How to calculate transmission efficiency in vehicles?

Answer 1

You most certainly can, I have made a formula to calculate the efficiency of the transmission+torque converter, measuring the efficiency of the torque converter is difficult and would require machinery in order to do such because the torque converter multiplies torque but as it speeds up the torque multiplication decreases and if it's a lockup then the internal clutch locks and the unit becomes void in the equation except for it's weight which is calculated based on theoretical vs actual speed. Anyway's my formula uses theoretical data that is calculated by the constants and then by the actual data which you will also provide from what the vehicle tells you this is how it works.

You need to know these below:

MPH: Vehicle speed of which the efficiency test is being done

GR: The transmission gear ratio of which gear you are performing the test in

AR: The gear ratio of the axle

R: Is the rolling radius of the drive tire, measurement to be made in inches

ESs: The engine RPM, this measurement is taken at the TACH and the vehicle has to be traveling at the same speed you are testing for.

The formula is:

n% = (100*MPH*AR*5280*12*GR) / (60*2*PI*R*ESs)

Please note this formula is accurate within about 3% due to the accuracy of the tach and speedometer of vehicle plus the variable change in tire radius with speed and temp. But it's pretty accurate!

You can find the average efficiency by using actual data at different speeds and gears.

By gear ratio I mean lets say you have a Chrysler 46rh the gears are as fallowed:

1st 2.45:1

2nd 1.45:1

3rd 1:1

4th .69:1

reverse 2.21:1

you would input .69 for 4th in the formula. not 4!

Anyways my name is frank d. heizler (incase my friends trying googling my formula) and good luck.