I have been racing a Stock (PN 70T motor fixed gear ratio 13 Pinion 53Spur) category for a few weeks in our club. Car has been great and competitive but have noticed that my motor temperature has been too high (forgot to bring a temperature gun to the track, but to give you a reference, you can’t touch the motor after a few minutes of racing..)
I’m running a PN chassis with a Kyosho ASF board, PN 70T motor, 13 Pinion 53 Spur on a 94mm Lexus car. I have compared to other racers and their motor temps were much lower and OK compared to mine. I have cleaned and lubricated the motor, checked the brushes, diff, bearings, etc. everything smooth.
Car works great, and have won several Mains recently but I’m kind of confused at what’s causing the overheating.. I will try to cover all suggestions above... but do you have any updated suggestions or similar experiences/solutions?
In the following weeks, I will try to update the temp that my motor is reaching.
***
PD. Forgot to mention that (as far as I know) I'm the only one using gear diff
Last edited by refsiul22; 2016.08.11 at 06:22 PM.
Reason: additional info..
Look for any kind of binding first. Anything. I have seen the pinion work it's way out the motor shaft until the base of the teeth comes in contact with the spur. Almost not noticeable unless under load. Maybe a little change in motor pitch but little other warning. You may find a piece of hair wrapped around the axle at one or both hubs. Check solder joints for weakening connection which can cause excessive current draw. What condition are the brushes in? How is the tension. Using "comm" drops? Things like that. Heat means it is being overworked either electrically or mechanically. For the motor to be "on pipe" you should be able to use the lip test. If you can hold the motor to your bottom lip for a second or two without raising a blister you are where you need to be gear wise. Any hotter and you need less gear. Any colder and you need more gear. At 13/53 or 4.07:1 I would say you are geared way to high unless you are running the Bonneville Salt Flats. You said that was a "spec" ratio. I would like to be the one selling motors with that ratio. Just for sh1ts and giggles try an 11T pinion with no other changes and see if the motor cools down along with quicker lap times. If it does I would lobby for a different required ratio.
if others are running the same ratio and do not have the same issue, hard to point to the ratio in this case... if it were so, all would have the problem. in the end, it could be he just got the bum motor, it happens.
have you tried another of the same motor? just one thing to add to checklist of things to run down.
tried a backup 70T motor and had the same problem..
some findings/updates:
-temp after a few minutes of racing reaches 130F
-motor were cleaned and lubricated prior to racing.
-peer racers (same ratio and track conditions) reach 95-100F
-changed from gear to ball differential to see if it made a difference. Temp was slightly lower, but still way above peers.
will try 70Ts motor on second car and solder some 50T, 39T motor to racing car for tests.
tried a backup 70T motor and had the same problem..
some findings/updates:
-temp after a few minutes of racing reaches 130F
-motor were cleaned and lubricated prior to racing.
-peer racers (same ratio and track conditions) reach 95-100F
-changed from gear to ball differential to see if it made a difference. Temp was slightly lower, but still way above peers.
will try 70Ts motor on second car and solder some 50T, 39T motor to racing car for tests.
Have you made any ICS adjustments for power delivery? Are you aggressive with throttle/brake? How low is your motor, depending on mounts, some can rub the track when in the lowest positions increasing heat.
How new is the motor? Do you have an OLD motor you could try, or borrow from someone that you know does not get hot over a battery pack.
I have had some electronics that made the motors get a little hotter, and they were always a little faster than others (they would be used for stock classes). The difference was not 30f though, maybe 5-10f at most.
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