with the t66 i see this turbo on a lot of H/C/I mustangs and a few imports this truck thing must be a growing. i have a guy at work that got a 1990 gmc short bed 1500 as a roller we went to the junk yard and found a really nice sbc 350 dirt cheap. we sat it in a few days ago and fired it up and feels strong no issues. on or local bookoo a guy had a t66 and he got it as well. we want to put that turbo on with a csu carb and other turbo mods. at first he just wanted a fun lil truck but he wants to race it at the track in the spring..... he wants the truck to go from 7.50s to 8.0s in the 8th mile......the truck scales 3950 with him in it. we figure the motor makes about 225-250 at the fly wheel with the 041 heads and stock bottom end


will the t66 in the gmc @3950lbs go those numbers at around 10-14 lbs of boost

 

ok so doing more home work and trying to read the turbos map

lets say that the junk yard 350 needs 50lbs/min and density ratio of 1.65 when you look at the t66 map as long as we run up to the 14 lbs of boost this turbo will actually work well but if we need to turn it up to run the number this turbo starts getting close to the max eficiency meaning a larger turbo would be needed if it doesnt make the power needed to run numbers he wants?

or do i have it all wrong
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Persoanlly I'd run a chicomm gt45 and be done with it. Or a BW unit if you can throw a bit more coin at it. Lots of guys going those numbers easy with a $300 spinny muffler thingy from china.

 

He already has the t66 and started building money is already spent ..... How will this turbo perform .....it has a p trim wheel and .96 a/r turbine housing

 

It will work fine. Turbine is smallish. But should do the job you need it to do.

 

Honestly if I were going to do a combo with this it would be a nearly stock engine. Ditch the stock intake to even up air flow, switch toa DP and leave it at that if carb, or run it with a TPI intake if EFI. The more modified your engine is the worse the mismatch will become. The old Turbosonic kits used to use a smaller head unit than this, but you're also talking a 350 that made 200hp net as well. I would keep a tight converter in it (AKA stock) and see what it does with that before buying a stall converter. I would also try to keep the shift points low at first and see what the turbo does. Depending on the weight 8 flat may be a bit of a stretch, but using a T4 foot print it will be easy to size up later.

 

how much boost will this turbo need to run those numbers

 

My estimate, 17-18psi. The turbo will flow the air if the motor will hold together. Put good gas in it and let her eat I say.

 

why so much boost. i told him that at that boost level back pressure and the IETs would be high....i think the turbo would be over speeding to keep up with the lil 350.

 

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this mustang is coming on boost like he has a supercharger vs a turbo lol this cant be good again fun for the streets but seems like the turbo is working hard as hell to keep up with the 331

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[video=youtube;J8RFY2fv4LU]https://www.youtube.com/watch?feature=player_detailpage&v=J8RFY2fv4LU[/video]

 

Because the turbo is small. Your 100% right, most likely the temps are going to be high, and the boost will need to be high to make enough power with that turbine. But that turbo is capable of doing what your going to ask it to do, its not ideal.

 

I just ballparked it and figured you'd need 500-550hp to run those times, then figured how much pressure you'd need to flow the air mass necessary for that power level. Since atmospheric pressure is just under 15psi, another 15psi from boost will roughly double your power. But nothing is ever perfect, (parasitic losses, plus chassis set-up,) so I tacked on a couple extra psi to get 17-18. If you open up the engine to flow more air, less boost will be needed.

Back pressure may be a little on the high side, but there are a few things you can do to help with that:
-Run a cone directly off the turbine outlet expanding from the turbine's 3" diameter to 3.5" or 4". Maintain that diameter for the remainder of the system, being mindful to keep the flow path as short and straight as possible. Smaller tubing with fewer, or larger radius bends is more favorable than a twisted mess of large tubing. This actually goes for all other parts of the turbo plumbing as well.
-If you use a muffler, use only a straight-through, perforated core type design. Magnaflow, dynomax ultra-flo, etc. No baffles, chambers or louvers.
-Use thick wall, stainless tubing for your headers and crossover, and wrap them to hold heat in.
-You have the option of some much larger turbine housings should you need it. 1.15, 1.32, and even 1.52 are available.

So long as your intake into the turbo isn't restrictive, over speeding will not be a problem. That compressor could make somewhere around 750hp and 30psi or so before you're out of the map. I actually think that turbo is a pretty good fit for your motor.