Oil Catch can

[noob2a4]

I'm going to do my carbon cleaning soon and considering buying a catch can next week. Can you vets give me more info on whether or not it'll be worth buying(any brand recommendation is welcome)? If you don't think it'll be a good buy, then let me know what other mod will be a better option.

Thanks in advance!!!


2010 A4 B8 No mods...yet

[b6Hate4]

Yes it's a good mod. I love mine. Gets rid of the unreliable PCV valve, gets all that crap out of your intake tract/ intercooler.

[adamazing]

A lot of people will say its worthless. They're not completely right, but they're not completely wrong either.

I think the problem is that catch cans are kind of marketed as a full-stop solution to carbon buildup - which they're not. They do add a layer of additional filtering which prolongs the build-up process... but they're not the end-all solution to avoiding it. The truth of the matter is, you can't avoid it on direct injection engines like ours. People tend to overvalue it's benefit, which leads to disappointing reviews or results.

With that said, I have a catch can and I can tell you that it certainly does catch and condense oil vapors. But I will also tell you that the proportion of sludge collected is very small compared to the amount of condensation & water. I dump it once a week in the summer months, and twice a week in the colder months. Ninety percent of what I dump every time is water condensate. The remaining ten percent is sludge.

In summary:
They DO collect oil vapors.
They DO help to reduce the amount of vapor making it's way back into the intercooler and intake tract.
The DON'T prevent carbon buildup, they only prolong it.


Is it worth the investment?
I can only speak for myself, but the amount of oil blowby in my IC piping is virtually nil now. That has has saved me from my chronic issues of blowing charge pipe couplers loose on the freeway several times a year. That alone it worth it to me even if it does nothing for carbon buildup.

[IHave2Turbos]

I also noticed that on my CTS catch can it actually increased vacuum over the stock PCV system which should help prevent leaking seals. I don't think I've seen anyone else mention or explore this "feature".

[b6Hate4]

Catch cans were never, ever, ever designed to prevent carbon build up. Big misconception on this forum which led to them having a reputation as useless.

[Marko S]

Id recommend getting one. Ive been running mine for over a year (spulen) and i was very suprised at all the sh!t than comes out. I wouldnt recommend the spulen one (had issues with the drain). I ended up putting on a quick drain plug from 42draft and ran the hose down to under the car. Now I just leave it open.

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[Jerry1847]

I didn't take pics but I installed after a manual cleaning at like 55k and my valves were shit at 75k. I don't think they do much. It will def collect some gunk but didn't seem to help the valves much.

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[adamazing]

Id recommend getting one. Ive been running mine for over a year (spulen) and i was very suprised at all the sh!t than comes out. I wouldnt recommend the spulen one (had issues with the drain). I ended up putting on a quick drain plug from 42draft and ran the hose down to under the car. Now I just leave it open.

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Wait, if I'm understanding that correctly, you have an open tap in your can to allow contents to drain out as they accumulate?
Wouldn't the open port kill the vacuum pressure required to pull vapor from your crank?

[Marko S]

Wait, if I'm understanding that correctly, you have an open tap in your can to allow contents to drain out as they accumulate?
Wouldn't the open port kill the vacuum pressure required to pull vapor from your crank?

I was thinking the same thing but i figured the pressure from the drain plus hose would be enough.

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[adamazing]

I was thinking the same thing but i figured the pressure from the drain plus hose would be enough.

Ehhhhh, I wouldn't be so sure about that. Depending on your can set-up, the vacuum source should be coming from the intake manifold or the turbo. If you have a hole in the middle of the system between the vacuum source and the PCV plate, your drain hose is more likely acting as a straw instead of an drain - which could probably be equalizing the pressure on the PCV.

You might not be sucking vapors out of the crankcase like this.

Worst case scenario, the positive pressure buildup in your crank could lead to a main seal leak.

[IHave2Turbos]

Agree. Also, First mod on a turbo car should always be a boost gauge for myriad of reasons, this included. Additionally, if you put your finger over your "drain" do you feel suction? If you feel suction at idle your system may be broken.

There is an off-boost and an on-boost mode in the PCV sytem, so "on-boost" is where you'd get blow-by (positive pressure) but the majority of the time time you're in vacuum and as adamazing said, you're likely sucking in unmetered air.

[noob2a4]

Seems as though the oil catch can wouldn't be worth it for right now (perhaps I'll get that sometime down the line). I mean, if I have to do carbon cleaning on pretty much the same schedule, then I don't think it'll be worth it now. I do have a few things parts to throw on soon, but what'll be the best bang for my buck to add power??
Here's a list of my upcoming mods:
Intercooler and chargepipe kit
Forge diverter valve
Afe filter
034 motorsport hfc
Milltek downpipe
United motorsport tune


2010 A4 B8 No mods...yet

[Zach L]

gets *most* crap out of your intake tract/ intercooler.

