If I had the money, I'd run the .91 non-gated with a turbine diverter valve.

 

Mine works well...

 

.91 would be cooler on top. And a diverter valve is not needed for any s300 turbo. A diverter valve is best suited with a minimum 66mm s400 charger.

 

Thanks fellas.

I will probably go with the .91 suited nicely with a Turbosmart b.o.v.

 

You need a external wastegate instead of a blow off valve. A bov will not limit your boost like a external gate, it will only relieve boost pressure when you let off the throttle.

 

I'm running a 63/68/.91 I can spool it with stock injectors but it's not the best. would be better with some bigger sticks. I've only hit 20psi and external gate still eating on the trans to break in

 

Sorry to hijack the thread but im ordering a 63/68 .88. Ive got a t3 .70 hx40 housing that i would like to use with it, for those of you with a 63/68 do you know what the exhaust housing needs to be machined to to fit the 68? Both width and depth? Thanks

 

I'm surprised at the number of guys saying run the .91...

Run the .80 housing. It will have plenty of flow up top, and it should be gated?

 

A lot of people under estimate on how much these Borg housings actually gate.

Pushing this 62fmw to 55 psi (60+ with gate closed) worth of fuel on the RC. I can't override the gate a single psi when it is gated at 40 psi. And that is with the .70 T3 housing.

A wastegate does wonders.

 

I wanted the .83 gated housing but didn't have the money at the time.

 

Sorry for the off topic question, but how would I correlate AR ratio to cross-section size in sq. cm? (like what AR is the stock 12cm2 gated housing on the HX-35, for example)

 

There is no accurate way of crossing it over.

However the general industry standard for a correlation is .80 is a 14, and a .70 is a 12 when talking about T3 foots on the S300 based turbos.