If gears multiply torque then why does a Dyno read less?

[mvrick208]

If the selected gear ratio and final drive ratio multiply the torque and reduce the speed then why does the dyno read less torque?

e.g a car with 200 Nm (@5000 RPM) of torque with a 2nd gear selected (Ratio = 2) and final drive ratio 3.5

200*2*3.5 = 1400 Nm of torque
5000/2/3.5 = 714.3 RPM

Why would the dyno read close to 200 Nm then? is it the corrected torque? If it does show corrected torque then how does it know the gear ratios for every car? Surely the gear ratios for every single car are not known.

[Stealthee]

The car needs to be dynoed in the gear closest to a 1:1 ratio. This throws out the dyno needing to know every gear ratio.

[mvrick208]

Originally Posted by Stealthee

The car needs to be dynoed in the gear closest to a 1:1 ratio. This throws out the dyno needing to know every gear ratio.

There are some cars that don't have a 1:1 ratio.

I am trying to model a Formula Student car which has a bike engine so the lowest ratio is 1.86 which is nowhere near a 1:1. The maximum torque we got on the dyno was 44 Nm. I want to know what torque the engine produces at its flywheel but I can't divide by gear ratios as that would give me a false torque now. I doubt the person running the dyno tests knew the gear ratios so I was wondering how the dyno gave a torque of 44 Nm which is pretty close to what other people have got with the same engine.