Catch Can Chapter 63

[Higgs Boson]

If anything, adding a catch-can adds to the flow restriction on the PCV system and you'd think that would actually cut down on the flow and the amount of oil caught, but it doesn't seem to. The flow through the PCV system is very low, so a little more restriction in the system doesn't seem to affect it at all from my experience.



I've seen some photos posted where the catch-can has both oil along with some water that was caught. I would imagine on a short trip on a cold day the can probably does catch some water vapor that might condense out. If there is water vapor in the gasses being sucked out of the engine and into the can, there's the possibility for water to condense. If it doesn't condense in the catch-can, then it goes into the intake manifold. Water vapor back into the intake isn't as bad as oil vapor into the intake.



Because no catch-can is 100% effective. I'd say a good catch-can is probably in the 80~90% effective range. I guess I'd still only want 10~20% of what could have gone into the intake verse 100% without a catch-can.



Of course, don't you? See answer above.



I guess I have to disagree. I just drive my GT 'spirited' on the streets but usually just cruising around normally like a daily driver would be, and the catch-can seems to catch a fair amount of oil that would otherwise go into the intake manifold for no good reason.

IMO, breathers might be good to install for only full out race track use. Running open breathers on the street is not good IMO because the crankcase is not getting fully evacuated and cleaned of nasty shit like it would with a functioning PCV system.

Think of it like this then. A catch can may slow the saturation rate of the intake manifold but it will still become fully saturated and then it won't matter anymore. If you are removing your intake manifold on a regular basis to clean it then a catch can will extend the intervals but it won't keep it clean. How do you know a catch can is 80-90% effective? Did you test this using the scientific method or is that a "feel-good" number? What if it is only 10% effective?

With that said, when I swapped my intake for the gt350 it was completely dry and free of oil. Catch can not needed? I'd bet you 100 bucks that if I installed a catch can it would "catch oil." I've tested that on a few cars at least....

I didn't wake up one day and decide not to like catch cans. It happened over 15 or so years of screwing around with the them and pcv systems and getting nowhere.

How many people just take it for granted that if there's something in their catch can then it's doing its job and they're so relieved to have it? Everyone, lol.

By the way, you're getting lots of oil and exhaust and carbon all over your intake manifold and valves from the other direction, up from the cylinder, during camshaft overlap which is......every rotation of the crank.

A catch can is just lipstick on a pig. I guess it makes the pig look better but will you take it on a date?

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[GT Pony]

Think of it like this then. A catch can may slow the saturation rate of the intake manifold but it will still become fully saturated and then it won't matter anymore.

Granted, every engine and it's PCV system will work somewhat different. When I had my C5 Z06, guys were reporting their intake manifold had literally a pool of oil laying in the bottom of it. Catch-cans came out and guys who had removed their intake manifold without a CC, and then again thousands of miles later with a CC saw a night and day difference. Instead of a huge pool of oil, there was maybe a slight film and no sign at all of pooling.

If you are removing your intake manifold on a regular basis to clean it then a catch can will extend the intervals but it won't keep it clean. How do you know a catch can is 80-90% effective? Did you test this using the scientific method or is that a "feel-good" number? What if it is only 10% effective?

I doubt many people are going to remove their intake manifold just to inspect and clean the oil out of it. Based on what I said above about the C5 Z06, I'd say those CCs were pretty efficient.

With that said, when I swapped my intake for the gt350 it was completely dry and free of oil. Catch can not needed? I'd bet you 100 bucks that if I installed a catch can it would "catch oil." I've tested that on a few cars at least....

Guess you don't need a CC then. Not sure I'm buying your intake manifold was bone dry - probably still had an oily film inside it.

I didn't wake up one day and decide not to like catch cans. It happened over 15 or so years of screwing around with the them and pcv systems and getting nowhere.

And based on what I've seen and my own experiences (I also had my intake off on the Z06), I'd rather run a CC than not.

How many people just take it for granted that if there's something in their catch can then it's doing its job and they're so relieved to have it? Everyone, lol.

If there is something inside the CC, then it's doing something. If it keeps even just 1 oz of oil out of the intake manifold every 1000~2000 miles in normal driving or much more than that if tracked, then IMO a CC is worth having.

By the way, you're getting lots of oil and exhaust and carbon all over your intake manifold and valves from the other direction, up from the cylinder, during camshaft overlap which is......every rotation of the crank.

Valve over-lap blow by isn't contaminating the intake manifold enough to even detect. Besides, if over-lap happens the exhaust gases will go into the cylinder, not the intake manifold because the cylinder is at lower pressure (due to the intake stroke) than the intake manifold is. And with port fuel injection, the intake valves should stay very clean if you're using a decent fuel that contains cleaning agents.

 

[Higgs Boson]

Granted, every engine and it's PCV system will work somewhat different. When I had my C5 Z06, guys were reporting their intake manifold had literally a pool of oil laying in the bottom of it. Catch-cans came out and guys who had removed their intake manifold without a CC, and then again thousands of miles later with a CC saw a night and day difference. Instead of a huge pool of oil, there was maybe a slight film and no sign at all of pooling.



I doubt many people are going to remove their intake manifold just to inspect and clean the oil out of it. Based on what I said above about the C5 Z06, I'd say those CCs were pretty efficient.




Guess you don't need a CC then. Not sure I'm buying your intake manifold was bone dry - probably still had an oily film inside it.



And based on what I've seen and my own experiences (I also had my intake off on the Z06), I'd rather run a CC than not.



If there is something inside the CC, then it's doing something. If it keeps even just 1 oz of oil out of the intake manifold every 1000~2000 miles in normal driving or much more than that if tracked, then IMO a CC is worth having.



Valve over-lap blow by isn't contaminating the intake manifold enough to even detect. Besides, if over-lap happens the exhaust gases will go into the cylinder, not the intake manifold because the cylinder is at lower pressure (due to the intake stroke) than the intake manifold is. And with port fuel injection, the intake valves should stay very clean if you're using a decent fuel that contains cleaning agents.

LS1 and LS6 were probably the worst ever for poor PCV systems, I had one too, it was horrible.

If the piston is on the upstroke and the intake valve is open, which it is, the gasses are getting into the intake manifold. It's reversion. And it's no more (in)consequential than PCV gasses. In a normal daily driver PCV is not effecting ANYthing.

 

[GT Pony]

LS1 and LS6 were probably the worst ever for poor PCV systems, I had one too, it was horrible.

Well, for that engine at least a CC was definitely helpful. And in general, having a CC isn't going to have any negative effect on the PCV system, and in the long run will be helpful by keeping a big percentage of the oil vapors out of the intake manifold. I like 'em, I use 'em. If you don't believe in them, than that's all good and fine for you. Nobody is going to convince me that I shouldn't run one on my Mustang.

If the piston is on the upstroke and the intake valve is open, which it is, the gasses are getting into the intake manifold. It's reversion. And it's no more (in)consequential than PCV gasses.

Exhaust gasses are not "oily", so it doesn't cause any oil residue inside the intake manifold - really a non issue.

In a normal daily driver PCV is not effecting ANYthing.

I'd say it is, by evacuating the crankcase of harmful condensation and combustion byproduct blow-by. The last thing I'd do is run open breathers on my engine for street use. For full out track use, yeah open breathers would probably be better due to lots of WOT use. But I would configure the breathers only for use during the track event, then go back to the closed PCV system afterwards.

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