Funny, because the guys who built the dyno are the ones who say that the dyno measures horsepower based on the speed and weight of the rollers, then calculates torque using the supplied gear ratio input. Check out the video I posted of the 75D, and you will notice that the torque number changes as we manipulate the gear ratio on each run, but the horsepower stays dead consistent. Funny how that works.
That
would be really funny. Since it contradicts literally everything every other source on the internet says about how dynos actually work.
I guess it might explain why their results don't match anybody elses though...they don't know how their own dyno works!
Also funny as it's pretty obvious your results prove you wrong.
The fact the gearing changes your
measured result (torque) is proof that
that is the figure you are actually measuring
The dyno then
computes horsepower by knowing that
measured torque figure
and the rpm of the motor.
Since HP = Torque x RPM ÷ 5252 the only way the HP number
can stay the same if the gearing changes is if HP is
computed
(the fact the dyno is measuring torque and rpm, and then calculating HP, is also pretty obvious by the fact the formula is
literally written that way- you need to know torque and rpm, and then you can compute HP)
Here's some more folks who
actually know how dynos work....
Chassis Dyno Guide - Frequently Asked Questions About Dyno Tests - Hot Rod Magazine
This one includes input from Dynapack, Dynojet, Mustang, and SuperFlow, all of whom actually manufacture dynos.
Inertia dynos extrapolate horsepower output by analyzing the dyno drum’s acceleration rate
Oh look- they measure torque (force on the drum) and compute HP.
How bout a hydro dyno?
A strain gauge may be used to measure the torque reaction between the rotor’s rotating element and a stationary element, then (just like an engine dyno) calculate the horsepower output.
Torque measured. HP calculated.
How bout an eddy-current dyno?
Also known as an eddy-current dyno, this type of dyno controls the brake/absorber using electric current instead of fluid, measuring torque output and calculating horsepower based on a strain-gauge
Oh- this article is also good because it discusses your claim regarding final drive ratio too-and why with proper setup and software, and running the car in the right gear, this largely isn't a problem.