After some advice, just purchased a single turbo converted rx7 using a power fc. I was amazed to see the knock levels, cruising at 60-70mph the knock is around 20-30 wih very rare occasional peaks to 40-50. The engine still has warranty so I spoke to the builder who assured me it was normal. The reason I find this odd is I also have a moddified impreza sti with a power fc, it normally never goes higher than 5/6 with a very occasional high of 15.

Can someone put my mind to ease, thanks.