swissprecision

Hello there, just one question

I just purchased a tb-02. I put on it a 13t D5. I ran it once with the original gearing but I noticed that the motot was gettin too hot. Then I changed the gearing to 18/61. I thought that it would help, but it's still getting extremely hot.

I have the car with the nissan gtr body. I think that the body could be a cause of the problem, since it barely sits 5mm above the ground; so I guess not enough air is coming in to help cool down the motor . Or maybe it's the gearing. What do you think?

Cain

iTrader: (294)

What does Tamiya recommend for gearing?

You can undergear a motor and get it cooked just like overgearing it. The trick is to get the sweet spot.

I would do this first:

1. identify the gearing you had before you went lower
2. Go down 1 tooth and run the vehicle for about 3 minutes and see if the motor still feels as hot as before.
3. If the motor feels hotter than before, you probably are undergeared.


Make sure you let the motor fully cool before doing this testing when you change gearing you get a true value.

If you feel like your motor is just getting to top speed really fast, thats a sign of being overgeared. I don't know if you race your vehicle, but you usually want the motor to top out about 3/4 down the longest straight within reason.

A-Ko

iTrader: (2)

What Cain said and if you are testing I would probably stop running between 5-6 minutes. You probably have good runtime and the car will hold in the heet. Some guys also have installed fans to cool their motors. The trick is finding a low voltage one that pulls a lot of air.

swissprecision

So what would work better; do I put a smaller pinion gear or do I put a bigger spur gear?

Cain

iTrader: (294)

I think for testing it would be easier for you to change the pinion gear instead of keep changing the spur.

Cain

iTrader: (294)

As for the time to run the vehicle and then check, I usually do about 3 minutes myself since alot of times when the motor is overgeared it goes into cruise control around that point. This way you can catch it before it does that but it still is so hot you can tell something is up.

RCGaryK

iTrader: (3)

I don't have my manual in front of me, but I think that 18/61 is the shortest geat the TB-02 can take. At most you might be able to go to a 17 pinion. You're fighting the fixed gearing is part of the problem. My Monster stock is about the same temp in my TB-02 as my Evo 3 with almost the same fearing. The tub chassis will reduce airflow over the motor somewhat, so it will run a little hotter.

What speedo are you using? What is the timing set to on the motor?

swissprecision

actually the manual says it can be geared as low as 16/61, so I don't think mine is too undergeared. In a few minutes I will try with 19/61
let's see what happens

swissprecision

OK, I just ran the car with a 2400 battery, a fusion, and the d5 13t 20d timing.
I went up a pinion since I thought it was undergeared (19/61). The temperature went down considerably, but still when I put my finger on the motor it feels hot, and if leave it there it will start to burn , so I think it's still getting too hot and this may screw up the motor if I keep running it like that. What do you guys think? is it normal that the motor burns your fingers if you leave them there?

RCGaryK

iTrader: (3)

I was temping my motors last weekend during testing, and the temps were in the mid 160 range. I've gotten them into the 180s which is too much.

swissprecision

at 180 do you fingers get burn if you let them on the motor? i don't have a temp gun, so no way of knowing whether it's getting too hot or not

swissprecision

at 180 do you fingers get burn if you let them on the motor? i don't have a temp gun, so no way of knowing whether it's getting too hot or not