TT-02B: Gears vs Motor Temperature

[skom25]

Hi,

I did few runs with my TT-02B and found two things. Now it has stock gears, Sport Tuned motor, FDR is around 10.9.

1. It reaches top speed after about 5 meters

2. Despite 10.9 FDR motor is quite hot

Explaining a little bit more. I am not satisfied with current top speed. I mean, when model reaches top speed so quickly, that it starts to be little boring even on tight tracks. Second thing is motor temperature. I am surprised that it gets so hot in current setup. My DT-03 with FDR around 9.1 makes this motor hot, so I thought that with with FDR 10.9 it will be better, especially that TT-02B has bit better cooling.

Time for main question!

I can buy High Speed Set 68T + 19T pinion. It will give me FDR around 9.1, similar to DT-03.

What will happen then? Currently I go full power almost all time. When I will change gears, I expect that I will use full power for shorter time or at least, motor will not go with full RPM all time.

On which setup motor will be cooler? Running with low load and RPM on limit or moderate load and RPM probably around 80/90% of range?

In terms of performance, I am fully happy with my DT-03.

[alvinlwh]

.

[OoALEJOoO]

@skom25 On the TT-02B you can get a wide range of FDR without the need of the High-Speed gear set (which is more useful on TT-02 touring cars) by just changing pinions. With the 70T stock spur, you can get FDRs from 11.38 (16T pinion) to 7.28 (25T pinion). If you are running the car stock (17T pinion + 70T spur), that's 10.71 FDR which is quite short. Indeed, with a Sport-Tuned motor you will reach top-speed very quickly.

Assuming you are running the car on the patch of concrete you showed in a vide on a different thread, you might see very little difference by switching to your intended 9.1 FDR (20T pinion + 70T spur). It might not be worth the change since as @alvinlwh mentions, going for a taller (smaller value) FDR will increase the temperatures you currently have. You really need a longer straight to benefit from taller FDR.

Regarding temperature, the good thing is that the TT-02B can be cooled far more effectively than the DT-03 if you do opt for taller FDRs. The TT-02 heatsink (54571) can fit the Sport-Tuned and with its massive fins, coupled with a fast fan,  does a superb job at keeping heat under control. Search ebay item 474720514440 for 30mm, 593403692355 for 40mm affordable fast fans (you'll need to trim their plastic connector and they can be plugged directly into the receiver). I am currently running my TT-02B with a still fairly short 9.58 FDR (19T pinion + 70T spur) coupled to a Super Stock TZ and the car clocks around 40kph on a 20m straight. Heat is not an issue even though the Super Stock TZ cannot fit the large TT-02 heatsink (since it has an end-bell) so I run a smaller heatsink + fan. I reckon I could push the FDR to 7.28 for ~50kph but would probably need a second fan. Note I am running in ~33C weather.

[skom25]

How you installed Heat Sink ( I have it) and fan at the same time? Could you share photo?

[OoALEJOoO]

@skom25 You can see on the right picture a small heatsink with a 30mm high-speed fan above. On top of the fan, I attached the included TT-02 scoop just to prevent anything going into the fan (fingers included). I fastened the scoop to the fan using screws, then the fan to the heatsink using zipties in-bewteen its fins. You could fasten both the scoop + fan to the heatsink with zipties in a single go. Fan blows towards the motor. Note there is also a regular speed fan on top the HW 1060 ESC.

EDIT: You need to remove part D8. If you want to keep the switch mount from D8, you can trim the unnecessary top section just to keep the edge and the switch mount.