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PCV “Blowby” and Oil Surge

scrllock

Autocross Champion
Location
MI
I disagree that cc do nothing. On the street, I'd agree, but I catch oil in my cc on track and at autocrosses, which would have ended up inceasing buildup.
he said "all the carbon buildup" and a lot of that is just a byproduct of direct injection. and depending on the setup you're possibly still getting oil in the intake. I put an intercooler and catch can on a friend's car with a BL plate, checked it after a month and still found the usual puddle of oil in the inlet. hence some people still getting white smoke with just a can.
 

scrllock

Autocross Champion
Location
MI
So if direct injection cars spray the fuel straight into the cylinder, and the only thing moving through the intake is clean air, where does the carbon come from? I thought it's from the PCV system venting oil and vapors into the intake.
it comes from the cylinder. the intake valve doesn't have a perfect seal. and during scavenging both exhaust and intake valves are open, on a lot of turbocharged DI motors. and the intake valves just never get as hot as the exhaust valves to burn it off.
 

Supermoto

Autocross Champion
Location
San Diego
Car(s)
2019 Autobahn DSG
it comes from the cylinder. the intake valve doesn't have a perfect seal. and during scavenging both exhaust and intake valves are open, on a lot of turbocharged DI motors. and the intake valves just never get as hot as the exhaust valves to burn it off.
Ahh didn't think of that, fair point.
 

tmw2442

Drag Racing Champion
Location
Approved NPC storage contanier
Car(s)
Mk7 R
it comes from the cylinder. the intake valve doesn't have a perfect seal. and during scavenging both exhaust and intake valves are open, on a lot of turbocharged DI motors. and the intake valves just never get as hot as the exhaust valves to burn it off.

Ahh didn't think of that, fair point.
10% percent pcv oil gunk....90% what scrllock said.

If only they put 1 or 2 low volume injector(s) in the intake manifold to spray part time...much of the buildup would get washed away ..but that would make tailpipe emissions rise minutely and could possible kill life all on the planet by 2030.... :rolleyes:
 

GTIfan99

Autocross Champion
Location
FL
he said "all the carbon buildup" and a lot of that is just a byproduct of direct injection. and depending on the setup you're possibly still getting oil in the intake. I put an intercooler and catch can on a friend's car with a BL plate, checked it after a month and still found the usual puddle of oil in the inlet. hence some people still getting white smoke with just a can.

I went from BM with oil smoke every event.

To BL with smoke at one really high speed autocross over a year period or if I intentionally tried to make it smoke.

To BL and cc and zero smoke and I can't even intentionally get it to smoke.

I'm sure there is still some getting through, no doubt, but it's a fraction of what I was getting I'm not getting visible smoke.

I know people's results have been highly variable, but I think a BL or BM and CC in proper working order stops most of the oil from getting to the intake on track.
 

scrllock

Autocross Champion
Location
MI
I went from BM with oil smoke every event.

To BL with smoke at one really high speed autocross over a year period or if I intentionally tried to make it smoke.

To BL and cc and zero smoke and I can't even intentionally get it to smoke.

I'm sure there is still some getting through, no doubt, but it's a fraction of what I was getting I'm not getting visible smoke.

I know people's results have been highly variable, but I think a BL or BM and CC in proper working order stops most of the oil from getting to the intake on track.
I should clarify that it was a stage 2 IS38 car, not a stage 1 IS20. I believe that the stock PCV is much more effective on less boost.
 

GTIfan99

Autocross Champion
Location
FL
I should clarify that it was a stage 2 IS38 car, not a stage 1 IS20. I believe that the stock PCV is much more effective on less boost.
That's my understanding too. The stock PCV, whether BM or BL, struggle with higher boost.

If the aftermarket abandons the products that replace the stock PCV, it may make running higher boost and big turbos more difficult, unless VW releases more revisions after the BL revision.
 

scrllock

Autocross Champion
Location
MI
That's my understanding too. The stock PCV, whether BM or BL, struggle with higher boost.

