To much fuel it starts to make the HP go down. Thats why most guys with P-7100's dont need to run the plate full fwd. Not enough timing and air to handle it. Looks like the same thing on the 3rd gens to me. Could also be low fuel supply pressure.

J.R.

 

That was certainly my observations when I dynoed my truck. I ran various combinations of TST and Edge EZ settings, and found that fueling beyond a certain point (in my case, power 5, torque 5, an EZ on 4) caused a loss of power. The higher the settings, the lower the power (5/5/4 produced 490HP, 7/5/4 made 420HP, and 7/7/4 made 400HP)

Fuel pressure was never a problem - always had >7psi.

I suspect that the reason the torque curve mimics the HP curve is that the inertial dynos (mine were done on a Dynojet) don't provide enough resistance to allow the boost to spool up. I wasn't making peak boost until about 2300RPM. We know these engines make their peak torque at around 1800RPM. Next time I'm on the dyno, I'll power-brake the engine to build some boost first.

Also, along the lines of defueling... does the TST do any kind of defueling based on boost, or is that dip in the middle of my graph just the wastegate on the turbo opening up?