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Yoshifab Catch Can or Provent Feedback?

Any suggestions for a PCV er, valve to use?

I just used a random one from the auto parts store, maybe a ford one? McMaster Carr has a bunch of low pressure check valves that would work as well. Silicone Intakes has some that are 12mm hose size as well as a few AN sizes if you want to get fancy.

http://www.siliconeintakes.com/liquid-air-adapter/aluminum-one-way-check-valve--6an-p-9586.html

On the NA race engine, I drilled the underside of the oil filler cap with a ~3/16 or 1/4” hole. I also stuffed some foam filter media into the cap (they pop apart) to filter the air going in.
Then a hose from the breather box to PCV to catch can (stuffed with steel wool), and then to the intake manifold. This allowed for a constant flow of fresh filtered air to go from the valve cover down to the crank case, and out the stock breather box. Idle was adjusted for the added leak rate from the cap.

A well working stock turbo “PCV” system works okay, but it all needs to be clean and functioning properly. Also, the small vacuum/boost “t” just above the breather box needs to be clean and in good working order. Also, the breather hose pre-turbo in important at it supplies a vacuum (bernoulli effect).
 
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I just used a random one from the auto parts store, maybe a ford one? McMaster Carr has a bunch of low pressure check valves that would work as well. Silicone Intakes has some that are 12mm hose size as well as a few AN sizes if you want to get fancy.

http://www.siliconeintakes.com/liquid-air-adapter/aluminum-one-way-check-valve--6an-p-9586.html

On the NA race engine, I drilled the underside of the oil filler cap with a ~3/16 or 1/4? hole. I also stuffed some foam filter media into the cap (they pop apart) to filter the air going in.
Then a hose from the breather box to PCV to catch can (stuffed with steel wool), and then to the intake manifold. This allowed for a constant flow of fresh filtered air to go from the valve cover down to the crank case, and out the stock breather box. Idle was adjusted for the added leak rate from the cap.

A well working stock turbo ?PCV? system works okay, but it all needs to be clean and functioning properly. Also, the small vacuum/boost ?t? just above the breather box needs to be clean and in good working order. Also, the breather hose pre-turbo in important at it supplies a vacuum (bernoulli effect).

I know it's only one datapoint, but my freshly rebuilt B23 with the stock breather box, then a Yoshifab catch can + stock box had blowby problems. Probably due to excess ring gap or something I messed up, but still, I really want to eliminate it. I don't think the stock setup is going to cut it on a high rpm, high boost 16v. That's why I want to add more venting in the block and valve cover.
 
I just used a random one from the auto parts store,

Thanks. I'm planing to use draw air via the pre-Turbo hose. This way any air going into the system has already been counted via the MAF. Also, when under boost and there being no inlet vacuum, the air inlet will act as a breather back out. The PCV would between the valve cover and inlet.
 
I have this one:
http://www.radiumauto.com/Universal-Air-Oil-Separator-Return-AOS-R-P890.aspx
my understanding was that you don't want any excess crankcase pressure, it causes excess stress on the block and rings. The high horsepower cars usually use additional vacuum pumps to reduce crankcase pressure at high RPM
https://www.gzmotorsports.com/vacuum-pump-guide.html
https://www.dragzine.com/tech-stories/tech-how-external-vacuum-pumps-free-up-horsepower/

The Radium catch can is nice because it's heated to prevent water condensation in the can mixing with the oil that's draining back into your sump pan. The cheap ones don't have this heating element, which is why they fill up with sludge much faster.
AOS_Section_View-4.png
 
Over the winter I played with a handful of PCV valves in a line running from the oil separator box to the intake without success (car ran poorly). On my old Chevy V8 there was a PCV "intake" on one valve cover and an "exhaust" on the other that was plumbed to manifold vacuum. On the Volvo I was concerned about the boost pressuring the crank, but figured the (back fire / PCV) valve would prevent it. I believe, at the oil separator, that the early turbo cars had the larger hose running to the turbo inlet and the smaller to a metered orifice manifold vacuum? I think this "dual" set up would, more or less, present vacuum to the PCV whether on vacuum or on boost.

I think it's a worthwhile effort, I just could not figure it out.
 
I have an eBay catch can that I've been using for a few years, previously just vented from the valve cover only on a B21. I now have a B23 with the black plastic flame trap on the block, which I will run to catch can and I bought a vented oil cap which will go to the catch can. The catch can will be connected to a factory 940 intake hose with the heated hose barb after the air filter and before the turbo. I haven't had a chance to run this yet and I don't even know if the oil cap will fit under the hood but I will update once the motor is back in the car.
 
You might want to have a chat with every engine manufacturer out there. The stock oil separator drains back to the crankcase. The provent is just doing a better job of separating the oil from the blowby gases. There's no functional reason not to drain it back. You should be getting your oil up to temp so the water vapor and other volatiles will evaporate.


Your oil stays cleaner longer if your not returning the **** you filtered to the sump. Factory returns to sump because they know no ones going to drain the catch can. But we will. Personally I wont drain it back to the sump. But as a cnc machinist, a similar thing goes on with my cnc machines. They make oil vapors from coolant and its collected in mist collectors, the factory returns that **** to the sump but its disgusting and no coolant manufacturer recommends that. Theres no combustion taking place in my CNCs either so their waste oil is even cleaner than a cars engine oil.

Basically this argument is everywhere, return to sump for simplicity if you dont give a ****, drain it yourself if you do.
 
Your oil stays cleaner longer if your not returning the **** you filtered to the sump. Factory returns to sump because they know no ones going to drain the catch can. But we will. Personally I wont drain it back to the sump. But as a cnc machinist, a similar thing goes on with my cnc machines. They make oil vapors from coolant and its collected in mist collectors, the factory returns that **** to the sump but its disgusting and no coolant manufacturer recommends that. Theres no combustion taking place in my CNCs either so their waste oil is even cleaner than a cars engine oil.

Basically this argument is everywhere, return to sump for simplicity if you dont give a ****, drain it yourself if you do.

Really depends on what you're doing. Higher than stock rpm, high hp you will be pushing so much oil through the CC, you really, really need to drain it back, and as Homer already pointed out, condensate & vapor leave at normal operating temp. If your car is occasional use, low miles, where the condensate won't burn off consistently, then what you're saying makes sense, otherwise, not so much.

Can't say comparing to CNC setup is a valid argument - in that case it would make sense if the system doesn't generate the heat to remove the vapors..
 
The key point is to learn from the OEMs, Volvo redblocks have it right, no idea about white ones, SR20 have it fairly right. What's right you say? Hot. IE, in close contact with the block/head so as to drive water out of the separator, then you're just draining oil back and it's a non issue. Putting these catch cans in various places around the engine bay is only okay if you have your ducks in a row with respect to keeping the oil from getting there in any quantity in the first place. Many engines when held at 7000+ RPM will flood the head and drain the sump, which can be bad for the bottom end, too, but can also overflow bulk oil out of your breather setup if you've designed it poorly. Factory Volvo redblock breather box is pretty decent flowing, too, easily enough for mild turbo setups, but would probably be borderline on a more serious engine north of say 500hp.
 
it sounds like running a catch can between the oil separator and the intake (pre-turbo) only helps prevent oil getting into the turbo/intercooler/throttle body/intake downstream.

whereas an ideal setup would be having a 4-port catch that runs from oil separator, drains back into the block, is vented at the valve cover/oil cap, and is vacuumed by the intake. basically - like the yoshi deluxe setup.
 
is there any risk or issue locating a catch can near the exhaust/turbo on these cars? or would it be better to plumb longer lines and locate it near the evap can?
 
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