The Effect of Dynoing in Different Gears

Jordo!

Hey folks,

After reviewing all of the dynos people have been nice enough to share with me (thanks!) I have made an interesting, but not really surprising discovery:

The gear you dyno in affects the torque output --A LOT.

See here for reference DYNO G37 Vert 6mt

Note the different torque values --a range from 226 (what I would consider typical on a dynojet) to as high as 240 (way high on a dynojet)!!!

I know the 7AT should be dynoed in 4th; converting from RPM to MPH, everyone is around 115-125 MPH, and that appears to be consistent after reviewing all the drfs I have.

Thus, I find very consistent torque data for the 7AT's (BTW, at worst, about 1% lower than the 6MT, often equal, so no clear evidence of significant differences in drivetrain losses).

However, for the 6MT, some show speeds reaching 115-125 while others are over 140 MPH! Clearly different gears!

Everyone exceeding 140 MPH also shows as much as 5-15 more lbft of torque (again, see link above for reference)!

I think what we need is offical consensus on what gear is appropriate so that comparisons are consistent across dynos -- without this it will be even more difficult to figure out what is going on from dyno to dyno even using the same dynamometer!

Thoughts?

I say whatever gear takes you to no faster than 115-120 on the 6MT is the correct one to use -- is that 4th???

Also, it takes several pulls in the same gear, activating the same load cells in the ECU maps to get the ECU to adjust to changes from mods or tune -- if you vary the gear from run to run, this will also obfuscate the impact of a given change.

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