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911nut 911nut is offline
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Join Date: May 2001
Location: Michigan
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Originally Posted by TurboKraft View Post
Power is a function of torque:
(Torque x rpm)/5252 = Horsepower
Can you elaborate how power is increased but not torque?
Look at the equation that you posted. The answer is there.
Torque and rpm are measurable physical quantities. Horsepower is a calculated quantity. If you look closely at that equation, the number 5252 is not any real physical quantity but a constant.
Say we have two engines that produce the same torque but can run a different maximum speeds. According to the arithmetic, torque stays constant but increasing the rpms will yield a bigger number for hp.
A real example would be a Porsche turbo six that produces 450 ft-lb of torque and has a max engine speed of 7000 rpm vs. a normally aspirated F1 engine which also produces 450 ft-lb of torque and has a max engine speed of 18,000 rpm. The Porsche engine produces calculated 599.77 hp while the F1 engine produces a calculated 1545.69 hp. In reality an F1 engine makes around 850 hp due to friction and other losses that aren't accounted for the simple power equation but the point is that if an engine spins faster, hp increases.

However, spinning an engine faster isn't a good real world solution so we are all doing things to our engines that increase torque. Torque is what you feel when you press on the accelerator. We are all conditioned to talk about hp but really what we are concerned about is torque.
Paul B.
'91 964 Turbo
Port matched, SC cams, K27/K29 turbo, Roush Performance custom headers w/Tial MV-S dual wastegates, Rarlyl8 muffler, LWFW, GT2 clutch & PP, BL wur, factory RS shifter, RS mounts, FVD timing mod, Big Reds, - 210 lb

Last edited by 911nut; 12-11-2011 at 01:27 PM..
Old 12-11-2011, 04:21 AM
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