[200q20v] RE: [birabrakes] Audi 20V Turbo Crankcase Breather System Tu ning, help neede d !

tommy.arnberg at nokia.com tommy.arnberg at nokia.com
Tue Oct 31 16:46:33 EST 2000

The file  [ Crank_breath.ppt ]     can be found from here:
Site contains some other nice material also
-----Original Message-----
From: EXT C1J1Miller at aol.com [mailto:C1J1Miller at aol.com]
Sent: 31. October 2000 16:24
To: tommy.arnberg at nokia.com; ouellette at snet.net; birabrakes at egroups.com
Cc: 200q20v at audifans.com
Subject: Re: [birabrakes] Audi 20V Turbo Crankcase Breather System Tuning,
help neede d !

In a message dated Tue, 31 Oct 2000  6:40:05 AM Eastern Standard Time, 
tommy.arnberg at nokia.com writes:

Hello !

As you all know the breather system is closed 
and when boost is a little higher than stock, 
then the crankcase ventilation system in 3B 
engine (200 20V)  pushes the polluted oily air fume back 
to Turbo charger "mouth"

- conceguences:
    * fuel octane rating in mixture to be burned gets lower 
    *   Inter cooler cooling ability gets worse because of oil-air fume
     *  the inlet valves get burned oil build up (the worst of  all)
     * air into engine gets warme
The operation of the crankcase breather hose is explained in detail on Scott

Mockry's excellent (as always) pages, here:

"This breather hose is routed around the back of the engine and one end 
connects to the round black crankcase pressure
     regulator valve near the back of the valve cover. This black regulator 
valve, controls the flow of crankcase fumes to the turbo
     intake boot. The valve has two ports inside, one is approximately 0.400

diameter and a smaller one that is approximately
     0.180 inches. The larger port and the smaller port are open during low 
boost operation but when the turbo makes enough
     boost and flows enough air to produce a vacuum on the suction side of 
the turbo, the regulator valve diaphragm sucks closed
     and blocks off the larger port. This leaves only the smaller port open 
to flow crankcase breather fumes. "

There is more, including a diagram, but the basics are that the breather is 
mostly closed off during higher boost conditions.

The Gastank ventilation is operated with the 
"Blue valve" to inlet manifold. The piping has a 
valve that prevents back flow from inlet manifold during boost 
condition and during vacuum it sucks the air from crank case and 
through the blue valve from gas tank ventilation system.

Has anyone disconnected / modified the stock system following
way or better way ?  what is the right way.   (I know this is not 
legal but otherwise the engine gets older a lot faster !)

[ Crank_breath.ppt ] 

If someone knows good  product that solves this problem, 
please mail www-pages and/or source s  for it !

Looks to me like you want an oil collector system to limit oily vapor from 
being combusted. I've seen other turbo cars install a "settling tank" where 
the vapor can collect, condense, and later be drained...

Tommy:  can you store that file somewhere that the 200q20v owners can access


On my car, with 5000 mile oil intervals, I burn very little measurable oil; 
perhaps 1/2 quart at most?  

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