I couldn't help it, I had to run some numbers.
https://docs.google.com/spreadsheet/...V9hQ1JZTVlDbFE
Note there are a lot of assumptions here. I've used the stats provided by Keda motors, who make cheap inrunner motors, and proved their torque is roughly equivalent for that particular size of motor.
I've then calculated the comparison of a 5000Kv motor (roughly an 8.5) against a 3500Kv (around 13.5 these days), then added a boost component, which presumed that Kv increases by 1% per degree of timing. Timing is assumed to ramp up linearly from a base of 0 at 0 rpms, to the maximum 60 degrees (any more, and the motor can go backwards!) at the maximum rpm.
Note that the boosted motor will lose torque as the timing increases - however, the requirement of torque diminishes as the car's momentum increases (if I've read those Force calculations correctly), which coincides with higher RPMs, where boost is at it's maximum.
The conclusion is the comparison of these two motors is quite close - the boosted 3500Kv actually beats the unboosted 5000Kv by a little in RPM terms - this gain may be diminished by loss of torque.
In a real world comparison, two identical cars, in terms of weight and drivetrain, and geared to the same FDR, with the two motors, would give a definitive comparison.
I've just realised I can use the
Novak Brushless Motor chart to do the same comparions, this time with motors specifically for racing cars...check the spreadsheet for updates!