[200q20v] Audi 20V Turbo Crankcase Breather System Tuning

[Kneale Brownson]

Aren't most of our (US) boost enhancements more or less efforts to make the 
engines perform the way they were designed for other markets?  Did Audi 
include in its US designs a different crankcase pressure regulator than in 
the engines we've tried to emulate?  Do those "other" engines use the same 
air filtration as "ours"?


At 12:08 AM 11/02/2000 -0500, Phil Rose wrote:





>My own naive view is that you need to maintain a closed loop and just take
>out as much oil as possible from the crankcase air flow before it reaches
>the MAF, turbo, IC, MM-hose or IM. Seems to me that the "vented" approach
>will have inherent problems (unmetered air, carbon canister fumes, etc.)
>
>An important preliminary step was indicated by Chris, which is to establish
>whether or not the oem crankcase pressure regulator is at fault if
>excessive quantities of oil are observed to coat (contaminate) the intake
>tract. Possibilities are (1) that the crankcase pressure regulator is
>simply defective, or (2) that if not defective it is inadequate; that is,
>that minimum breather pathway (0.180" dia aperture) through the
>regulator--when seeing turbo-intake vacuum--is simply too large for boost
>levels that exceed the stock 1.8 bar design.
>
>One further question that comes to mind is: to what extent is a
>crankcase-breather problem caused by an air filter that's too restrictive
>(e.g., too dirty)? I raise this point since the turbo intake-tract vacuum
>(which is what pulls in the crankcase gases) ought to be be significantly
>impacted by the airbox/cleaner restriction, right? Hence, I wonder if the
>people who use K&N air filters (and have boost mods) experience less severe
>"contamination" from the crankcase breather, since wouldn't they be
>operating with a lower vacuum at the turbo intake?
>
>Phil