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Gaijin Smash Wayhoff

Crankcase Ventilation / Catch Can Setups

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I can try it, if I fail I just can't insure my car for long, I was thinking maybe I could just route it into the external gate's dump pipe? cause it doesn't recirculate into my exhaust...

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That might work, at least it should would work under full load when the gate is open... other than that it'll act like a draft tube. Wont be picked up from emissions testing. But the main thing about the exhaust venting is you do need flow to create a vacuum right?

Just a example

So say you're cruising on the highway at 3000 rpm, gates not open, pressure will build up in the crankcase and open the check valve, so crankcase pressure is higher than atmospheric in this case to even open up the valve. Might cause oil leaks, less cruising power, lower cruising gas mileage. Maybe the gate dump could placed and the end shaped in a way to create a venturi to create the vacuum you need for non-WOT venting.

 

I don't know how well the exhaust venting actually works but my understanding is its suppose to use the low pressure that follows each exhaust high pressure pulse to create a vacuum on the crankcase. There should almost always be a vacuum with the outlet in the exhaust flow and the engine running.

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These check valves open at less than 1 psi, won't cause any oil leaks unless your engine is completely shot, in which case it won't pass any sniffer tests anyway.

 

The vacuum is caused by the exhaust gas rushing past the tube, just the way carburetors work.

You can see this by sticking a straw into a can of soda, and blowing air across the top of the straw with a blow gun.

You get an instant home made spray gun.

 

And unless your engine is worn out anyway, about all you get out of the crankcase is exhaust gas that is leaking past the rings.

Very little, if any, oil will make it past the seperators in the cam covers.

And if you are really concerned with it, throw a catch can on just for the inspection, and fill it with charcoal briquettes.

That will absorb a lot of contaminants, for a short period of time.

 

NOx readings can be reduced if you have adjustable cam gears, just dial in a little more overlap, and you get the same results as an EGR system.

 

There are all sorts of ways to get by sniffer tests, but it's helpful to have a sniffer yourself.

Down here, they just tell you what's wrong, and tell you to come back with it fixed.

I have one buddy who took his MR2 to the inspectors like 4 times before it passed, but once it did, he just put things back to where they were before.

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maybe I could do some sort of air injection, a air pump that has its own check valve and feeds into the dump pipe before the feeds for the PCV valves. That could create the vacuum I need, wouldn't it?

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I think you are trying to over complicate things.

I have the same silly ideas.

Went as far as to pick up a large Co2 tank, and a solenoid valve so that I could blow strait Co2 into the exhaust to make the percentages of everything else look lower.

Never used it, never had to. We didn't even have tail pipe sniffers here in San Antonio.

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My thought about the oil leaks was if it was just to atmosphere, pcv to open waste gate dump tube. Because there would only be flow past the pcv outlet when its open - WOT. I haven't tried just venting to atmosphere.

 

Also remember k.i.s.s. - keep it simple stupid

 

Or

 

You could do a trifecta of crank case ventilating power, intake manifold vacuum, exhaust pcv, and catch can.

 

Or

 

You could copy Audi crankcase/oil separator design, they maintain an almost constant 14 hg vacuum on the crankcase.

 

Or

 

You could dry sump it, pretty expensive pcv solution

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I pull and fill the exhaust side nipple next to the the turbo and weld a -10an to the back of the valve cover than I route -10 hose from the valve cover to another -10an welded to the turbo intake pipe . I consider the catch can optional but if I were to use one it would go inline between the -10an valve cover and the -10an turbo intake pipe . This technique works well for vvt-i jz engines as you can use the easier to find non vvt-i valve cover gasket on the exhaust side valve cover if needed . Also you can use an exhaust pan-evac valve instead of the -10an turbo intake pipe .

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my original L-shaped tube on the exhaust side valve cover from my 1J twins just sits there venting to atmosphere after i went single lol

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