The road dyno reads very similar to the mustang dynos in the area given similar conditions. I have, however, found that when using the standard configurations on the mustang dyno, the dyno doesn't create enough load in the low-mid range to simulate a real-world pull on flat ground. This results in slower spoolup and lower torque numbers. By playing with the weight/drag configuration on the Mustang, its possible to get a more realistic load curve. So depending on the dyno operator, a mustang dyno may read a bit less torque than my road dyno, but the top end numbers shouldn't vary much.

As far as vf34 cars making similar torque to some of the UP/TBE cars, that's actually not that far off. With the larger turbo running on pump gas, its very difficult to get a lot of torque. Depending on setup, VF series 2.0 cars on pump gas have made from 220ft-lbs to 250ft-lbs on my road dyno. So as you can see, even some of the VF3x cars I've tuned and measured on my road dyno actually make similar peak torque numbers to a stock turbo car. They always make significantly more top end, however, because the turbo can hold that torque through much more of the power band.

In the end every dyno is a bit different in the way it applied load and measures power. The Road Dyno software uses sound physics to calculate acceleration, torque, and whp when used on flat ground with the propper weight, drag, and gearing info. So in ideal conditions, I would say that the road dyno comes very close to ACTUAL power output. From working with the Mustang Dyno, I believe that if the configuration was good enough to create a very realistic load curve, it should also measure power output very accurately. The problem is that nothing is ever ideal. I don't have the ability to weigh and find the exact aerodynamic properties for each car I road dyno just as most dyno operators don't have the ability to configure the dyno to produce a load curve that's exactly what the car would see on an actual road for each car they dyno. So in the end, all of these numbers are just estimates with what most consider to be an acceptable margin of error. They give you a good idea of what the car is actually making, but its never an EXACT measurement.

Thanks