Quote:
Originally Posted by SilentBob420BMFJ
Example-An engine that produces 300 pound-feet of torque at 4,000 rpm produces 228 horsepower at 4,000 rpm. This is based on the formula that horsepower is equal to torque multiplied by engine speed and that sum divided by 5,252. The constant, 5,252, is used to convert the rpm for torque and horsepower into rpm's.
then how come all cars dont have the exact same hp to tq ratio? my car has 290 tq and 205 hp, yet the si has 139 and 197.. seems that "constant" is not a constant at all.. btw im a noob to this stuff
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thats not what its saying. its saying that the torque @ 5252 will equal the power @ 5252 no matter what teh car is. its not a constant per se, but the definition of horsepower and a unit conversion. it makes no mention of whether peak HP and peak Tq happen at 5252.
another problem is this.
it makes zero sense to talk about torque without talking about RPM.
the reason your ratio of tq:hp is less, is because of two reasons.
the main reason is that the peak power is achieved at a higher RPM.
if the peak power of one car comes at 4k, and for another comes at 8k, the peak torque SHOULD be around half in the car that revs to 8k. (but the torque @ peak HP will be EXACLTLY half)
the second reason (and the reason its not exactly half) is that peak torque and peak hp dont always happen at the same RPM.