I've got the HTT 35/40 hybrid, 60mm wheel, and a 14cm WG housing.

I did my first dyno run with the WG set to 35psi, and the second run immediately afterwards with the WG basically blocked.

I made a few more HP/TQ on the second run (which should be less because of heat soak), the power came on a little more quickly, but most notably, EGT's are slower coming up at the higher setting .

This is comfirmed by road driving as well.at 35psi, on-ramp runs have me swinging to 1400 quickly, but with the WG blocked, it takes MUCH longer, and usually doesn't get past 1300-1350 before I have to let off because of speed.

So yes, drive pressure may be up.. maybe I'm just blowing superheated air, but the truck responds better.

Just an observation.

 

How much boost are you running with the wastegate blocked?

 

41psi is about perfect for that compressor wheel...

your drive pressure is probably pretty good. you could experament with a pressure relief type wastegate adjuster, but I'd just leave it pinched.

 

Agree with above !
I would think you are right at the upper limit of the efficiency map... right where you want to be. Your street observations confirm that. I would not go any higher on the boost but good as is!

RJ

 

Oops! forgot to mention it.. about 41-42 PSI.

And it sounds GREAT at those pressures...

I only made this thread because I was told several times that 35psi is the optimum for good operation by several different people, even on the 35/40.