What's this "Valve" for?

[macspring]

Can someone advise what this valve is used for?

http://translate.google.com/translate?hl=en&sl=de&u=http://www.pk-motorsport.de/&sa=X&oi=translate&resnum=4&ct=result&prev=/search%3Fq%3Dpk%2Bmotorsports%26hl%3Den%26client%3Dsafari%26rls%3Den-us

Page 5, the last item in the list, "Pierburg exhaust valve"

Thanks in advance.

[Jamo]

Exhaust bypass valve, you have it as a bypass in your exhaust system so the gasses have a shorter route to escape without going through cats and silencers

[S2central.net]

Fitted to original RS6 IIRC to keep the sound levels down at low revs, but bypasses the rear silencers at when the loud pedal approaches carpet.......

I've always thought this would be a nice idea on the S2 - for a scream pipe on the wastegate - pressure controlled - but with override from the cabin via simple solenoid. Easy to say - harder to build and make reliable / robust for daily use... there is limited space to graft such a thing into the downpipe and with all the heat in that area I'd be doubtful of the longevity of an ordinary exhaust bypass valve.

[UrS4boy]

You mean this:

[UrS4boy]

You mean this:



The "can" is a vacuum activator that opens up the "exhaust valve" to create a bypass.

A manual version of the same is something like this:

[macspring]

Perfect,

Thanks guys.