So I finally tuned the new setup on E85 with the fully built motor, S366, full race manifold. I'm happy with the power but something wasn't right. Granted it was hot in the Dyno bay, and the motor was super heat soaked, it was still way lower than I expected.

665whp / 429 tq @ 30 psi

3" dp to 3" exhaust
9.6:1 CR
Stock IM
Stock ported head and cams
S366 .91 twin scroll

I threw more boost at it but didn't gain 1 hp. This motor has always been known to flow like crazy and back pressure may be an issue here I don't know without testing. The 6266 I had made way more power sooner (500-600rpms) everywhere in the powerband.

The 6266 with stock motor made 685whp/495tq @26 psi.

The chart from today at 30psi.

 

a Twin-Scroll .91A/R isn't really that big...without logging EMAP it's hard to know forsure, but I would look in that direction.

 

Any engine bay pics? What size t4 twin scroll hot side are u running? Something is not right here. This turbo should max out at a much higher hp level. I'm guessing you need a 1.10 ar t4 divided hotside. This is a 2.2l engine? Dyno chart also looks really laggy to me for a 600hp twinscroll setup.

 

It's not that big but when I see passman making 800hp with it at 33psi it makes me wonder. That's 135whp different with damn near identical setup.

yeah 2.2L 9.6:1

 

I'm pretty sure Pass was using a 1.10 on his setup, I'm in agreement that the .91 seems rather small. It not making more power with more boost is a pretty good sign.

 

I think you'll be surprised how much more better the 1.10A/R performs...with high flowing, high rpm engines you need the biggest A/R you can get your hands on.

 

^ what those guys said.

 

I beleive it was JEff Evans that did testing on the twin scroll setups, and how he was having back kpressure issues, until he want crazy large.

Check out his site/blog for more info.

.91 is super small on a twin scroll mani/turbo.

 

Passman had the .91ar when he made 800 but every setup is different. I really need to invest in one of those pressure sensors.

 

Really? That seems way small for that power. I'm using a single scroll .91 on my s366.