Did lots of searches between 1.5" id and 2" id manifolds but most debated velocity and spool. Would I be at a disadvantage using my 1.5"id short runner manifold in the interest of response and spool over my presently installed 2" id manifold? Could the 1.5"id runner manifold flow enough make 550rwhp. I know Turblown uses 1.5" pipe, not sure about A-Spec.

 

Most definitely will work. Made 703 with 1.5 runners.

 

700HP on 1.5 id runners? , great to hear!! rx72c is your mannifold have long or short runners?. Do you have any pictures?

So are there any downsides to 550rwhp on short 1.5 runners?

 

So are there any downsides to 550rwhp on short 1.5 runners?

Only thing I am aware of is that wastegate placement/lead in becomes more critical.

The higher velocity exhaust gas is less likely to find its way out of a low WG priority junction.

Also, you will have increased affects from WG junction turbulence if you employ a high WG priority design.

 

Dont have any pics.
had 1.5 runners.
2 inch exit under turbo flange 60mm wastegate.
Was able to control boost from 10-35psi.

 

Is there anyone else making big power on 1.5 (38mm) runners