MadocHandyman

Please elaborate then.
If the oil is mixed in the air and the air is part of combustion then how does it not get burnt off?

Left Plate

Why don't you get Google Guy to look that one up for you?
Anybody that has done any kind of research knows that if you torture the numbers long enough, that you can get them to support most anything? I don't know what is up your *** over the use of catch cans, but you have brought forth no data to support any of your claims! On the other hand, there is plenty of supported data on this forum alone in the pictures of gunk captured to support the use, so why don't you do everyone a favor and go crap in someone else's thread? I have yet to see a certified mechanic or Mechanical Engineer dispute any benefits of catch can use!
Once again, what kind of engineer are you?

Left Plate

Because the combustion occurs on the side of the valve face and not the valve stems. The PVC system evacuates into the intake manifold directly above the stem side. If it got burned off then there would be no build up on the valve stems. Eliminate the buildup on valve stems, eliminate valve and valve guide failure.

Left Plate

This is the intake manifold setting upside down. Each on of those chambers sets directly on top of the valve guides shown in the above picture.

Left Plate

Unfortunately there are a lot of assumptions that happen on the internet, it goes both ways!
The question should be not if you "need" a catch can, but rather, why would you "want" a catch can? If you are one who is not having issues, or is satisfied with Fords fix, then you may not need a catch can? If you are one who trades every couple years, then you may not need a catch can?
The only reason that I mentioned RX is that as far as I know it is the only one that evacuates all the time. That is why you need to tap into the intake tubes so you have a draw while under boost as the intake manifold would be pressurized at that time and the PVC would be closed. One could run a single valve can and get some evacuation which would be better than none!

Theocoog

You're right about that. I assumed the guy meant what he said when he asked if he "needed" the catch can.

Peace

MadocHandyman

Sorry, pictured it wrong in my head. Statement retracted.

packplantpath

Pcv systems have always evacuated into the intake on every vehicle I've ever had. This isn't new. Burning it in the intake would be a backfire, and a sign of other problems.

The difference with DI is there is no fuel flow over the valves to wash pcv deposits off. But as said many times, most deposits come from the egr system. So a pcv can wouldn't really help there. And that comes straight from an engineer that works for ford. And is why they have done work on valve timing to minimize it. I'd say it is too early to get an answer. But there is currently no evidence of any of these trucks having valve deposit problems. There are deposits, but no evidence of harm or power loss has ever been documented. Doesn't mean it isn't there, but the more time that passes without some evidence the less likely it is to be true that valve deposits are a problem.

It is a calculated gamble either way. Anybody that says you need a can is making things up and anybody that says it is a waste of money is too. Pick your poison and in 3-5 years you can be vindicated or proven wrong.

jcain

They've had naturally aspirated direct injection gasoline production car engines since 1953, bud. Surely you meant to compare port injection to direct injection?

engineermike

So, we post dyno tests, mpg data, pictures of clean high mileage intake valves, patent info, oil analysis results, and calculations and that's "no data". Meanwhile, you all post pictures of Audi intake valves and bottles of liquid and that's "plenty of supported data"?

Well now you've seen one and I work with a dozen others that will tell you the same thing. None of us are selling catch cans though.