Water cooling vs air or Neu v Lehner?

Re the motors have you seen dyno charts - not just calculator graphs?
Lehner efficiency is OK, as are Hackers, which are same gen technology but

Neu
* make motors for planes - most use smooth cans - I know how Neus were introduced to marine racing I did it... when I raised their performnce on RRR many years ago.
* uses finer laminations and 4 pole is easier than 2 pole on ESC's and the designs 4 years old the 2280s date from the mid 90's
* have better peak efficiency (claims means nothing - dyno charts tell the real story) and also much better efficiency at low amps and very high amps ie a wider band of high efficincy - this is very important for cars which spend most time at very low amps - less than 50 amps but spike into the 150A's under acceleration and high loads
* produce more torque per amp - in practice this usually means they do more with less or they give harder acceleration or better runtime
* are lighter for the same power and torque - means better p:w ratios and handling

In a car the avergae amp draw is so low a motor with enough torque shouldnt require additional cooling. IMO this mean water cooling is a complicated and redundant.

However given that Lehner;s specs will be running out of it efficiency band most of the time due to the high iron losses at low power and will run hot with air cooling.

With electric bigger isnt better. The smallest possible motor with sufficient torque and the correct efficiency point is the way to go. Electric motors are like the rods and crank - they dont make power they just covert it and waste it to varying degrees. Only batteries make power.

Water cooling is used on race boats but the power throughput is 150-190 amps average... or about 5 times that of a car.