VGT compounds

kidturbo

Piston Tester
Jul 21, 2010
2,320
1,082
113
Somewhere On The Ohio
www.marinemods.us
Yeah, we actually learned the 2x T4-61mm Nelsons were TOO DANG BIG for a Duraamx in a sequential configuration. With smaller 80% injectors they would make about 32lbs boost open scroll with lots of smoke and lag below 2500R. We blocked a scroll on each housing, got em up to around 35psi with a little cleaner bottom end. Then we changed injectors to 100% overs, opened up the scrolls again, and they were just starting to come on hard at 4200R and 37psi boost when we ran outa camshaft. Made around 750hp..

Banks guys tossed us a bone and said they'd tested with a pair 300 series running mid 50 mm wheels on similar engine setup. Those performed decent but made no more power. So due to time constraints, and the fact no options for 58mm T4's out there in the R/L design, we scrapped the twins testing and went to a S476 Bullseye single. Same engine setup jumped to over 56psi boost at 900hp, and made more boost at lower RPMs with less smoke.

I still want to experiment more with an actual twin VGT setup to see what can be gained. But that's gonna require a half dozen different turbos ready and loaded to swap out to make it worth while. If your goal is quick reving power under 750hp, I believe there is something to be gained with this type setup.
 

Robby Avery

GM TECH @ FENDER GMC
Jul 31, 2008
820
2
18
Norman Park, Georgia
If say a said compound arrangement like a 71.5mm cheetah and what larger vgt would work just curious? Would be nice to have compound Garrett vgts just need a controller for larger vgt