I'm a newby to tuning and trying to tune my mates car, it was going good then all of a sudden lost boost during a wot run at about 5200rpm.
Now it will only see boost up to about 3000rpm then bleeds down to normal map.
The engine still runs fine, its not pressurising the sump or blowing smoke or noisy.
Car is a 2008 holden commodore L98 (6 litre with 0821 heads) 6 speed manual, cam is 227/227 .598 .598 112lsa, harrop hh122 supercharger kit (third hand)
It has gilmer rear belt setup and 8pk front belt setup (the belt is too short and there is not much movement on the tensioner.)
I have replaced the manifold gaskets and tried holding the bypass valve closed but still does the same thing
In the log file "lost boost" you can see were the problem first started at 13:30:25
any ideas?