Having owned and used both the Dynologic and Mainline Dynos, as well as used countless other dynos, I would have to rate the DynoLog Software (common to both DynoLogic & Mainline) the best I have ever used. The software, data logging, speed control (even tacho based speed control for autos), makes DynoLog hands down FTW.
DynoLog software, originally designed as cutting edge engine dyno software, has been modified to run as a chassis dyno. With as many inputs as you could possibly imagine, and data analysis that would satisfy the most data hungry scientist.
The differences in all the power outputs come down to a few factors, the main being atmospheric compensation (mainly AT on DD). Dyno Log dynos use their own discreet weather station, constantly sampling atmospheric pressure, temperature, and humidity. Dyno Dynamics dynos sample air temp from the probe, which is placed under the bonnet or other high them areas by some operators, hence 'inflating' dyno figures. Atmospheric pressure and humidity are a 'user' input, and are certainly not updated automatically, let alone real time.
One other major variation is the SAE standards used to calculate atmospheric correction. The older standard J607 is still found to be used on many dynos, and in general can read around 3-10% higher that the newer SAE standard J1349, which is what is used by most newer DynoLog dynos, and also on the Mainline/DynoLogic dynos used for the AutoSalon series.
That I think, is the difference in Dyno Dynamics (dyno for mechanics) and Mainline/Dyno Logic (dyno for technicians) Dynos.
Apart from the above atmospheric corrections, there are other 'intentional cheating' methods employed by less honest, or less educated, dyno operators, such as roller intertia values, and other rudimentary calculations...
If anyone would like to discuss my opinions, or needs some contacts with either Mainline or Dyno Logic, please do not hesitate to call.
Sam.
0425 818 755