MMM getting HOT!
 

Today I practiced for about an hour and 45 minutes straight, running packs back to back, and temps never got above 150 on ESC. Geared 16/48 on a losi 8ight with 2200. Ran my first heat (7 min) with same gearing and thermalled at 225F!:surprised: Could not figure out why! No binding anywhere, fan was on, mesh was fine, gearing did not change, so something must have happened. Ran the same packs I did while practicing. For my second heat I dropped to a 14t pinion (undergeared) and I was still at 199F by the end of the 7 mins. I ran my 15 min main and thermalled twice. What could be making it get hot like this? I am not running it all that much harder during the races than I am during practice. It is just getting dangerously hot.:neutral:

well 16t pinion is wayyyy overgeared about 54 mph or so, i have a 13 on my 2250. that is right at 40. but even with a 14t pinion it should run around 150 or so, i bet your fan stopped working, they cant live without some type of airflow

how is a 16t waaaaay overgeared? I am running a 48t spur! Speed Calc says 43mph. I run 4s, and the fan is working properly.

you forgot to add about .5 inches for tire ballooning, they do that easily if not more, but if your fan is working i dont know? it shouldnt be running that warm unless your motor is developing a bad bearing or such

Regardless of the gearing and tire ballooning the vehicle should run the same during practice and during a race. Like he said he wasn't running the race much harder than practice, so if there was going to be an increased temp it should only be a little bit. If the gearing and tire ballooning were the cause it would overheat in practice too, not just racing.

I would think something happened during the race that is now causing the overheating. The issue is figuring out what that cause is. Try another couple practice runs without changing anything and see if it still thermals. If it still thermals you know something has changed. If it runs cool then that's a tough call. If you really think you are driving it the same during practice and the actual race it shouldn't be any different.

Brushless Moose;

You stole brushless boys "LOOK" you know the yellow roadsign thingy.:na:

Lol!

Skimming through threads I see him, read the first couple letters of the name and look for the yellow sign- then go "wait a minute I didnt post that!" :lol:

Its all good

well, I tried a practice run today. Bad things happened. Whenever a bad thing happens, it ends with a "Y". Lets see, strippY, grindY, breakY, crunchY, shortY, snappY, wreckY, crashY, And today... MELTY!...

Plugged in the packs, ESC armed, touched the gas, the motor cogged, and Whoosh, Mushroom cloud of smoke, then large flames. Melty.

I said oh $hitty.

Needless to say, bad day, and something was obviously wrong. Already have a Tekin coming, and when the MMM gets back, it will be sold. I got the RX8 2050 buggy combo.

There, fixed the avatar thing. Now he runs with scissors, and I become just like my MMM

well that would explain it getting hot, caps or fets weakining, not being able to handle the power as well as they used to. the little cloud of smoke is never a good feeling eh?

Not to be the pessimist. but I Am in the same situation. My rx8 lasted a total of a half hour.:neutral:

Changing a MMM 2200kV combo with a tekin 2050kV buggy combo would be bad :( Tekin buggy motor are undersized for 40mph geared races and will overheat compare to your castle/neu motor :(
At least, use the castle motor if you want to keep same top speed and lap time, other than that you will have to gear the tekin lower if you don't want to kill it...

I am a little confused as to why all your motors are running so hot???
The stock savage flux comes with the torq2200kv motor. With the stock gearing 20/44 going through the tranny on a 6s it can 55-60mph without any heating issues.
The savage is also much heavier than your performance truggys and yet you are all having problems...
I bought a neu 1520 motor thinking that this torquey motor should be able to handle this gearing as it would be much more efficient... yet people are telling me that its over geared even though HPI sell these stock with this gearing....

The stock gearing on the SAVAGE get you to 50-55mph. 20/44 but in the savage you have additionnals pinions and spurs which add internal ratio.
More over the heat sink of the tork motor is well designed.

i dont really want to reply on an additional fan to keep my temps low on my motor... It shouldnt be a cure for hot motors but ill have to see... I may just lower my gearing and see how it runs... I just want reliable bashable fun rather than worrying about that poof of smoke coming from the ESC....

A hot motor could be caused by gearing that is too low too. If you are maxing out the throttle a lot (winding the motor out for long periods), then it will get warm/hot.

But if geared "right" a decent motor that runs hot could mean partial rotor demagnification.

Thing is, the stock flux is lighter than your custom flux, and it comes with a 1515 2200kv motor; on 6s lipo with stock gearing 55-60mph is about top speed roughly, and even then thats an on-road kind of setup, 60mph offoad would be pretty much uncontrollable over about 50% throttle. Your truck is running a larger, more powerful motor yes, but its a much lower kv, and the voltage is the same, so gearing it for higher speeds than the stock flux places a much larger strain on all the electronics, hence the high temps. The 1520 and 1717 are great motors for heavier weight vehicles running the same speed as lighter vehicles that use higher kv motors. For example, my 1518 1800kv motor ran nice and cool on 5s lipo in my 13.5lb TXT-1, but my 1515 ( ish) sized medusa 2000kv motor runs somewhat hotter in my 13lb Gorillamaxx on 5s lipo too. The Gmaxx is geared for 40mph, the TXT-1 for ~35mph- if I wanted to run either truck faster I'd go for 6s & a 1518, and aim for about 50-55mph tops- keeping my speeds and expectations realistic...

Knowing whats realistic and why comes with time, and lots of research/reading around to learn from other's experience. That said, you're in the right place for certain; Rc-Monster is known as 'The Encyclopedia Brushless' :yes:

neil.. thanks for taking your time to explain this to me... It really has put things in perspective... I tried doing my reading and asking people what would be an ideal motor that would meet my expectations. I guess i am pushing it a little too high.
I was originally wanting to go for the 1518 but due to having no motor at the time and no 1518 in stock anywhere... i went for the 1520.
I have a few gearing options... I will chuck my 17t clutch bell in there first... with the rc calculator it will bring the top speed down from 75mph (very unrealistic, i wasnt even aiming for these speeds) to 60mph... if its still running too hot. I will take out the the high speed idler gear and put the stock one back in and run the 21t pinion which should gear me for around 50-55mph... I will just watch my temps and gear accordingly.

I am going to work out a way to try and cut weight on my truck... At the moment its only weighing 1 ounce heavier over stock. each wheel is 10gram heavier and the tvps weigh only very slightly over stock. Thats the only weight i have added. (maybe the motor too)

Anyway i really appreciate your help! I will get back to you and tell you what happens.

THANKS!

Hmm, I thought it was heavier than that, but anything you can do to save weight is always a plus, regardless. I tend not to follow all my own advice though; my tyres weight 1lb each on my TXT-1 :lol:, but I have gone to lighter ones for my Gmaxx- have yet to see how that performs though.

neil i weighed the truck today... and with my wheels and tires and depending on what batteries i am using the weight is 13.1- 14.2lbs.

THAT IS LIGHT FOR A LARGE TRUCK!!! BUT at its heaviest with the large wheels, and large batteries and heavy body... it reaches 17lbs.

I will keep you updated on how it runs with the 17t clutchbell.. .I hope it doesnt cause any more heat problems.