Thanks for reply Horsham have done several dyno tests . Supercharger showing same boost no obvious engine problems supercharger pressure tested ok no leaks,
 
	Test pipes fitted still 354whip . The only thing there thinking is a blockage in the back box. I have a Stillen cat back system fitted. My next step is to dyno with back box removed what do you think any ideas?
 
	 Cheers 
 
	Terry