TXT-2 overheating...any ideas?

[mheald 351]

Hey guys,

This is my first question on the forum so please excuse me if its a stupid one. I've never had a car/truck overheat before but my new TXT-2 is struggling.

I've dropped in a brand new TEU-106 esc and two Sport Tuned motors. All ok according to Tamiya. I'm only running a 3000mah 7.2v Nimh so can't see any reasons for the overheat. It only seems to happen off road when driving at slower 'crawling' like speeds. When I'm belting around at top whack its all fine and dandy. It cuts out completely (still got steering) and the esc gives off the 'overheating' alert.

The truck is running smooth and will happily free wheel down steep hills, so nothing seems to be overly tightened etc.

The only other difference is that I've got two hi torque servos in, but I didn't think this could cause an overload?

Totally confused.

Any help or ideas would be muchos appreciated. Thanks in advance.

Mike.

[dyahipfakta 50]

Going slow causes heat to buil up much faster. Ironic huh if your more into going slow I suggest higher turn motors or gear down a touch. They will be fine belting around but will struggle going slow.

[mheald 351]

Blimey, 20 odd years in the hobby and I never knew that! Thank you!

I might just go brushless on this beast. Any ideas what brushless setup would be similar to this power wise? I'm not fussed about more speed, just longer running times would be great.

Thanks again!

Mike.

[wolfdogstinkus 1717]

5000mah 2s lipo will make a big difference to runtimes. 3s lipo will be insane power.

You will need a lipo cut off or alarm, check out hobbyking for cheap lipo's.

E2a: Not sure about overheating though?,

[dyahipfakta 50]

Blimey, 20 odd years in the hobby and I never knew that! Thank you!

I might just go brushless on this beast. Any ideas what brushless setup would be similar to this power wise? I'm not fussed about more speed, just longer running times would be great.

Thanks again!

Mike.

Me either til recently I never tried to go slow before and when I did try it I discovered its not as simple as you might think lol

[billg4 25]

a 3300kv will be like silvercans

3500 or up to 4600 is a good speed for txt's

racers like 5700 and above

[Sayer 717]

Overheating seems highly unusual with motors as mild as sport tuned. Is the esc rated for an 11 turn motor? (Which is what it will think 2 23 turn sport tuned are if wired in parallel)

[MadInventor 3881]

If you want to go slow, two 12 tooth pinions will make help a lot, (20% reduction in speed over stock). I use unlimited speedos in my TXT's and have no probs with overheating, even when hill climbing.

[mheald 351]

It's apparently fine with 2 sport tuned which is what's confusing me. The instructions state that explicitly. Weird indeed. I may try swapping this teu-106 for the other I have and check if this one faulty somehow. Hmmmm. Or I may just throw in the towel and buy a brushless setup...Hmmmm.

[mheald 351]

If you want to go slow, two 12 tooth pinions will make help a lot, (20% reduction in speed over stock). I use unlimited speedos in my TXT's and have no probs with overheating, even when hill climbing.

Interesting, I've been looking at other pinions as when I stuck on a set of TXT-1 wheels it REALLY affected the performance, so I dropped back to the stock wheels. But from what I've read the original TXT-1 had 15 tooth and the TXT-2 has 19 tooth, which would explain that issue.

Do you need specialist pinions for these trucks? Sorry if that's a stupid question but I haven't looked to change pinions on a car/truck since my racing days 20 years ago

[DCLXVI 3]

Two high torque servos could be the fault, they could have enough load to make the BEC in the ESC overheat...

You could try using a separate reciver pack or using just one servo and see if the problem persists...

[kontemax 1698]

At first you absolutely need steel pinion gears.

Then you can run TXT-1 wheels but you must adapt the gear ratio to the wheels.

The wheels are a component of the final gear ratio, if you change the wheel diameter this affect the performance and the transmission ratio.

So with TXT-1 you must use smaller pinion gear. I suggest 15T if you use silver cans (as per manual). If you use a powerful motor you must choose smaller ones (also the motor characteristic affects the performances), so 13T or 12T should be the right choice.

Max

[mheald 351]

Thanks for all the info guys. You might be right about the servos too! It's only just dawned on me that...

1. I initially ran with only 2 wheel steering and had no issue (although I hadn't done any crawling/off-roading at this stage).

2. When I'm driving slow I'm off road, proper off road and trying to intricately traverse the truck over some tough terrain, hence more intensive load steering due to the surface and lower speed.

...****, I really liked the 4 wheel steer too. Maybe I'll try dropping in a standard acoms/futaba servo for the rear and see if that alleviates it.

