I am starting a turbocharger setup on my slant, and have been curious about this - I want to keep the pcv system but don't see how it will work being hooked up to boost, rather than vacuum at some points.

I've read around on the net about catch cans, running it to open air, running it to the front of the turbo, etc... and the only one that seems feesible is some kind of catch can off the pcv, with a oil drail line down (thinking of teeing into the turbo drain line) and then the other side of the can routed to the front of the intake. In my head this seems like it would have a draw/ vacuum effect, and the catch and drain would minimize oil going past the baffles in the valve cover and into the turbo impeller.

What are you guys running, and does it work good? I am going for a reliable transport build as that's what the car is now, so I am trying to plan literally everything out, rather than, bolt on turbo then go.

I believe this is the PCV valve I use on m 62 turbo Valiant; toyota P/N 12204-46020 It was used for turbo Supra's and easily replaced the stock pcv.

It seems to be a go to piece on many custom turbo builds.

B

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These ones go to eleven...

Thanks for the question and the answer, folks. I have been using a stock PCV run into the base of the throttle body. I have seen no ill effects, although I'm sure there's some crankcase pressure developed while under boost.

Will get one of those Toyota units...

Lou

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Home of Slant6-powered fun machines since 1988

Thank you for the idea of the Supra Valve. I'm just curious what the actual Supra itself was using to pull vacuum to it? Probbably some kind of check valve I'm sure. But you've not seen too much oil in the mix or anything?
Are you using a catch can as well or just the valve? I like the idea of it being that simple. Or perhaps the supra valve somehow functions under boost pressure?

I have a port for PCV on the base of my 2150 but i was wondering if that was ultimately the location I was going to use. This sounds doable and easier than what I had in mind.

Personally, I don't see the need for a special PCV valve. A stock PCV has three operating positions.
1) At high manifold vacuum, the valve is pulled forward, and a restricted oriface meters the amount of air flow.
2) at low vacuum, the valve is in the mid position, and can flow more air.
3) with positive pressure, the valve is back seated and closed, the original design purpose of this function, is to prevent an intake backfire from finding it's way to the crankcase, but it will also keep boost from reaching the crankcase.

Any crankcase pressure under boost will normally be from ring leakage. It will be relieved by venting out the crankcase air inlet (breather cap, or hose the the air cleaner).

I use a stock PCV on my turbo engine.

I'm thinking the "special" PCV systems, on the newer turbo cars, are to meet emission standards, by not allowing the positive crankcase pressure to vent to atmosphere.

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 170 nitrous
64 Valiant Signet
64 Valiant 4dr 170
64 Valiant 4dr 225

I was not aware of #3, Charlie. Thanks for the lesson.

Lou

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Home of Slant6-powered fun machines since 1988

here is a nice simple explanation of the valve operation.
http://www.aftermarketsuppliers.org/Cou ... 94-2R1.pdf

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 170 nitrous
64 Valiant Signet
64 Valiant 4dr 170
64 Valiant 4dr 225

Nice document. Thanks!

Lou

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Home of Slant6-powered fun machines since 1988

Just the stock PCV. As noted before, it closes under boost conditions.

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11.02 @ 120.56
http://www.youtube.com/watch?v=EAxRmoDgsdY
Chassis dyno
http://www.youtube.com/watch?v=wd6hFGzLJMc

Thanks Charlie, it looks like I could have saved a few dollars.

However over the years I have had a few issues with the over the counter PCV valves that I've used. Is there a preferred manufacturer. One sheered in half and another rattled like a popcorn popper.

B

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These ones go to eleven...