I'm fitting a 7a cam cover to my 3b project so wondering what breather options people have done ?
7a Breather Options
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Where ever you put the breather outlet, don't fit it in the back of the cover. Put is somewhere in the middle, like this:

Audi UrS4 Avant 2.5 20vt - twincharged - Project
Audi 80q B4 Sedan 2.2 20vt - Daily user
BMW 320d Touring e91 M-Sport - Daily user
BMW 740iA e38 - Project -
Here is a proposed location for a catch can on an AAN, ABY or ADU (after the pressure control/regulating valve, downstream of where the crankcase and cam cover vent hoses come together):

Here is Steve Y's (now Posto's) 7A cam cover with an external pipe to the turbo to intake hose (which is unnecessary with a catch can):
RS2'd 93 UrS4 5 spd sedan
94 UrS4 V8 6 spd manual avantComment
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I was looking at that, but wasn't sure if it came from the valve cover..? Does the 7A cover has a breather in the back of the cover as stock, can't see one in this pic? The back of the cover is the worst place to take the breather out, you practically flood your breather system with oil on high rpm drag launches. Of course if you do a stock everyday driver there is no need for extreme breathing systems and catch tanks, but that does not mean the orginal location of the 20vt head breather is any good.
Audi UrS4 Avant 2.5 20vt - twincharged - Project
Audi 80q B4 Sedan 2.2 20vt - Daily user
BMW 320d Touring e91 M-Sport - Daily user
BMW 740iA e38 - ProjectComment
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From memory the 7A cam cover does not have a breather, you'll have to get one welded on. I welded mine on the back of the cover in the same location as the ABY breather but bigger, 16mm I think. I also welded a baffle on the inside to stop it getting flooded with oil under hard acceleration.sigpic
1991 Audi S2 3B - 2.5 Stroker engine
1997 A6 2.5TDi quattro avant - C4
1976 RD250E / 350LC cafe racerComment
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My 3b cam cover only has this as a breather, running nearly 400hp it worked ok. If my goal is to be 650hp on my project then double up the size of the breather to say 12mm dia, or do i really need a breather in the valve cover ?? Any thoughts anyone, realise that the rear of the cover can cause issues with oil into the breather system !Last edited by ian4455; 16 February 2012, 18:08.Comment



this system works very well on my car , I hope you find a solution
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