Originally Posted by lucid
Also, do you know what kind of accelerometer the DashDyno unit is using to estimate torque? How many axis?
The DashDynoSPD doesn't use an accelerometer to compute torque. You can find out a bit more about it here: http://www.auterraweb.com/dashdynohpandtorque.html
I have absolutely no connection with the company at all, other than as a customer on another continent
To do a Power/torque calculation you first need to set up a profile of the car, where you need the frontal area of the vehicle, weight, Cd, tyre diameter, gear ratio, air temperature, altitude and humidity. The DashDyno software then makes its calculations based on vehicle RPM sensor. The figures that are given are "at the wheels" and are corrected for all the variables of environment (altitude, temperature and humidity) so that the figures are "standardised" and thus comparable for the same vehicle driven in widely differing conditions. I have found the reproducibilty of the data on different runs to be very accurate and this works with all the different vehicles I've tested of varying performance types. I always get the environmental data from a local weather station via its minute-by-minute updates on the internet before and after I do dyno runs, to be sure that I'm logging the data as accurately as possible.
The device is not a toy but a serious bit of equipment that also reads fault codes, so for me is a sound investment.