Hi hardmankam,
I did another run yesterday. Almost similar weather condition. The old different is the FDR I use now is 6.9. The motor is now 10 deg celsius cooler. Now it is 88 deg cooler in the acceptable range.
Does lower ratio actually lower motor temp, where all other conditions remains?
My esc setting are
#4:3
#9:4
#12:4
#13:6
#14:4
#15:5
Question, what affect motor heat. I notice that this track, (the city is in a valley) we ran on is always hotter on motor. However earlier this month, we ran a race up north. 400km away closer to the seaside, we can run higher boost and turbo and yet the same motor is cooler. That put a question mark on my head!
There are a lot of factors that affect motor heat. Both over gearing and under gearing CAN produce motor heat. HW suggests to use 6.0-6.5 for 11.5R, so for your 10.5R, 6.9 is prob. about right.
Of course FDR is quite driver and track dependent. eg: the amount of drag brake, the driving line, # of turns etc...
But yes, keep the LRP under 90C is the goal while finding the right combo is part of the fun.