authority 600 hp kit
#31
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560hp @ 4500rpm
torque(in lb/ft) X revs/5252=hp
560 X 5252/4500=653lb/ft
I was going from your statement of 500rwhp @ 4500rpm.
If your stock 408hp car dynoed at 380hp then the loss is about 7% on that dyno, so 500FWHP would be about 535FWHP hence the624lb/ft
torque(in lb/ft) X revs/5252=hp
560 X 5252/4500=653lb/ft
I was going from your statement of 500rwhp @ 4500rpm.
If your stock 408hp car dynoed at 380hp then the loss is about 7% on that dyno, so 500FWHP would be about 535FWHP hence the624lb/ft
#33
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Originally posted by msobota
So torque as reported on a chassis dyno is rear wheel torque?
where does the 5252 number come from?
Mike
So torque as reported on a chassis dyno is rear wheel torque?
where does the 5252 number come from?
Mike
The 5252 is just part of the formula - engine dynos measure torque then calcuate power using that formula.
#35
Lifetime Rennlist Member
Originally posted by msobota
So torque as reported on a chassis dyno is rear wheel torque?
where does the 5252 number come from?
Mike
So torque as reported on a chassis dyno is rear wheel torque?
where does the 5252 number come from?
Mike
1 HP = 33,000 lb ft/minute of work
The ft-lbs of torque are just a twisting force - no work is actually done unless we (theoretically) make that force move some weight over some distance. So to get torque to do some work, we will move weight over a pulley that is 2 feet in diameter, which means we have a force in lbs, equal to the torque (in ft-lbs) at the 1 foot radius. We move the weight of 1 lb, over 1 revolution (to cancel out the rev component of rpm and that means the weight has traveled over a distance of 2 * pi feet.
Now 33,000 / (2 * pi) = 5252 and there is your conversion. It is confusing because we use ft-lbs for torque and lb-ft/min for work and they are not one for one - they convert with the 2 foot pulley concept.