FTFY!

Catch cans are great, but they'll unfortunately only get about 80%. That's a good improvement. Intake valve carbon buildup will happen a little slower, but valves will still need to be cleaned. In addition, all engines naturally weep a bit of oil from the valve guides, which is necessary. So even if you were to cap off the PCV and run a hose to the pavement, you'd STILL even have to clean the valves. Water meth won't even eliminate it... that's been proven through multiple cars that always run w/m daily driving. Just part of having a direct injection engine.

I've been running an exhaust-routed PCV setup on my Mk5 GTI for years, so much slower buildup. I've done 3 valve cleanings (manually scrubbing) on that car in 215,000 miles, and have cleaned done 10-15 valve cleanings on other people's cars.

[IHave2Turbos]

it's more so your intercooler and intake tract don't get oil and crap in them. carbon buildup is a fault of the direct injection system not flowing fuel with cleaners on top of the valves. these are completely unrelated things.

[Zach L]

it's more so your intercooler and intake tract don't get oil and crap in them. carbon buildup is a fault of the direct injection system not flowing fuel with cleaners on top of the valves. these are completely unrelated things.

They're not unrelated. A recirculating catch can setup will still allow PCV gases/oil into the intake tract.

As for the guy venting your PCV gases to atmosphere... that's not a great idea because consistent vacuum is necessary to 'pull' the PCV gases out of the crankcase. Then end result of not having vacuum is having your oil degrade more quickly and not lubricate as well. In addition to oil vapor, the PCV gas contains atomized fuel particles, nitrogen and other volatile byproducts of combustion from blow-by at the piston rings. All of these chemicals, especially fuel will turn the oil acidic and breakdown it's lubricating properties. That is the honestly the most damaging aspect of combustion blow-by. The vacuum is needed to evacuate these fuel vapors quickly before they join with the oil.

Necessary vacuum on the crankcase is the reason I routed my PCV to the exhaust rather than venting to atmosphere or running a hose to the ground. There is a venturi-effect created where the line joins the exhaust and it creates a constant vacuum on the crankcase.

[b6Hate4]

FTFY!

Catch cans are great, but they'll unfortunately only get about 80%. That's a good improvement. Intake valve carbon buildup will happen a little slower, but valves will still need to be cleaned. In addition, all engines naturally weep a bit of oil from the valve guides, which is necessary. So even if you were to cap off the PCV and run a hose to the pavement, you'd STILL even have to clean the valves. Water meth won't even eliminate it... that's been proven through multiple cars that always run w/m daily driving. Just part of having a direct injection engine.

I've been running an exhaust-routed PCV setup on my Mk5 GTI for years, so much slower buildup. I've done 3 valve cleanings (manually scrubbing) on that car in 215,000 miles, and have cleaned done 10-15 valve cleanings on other people's cars.

Okay. Most. Still, 80% like you said is a HUGE improvement, I don't know why people are so quick to bash them because its only 80% instead of 100%.

[IHave2Turbos]

They're not unrelated. A recirculating catch can setup will still allow PCV gases/oil into the intake tract.

Maybe unrelated was a poor choice of wording. Point I wanted to get across was don't conflate "I need a carbon cleaning on my DI motor" with "My catch can doesn't do anything".

I agree with all of your points and the benefits of a catch can.

[coryjoon]

Adding an oil catch can is a beneficial mod to reduce carbon buildup. It helps trap oil vapors and prevents them from entering the intake system. It's a good investment for engine health. Check out this link for a recommended product: https://www.ngrperformance.com/colle...oil-catch-cans

[old guy]

Read from this link to the end of the thread for a little catch can discussion.

[skematix]

Give this a view,

https://www.youtube.com/watch?v=va7nnO-YuMg

[audrobotic]

Guys - "coryjoon" is a spam poster for NGR performance, some cheesy Pep Boys go fast products, if it's even a real website and not a front for other scams.

"coryjoon" has been posting all over car forums acting like a regular member, but obviously promoting links to their website.

Cory - nice find picking up a post from 2017 to promote your lame products.

[bb-tt]

Guys - "coryjoon" is a spam poster for NGR performance, some cheesy Pep Boys go fast products, if it's even a real website and not a front for other scams.

"coryjoon" has been posting all over car forums acting like a regular member, but obviously promoting links to their website.

Cory - nice find picking up a post from 2017 to promote your lame products.

Yeah brought a zombie back to life a week or two ago to tell everyone they should get a pedal commander. (Tell me you know absolutely nothing without saying you know nothing) can we not get him banned

[Theiceman]

Yeah brought a zombie back to life a week or two ago to tell everyone they should get a pedal commander. (Tell me you know absolutely nothing without saying you know nothing) can we not get him banned

yeah but then what would we do for entertainment. :)