Anyone bypass the PCV system to reduce pressure in FI cars? and if so how to we do this?

 

You're not really running enough boost to benefit from bypassing it. I've been running 35psi of boost lately and I don't have much any blowby at all. Are you shooting oil into the intake or something? That could be a sign of worn piston rings.

 

Having a 400 youre setup will be a bit different than mine or most supra setups, but sure you can do that.

I would not just run breathers for a couple reasons, one reason is just that you may get oil misting into the engine bay and it will just get a light coating in the areas near the breathers that then in turn collect dirt and grime. I had this happen in previous vehicles when using mini-air filters on the valve covers.

The second real reason is that you want to pull a vacuum on the crankcase, this can help seal the rings better as well as help evacuate any pressure buildup faster to help eliminate any push on the seals, especially on a 2J that is famous for blowing the front mains if not pulling any vac on the crankcase when running high boost.

The issue is more exaggerated when the boost is cranked up higher and higher, but like 10-15psi or similar is no issue, the biggest problem is when the pcv valve leaks backwards.

So the typical solution is to run the valve covers outlets to the turbo inlet, so that when you start boosting it pulls a good vacuum on the crankcase. Downside of this is that you may get oil buildup in your intercooler/piping. So that's when you would want to install a catch can inline.

When doing this you will not run the pcv valve anymore. Most stock pcv valves start to leak at high boost pressures, so that is why you'll see most big turbo'd cars eliminating it, because leaking boost into your crankcase can blow out front and rear seals in an instant. There is a oil trail from the main road, down my drive, into my garage from a friend that did just that while boosting hard on the way here with just open valve cover breathers and no pcv or vacuum being pulled. Luckily in just about 1.5hrs we tore down the front of the engine down installed a new seal (gotta love the easy access of working on a 2J), then added a vac feed to the turbo inlet, been like 8 months now with mad boosting all good.

I recently redid my catch can setup, see if I can find a pic to post up in a few.

 

thanks for the tips Turbo gods. lol

my main issue is my unit still has a small leak via the highspeed impeller side. ive replaced the seal with 3 types so far.. 1 single lip viton, 2 dual lip viton and 2 graphite mechanical seal (current)

still leaks a tiny bit which bugs me cuz i want 0 leaks lol..

im not sure if its the seals fault or not which i dont think it is.. so i was leaning towards high internal pressure in the crankcase.