[SilentBob420BMFJ]

Originally Posted by e60.deluxe

cars dont make equal torque at any RPM. they make a certain torque at a certain RPM. the measure of torque along the RPM range is the torque curve. when we say a car has 300lb-ft @4000RPM, that only refers to the peak torque and what RPM peak torque happens at. for all we know, torque could be only 200lb-ft at 5000RPM. staying close to peak torque throughout the rev range is ideal and is whats called a "flat torque curve"

yes, i already knew this, this was not what i was asking.. the below quote answers my question

Originally Posted by BigT

The torque curve comes because the engine makes varying amounts of power at different RPMs. There is a certain RPM where the engine will make the peak amount of torque. This curve and the point of peak torque depends on the design of the intake, exhaust, cylinders, pistons, valves, cams, etc., etc. By changing any of these things you change the torque curve.

This is why v-tec works so well. If the car simply made more power with the higher profile cams they would simply put high profile cams in and call it a day. However, at low RPMs a lower profile cam makes more torque. Once the engine gets to the point that torque starts to drop off because the RPM is above the peak for that cam profile the v-tec engages the higher profile cam and esentially changes the torque curve to keep the engine making torque.

yay