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Oil Catch Can DIY

DIY or Mechanic

  • Do it yourself

    Votes: 15 100.0%
  • Hire Mechanic

    Votes: 0 0.0%

  • Total voters
    15

crxgator

Autocross Champion
Location
Raleigh, NC
Car(s)
All the MQBs
If that was the case how come the FSI, Ea888 gen 1 and 2 collect oil in a catch can with the stock PCV?
 

victorofhavoc

Autocross Champion
Location
Kansas City
I vote for Spulen but whatever you buy don't buy one that doesn't delete the PCV valve. That kind won't collect anything.
This is 100% wrong. You've said this numerous times on this forum and I'm not sure what your source is, but it's not right. I've talked to several race mechanics (one is a well known crew chief for two teams, one IMSA) and implemented numerous catch cans. The systems that are add ons to the pcv will collect what the pcv let's through and would normally dump into the intake as a liquid (there is no harm in burning the gases). The oil dumped into the intake is definitely an issue, but pcv prevents this in most normal circumstances.

I can go pull my bfi catch can right now and show you the actual OIL that it collected last time I was on track. On the street it's dry because the pcv works fine. On track is a totally different scenario with oil surging under heavy braking and right turns which causes the actual blowby (billows of blue smoke coming out of your exhaust).

Removing your pcv valve entirely, you're relying on aftermarket parts to seal properly and avoid boost leaks. Do you really trust aftermarket parts that much? Not to mention without the pcv you have the possibility of smelly gaseous output and more pollution.
 

crxgator

Autocross Champion
Location
Raleigh, NC
Car(s)
All the MQBs

jimlloyd40

Autocross Champion
Location
Phoenix
Car(s)
2018 SE DSG
This is 100% wrong. You've said this numerous times on this forum and I'm not sure what your source is, but it's not right. I've talked to several race mechanics (one is a well known crew chief for two teams, one IMSA) and implemented numerous catch cans. The systems that are add ons to the pcv will collect what the pcv let's through and would normally dump into the intake as a liquid (there is no harm in burning the gases). The oil dumped into the intake is definitely an issue, but pcv prevents this in most normal circumstances.

I can go pull my bfi catch can right now and show you the actual OIL that it collected last time I was on track. On the street it's dry because the pcv works fine. On track is a totally different scenario with oil surging under heavy braking and right turns which causes the actual blowby (billows of blue smoke coming out of your exhaust).

Removing your pcv valve entirely, you're relying on aftermarket parts to seal properly and avoid boost leaks. Do you really trust aftermarket parts that much? Not to mention without the pcv you have the possibility of smelly gaseous output and more pollution.

I'm not familiar with the BFI OCC. And you mean the the PCV prevents the oil from going into the intake because you have the BFI OCC? I have no smelly gasses with the Spulen OCC. I also have no boost leaks either.
 

victorofhavoc

Autocross Champion
Location
Kansas City
I'm not familiar with the BFI OCC. And you mean the the PCV prevents the oil from going into the intake because you have the BFI OCC? I have no smelly gasses with the Spulen OCC. I also have no boost leaks either.
No, the pcv reduces crank case ventilation when there is vacuum. When there's a positive pressure in the crank case, the pcv is open and allows crank case gasses to escape, which for smell and emissions reasons are dumped into the intake for the engine to burn on the next combustion cycle. Burning these gases is not where your valve sludge comes from.

When you're on track in a very high G scenario, oil will blow out of the pcv valve when off throttle (vacuum) and through the connecting tube into the intake. If you put a catch can inline, then gasses still flow, but oil will get trapped in the can. When on throttle the pcv remains in stock function. When you replace the pcv, you're now allowing ventilation at all times, which is why it will catch so much "gunk". You're not doing anything to extend the life of your engine or keep clean valves or anything by collecting this extra gunk, and if you didn't catch it in the can, it would have been a gas that burns and evaporates. A lot of it is water that would have otherwise evaporated.
 

jimlloyd40

Autocross Champion
Location
Phoenix
Car(s)
2018 SE DSG
No, the pcv reduces crank case ventilation when there is vacuum. When there's a positive pressure in the crank case, the pcv is open and allows crank case gasses to escape, which for smell and emissions reasons are dumped into the intake for the engine to burn on the next combustion cycle. Burning these gases is not where your valve sludge comes from.

