[Big Tom]

Originally Posted by joshuo

See above, there's a check valve inside the PCV system to prevent backflow to the crankcase.

that said, i'd still put a filter on it lol.

Trust me, the engine will suck air even if the check valve is there or not.
This is the check valve (which I believe dzenno already has removed):







And this is why the engine will suck in air, even if the check valve is closed. It's a hole inside the check valve that always will be open:






Conclusion; A filter must be used, even if the check valve is still in the system.

[dzenno]

Ah ok the valve is there? Ok..with the filter there how can you guarantee it will preserve flow out of the crankcase though...you wouldn't need much to clog it with oil...IMO you'd need to clean/replace it very often to keep it from becoming a restriction..

[Big Tom]

Originally Posted by dzenno

Ah ok the valve is there? Ok..with the filter there how can you guarantee it will preserve flow out of the crankcase though...you wouldn't need much to clog it with oil...IMO you'd need to clean/replace it very often to keep it from becoming a restriction..

The placement of my filter/OCC makes it very easy to reach, so I don't see any problems with cleaning the filter once per month or so...

[dzenno]

But that's my point, I think u may need to clean that filter after every harder driving session...what if you clog it during a 30 min track session?

Also, for a hole THAT tiny and given very low vacuum there at idle and cruise I think putting a filter on that end wouldnt really matter...what are the chances with that size of a hole and low vacuum to suck something in through long tubing stretching behind the back of the engine honestly??

[Big Tom]

Originally Posted by dzenno

But that's my point, I think u may need to clean that filter after every harder driving session...what if you clog it during a 30 min track session?

Also, for a hole THAT tiny and given very low vacuum there at idle and cruise I think putting a filter on that end wouldnt really matter...what are the chances with that size of a hole and low vacuum to suck something in through long tubing stretching behind the back of the engine honestly??

I don't want any unfiltered air to enter my engine, but it's of course up to you what you want to do...

My OCC will catch most of the oil before it enters the filter, and I never track my car, so that shouldn't be anything to worry about.

[Transport3r]

If these breather filters would clog every 30mins, how would people use them on track cars?

I'm sure you're gonna have to give it a good cleaning after the track day, but i'm assuming these filters are designed not to become a restriction.

[dzenno]

Originally Posted by joshuo

If these breather filters would clog every 30mins, how would people use them on track cars?

I'm sure you're gonna have to give it a good cleaning after the track day, but i'm assuming these filters are designed not to become a restriction.

That's a good point but show me a crankcase filter that was used on a dedicated track car I'd be very surprised if you found a single one as emissions, smell at the track don't matter and I'd expect most of them to just run an open dump tube..

I'm not saying this isn't the case, just saying I'd be surprised that on a track car you would run a filter there..

[Transport3r]

Actually most full on racecars use a dedicated vacuum pump on the Crank case vent if i recall correctly.

[dzenno]

Originally Posted by joshuo

Actually most full on racecars use a dedicated vacuum pump on the Crank case vent if i recall correctly.

Interesting, have a pic of how that setup works? wouldn't some of the vapours enter the vacuum pump in that case??

[Joshboody]

ok, I'm just thinking here.

cc gases would create only pressure and not suck in air. Check valve maybe for... backfire?

pcv setups use vacuum to operate the pcv valve, pull gases and a breather for outside air, so it was a circulating system.

We don't have an outside circulating system, but oil vapor is suppose to be cleaned by the internal cyclones and cleaned air recirculated internally. The release to the intake piping is to relieve pressure.

before pcv... i think it was just an opening to relieve cc pressure

[dzenno]

check valve is there to prevent the return into the crankcase from happening as well as to regulate opening of that vent..when crankcase pressure builds up the valve opens, otherwise its kept shut...i keep saying that if you don't run your car under BOOST, just cruise, you won't see a drop in your OCC, which many users on this board have actually been reporting...how many threads are there with ppl saying "hey my OCC doesn't have any oil in it, why, is it not working" they're just not pushing their car much on the road, guess mostly daily drivers with not much WOT action

[MicaCeli]

I've used compressor Water Seperators (Husky and so on) on a bunch of street and race cars for year. They work well if you take out the filter and glue the drain nipple at the bottom.

[Big Tom]

Originally Posted by Joshboody

cc gases would create only pressure and not suck in air. Check valve maybe for... backfire?

Well, it DO sucks in air. Believe me, I've tried it IRL.
You can perform a super easy test by holding a thin piece of paper in front of the CC pipe.
The paper will be sucked against the pipe during idle, even after the check valve.

[Forcefed3]

For people that already have the BSH can, why not just put a filter on the intake side of the OCC?

[dzenno]

Originally Posted by Big Tom

Well, it DO sucks in air. Believe me, I've tried it IRL.
You can perform a super easy test by holding a thin piece of paper in front of the CC pipe.
The paper will be sucked against the pipe during idle, even after the check valve.

Thanks I'll check that...you think with a 1m long 3/4'' hose it would be able to suck anything UP a hose? I wouldn't think it'd be enough vacuum to suck anything up a hose that long

[Joshboody]

Originally Posted by Big Tom

Well, it DO sucks in air. Believe me, I've tried it IRL.
You can perform a super easy test by holding a thin piece of paper in front of the CC pipe.
The paper will be sucked against the pipe during idle, even after the check valve.

awww, interesting... thanks for the confirmation! then i would definitely filter that bad boy Dzenno.

[Big Tom]

Originally Posted by dzenno

Thanks I'll check that...you think with a 1m long 3/4'' hose it would be able to suck anything UP a hose? I wouldn't think it'd be enough vacuum to suck anything up a hose that long

It's absolutely strong enough for sucking up dust.

[Zasquatch]

Originally Posted by gbreeE90

For people that already have the BSH can, why not just put a filter on the intake side of the OCC?

Reading through this thread, that's exactly what I was thinking. If I were to do anything, I'd try that. My car seems to be running fine with the BSH installed in recirc mode tho.

What symptoms are people getting that causes them to take out their OCC?

[Jake@MOTIV]

Surprised no one has looked into the venturi style into their exhausts.

[Transport3r]

Yea i was wondering that too, but you don't want to drag that crap through your cats i think. maybe after the mid cats, but you'll need a long pipe..

[Forcefed3]

What about adding some sort of flap to a 3/4" tube. One that would open on the slightest bit of pressure but it wouldnt allow anything to be sucked up.

[Jake@MOTIV]

Originally Posted by joshuo

Yea i was wondering that too, but you don't want to drag that crap through your cats i think. maybe after the mid cats, but you'll need a long pipe..

I figure the guys looking to evac the crank case in this fassion won't have cats. Its definately a very effective way of solving the issue though. The venturi setups create substantial pull to evac the cc.