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    More G-tech: this time hp and tq. numbers

    Ok, here are the results from my G-tech hp and torque runs.

    390 hp at 6850 rpm
    375 tq. at 4500 rpm

    The weight I entered was 3675 lbs. Air temp. was 83 F.

    The car is an '02 996tt with GT2 turbos, reprogrammed DME, air filter, blowoff valves, exhaust and headers. It is supposed to make about 550 flywheel hp. I am not sure what factor to use for the driveline and aero losses. The above numbers are after those losses. Max hp came at about 75 mph in second gear. Normally, I would use 15-18% for a 2 wheel drive car. This does not include aero losses or the 4-wheel drive loss factor. So, I would assume that the losses would be upwards of 20%, so you can do your own math to back into hp and torque at the flywheel.

    Dan

    Re: More G-tech: this time hp and tq. numbers

    For 390HP, I assume this is equivalent to RWHP (rear-wheel HP) with drag losses included, so if you're 20% off, then 390 + drag loss (390 x 0.20 = 78) = 468HP. But since RWHP x 1.15 = FWHP (fly-wheel HP, the #'s published everywhere which the factory uses, which is HP generated at the engine's crank, as opposed to RWHP which is the actual HP the tires put down on the pavement to transduce into force for propulsion), 468 x 1.15 = about 538FWHP, close to expected-assuming all "fudge factors" are accurate.

    Re: More G-tech: this time hp and tq. numbers

    Al-

    I'd like to say that I agree with the theory behind your math, although I agree with your math. I say this, because I'd like to see results close to the claimed 550 hp. Anyhow, what I mean is that your numbers assume almost a 30% loss from flywheel hp to FWHP. I was suggesting it was more like 20% total driveline loss with maybe 2% thrown in for aero losses. Does the factory really quote such high losses from flywheel to four wheel hp?!

    Dan

    Re: More G-tech: this time hp and tq. numbers

    The correction factor used on an AWD dyno is 20-25%. So split the difference and use 22%...390 hp divided by .78 = 500 hp at the flywheel

    Re: More G-tech: this time hp and tq. numbers

    Dan,

    I'd like to raise a little question here. The conversion on your engine doesn't rely solely on using the GT2 components, does it? If I understand correctly, it gets an additional hp increase by modifying the ECU?

    I assume that this system causes greater turbolag than on the std. engine and addtionally the intercoolers won't be feeded with enough cold air to fully use their potential. I could imagine that third gear would be best as a solution between this and greater aerodynamic losses. Maybe you find a way to subtract aerodynamic influences from the oberved data? Drag coefficient and frontal aera should be easy to obtain.

     
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