I. I guarantee you that if you log your exhaust pressure now, with the current engine, and later put a bigger compressor wheel in it, you would see a drop in exhaust pressure, and more power.
I can't wrap my head around this one, could you explain more?
Think about what is going on. How does a turbo work? The compressor section is a centrifuge. The bigger the wheel diameter, the lower the rpm the centrifuge needs to spin to move the same amount of air. (Lower cent. force per diameter with higher air flow.) If you agree with this, then you need to do two things to make sense of what I said. You have accept that BOTH wheels are spinning slower with the same intake airflow, and... you have to accept that centrifugal forces do not cease to exist in the turbine side of the turbo. Higher turbine speed will have a negative effect on flow through the exhaust side of the turbo, regardless of a/r, because the gasses are fighting the centrifuge they have to move through to exit. The profile of the turbine wheels are designed to minimize the effect, but you can’t eliminate the fact that you are essentially using the engine to force its “waste” through a centrifuge in a direction that fights the natural tendencies. Slowing down the wheels helps with the fight.
