Thread: HOW TO: Reroute Oily Blow By Gases to Clean Up the Intake Manifold

Vadim, are you still using the stock oil seperator with the catch cans? I'm asking because my oil seperator started leaking oil on top of my turbo and I was not sure if I should replace it or just go with a catch can, or do both

Stock yes, I have only one catch can total so far. Just the stock one. Get it replaced, they should be fairly cheap on the forum used.

Or simply go with a VE/RR valve cover

ok, so your saying to just use the stock oil seperator (black box) for now and run the hoses the stock way?

So no need to add an aftermarket catch for the valve cover, just the pcv valve?

Just trying to do this right

Basically, you can add a catch can between where the VC and Intake is. The only thing is having to empty it. But that shouldn't be bad because most car's blow by is low, not like my old motor was

this thread has me corn-fused. rerouted now back to stock... 2 catch cans no three catch cans or is it two catch cans and 1 oem oil seperator. Brass t plastic t heater hose and powerstearing hose. blah blah.....

can someone tell me why they think there is metered air in the VC and Crankcase. How does it get there. As far as I know Basic mechanics tells me the metered air gets burned and out the exhaust. So how does it get in the crank case? And if its been metered once for A/F ratio/burn how does the ECU know to compensate for the tiny bit of air that slips past the rings and valve seals that is suposed to go back into the intake.

I think it's routed back to the intake (stock) on the assumption that blow-by won't be significant enough to alter A/F ratios and it gives it another chance to be burned, thus reducing the vehicle's harmful output.

My old car's setup was- no separator, valve cover to catch can, catch can to intake.
My new car's setup is (not nearly as pretty )- no separator, valve cover to catch can, catch can vented to atmosphere.

damn swiss your engine back looks f***ing hot! I am impressed.

So i see your have a hose from the valve cover to your block. Just without the seperator.

Thanks man. That's the car I sold though. The new one is alright, but I daily drive it, so I toned it down a bit, lol.

Always looked good.

I'm thinking VC to OEM seperator then T under seperator to Intake before turbo. Cap off VC T or remove T and tap in a single 90* barb fittin.

I probably will can this thread and or take it out of the How TO's.

The when I first did that mod I was following the other instructions thinking that they were smarter then Nissan engineers.

Granted the stock system works until your blow by increases, but even then it's not bad.

After a bit of research and some conversations with BenFenner, here is what we found.

This diagram doesn't quiet justify the air flow of blow by. If it did, then this method would work.



Here is how blow by flows in reality:


Thus what would happen is, blow by from the crank would actually go into the VC, into the baffels backwards, instead of though VC to baffles to intake.