had peak torque at about 490ft-lb and peak horsepower at about 460HP for the Performance (390ft-lb, 370HP for the LR-D).
A dyno inherently measures at the wheel. Do we have any details about that test that say they used a fudge conversion factor to try quote the numbers in "crankshaft" terms?
Right, it measures at the wheel. It can only measure the force that is applied, and plot that vs. the velocity at which that force is applied (and it apparently doesn't do a good job of measuring force for wheel speed less than about 20mph). Everything else is translation. To get the "490ft-lb" and "460HP" numbers, clearly they had to apply information about the final drive ratio and the wheel diameter. And if they're doing that, I assume there is a field in the software program that generates the curves that allows you to include "drivetrain loss".
The thing is, let's assume those numbers are no drivetrain loss. We do know that the drive reduction is 9:1 (within 1%, I think it is very slightly greater than 9; I read or watched a video somewhere). And we know the wheel radius is 13.26 inches.
So that would mean 9* 490ft-lb*12in/ft / 13.26in = 3991 lbs of force applied to the wheels.
My VBOX data (after the first power boost), posted
elsewhere, shows constant acceleration between 5mph and 40mph (torque is therefore constant in this region and proportional to this acceleration). For a 3.17sec (3.47s including rollout time) 0-60 run (which implies it must have been a roughly flat course (which it was) since this is basically the rated number and what people see), it takes 1.84s to go 5mph to 45mph (and each 5mph interval was equal time within 4% (rounding error), so the torque was constant in this region). This was a stock Performance + PUP vehicle with all excess weight removed, with a 160lb driver. (So 4072lb + 160lb = 4232lbs). (Here's another picture showing that torque is definitely constant between 10mph and 40mph -
torque is flat - and the acceleration is 0.87g)
This is:
35mph/1.84s - Wolfram|Alpha
So, 0.87g. For that weight that means about 3680lbs of force.
If you can reconcile these numbers (3991/4232 = 0.94!) without concluding that there must be drivetrain loss included in the dyno result, I will have learned something today. I am not accounting for the contribution of wheel rotational kinetic energy, but I know that is a very small effect. I am not accounting for wind resistance, but that can also be calculated (~200Wh/mi drag loss at 70mph is 100lbs of drag, and between 5 and 40mph it will be much smaller of course).