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??? for Turbo Gurus


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I'm always thinking about the TT SBC inthe back of my mind (which I should forget about until the damn car is finished and on the road malebitchslap.gif ), but if one were to TT a 383 SBC, what would the ideal Turbo specs be?

Assuming: 8.5:1 SCR, FI, maximum boost of 10-12psi, and boost to come on at about 3500 rpm to a max rpm of 6500rpm.

Like I said, nothing I plan to do in the very near future, but it is a helleva sexy topic, no?

 

Tim

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Tim, I have no real experience, but I enjoy playing around with TurboCalc. According to it, a 383 with an 80% VE, Ambient Air temp of 90*, 12 PSI, Compressor efficiency of 75%, and a 75% efficient Intercooler, the engine could support 710 HP and 574 Ft-Lbs at 6500 RPM. Also according to the program, the correct turbos would be a T3, 60 Compressor Trim, 1.06 A/R, or a GT25 350 HP model. I know virtually nothing about what these Turbo Specs mean, but there are plenty here that can elaborate.

 

The program also says you will need 101.19 Octane with 8.5:1 and 12 PSI.

 

Also, for a 12.1:1 A/F ratio, you would need 439 CC/min of fuel flow at each injector. It suggests this injector: Bosch 0 280 150 351 6Amp Peak, 2Amp Hold.

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Guest Anonymous

I could be wrong, but I think a T-3 would be rather small for that displacement (on the exhaust side especially). Wouldn't something like a T04E or something bigger be a bit better matched? I don't know alot about that either and best advice is if and when your ready call majestic or one of the turbo people and let them lead you to the right one, a badly sized turbo will either be restrictive or want to rip your neck off when the lag quits (although with a V8 I still contend the torque of the motor will cause you to pass through most lag before you know it). Just some thoughts and yes its a very sexy topic. :D

 

Regards,

 

Lone

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The program also says you will need 101.19 Octane with 8.5:1 and 12 PSI.

I think we should use propane injection for this fantasy project. 110 octane, so we could jack the boost up some...

Thure

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Guest Anonymous

TT SBC

This is a loaded questions: The 'correct' turbo has more to do with driving style than engine size, but if you were to ask me (I've done SBC turbo installs) something in the T04e-54-60 would be an ideal street/strip turbo. It would give the proper balance of spool up and high-end boost efficency. When it comes down to it, you can look at compressor maps all day, and crunch the numbers till the cows come home, but you really have to pick the one that looks best on paper, install it, and then see how far off you were.

 

10 to 12 psi on CA 91 octane pump gas is possible with the correct air/fuel/ignition maps, proper head configuration, static and dynamic compression, after-cooling, engine management, and H2O/Alcohol injection. I would never run this much boost without some sort of knock detector/ignition retard device, and the motor would have to be built to sustain some inevitable detonation. 8 psi is a more comfortable and forgiving boost level on the crappy CA gas, but even then, you're looking at detonation on hot days.

 

Anybody interested in this subject, please drop me a line - I know how to build a TT SBC, and I'm interested in getting involved in such a project.

Cyrus

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Guest Ziggy Vulcan

a TT SBC sounds like a cool idea to me. I have an issue of super-rod that has a sbc with twin turbos running 1370hp!! :eek::eek: They even said it was safe enough to run on the street!! but it was build by this professional guy who actually knew what he was doing and seeing as how I don't, I'll just stare at his with my jaw hanging wide open while trying not to get too much drool on the magazine.

 

Too bad he wouldn't share too many specifics because he makes money buy building these for people I think. It says to call him if you want him to build you an engine.(probobly costs a fortune and a half :rolleyes: )

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Guest Anonymous

Popular Hot rodding I believe did a TT LT1 making 900hp!! on 93 or 94 octane. But they also had lots of ceramic coating done, and Swains or something piston head coating. $$$$$ is whats is about of course, T3 definatly too small. 8.5:1 sounds good but remember the more compression you pull out the lazier the motor will run when not under boost. Which is where most of us drive 97% of the time, never reduce an engine to a low compression slug just for boost, when both can be had with careful build up and tuning. I have been studying on a 4.6/5.4 4V TT. The way more efficent combustion chambers can allow 9:1-9.5:1 with 14 lbs. on pump gas. Fun on the street all the time 2000-7000

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I do not think that a t3 would be too small in a twin application. They are used regularly as singles on 2L-3L engines, so therefore should be able to handle up to a 6L as a twin. I agree that there is no way that a single T3 would be able to handle a V8. This is all purely theoretical, as I have no real experience.

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