Charting A T04E 57-trim Compressor WheelUsing a 15-psi max boost level the pressure ratio tallies 2.02. Plotting 2.00, we see peak efficiency will be realized when the wheel is moving 26 to 33 lb/min of airflow, which is capable of supporting 260 to 330 horsepower. If the engine in question is tuned to pump out 400 horses this T04E 57-trim wheel will need to see a rise in max boost to about 23 psi. Can the engine handle that kind of pressure? Does it have forged pistons and upgraded rods?
Even at this setting the efficiency is in the second ring. Also, look what happened to the wheel speed. It went from around 87,000 rpm to nearly 106,000. This will heat the charge air even more, working the intercooling system. While this wheel would get it done at 400 hp, a move to a bigger wheel may be better while also leaving some wiggle room for turning up the boost at a later date when the engine and/or the fuel system etc. are modified to handle the extra pressure.
Shaded Area
Peak efficiency for this compressor will be realized on an engine running 15 psi that is expected to generate 260 to 330 hp.
Dot-1
Here we see where 15 psi and 300 hp plots; right in the peak efficiency island.
Dot-2
With expectations of 23 psi and 400 hp, efficiency is bumped into the second ring. Wheel speed goes from 87,000 rpm at Dot 1 to more than 106,000 rpm here. Intercooling will be of prime importance. Can the engine handle 23 psi?
Dot-3
Expecting 15 psi and 450 hp, we see the combination plot outside the map in the overspin choke area. This compressor is way too small. A better flowing wheel or the move to a bigger housing/wheel combination is in order.