When you're on track in a very high G scenario, oil will blow out of the pcv valve when off throttle (vacuum) and through the connecting tube into the intake. If you put a catch can inline, then gasses still flow, but oil will get trapped in the can. When on throttle the pcv remains in stock function. When you replace the pcv, you're now allowing ventilation at all times, which is why it will catch so much "gunk". You're not doing anything to extend the life of your engine or keep clean valves or anything by collecting this extra gunk, and if you didn't catch it in the can, it would have been a gas that burns and evaporates. A lot of it is water that would have otherwise evaporated.

I could be wrong about Spulen eliminating the PCV. I thought the plate they use did but maybe I misunderstood the guy who installed it. As far as the black gunk that my catch can is collecting I don't see how that would be burned off. I can only tell you that when I had manual carbon cleaning done I was told mine was not nearly as bad as cars with similar mileage without an OCC.
 

Navi

Autocross Champion
Location
BK/NYC/Hamptons
No, the pcv reduces crank case ventilation when there is vacuum. When there's a positive pressure in the crank case, the pcv is open and allows crank case gasses to escape, which for smell and emissions reasons are dumped into the intake for the engine to burn on the next combustion cycle. Burning these gases is not where your valve sludge comes from.

When you're on track in a very high G scenario, oil will blow out of the pcv valve when off throttle (vacuum) and through the connecting tube into the intake. If you put a catch can inline, then gasses still flow, but oil will get trapped in the can. When on throttle the pcv remains in stock function. When you replace the pcv, you're now allowing ventilation at all times, which is why it will catch so much "gunk". You're not doing anything to extend the life of your engine or keep clean valves or anything by collecting this extra gunk, and if you didn't catch it in the can, it would have been a gas that burns and evaporates. A lot of it is water that would have otherwise evaporated.

quoted for truth because no one knows this and thinks otherwise
 

Navi

Autocross Champion
Location
BK/NYC/Hamptons
This is 100% wrong. You've said this numerous times on this forum and I'm not sure what your source is, but it's not right. I've talked to several race mechanics (one is a well known crew chief for two teams, one IMSA) and implemented numerous catch cans. The systems that are add ons to the pcv will collect what the pcv let's through and would normally dump into the intake as a liquid (there is no harm in burning the gases). The oil dumped into the intake is definitely an issue, but pcv prevents this in most normal circumstances.

I can go pull my bfi catch can right now and show you the actual OIL that it collected last time I was on track. On the street it's dry because the pcv works fine. On track is a totally different scenario with oil surging under heavy braking and right turns which causes the actual blowby (billows of blue smoke coming out of your exhaust).

Removing your pcv valve entirely, you're relying on aftermarket parts to seal properly and avoid boost leaks. Do you really trust aftermarket parts that much? Not to mention without the pcv you have the possibility of smelly gaseous output and more pollution.

ALSO, quoted for truth
 

GTIfan99

Autocross Champion
Location
FL
No if you keep the PCV valve the catch can doesn't get anything running through it. I had a Veloster Turbo before the GTI. I put the exact same OCC on the GTI that I had on the Veloster and the inside of the can was just as shiny new after several thousand miles because nothing goes through it without deleting the PCV. I asked the shop that installed it and that's when I found out the GTI has a completely different system. So I got the Spulen OCC and it collects the blowby on the GTI. I empty the can once a week which is a thousand miles for me and the catch can has between 1/2 to 1 ounce of runny black blowby in it. That crap would have gone to the back of the valves otherwise with the OEM system.

You still aren't getting it.
 
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