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Discussion Starter #1
what sort of air volume is needed to make 1500 hp?
 

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Roughly what size turbo would support that flow? Gt4788?
Depends on how much boost you want to run to make 1500hp, and also your cubic inch to make sure the turbine side can handle it.
 

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Garrett says the GT4718 flows 139-140....are they stretching the truth?
 

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Ok im a bit confused. The 4788 is from PTE right? the 4718 is garretts model name for the same turbo 88mm inducer 118mm Exducer. 92.7mm inducer turbine wheel. They are essentially the same units...

I agree it would take way more turbine to get that thing to 140 lb/min and beyond.

If you arent impeller size restricted, just run a 91 or 94.
 

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A BW S510-95 or 98 would be my pick for a 1500HP turbo. 111mm turbine wheel and A/R choice as application warrants.
(.85, 1.0, 1.15, 1.45, 1.6 ) The 95 is rated to 1750 and the 98 is rated to 1850 but those appear to be at maximum conditions.
 

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Ok im a bit confused. The 4788 is from PTE right? the 4718 is garretts model name for the same turbo 88mm inducer 118mm Exducer. 92.7mm inducer turbine wheel. They are essentially the same units...
Just a different form of nomenclature for the same turbo. Most drag racers seem to only care about or refer to the inducer size.
 

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I did look up the Garrett unit, 4718. Same turbine. Compressor will out flow it. I am the guy that watches the boost control duty cycle to tell when you are running out of turbine. When you have to add an exponential amount of duty to achieve the next level of boost, you are running out of turbine. For example, if the car makes 15 psi o gate spring, and you have to add 7% or 8% duty to reach 20 psi, then 7% or 8% duty more to reach 25 psi, then 20% or 25% duty more to reach 30 psi, you are running out of turbine. The 4788, or the 4718, what ever you want to call it, runs out early. That has been my experience, and 1200 rwhp is a task for that turbo on an efficient motor.
 

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One of the reasons the GT47 turbine seems limited is the aero design of the turbine. PTE may have a better variant at the same inducer/exducer sizes but don't know for sure.

Without going into too much detail, the GT55 turbine has far better aero for a competition charger. The efficiency is very high to start with and stays there as you go up in pressure ratio.....heads and shoulders above the stock GT47 turbine.
 

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I ain't that smart, I have just played with turbo's in that size range.
One of the reasons the GT47 turbine seems limited is the aero design of the turbine. PTE may have a better variant at the same inducer/exducer sizes but don't know for sure.

Without going into too much detail, the GT55 turbine has far better aero for a competition charger. The efficiency is very high to start with and stays there as you go up in pressure ratio.....heads and shoulders above the stock GT47 turbine.
 

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Discussion Starter #15
what is an affordable single turbo (i know hp = $$, but what off shelf units, not billets etc), t6 flange, for a sbc, to pass that much air?
 

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BW pn 179191. Billet 91mm, newly designed front cover, with a 110mm turbine. Rated at 155lbs/min. $2600.
what is an affordable single turbo (i know hp = $$, but what off shelf units, not billets etc), t6 flange, for a sbc, to pass that much air?
 

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what is an affordable single turbo (i know hp = $$, but what off shelf units, not billets etc), t6 flange, for a sbc, to pass that much air?
pt94
pt101
pt106
gt5533
 

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Shearer....just curious but any particular reason you left the PT98 off the list? something bad about that particular wheel size?
 

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FWIW apples to oranges comparison but I know of a similar HED sbf that made 1200-1250 to the tire if not more now with a PTE Billet wheel LF 88. I know you said no billet wheels and cheap, but a 88 does have the capacity to do it with a set of great heads and the best sheetmetal intake money can buy along with a really efficient a/w intercooler and it can be done.

That being said it will be a lot easier to do it with a PT94 or PT98 or comparable BW unit.
 
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