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408 TT sizing

 
Old 01-04-2019, 05:45 AM
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Default 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?
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Old 01-05-2019, 11:01 PM
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I currently run 6266ís .81 A/r on my 416 LS3. Peak power is around 6k rpm and boost comes on hard. For more rpm you could go bigger turbos or .96 A/r. Graph attached (10psi and 13psi).

what are your power goals?

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Old 01-06-2019, 10:11 AM
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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+
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Old 01-06-2019, 12:19 PM
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Originally Posted by turboed370 View Post
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+
what cam and heads?
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Old 01-06-2019, 05:18 PM
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Stock 317s stock ls6 intake. Cam is a custom grind very similar valve events to the ljms stg3
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Old 01-06-2019, 06:14 PM
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That cam probably peaks around 6200-6300rpm with those heads.

A lot of guys running twins... surprised nobodies chiming in.
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Old 01-06-2019, 06:25 PM
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Originally Posted by turboed370 View Post
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+
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.
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Old 01-06-2019, 11:28 PM
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Originally Posted by Game ova View Post
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.
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Old 01-09-2019, 04:54 PM
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Cam and intake will determine rpms more than turbos.
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Old 01-09-2019, 05:57 PM
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turbos will determine rpm more than cam and intake.
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Old 01-10-2019, 05:17 AM
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Originally Posted by stevieturbo View Post
Cam and intake will determine rpms more than turbos.
Originally Posted by subeone View Post
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.
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Old 01-10-2019, 12:03 PM
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he needs a 88/100 or 85/100 for that 408
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Old 01-10-2019, 01:34 PM
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Originally Posted by subeone View Post
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.
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Old 01-10-2019, 02:59 PM
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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.
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Old 01-10-2019, 11:19 PM
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69/73s in twin config s400 frame
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Old 01-11-2019, 03:11 PM
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Originally Posted by subeone View Post
turbos will determine rpm more than cam and intake.

load of bollox.
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Old 01-11-2019, 03:13 PM
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Originally Posted by stevieturbo View Post
load of bollox.
Settle down stevie, for us here in the U.S, what is bollox?
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Old 01-11-2019, 03:26 PM
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Originally Posted by Game ova View Post
Settle down stevie, for us here in the U.S, what is bollox?
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Old 01-11-2019, 08:52 PM
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Originally Posted by stevieturbo View Post
load of bollox.
its true
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Old 01-12-2019, 06:42 PM
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Originally Posted by subeone View Post
its true
Please explain
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