The goal was to spec out a turbo to run in NASA TTS class at low boost. Even with the small billet and conservative tuning, I overshot my 330-340 rwhp target.

Relevant specs:
- Fresh rebuild, street ported by David Jerome
- Journal bearing PT6062, undivided
- 3" exhaust routed WG, resonated MP, RB cat back
- M2 medium SMIC, HKS Twin Power

362 hp / 304 tq on wastegate alone. It was supposed to be a .7 bar spring, but for some reason the boost jumped to 14.9 psi and tapered down to around 11.5 psi at peak hp.




429 hp / 349 tq, again the boost peaked at 18.6 psi and dropped to around 16.5 psi at peak hp.




400 hp was achieved at approximately 14.5 psi.

Not sure why the boost is dropping off at higher RPM, but it may be a happy accident since it fattens up the torque a bit in a horsepower limited class. Regardless, the WG will need a lighter spring to get under 340 hp because neither the car nor the driver is prepped to play with the big boys in TTU.
I'm not sure if PTE still makes the 6062, but it's a nice responsive little turbo for road course duty.

 

congrats... quite impressive actually!

 

nice numbers , looks like a good powerband.

 

Great results!! If the hotside is under a 1.0. I would assume that the turbo is choking up at the top end. Either has to be that or a boost leak. G

 

very nice indeed

 

Top end looks like around a 1.00 . It's re routed so it will flatline past 6k rpms

 

Thanks for the kind words guys. I'm pretty sure there are no boost leaks.

It's a T4 .81 A/R hotside. The 62 turbine wheel is bigger than a GT35R. I didn't expect it to choke, but that may be a bad assumption?

 

It really doesnt look too bad. It choking some but usually you see a real nose dive with an .81 after 7k. My 35r used to flatline up top but it was a t3 1.06 so fairly small turbine housing as well.