Originally Posted by BLUE TII

My BNR Stage 4 gets boost around 1,300rpm and full 15psi 3,300rpm, but I would not call that a ultra quick spooling turbo-

compared to what can be done with a stock exhaust wheel and smaller compressor wheel.

The BNR retains the stock 1.00:1 AR exhaust side even if you put a larger wheel as AR is Area to Radius ratio of the exhaust housing. It is a small T3 sized 1.00:1 AR. The compressor AR will most likely be 60:1 using the TO4B 60-1 HiFi compressor section.

By using a huge wastegate positioned so exhaust flow favors the wastegate over the turbo you can keep the quick spooling "undersized" turbos from killing top end power.