I just got back from the track. I dropped the pinion from 46-13 to 46- 11 & it still stopped. So i called castle creations & talked to JOE FORD he was very helpful. He told me to try the following i order #1 when the car stops go to neutural immedaitly then pull the trigger to full throttle if it lurchs foward then stops reapete if it does it again then this means the LVC kicks in. He said even with the LVC turned it will still cut the power at 2.5v. He also said to drop my gear even lower. I dropped it by two teeth already & did'nt notice ant loss in speed. He said it sounds like it still might be overgeard, sinice i did'nt notice any loss in speed when dropping from 46-13 to 46-11. So i guess i'll have to get mike to make a adapter for my mugen diff.

Here ia a update

I got my OFNA gear adapter from mike yesterday & installed it. Went out to test my new gear ratio 11/51 or a 4.6 ratio, to see if it solves my thermeling problem. Well i was running up & down the street & a screw that holds the adapter on backed out & locked up against the diff mount & stripped the spur. So i have a new spur & diff cup on order. So i'll keep you updated.

Thanks for the update! Sorry to hear about the stripped spur. Hopefully once its fixed it will run a full run without thermalling.

Here's another update.

I just ran my mbx5 with 7xl & MM on a 11/51 or 4.6 ratio. I disconected the fan for this test i got about 8 1/2 plus minutes before thermal. I temped the controller it was about 175- 180. I then connected the fan & the temps dropped to 120 in less than a minute. What do you guys think ?. I could go lower on the pinion but i would loose to much speed

I take it you're running 4s? That's a pretty good total gear ratio (15.3:1) considering it's a buggy. Ratios in the range of 9:1 to 11:1 are more common so it's not a gearing issue. It sounds like the 7xl is simply pulling enough average current to heat up the ESC quickly. Can't forget the MM is a 10th scale ESC meant for lighter duty use and smaller motors, so you might just be stuck using a fan or adding more heatsink area.

Brian thank's for your repliy. I purposly did not use a fan for this test to see how long i could get, & i got about 8 1/2 plus minutes. Know i will hook up the fan & see how long i get . I'm running 14 cells. If it's the motor What fiego motor would you suggest ?.

Someone else with experience on using the MM on a heavier truck will have to chime in here, but I think anything under a 9XL will thermal eventually, but that'll probably be too slow. Gearing up to compensate for speed will just take you back where you started temp-wise due to the added load. If you're handy, you can try to fab an added heatsink if you don't want to use a fan. Just my $0.02.

Using a fan is not a problem at all. I just disconected for testing purposes. I have a 9L motor would that better if not what would you suggest motor wise for 14 cells ?.

LOL, the problem with using a smaller motor is that it will be loaded more and still draw the current to heat the ESC. It's really the mass of the truck that's the problem IMO. It takes power to get the truck moving. You'd have more motor options if the ESC handled more than 4s safely. If you don't mind using a fan, I'd stick to what you have and just use the fan and/or more heatsink area.

You might also try to reduce the timing and/or "start power" to the lowest setting. That will ease the burden somewhat and should help temps.

This is a mugen mbx5 buggy not a truck.

Yeah, I knew that. I don't know why I said "truck"; maybe just easier to type...

:005: LOL Im going to try it know with a fan. Is there any other fiego motor you might recomend to use with the MM on 14 cells ?.

How heavy is the "truck" ;)? If 10lbs or less, you might be able to go with an L size motor, but I'd see what the experts say (Squee, MM, CHC, etc). :)

Just as a reference... I have had a MM over 200 without a thermal. I believe they aren't supposed to thermal till the sinks hit about 210-220ish. The internal temps is what counts of course, but 180 or so shouldn't trip it. Mine hits that all the time in my XX4/7700.

Personally, I think an 8XL might be a better option, but it could still possble be an ESC problem. I would stick with an XL for sure. Perhaps you can gear even lower? Try the Century 9T pinion. Let us know how the fan helps!