OCC and crankcase pressure testing diaries

[himurax13]

Originally Posted by Realgib3 At idle and low load, the venturi setup will actually push exhaust gas back up into the VC. For this reason, you have to run a CV on the venturi pipe.

That's odd. There is a lot of vacuum from the venturing setup at idle. The check valve is needed to prevent pressure from coming from the exhaust.

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[Realgib3]

Originally Posted by himurax13 That's odd. There is a lot of vacuum from the venturing setup at idle. The check valve is needed to prevent pressure from coming from the exhaust. Sent from my SCH-I535 using Tapatalk

Yeah back pressure, however small it is even with a 3" exhaust, will push back up the venturi pipe at low exhaust speeds. I wasn't able to test it with my cutout open, but I would suspect that to be the only way you wouldn't have this happen, if you truly had zero back pressure after the venturi pipe.

[Voltwings]

I had HTP make me a custom intake with 2 breather nipples to use with my Perm plate. Its been a while, but let me see if i can remember what i did.

Plate outlet 1: Routed like a standard OCC.
Block > PCV > Can > CV > IM

Plate outlet 2: Routed to the intake to pull a vacuum on the crankcase at WOT
Block > CV > Can > intake

This route was on a check valve so it only placed vacuum on the crankcase at WOT conditions. For daily driving the IM still pulled on the crankcase like the stock design.

The second port on my intake was just routed to the VC like stock. I figured this helped with DD conditions as far as engine seals and just overall engine health was concerned. I Designed this setup so there was always some type of pull on the Crankcase.

DJ's original perm design worked great, but since i was in the market for a 4" and i like to tinker, i figured id give it a shot. Id say it worked fine, but i really have no quantitative proof either way. In theory i dont see why it wouldnt work.

[breakfstincluded]

Thanks again Matt, found the thread you mentioned, I'll be readin (:

[Tokay444]

Ignore Kevin.

[breakfstincluded]

Thanks again to Tokay too, fuel trims bug the shit out of me when something is off.