Temp/gearing question about T4.

[majikmike]

Ok I have a stock AE T4 with a MM5700 motor. It is geared 15t pinion and stock spur...86t i think. What kind of temp range is safe for that motor and the 7700 as well cause I run it too? Another question, is the tranny on the T4 strong enough to handle the brushless? I mean so far it is but then again I am being easy with it to. Thanks for any info ya'll can give...laters :wave:!!

[GSMnow]

Seems you have found out the issue with high KV motors for yourself. I run a MM5700 in my Losi XXX-T and I am running at 15 to 86 with an internal 2.55 ratio which I think is pretty close to the T4. The 7700 is just plain too hig of an rpm to use in a truck on any normal race track. If all you want to do is high top speeds in a big open area, sure you can run it, but it is just plain crazy. The 5700 can be geared up for the biog open spaces, but allows you to run it on a tighter track with the 15 or even a 14 pinion. I am seriously thinking of getting a 4600 motor for the truck and moving the 5700 to a buggy where it can use a bit more rpm.

As far as temps go, Castles says keep the motor under 200F. I have gotten mine over 205F a couple times and it is still alive, but I think I did weaken it a little. Either it has gotten weaker I am just getting better at driving it since I am pushing it much harder on track. It still pulls wheelies from 30 mph so it is certainly not very weak, it just feels easier to control on a tight course. When I first got it, I had to baby it around to keep from spinning out. Then again I went from a 27 turn stocker right to the 5700 geared for 45 mph. The 15 tooth pinion works out more like 33 mph and is far easier to drive.

[chilledoutuk]

I am not certain how the cm36 motors react to low gearing but i suspect that under gearing them might make them run hotter than if geared to provide a decent amount of load to the motor.

If i was using a cm36 still I would experiment with gearing and try to gear to get the lowest motor temp possible and then just reduce the number of cells should you need less power.

I know that when I was running 11.55 fdr in my cat 3000 the 7700 got a lot hotter than when geared to 10.22 fdr.

Another solution is to as GSM stated use a lower kv cm36 motor or perhaps a better motor such as one of the German made motors.

ON the note of the T4 the only weakness of the T4 really is the front wishbones the transmission like all associated transsmisions is very strong and should be able to handle almost any brushless setup with ease.
Also i heard there slipper works a lot better than losi's.

[GSMnow]

If you are way undergeared, like totally unloaded, the motor will warm up a bit, but it does not get too hot and the ESC runs very cool. I have seen the rule of thumb is to gear where the ESC and motor run at the same temp. Overgearing really heats up the ESC. But if you gear way too high, the motor and ESC will both get very hot. Max temp of either should be under 180F in normal conditions. Here is the So Cal desert with 105 ambient air, I have seen over 200 a couple times before I geared it slower. Now with a small heat sink on the motor can and a fan on the ESC, I get 160F on the motor and 130F on the ESC. I could gear up a little but it is plenty fast on course and I get 14 minutes on track with 6 cell IB4200's. Oh, this is a MM5700 setup in a Losi XXX-T MF2 currently geared 15 : 86 for about 33 mph, not accounting for tire ballooning.

[rhino131]

Have run the novak gtb w/ 4.5 velocity motor ......very fast on asphalt just stupid on dirt......nooo traction so the t-4 tranny has held up to some real dumb bashing and hard racing as well .... I have been running the 5800 ss motor lately and have setteled in on 14 pinion and 87 spur good speed and lowest temps AZ = HOT (around 165 on ESC and 185 to 195 depents on traction) get good run times but I also run Lipo 4800 so thats cheating I know but Love the speed