View Full Version : Drivetrain loss & torque
erlrich
03-28-2008, 09:47 AM
Dumb question; does drivetrain loss apply equally to torque as well as HP? Would you expect the % of loss to be the same?
Ron Earp
03-28-2008, 10:14 AM
Earl, there is only torque being measured on a dyno (I assume you are asking with respect to dyno numbers). The hp is calculated from the measured torque. Therefore, if you assume a simple percent loss for the torque due to the drive train then this loss would also apply to hp.
HP = Torque * RPM / 5252
Torque is measured in foot-pounds for this equation to be correct.
Ron
erlrich
03-28-2008, 12:22 PM
Thanks Ron - geez, if I had spent another 30 seconds thinking about it I probably would have realized that.
GKR_17
03-28-2008, 02:02 PM
Earl, there is only torque being measured on a dyno (I assume you are asking with respect to dyno numbers). The hp is calculated from the measured torque. Therefore, if you assume a simple percent loss for the torque due to the drive train then this loss would also apply to hp.
HP = Torque * RPM / 5252
Torque is measured in foot-pounds for this equation to be correct.
Ron
Right on.
This is precisely why it's very near sighted to use a toruqe measurement to compare cars. HP through the useable RPM range is what matters.
Grafton
JimLill
03-29-2008, 01:20 PM
HP through the usable RPM range is what matters.
AKA "power under the curve"
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