Originally Posted by fastgti69
The turbo is using custom wheels so it's always possible there is just a design flaw with the wheels or they are not properly matched up. As far as I know he did not touch the flapper/wastegate so I doubt that is screwed up but it's possible. But most likely the turbine side is choking it off. There isn't a bung in this manifold so I have no easy way to check the back pressure ratio but even at 3:1 I'd expect more top end boost based on the wheels. The way it quickly spools to 4 PSI then slowly goes up from there leads me to believe there is some sort of turbine side issues. Maybe related to the twin scroll. I've never seen the turbo so once it's off I'll look at it more closely.
He keeps claiming tuning so I ask what they'd like changed on the tuning end and I get back silence. If I can get the DME updated I will crank the timing up and fix the low end AFR. Maybe with tons of E85, meth, and timing, this turbo will hit 440whp. But I expect the factory turbo will hit 415whp with that same tuning.
The funny thing is this is using the same dyno Tony proclaimed as "high reading" when we were making 530-550whp using RB turbos. Suddenly now it's a low reading dyno, lol. "