8XL Overheating (Mamba Max, Losi 8ight, 4S)
 

Hey, guys.

So I have a Losi 8ight (Buggy) with a Feiago 8XL motor. The Mamba Max has the capacitor mod and a 25mm fan mounted on top. Also using a CCBEC. 4S lipo.

The motor has SICK power. Tons of speed and tons of torque. Problem is - the motor is getting REALLY hot REALLY fast. After 4-5 minutes of race-pace the motor comes off between 190-210f. the ESC comes off between 120-130f. Ambient temperature is approximately 75f.

I've read over and over "If the motor is hot and ESC is cool.. GEAR UP!" I started at 14/48 and had a heat issue on the motor. ESC stayed cool. I decided to try 16/48 and the problem remains. I am currently running 16/48 gearing.

What might be the problem? Am I geared too high/low? Could my motor be faulty even though it produces massive power? The drivetrain and motor spin very freely. Binding is not an issue.

If you have a similar setup (8ight, MM, 4S, 8XL) I'd like to know what gearing you use and what temperatures you come up with. Any info would help me.

Any help would be very appreciated. I've been trying to figure this out for a very long time now. I just don't have the money to plop in to a neu motor.

Thanks, guys.

-Jeff

What is the oil thickness in the center diff? I'm thinking the front end is unloading too much and therefore letting the motor spin up too fast with not enough load.

"If the motor is hot and ESC is cool.. GEAR UP!" its not realy 100% true rule. Its depends from many factors from ESC, ESC timings, oil thikness to motor that you actualy use.

I think oposite try to gear it down! And look then that happends with temp.
If you have smooth can, buy Novak HV heatsink you will gain some mins
I had similar problem and i thought that I am run 9XL motors and it was geared to ~40mph. Then I hooked EagleTree Logger I found that actualy this is 7XL mootor and with current gearing that I used it was geared to 57mph which it way too high.

Did you try a 15T pinion??

When my mate was playing with gear ratios to maintain consistency with heat, changing 1 tooth made all the difference from a hot motor 80c to 60c just with one tooth difference.

MM, Maxxamps 14.8v 6000mah, Feigao 7XL.

7k in the middle. It definitely unloads on asphalt but when racing it seems to be about right.




Thanks for the thoughts. I have the 540C (finned) can.



Well right now I'm coming off at 100c and ideally I'd need to drop about 40c form that point. I haven't tried a 15t. I have the following options

16/46 (haven't tried)
16/48 (current - runs super hot)
14/46 (haven't tried)
14/48 (ran hot)
13/46 (haven't tried)

Any further suggestions? Thanks, guys.

-Jeff

I agree with the gearing down to lower motor temp plan.

It's probably because its a feigao motor. Has this been the problem throughout the life of the motor? I've noticed that feigao motors get worse the more you run them. I could be the rotor demagnetizing. I recommend you get a neu motor, and your problems will be solved. The novak motors solved my feigao problems. The hv4.5 geared 10/46 im my 8ght btw is slightly faster with less torque than my 8xl was geared 20/51 in my mbx r2. The 8xl seems to have more torque the higher I geared it, but no matter how i geared it, it still heated up the same amount.

What settings are you running in the MM? Set the start power to low and the timing to lowest. You will still have plenty of power, but it will make the motor run cooler. Especially the timing, it can make or break a setup as far as temps go.

The only reason you would ever need a high timing seting is if you were trying to squeeze every last drop of power out of the motor for short bursts. Like for drag racing. 10 seconds of full power, then shut down.

i got to agree with speedy here, I run a fegaio 7 and 9XL, both would run a bit warm no matter what i did. I went Neu and never had overheating anymore

there is a good reason 1 of the motors goes for $60 while the other $250...otherwise Neu would be run out of business

Wait till Castle release their Monster range. They'll be Neu quality with a Castle pricetag.

I dont think they will be as good as a Neu...but they will be better than a Feigao

I agree with the gearing down option. I’ve been struggling with the exact same heat issues with a Fiageo 7XL. I’ve been testing gearing the pinion down and with each tooth dropped my runtime gets longer (before shut-down due to excessive motor temp). The most surprising thing is that gearing down should be slower (from a gear ratio/calc standpoint) but the rig gets faster and runs cooler! Must be an efficiency balance by reducing the load on the motor due to lower gearing and resulting in greater performance.

Don't forget that higher currents cause the kv value to drop. As you gear down, you are getting closer to the unloaded kv value...

Funny you say that, cause, I was talking with the distributor of the Quark's here in Aust the other day & he said the same thing & after a bit of a think, I think you may be right.

Prove us wrong Castle Creations!! :na: :lol:

Plus, they were in the middle of doing a brushless 4 x 4 1/5 & a Baja. Running a massive outrunner & 15s packs. Can't remember the speedy, but, he said it was big.