If the aftermarket abandons the products that replace the stock PCV, it may make running higher boost and big turbos more difficult, unless VW releases more revisions after the BL revision.
This is my excuse for owning 4 different PCV plates at the moment (spulen, APR, VWR, BL). Just keeping stocked up for when the feds come knocking.
 

JerseyDrew77

Autocross Champion
Location
Virginia & NC
Car(s)
2016 TR GTI S 6MT
I believe that the stock PCV is much more effective on less boost.

That's my understanding too. The stock PCV, whether BM or BL, struggle with higher boost.

You both are correct. The stock PCV and other versions can handle stock boost levels and maybe even stage 1 levels. Anything higher than that and you will need to replace it with an aftermarket plate. Once you get into really high boost with BT's, then there isn't any aftermarket plates that can handle it. They all become wear items.
 

Half fast

Go Kart Newbie
Location
Jersey City
Car(s)
Mk7 GTI
I'm using the BL revision PCV, and a ECS cc. I have since eliminated any smoking under any condition, and my cc has remained dry.
This thread isn’t super old, so I’ll revive it. I have this setup and it’s not really working for me. I would get smoke after any section of successive corners on track. I put the ECS CC on, and the smoke just takes a couple laps to return—the catch can fills up.

So, I ran a line from the catch can drain down to the oil pan. No smoke, catch can doesn’t fill up. But now I’m going through half a quart of oil a session. So it’s going somewhere.

It’s not obvious to me why the drain line would create that issue. The PCV system just drains back into the oil pan. There should be a slight vacuum on the drain line, if anything, from the oil pump.

My hypothesis is that is doesn’t drain quite fast enough to keep the can from filling up. So, I’m still getting a bit of blow by, but not as much as I was when I was getting clouds of smoke. Theoretically, I could test it by closing the drain and just continuing to do hot laps when it starts to smoke and see how much oil I lose. But, I can’t get myself to keep my foot in it when the rear window turns white.
 

Superfreak

Drag Racing Champion
Location
Denver
Car(s)
'15 R, '05 Taco,
Have you scoped your cylinders to see if the rings are shot? No amount of PCV tricks would solve that.
So this is kind of where I’m at. I’m not getting a lot of oil in my little BMS catch can with latest rev PCV, but I do think about the condition that I’ve had and wonder about the future of the engine.

Unsure if my rings are faulty and need to be replaced, but I’ll have to have a look and see. If the rings do need to be replaced, would I be getting the engine built? I can’t imagine just replacing the rings without some new pistons, and I wouldn’t get that done without having the other internals replaced as well, correct? Sorry I’m a bit unfamiliar with engine builds but it seems like replacing piston rings would lead to a full build. Is there a cheaper or better alternative?
 

Half fast

Go Kart Newbie
Location
Jersey City
Car(s)
Mk7 GTI
No. But also don’t have any issues generally. Nor did I have an issue until I started running slicks. (More Gs, more oil in the head, etc.)

Also, none of the oil samples I’ve had analyzed have shown fuel in the oil, which I think you’d expect if the rings were shot (fuel goes past the rings in the other direction).

It’s possible, but given the progression of the issues, it doesn’t seem like the most likely culprit.
 

Diggs24

Autocross Champion
Location
de plains! de plains!
Car(s)
2015 GTI
No. But also don’t have any issues generally. Nor did I have an issue until I started running slicks. (More Gs, more oil in the head, etc.)

Also, none of the oil samples I’ve had analyzed have shown fuel in the oil, which I think you’d expect if the rings were shot (fuel goes past the rings in the other direction).

It’s possible, but given the progression of the issues, it doesn’t seem like the most likely culprit.
Excellent. Just wanted to confirm.

I also had issues with the BL PCV and I don't even track my car. See if you can find the older rev PCV.
 

Diggs24

Autocross Champion
Location
de plains! de plains!
Car(s)
2015 GTI
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