The Effect of Dynoing in Different Gears

1slow370

6MT at 1500rpm in 4th = 319.66 wheel rpm
7AT at 1500rpm in 4th = 316.45 wheel rpm

370z purist, your thinking about final drives and multiplying the numbers all wrong, the final drive is the differential gearing so it's after the driveshaft.

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Jordo!

Okay, my math was ***-backwards too..

If we divide not mulitply to get those values, then...

AT @1500 in 5th = 446.83
MT @ 1500 in 5th = 406.28

But... the same conclusion holds -- in 4th, both transmissions have about the same mechanical advantage, but if we dyno the MT in 5th and the AT in 4th it will be an apples-oranges comparison due to a greater mechanical advantage for the MT.

So then do you agree everyone should just dyno in 4th?

That seems to be the most commonly selected gear anyway... I see very few runs done in 5th, but when I do, those always show higher (i.e., outlier) torque values as I had noted above.

EDIT: Actually, the 1% better wheel RPM due to gearing for the MT over the AT in 4th corroborates with the occasional evidence I see of about 1% more peak torque for the MT over the AT too... hmm.

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