Bypassing the blowby gas system to a catch can?

Brett Dikeman brett at
Wed Jun 2 21:14:53 EDT 2004

At 9:03 PM -0400 6/2/04, Huw Powell wrote:

>Couldn't one use some sort of filter, like a compressed air water 
>filter, to trap that oil before it gets into the intake tract?

Yes, one can be made from brillo pads and a suitable container with 
two connections.  There's also something rather similar made by VW 
that was on some cars- a lister sent me a photo and P/N once, it's 
buried on my system somewhere.  It's kind of small, not sure how 
effective it would be on a tweaked audi motor.  That's the cheap way.

   The expensive way is an air-oil separator, which is made by 1-2 
companies for the aircraft market; aircraft engines tend to blow a 
LOT of oil out the crank vent since they run at full load most of the 
time; heavy oil consumption is the norm.  The air-oil separator 
condenses nearly all of the oil vapor and returns it via a drain 
line.  They cost over $200, I think....and when I asked them if 
they'd be interested in sales to automotive users, ie a group buy- my 
emails were repeatedly ignored.  The positioning of the inlet and 
outlet was also less than convenient.

"They that give up essential liberty to obtain temporary
safety deserve neither liberty nor safety." - Ben Franklin

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