Thread: 2015 Mustang
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Old 11-01-2012, 07:31 PM   #233
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1992 SVX LS-L


Originally Posted by Vostok 7 View Post
I would be amazed if the BOSS goes FI. The whole selling point behind the car is that it's a N/A Coyote cranked to 11.

I don't think the GT500 is destined for a twin-turbo setup. Sticking with a supercharger is much more likely.
The bigger the supercharger and the more volume it is asked to compress... the more power it takes to do it. It starts to cut into the net power benefit for the engine to be supercharged, and the engine has to be all the more stressed to push higher and higher output numbers.

Exhaust turbines are thermal waste recovery, and two compressors (twin turbos) can afford to be smaller each, and push the same combined volume in total. Since they aren't taking power from the crankshaft, only adding to it.... all added power is net added power.

If a supercharged 600hp V8 is using 100hp to turn it's supercharger at high engine speeds, where peak power is... it is actually stressed like a 700hp engine, but still outputting 600hp as a system.

A turbocharged 600hp V8 is not using 100hp to mechanically turn the compressors, waste exhaust thermal energy is doing that, rather than being wasted. The penalty of exhaust backpressure on the fluid dynamics of the engine is less than the mechanical power demand of a supercharger at peak RPMs, and the net gain of turbos are usually higher than the net gain of superchargers at higher RPMs.

If the turbines were mechanically compounded, rather than driving the compressors directly, they would be adding waste thermal energy as power to the engine mechanically, to more than off-set the mechanical subtraction of a supercharger... Like engines in some variants of the P38 Lightning. But that is another matter.

With Ford's V8, like the CobraJet project, The engine with direct fuel injection becomes part of Ford's EcoBoost family, if they choose to market it as such.... but a TT-V8 isn't exactly a greenie poster-child engine. It might be more fuel efficient per horsepower than most other ~600hp engines, and possibly even run on regular fuel, though...

It is not as if a 5.0-5.4-5.8-6.2 V8 is suffering for low-end torque as-is. If anything, supercharging the V8 makes the current GT500 less-useable, as the throttle has to be feathered all the more, to keep the rear tires from going up in smoke if you sneeze while your foot is near the pedal. Too much shock to the rear tires is not beneficial for traction, and positive displacement blowers sometimes have a hard time keeping up with the engine at higher RPMs.

Low end torque is even less of a problem with DI's allowance for higher static compression ratios to act more like an atmospheric high-performance engine when off-boost, and making less peak boost pressure make more of a difference.

If exhaust system packaging isn't too difficult (EB V6 seems not to have much problem) and maybe with air to liquid charge cooling in the intake manifold, (which they might already use for the Supercharger...) I can see how twin turbocharging the next GT500 would maybe be preferable than positive displacement supercharging.

But I agree... Boss 302 should be the best atmospheric 5.0 V8 in Ford's catalog.

Maybe they should do a Boss 380 drag-race special, with a twin-turbo 6.2... Sort of like a modern Boss 429. They could share that engine with the Raptor.
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Last edited by HipToBeSquare; 11-01-2012 at 07:47 PM.
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