what sort of air volume is needed to make 1500 hp?
Just a different form of nomenclature for the same turbo. Most drag racers seem to only care about or refer to the inducer size.Ok im a bit confused. The 4788 is from PTE right? the 4718 is garretts model name for the same turbo 88mm inducer 118mm Exducer. 92.7mm inducer turbine wheel. They are essentially the same units...
One of the reasons the GT47 turbine seems limited is the aero design of the turbine. PTE may have a better variant at the same inducer/exducer sizes but don't know for sure.
Without going into too much detail, the GT55 turbine has far better aero for a competition charger. The efficiency is very high to start with and stays there as you go up in pressure ratio.....heads and shoulders above the stock GT47 turbine.