Originally posted by turbo8uOriginally posted by FlyinEsi Originally posted by DarkOne Because of the "correction" the software does. This is why no chassis dyno is really accurate.
You've got me curious...what "corrections" does the software make?? And how inaccurate does it make a dyno??
a dynojet calulates horspower and torque based off a few things. one horsepower is equal to a 550 pound force through a distance of 1 foot in one second. so basically it would take 1 HP to lift a 550 pound weight up 1 foot in 1 second. to meausre hp you need to know the force in lbs as well as the velocity in feet per second. it emasures acceleration with the juge drums as well as how much forceis turning them. the force on the dyno drum is calculated from acceleration using newton's 2nd law, force = mass X acceleration. if they know how much the drums weigh and acceleration is measured, the computer can
calculate horsepower. torque is calculated as well with horsepower X 5252 / RPM once they have the numbers a few correction factors are applied, some made public, some hidden. public correction factor is the SAE correction. (standard) this formula assumes a mechanical efficiency of 85%. the formula used for a dynojet inertial dyno is: CF= 1.18 X (29.22/Bdo) X ((Square Root(To+460)/537)) with 'To' being intake air temp F, 'Bdo' being barometric absolute press. this correction factor is meant to predict output in varying atmospheric conditions and is a +/- 7% damn that took 3ever
