After suspecting mine was gone due to lack of boost at higher revs when I first bought my golf, I removed my old type valve which was split.
Put a rev D valve in and car was great boosted all the way through rev range and fuel consumption improved.
Now I'm back to square 1, inconsistent boost, can hear the boost leaking under acceleration and dumping a little at high revs, fuel consumption is awful again.
Valve has only done 800 miles, so I'm going to fit a rev G rubber type again, I no,it will split eventually but at least car will perform again.
So if anyone is thinking of getting a rev D dont bother there crap
