I have to replace the cylinder head on my GLH, which means it is a good time to revisit the turbo I've got in there.

The current turbo is a T04B V trim compressor wheel, T04B compressor housing, T3 a/r .63 turbine housing, stage III turbine wheel with a ATP ultimate wastegate.
It will surge above 27psi. Below is the compressor map I calculated using data from MS log and Dyno graph.

I potted the same graph on a T04E 50 trim, and it looks like I will stay out of surge but I am left with only a little bit of head room to make more power.

The new cylinder head will flow 10% or so more CFM, can I assume I will be less likely to surge if I stay with the V trim turbo?

I wanna see 400whp with my setup and a wider power band is always better.

T04B V, blue lines is 367whp settings, pink lines is 248whp setting


T04E 50 trim, blue lines is 367whp settings, pink lines is 248whp setting


Dyno, red lines is 367whp settings, blue lines is 248whp setting


MS on the 367whp