Thanks!

Mike.

[mheald 351]

How rude, I'd not included a picture of the beast

I'm still to add the upgraded rear shocks but once they're on ill update the post with a sexy chassis shot

[billg4 25]

why not use an external BEC unit??

I use a castle one, you can adjust voltage to the servos with it

[kontemax 1698]

You must immediately swap these little wheels with TXT-1 ones!

Max

[mheald 351]

why not use an external BEC unit??

I use a castle one, you can adjust voltage to the servos with it

Ooooh this sounds interesting! Thanks for the info. Would this be the one you have by any chance?

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=230881132225&fromMakeTrack=true&ssPageName=VIP:watchlink:top:en

Thanks again!

[mheald 351]

You must immediately swap these little wheels with TXT-1 ones! ;)Max

Ha haaaa, well it does look a boat load better with them that's for sure, but with the 19T pinions it's just too sluggish for now. I'll do some tasty pics with the big wheels and fully hopped up shocks (which set me back £130 with shipping but by Christ are they nice!) tomorrow and post an update

[kontemax 1698]

Can't wait!

Max

[MadInventor 3881]

Interesting, I've been looking at other pinions as when I stuck on a set of TXT-1 wheels it REALLY affected the performance, so I dropped back to the stock wheels. But from what I've read the original TXT-1 had 15 tooth and the TXT-2 has 19 tooth, which would explain that issue.

Do you need specialist pinions for these trucks? Sorry if that's a stupid question but I haven't looked to change pinions on a car/truck since my racing days 20 years ago

I use 32DP RW Racing pinions, available from Modelsport UK. The difference of 15tooth and 19 tooth between the TXT-1 & TXT-2 is to account for the different size wheels, so if you are going use TXT-1 wheels then a 15 tooth or less pinion will be what you want. I used the 12 tooth pinions in mine when I was using it for hill climbing, and needed torque rather than speed. Interestingly, when I wanted more speed from my TXT I put 20tooth pinions in it with a couple of kyosho magnetic mayhem (23 or 21 turn) motors in it and never had any overheating issues, but I tended not to use the brakes much on it.

Also if you are using a wheel tyre combo where the tyres are glued on you can look forward to destroying the centre drive shaft yokes in short order, as they are only made from brass. Look out on ebay for some REVO drive shafts, these can be fitted with a minimum of modification, and althugh made of plastic are much stronger as they are a larger diameter.

[mheald 351]

I think I've learnt more here in this one post than I have over the past 10 years lol. Thanks guys! So in short, I need an external bec unit to cut out the overheating caused by the two 13kg capacity servos, to swap my wheels back to the TXT-1 ones and add in some lower toothed pinions. Boom. You all rock, thanks!

Mike.

[gravetxt-1 84]

Glad to hear you have reached a solution does seem odd to me though as I ran my txt-1 with Tamiya twin motor esc/ boggo hitec receiver (built in bec) stock silver cans x2 and hitec hs 645 ultra torque servos x2 for 4 wheel steering. Ran it many times up very steep bomb holes lots of slow driving never had a problem with overheating. Hope it works out ok for you.

[dyahipfakta 50]

Sports tuneds are abit hotter 23 turns then silver cans and are probably at the limit of the escs capabilities.

[DCLXVI 3]

For an external BEC you can just use 5 rechargable batteries or 4 non-rechargables (4 rechargables works to but lowers the performance of the servos) and connect them to the reciver...<br /><br /><br />Some ESCs needs to have the middle cord of the reciver cable removed (on a Futaba system, I think Acoms or some other manufacturer uses a different order for the servo leads) when using an external BEC/battery

[mheald 351]

For an external BEC you can just use 5 rechargable batteries or 4 non-rechargables (4 rechargables works to but lowers the performance of the servos) and connect them to the reciver...<br /><br /><br />Some ESCs needs to have the middle cord of the reciver cable removed (on a Futaba system, I think Acoms or some other manufacturer uses a different order for the servo leads) when using an external BEC/battery

Ahaaa, interesting idea. I've just dug out an old manual ESC battery holder, a spare on/off switch (as when I hooked it up as standard it just switched the car on lol) and spliced them together. I've hooked it all up and its ready to test. It only holds 4 batteries, but slightly underpowered servos is currently preferred to overheating, so lets see how she does.

I wont be able to test the beast until the weekend as a **** pinion came loose yesterday so I need pull some bits off to get at the motors, disassemble, tighten, re-threadlock, re-build and then try again Actually it might be next week as I may just order those pinions now as I'm going into the gearbox.

Thanks man!!