Motors, RPM, and Efficiency

This is an interesting discussion. It brings to mind something I tested. I've always felt that my 9L (on 14 cells) gets much hotter than it should. I've got it geared so that full throttle is reachable in several places on my track (so I guess that means I've got it geared low, quick) In any case I did a test. Inside, normal day, temp around 70 degrees. I took the motor out of my truck and pegged the throttle to 100% and held it there for exactly one minute. I did this with two 9Ls and one 10L, same speedo and 14 cell pack.

Temps were 141 for the 10L, 154 for 9L #1 and 162 for 9L #2...

All seem a bit hot for 1 minute of use at no load. During the heat of the summer I would often break 200 after the 5 minute races. I'm starting to think the "L" series may not be as ideal as an "XL" but I've not tested, nor ever run an XL.