After I installed a stock 27T 540 motor into my RC18T, I quickly became addicted to the speed and power that this little truck could dish out. Soon after, the 2S 7.4V li-po battery I was using to power that stock motor didn’t feel quite so fast, so I upped the ante to a 3S 11.1V li-po with the same 27T stock motor. Now things were cooking. The truck could not be stopped, and the top speed was measured at just under 50MPH. But the car was still controllable, so I knew it could handle more speed. So this past weekend I pulled out the stock 27T motor and replaced it with a Trinity D6-series 10T single round-wire motor and then kept the same 3S li-po battery. Yeah, this is going to book. I had to replace my MC230CR ESC since it’s only rate for a 20T+ motor. So the Novak GT7 I have definitely fit the bill touting a 5T motot limit at 7.2V. Well, I’m running 11.1V, just a wee bit above what it (and the motor) are actually rated for. But for a few quick runs up and down the street shouldn’t be too much to handle.
In a nutshell, this thing is quick, amazingly quick. Now we’re to the point of out of control, as I can barely keep on the throttle for more than a second or two before the truck is all the way down the street. Though I haven’t measured the top speed, it’s got to be around the 60MPH region, since it’s much quick than the stock motor which clocked in at just over 47MPH. I’ve got it geared with a 25/60 pinion/spur combo and it feels perfect. I’ve got enough torque to being flying down the street at half throttle, about 20MPH or so, and then I can punch it and it will literally pick the front tires up off the ground and flip over over onto its shell, and this is not from a stop, or on carpet. The smallest pinion that would fit before the large can of the motor hits the center drive shaft is probably about a 23-tooth. The largest pinion that could fit is only limited by what’s available in a 48-pitch, which is a 36T made by RRP. Thought gearing that high would put a lot of stress on the battery, ESC and motor, and although could reach some insane top speeds, probably wouldn’t be practical for everyday driving around.
The biggest problem I’ve encountered so far is stripping the input gears and differential gears. I’m on my second set right now. I’ve basically had to resort to street-only driving, since driving around in the dirt fills the gearboxes with dirt and rocks, which then leads to the two gears inside wearing out much quicker. The plastic housings don’t do a very good job keeping things tight either, even though the diff is shimmed about as tight as you’d want. The housing and the gears need to be made of aluminum, Delrin, or even better, steel. I’ve lost all the springs that go into the output shafts, and had to replace them with springs from ball-point pens. Which works perfectly, thank goodness for small favors. I’d also like to get an aluminum spur gear. But the rest of the truck is pretty bullet proof. I’ve taken some nasty spills where the truck just flips end over end for hundreds of feet and it just keeps going. I haven’t taken it off jumps, and I’m extremely easy on the throttle, so I am babying it so it will last. One crash threw the li-po out of the truck and another ripped the 540 motor mount off. So it isn’t without its problems, but when it’s not running, I’m having fun sitting the workbench in the garage fixing it, tweaking it, making it more robust, and trying to come up with ways to make it just work better.
I wanted to say thanks to Chris C. for painting such a sweet body and sending it to me. Thanks Chris!