I have played around with a cross selection of N75 valves. The J &H made less peak bhp and less avg bhp across the whole rev range but the lower down turbo kick / power was a lost stronger.
What we did find is how the valves managed the boost. They made the turbo boost harder lower down in the rev range but lost some of the higher rmp boost. Its swings and around abouts at the end of the day. some drives like that harder kick of power, some like a stronger constsnt pull up the red line. I have remapped car with Audi H valves already fitted and I could tell the car didnt seem right when test driving. IMO stick with the stanadard spec valve. it will allow the remap to do its job right so you get the best perfomance across the "whole rev" range which will give you a higher avg bhp which will give you a quicker car. low down boost spikes make the car feel powerful, but when its on the dyno you will see where the power is lost higher up in the RPMs.
I think I will order some J & H valves in get them bolted to Bens AUM then stuff it on the dyno and do some back to back power runs and over lay the results, just to put FACT to this N75 saga.
Nick
