My dyno numbers

Jordo!

It really comes down to measurement variance; dynojets have less in the way of specific calibration options to enter, so you tend to see less variance between different units -- that's really the only reason I like it so much, but it's an important reason because it minimizes uncertainty in interpreting the effects of various mods.

The only real "fudge factors" on a dynojet are the correction factor used (I tend to view SAE as a "lower bound" and STD an "upper bound"), the weather data used by the dynojet software to calculate the correction, and, finally, the actual weather, including air pressure (and BTW, no correction factor can perfectly compensate for this).

As to the car itself, oil temps, fuel trims, knock sensor response, gear used for the run, air temps, and coolant temps, and good old fashioned wheel slip all create some measurement variance.

That said, if one tries to keep oil and air temps consistent, uses the same gear for each run, is aware of how quickly the ECU can approach target fueling (usually about 3 runs to redline, or so it seems), and makes sure the tires aren't slipping, you will still see remarkable consistency in dynojet readings across units.

That sort of sounds like a lot to keep in mind when measuring things (and it is), but so long as you do keep these ideas in mind, interpretation becomes far easier and clearer.

I have ton's of dynos posted that show differences in gear, effects of weather, etc floating around on here (especially the so-called "Proven Power Dyno Thread") as well as in my picture gallery.

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