Dyno Testing Questions

[Kyle F]

If you are to Dyno test your car on a chassis dyno, what gear do you put it in.

The idea of the tranny is to use gearing to multiply the torque transfered to the wheels which again gets multiplied by the rear.

So with the torque then calculated into horsepower by virtue of the RPMS, how do you not get inflated numbers?

Even if 3rd is 1:1... your rear end is still multiplying it some.

 

[StageII86]

I believe most dynos require the rear ratio to be entered in prior to testing in order to calculate the torque vs. rpm properly.

I see a major error though in the actual dyno tachs, they always seem to be way off and I wander if this causes err in the readings.

 

[turbov6joe]

My experience with dynos is that making the pulls in 3rd give you the most accurate numbers. Pulling in OD will prolly cause the tranny to kick down too many times for any good info, not to mention is hard on the OD clutches.