age old question. motor too hot.

[zoaman]

hi i run a 4wd indoor on mostly carpet slippy floor.i run a 9.5t 80/26.
this runs in the nice range of temps ,but i also have a spare car with a 8.5t 80/25.
yet the spare car runs way too hot.with the slippy floor area i thought using the slowest takeoff would help with traction so tried running what i thought would be the larger pinion.is 80/25 wrong for a 8.5t?
all drive area is free and not binding and mesh is not tight.
your input is appreciated

[fidspeed]

swop motors the known good 9.5 into the car that gets hot

if it stays cool then other motor is suspect if it too gets hot its not motor that is the problem
Normally when you fit a hotter motor you would go down in pinion size not up although 1 tooth shouldnt make that much difference
dave

[andrewc]

Defy try the motor swap and re-gear it first, but worst case just fit a motor fan. I run a 5.5 in my 4WD on EOS carpet, everything (even 2WD) runs way hotter than our old surface did as traction so high. Motor fan has seen my motor temp drop by 30*C.

[mark christopher]

check motor timing, too high and temp will go up, swap motors in cars,
are both cars the same make and model as they could have a different internal gear ratio, which you also need to know when working gear ratios out

think dave has been on the sherry as you have dropped a tooth for a lower wind??

[fidspeed]

depends on your viewpoint of "hotter" motor mark, in my old tired eyes a "hotter" motor is a lower wind ie a 6.5 is a lower wind and therefore hotter than a 10.5 therefore id go lower on pinion else it would be overgeared and overheat

apologies if I did not make that clear

original theory still stands if one motor overheats in one car and a "similar wind motor doesn't (one wind and 1 pinion wont make that much difference on a short test run fit to to car that overheats and that will prove one way or other

dave

[mattr]

Originally Posted by andrewc

but worst case just fit a motor fan.

Don't just fit a fan without trying to reduce the temp as much as you can first. You'll still have the problem, but will be masking it artificially. Then when the fan fails, you're screwed.

FWIW i reduced my motor temp by about 30 degrees by playing with the calibration, gearing and settings, reduced the ESC temp by nearer 50......

[mark christopher]

Originally Posted by fidspeed

depends on your viewpoint of "hotter" motor mark, in my old tired eyes a "hotter" motor is a lower wind ie a 6.5 is a lower wind and therefore hotter than a 10.5 therefore id go lower on pinion else it would be overgeared and overheat

apologies if I did not make that clear

original theory still stands if one motor overheats in one car and a "similar wind motor doesn't (one wind and 1 pinion wont make that much difference on a short test run fit to to car that overheats and that will prove one way or other

dave

i think you need spec savers or more sherry

"hi i run a 4wd indoor on mostly carpet slippy floor.i run a 9.5t 80/26.
this runs in the nice range of temps ,but i also have a spare car with a 8.5t 80/25."

9.5 on 26 pinion, and he has a 8.5 on 25 pinion?
he IS lower on pinion for the hotter motor! he has not gone up?

[andrewc]

Originally Posted by mattr

Don't just fit a fan without trying to reduce the temp as much as you can first. You'll still have the problem, but will be masking it artificially. Then when the fan fails, you're screwed.

FWIW i reduced my motor temp by about 30 degrees by playing with the calibration, gearing and settings, reduced the ESC temp by nearer 50......

Matt

Out of interest, what worked? I'd love to reduce temps even more...

[mattr]

Originally Posted by andrewc

Matt

Out of interest, what worked? I'd love to reduce temps even more...

In my case it was basically going back to basics. Reflashing the base firmware and switching all the feature off, no boost, no timing. Then working back up from there, much slower than before.

Now lapping quicker with a colder motor and ESC.
Also faster on the straight. (visually, not measured)