RX8 1700 truggy issues

I am running a 8T 2.0 with the Losi conversion kit and Tekin RX8 1700 truggy combo. The batteries I am using are a Neu 5S 5500 25C and Zippy 5S 5000 25C. I talked to Randy and he suggested using a 16 tooth pinion. I bought this combo in the winter and used it indoors with great success. I went outdoors last night for the first time and was having issues. It was cogging at low speeds so I put an external capacitor into the receiver and it cleared it up. Last time I did this with a Mamba Monster it worked for a couple of races and then the internal ESC capacitors blew in the Mamba Max. I am going to have the same issue? Any advice would be greatly appreciated. This is the newer ESC(Red Heatsink) and newer rotor(Aluminum Cap). The outside temp was 75 and after my fix the ESC was 110, motor was 175, and the lipo was 115 after a 10 min run on a track.

No help from me, but thanks for posting. Subscribed.

Is it possible that I am undergeared?

[simplechamp]

No, you are geared for about 43mph, definitely not undergeared. The Tekin combo should be able to handle that fine though.

Maybe a bad connection or solder joint to one of the phases on the motor? Have you gone through the drivetrain to make sure there are no binding or worn out gears? Double check all your ESC settings to make sure everything is where it's supposed to be?

I took out the center diff and checked for binding, there was none. I checked all the solder connections to make sure they were tight. I will check the ESC settings today. You thinks the temps are high?

[simplechamp]

175F on the motor is pushing it, the other temps are OK.

[nuz69]

A motor correctly sized and geared should not go above 140-150°F. When you were indoors, you did'nt have a motor temp this high ???
Check the diffs meshing, losi diff aren't well adjusted stock. It generates many transmission drag and loses...
the only option you have is to gear down with 14-15 T pinion. 35-40 isnt enough for your track application ??

Hey nuz69, I bought this combo in October and ran it at a semi heated indoor clay track. The pits are heated and the track is not. I talked to tech support at Tekin and they said it is close to the limit but still ok. Upon further inspection of the rear diff, there was a little play between the gears which I just reshimmed to fix it. I guess I could try to run with a 15 tooth pinion and try that. I previously had a MMM 2200 on 5S on the outdoor track and was used to those speeds running 14/45. Guys, I really appreciate all the advice given so far. You guys rock!

[itbvolks]

43mph is certainly pretty quick for track use. I'd guess the nitro guys are running 35-40 with most truggies so you should have room to come down (gear up) in pinion size. 15T would still pull 40mph and should decrease the current pull on the motor...

I'll be interested to see what mine pulls as I'm running the same setup (1700kv @ 18.5v geared 16/46) but in an MBX6T. I'm running Hyperion 4200mah 35c's though. Truck weight RTR should be under 9.5lbs....

[itbvolks]

What tire/traction?

[nuz69]

And geared for the same speed, The mamba 2200kV ran a little cooler or hotter than the tekin motor ?
Yes, the play in diffs is very bad, because the shimming is no constant, it eats your diff pinions and it drag the transmission + noise :(
175 °F is ok for the motor, but it is the limit, it means that you dont run it at its max efficiency (efficiency drops a lot with high temps...). You could increase significantly you runtime with a little lower pinion because lower amp draw and longer runtime ==> lower temp ==> best efficiency ==> lower amp draw ect...
Of course it wont give you an additional 10 mins, but it helps !

Upon continuing my work on the diffs, I noticed that the Red motor wire was not soldered well. If you jiggled it attached to the motor mount, it was snug but once I removed the motor you could tell it was not completely secure. I hope this helps also to lowering the temps. While I do agree that 175 is ok, I would rather be in the 140-160 range for my likings and efficiency. When I was running the MMM combo, it was the heat of summer and it ran under 160 all the time. It was extremely fast probably too fast and I really liked the idea of a sensored motor so I switched and ran semi indoors in the winter. And as far as tire/traction there were several other E-truggies running revolvers but I kept going back to bowties for outdoors. On the standard offset rims now, I am running AKA I-beams since they don't make bowties for 2.0 rims. My next tire purchase will probably be AKA City Blocks since I hear so many good things about them. I am going to run tomorrow to see what kind of temps I get and I will post them for you guys tomorrow night. Once again thanks for all the replies. It is people like you that make the hobby less frustrating and keep it alive.

[nuz69]

The sensor bring precision at very very very low speed like 1 mph, above low speed the system switchs on sensorless mode anyway. That's why most of 1:8 brushless system don't use sensor. You probably feel your tekin smoother than the mmv3 2200kV due to the lower kV, not because of the sensor.
The CC/neu 2200kV handle more power than the tekin truggy motors, so it is logic that it ran a little cooler...

[itbvolks]

I'm actually setup running cityblocks right now as well. Light weight and solid tread pattern. I had run bowties for years with good success so it'll be interesting to see how these work.

That being said, your clearly not running a heavy wheel/tire combo so that shouldn't be contributing to the heat issues. 175 is HOT regardless. 130-150 is about right with 160's being the absolute limit I'd be comfortable with. Too many rotor failures to be running them real hot. Plus, as nuz mentioned, your efficiency goes away as the motor heats up.

I gotta believe the 1700kv truggy motor makes more than enough steam to power a ~10lb race truck without significant heat issues. I guess I could see you pulling some serious current running in the grass or something but on the track, I gotta believe the load goes down significantly.

Any idea what your pulling for current? I could see some 150amp spikes causing some heat but like I said, in the dirt..... Going down a tooth or two on the pinion should keep the load on the motor down and thus the current draw (and so the heat). I'm hoping you have luck with your wiring rework. Keep us posted....

Itbvolks, I ran today at the track with temps being at the hottest 145 on the motor. It must have been that bad solder joint. Let me know what you think of the AKA City Blocks once you run them. I will say one thing about AKA rims, I am not sure they are the greatest for strength. At the outdoor track I run with big jumps, I cracked both of my rear I-Beams. Also let me know how your rims hold up.

Nuz69, the sensored does make a difference at all times. No matter what speed your at the throttle and brake are always the same meaning that 1/2 throttle is always 1/2 throttle and the same for the brake. A great example is jumping. Sometimes in the air the MMM wasn't always the same for correction meaning full brake would sometimes half correct an upright jump and sometimes it would make it nosedive. With sensored it is always the same due to the sensor knowing the position of the rotor. I had several hardcore racers drive my truggy and they all said how much smoother it was than the MMM. Just my .02 cents.