408 TT sizing
 

Ran a pt88 on my old 370 and it worked great! Sold the motor kept the kit and turbo. Put together this 408 with that same old turbo and it's done making power around 5800rpm. Picked up a huron twin kit but now debating on turbo size. I'd like the car to pull to around 6300-6500. Anyone have any recommendations? How big on the turbine side do I need to achieve these kind of rpm?

Dont necessarily have a power goal in mind. Looking for low 9s maybe clip an 8.9. I just dont know how to gauge sizing twins. The car has been 9.6s with the pt88 but my mph was like 137..the car falls flat after 5800rpm. Would like to carry the power out a little further and trap 145+

Stock 317s stock ls6 intake. Cam is a custom grind very similar valve events to the ljms stg3

I don't think your turbo choice was the problem with the 370. Should have been truckin up top imo, there are guys running 145 with the on3 stuff (7875)..... been 140 in a full weight f body leaving in vacuum at the track. Id say the problem was elsewhere.

137 was with the 408 I beleive I ran into back pressure issues with pt88 and 408...IATs would go insane once I clicked 3rd gear..I never actually measured it but can tell you I did blow out 2 exhaust gaskets from the manifold to crossover.

Cam and intake will determine rpms more than turbos.

turbos will determine rpm more than cam and intake.

yea I would figure he doesn't wanna end up with too small on exhaust side. At least that's what I'm gathering from this post. I think hes trying to avoid the back pressure issues that caused his previous set up to fall off at 5800.

he needs a 88/100 or 85/100 for that 408

I would agree for a single set up but the threat title says TT.

No track times but I'm running T-Netics 66/65's with a .68 turbine. The turbine housings too small but puts out a Massive amount of torque. Only pulled it to 6400 and laid down something like 770/880. On the gate, don't remember how much boost pressure.
408 ci BTW. I think if I get larger housings I'll see the HP go up and the torque still be very high.

I'd go with billet turbo's in the mid 60's compressor range with a Med-High A/R T housing.

69/73s in twin config s400 frame

load of bollox.

Settle down stevie, for us here in the U.S, what is bollox?

its true :cool:

Please explain