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Just curious, but how much power (RWHP) will twin 6766's support on a 404ci ls ? im really new to the turbo scene so im just trying to get a feel for what i have planned out, pros and cons, thanks.
 

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1000ish pump,1400ish on race gas depending on full specs, I suspect you might run outta turbo if you going for higher
 

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Our 70 chevelle just made 1104RWHP with twin 6766's on an LQ4 with E85. .96 T4 exhaust housings and spinning 7400rpm max.
 

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While were here, anyone know the power gains from the T3 sized turbine inlet/outlet housings vs a T4??
When George set me up with mine he said I could expect to see 45-60hp gains at that level.
 

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Geez, all these numbers make me very happy. We'll see in a few months........
 

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What sort of diameters or CSA do the different housings have ?

ie T3, T3 V-Band, and T4 say even for a same number A/R ?

We seen a thread discussing crossover diameter for a single setup, and it seemed that 2.5" OD was excessive in many cases, and than 2.25 or even 2" was better suited to keep faster spool, but no real negative effect on performance

So for a twin application, would even a large T3 V-banded turbine housing be much smaller than say 2" ?

What sort of pipe diameters entering the turbo is considered ideal for twins ?

Ive started to weld up some truck manifolds, and was going to stick a 90deg Sch10 2" ID pipe onto it. Would that be too small for the likes of a pair of 6766's and 1300hp or so ?

2.5" OD would be my other easy option with thinner wall tubing, although those bends are much longer radius, so might be difficult to fit.

And is w/g placement critical to overall flow ?

I'd be taking the w/g almost directly off where the cast is cut, so prior to, or part of the 90deg bend
 

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I have a sbf 331 with twin 6266, I had the t3 v band housings on and at. 18 psi she went. 9.30. Then we were seeing high back pressure so we switched to the t4. .81 housings. We did not change nothing I the tune and with just the housing changes we went 8.7 at 163 with same 18 psi. The t3 housings are big restrictions.
 

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Is it specifically the vband housings or just t3 housings in general?
 

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I have a sbf 331 with twin 6266, I had the t3 v band housings on and at. 18 psi she went. 9.30. Then we were seeing high back pressure so we switched to the t4. .81 housings. We did not change nothing I the tune and with just the housing changes we went 8.7 at 163 with same 18 psi. The t3 housings are big restrictions.
What was the backpressure before and after. How much rpm?
 

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The turbine side will become the restriction before the compressor side runs out of steam. Put some big turbine housings on them!
 

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Heat Effected Zone, what engine size? How aggressive cam duration?
No hard horsepower or back pressure numbers from me. But here's what I have to offer: 370" 3555# 159mph trap speed, 6262 .81 v-band housings 21# boost fairly aggressive cam. Added 2# boost IAT went up 24-26* car went 159 again.
 
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