off my cruise control drum and modifying my throttle body for fitment. It is an easy modification, and if you can stand to lose cruise control it will work. If you want to keep cruise control, a TB spacer might do the trick. Actually an entire thermoblock spacer kit is probably perfect for giving the clearance you need. Otherwise you might be able to take a hammer to the valve cover and grind a bit on the TB to make things fit. There is severe interference there that needs to be taken care of one way or the other.

(On the VE valve covers..)
The 5/8" line from the VC that goe pre-turbo... is there a factory line that has a restrictor built in? Or should I homemake something?

Im about to change over to a VE vc on my DET.