tvmax

My son has a stock stampede 4x4 brushed. We have overheated 2 motors. We do run a 7200 mah lipo battery for increased run time. Is there something I can do for heat? He is 7 and wants to play for long durations in the back yard. I have thought about a heatsink with fan that I have seen. It is stock gearing also.Would going to a brushless motor help? Any motor suggestions?

Thank you
Jim

spookie

iTrader: (25)

Going BL would defintelly help. BL is much more effeciant than brushed. I have messed with brushed, pushing to the extreme, but at the end of the day, went to BL. Is this 2wd or 4wd? Makes a differance on what motor Kv would be best for it.

Eta 4wd lol, still working on coffee. So a VXL 3500 setup would work, or a Castle setup. I assume it's a 2S battery?

edubRC

iTrader: (56)

I agree with spookie... a decent brushless system will get you better run times and a lot more fun. although the xl5 + titan 12turn are a very good entry level system for your stampede, the titan will always quit working on you at some point. a brushless system like the VXL or the Castle Sidewinder will set your back about $100, but it will be well worth it. you can also send your broken titan 12t motors back to traxxas and they will usually always send you new ones. all the times I have sent them my broken parts, they (traxxas) have always sent replacements. you can also try running a smaller pinion or a bigger spur gear (90t), or both. The truck will be a little slower, but gearing down will put less stress on the motor and give your son longer run times.

tvmax

Thanks guys. Yes it is a 4wd. Stock gearing. He doesnt need more speed but If brushless will give reliability it is what we will do. He does short burs accelaration over a jump or up a tree and then do it again. The batterys are 2s 7200s. I have seen the different motors. What size(5700,3800 ect) should I get? What do those numbers mean? I will need to get an ESC either way. How do youtell the 2 pol vs 4 pol motors apart?I may be able to buy a couple cars that have brushless setups in them prety cheap.
One last thing. My son destroys bodies on his trucks. Anyway to strengthen the mounting points so they dont break thru when he lands upside down?
Thanks again

spookie

iTrader: (25)

If you can dump some speed, in exchange for more torque and slower speed, just drop a tooth or two off the pinion or a tooth or two larger on the spur.

The castle 3800 was on my 4wd Slash, loaded down with larger Stampede 2.8 Talons. It did really well. Especially on 2S. The Traxxas Vxl will also, and probably be quite a bit cheaper, especially from an Ebay chop shop. Make sure to get the smaller 3.2mm shaft on the Castle, so the stock Traxxas pinions will fit. On 3S, both will heat up about half pack, and will require extra cooling, heatsink/ fan etc.

tvmax

So is a 3800 or a 5700 mean more power or torque?

mrgrimm

iTrader: (46)

3800 more torque, but could slap a 3s in there for amazing torque AND speed!

I think you should go with a 4 pole (also more torque, especially needed with 4wd trucks and running in grass, etc...) motor less than 4000 kv for the Pede 4x4.

3800kv on even just a 2s will be very fast for a 7 year old (or anyone without a lot of rc experience for that matter), so be sure the esc is programmable so you can tune it down, or even consider running some cheap 6-7 cell nimh packs???

The castle motors on 2s or nimh should really never give you a problem if geared right. Bearing failure has happened to me, but they are easily replaced since the motors just bolt together.

2uzferunner03

In my experience lipos will always eventually burn up a brushed motor. Just too much current for the brushes to handle.

3800 and 5700 are kv ratings. Kv times volts equals motor rpm with no load. So a 3800kv on 2s is 3800×7.4 = 28,120RPM.

For the 4x4 you need to stay below 4000kv. Traxxas 3500kv, castle 3800kv and leopard 3650kv are all 4 pole and will work nice. If you don't get a combo the hobbywing ezrun sct 120a is very nice.

spookie

iTrader: (25)

5700Kv is too high for a 4wd imo. It's a 2wd rear wheel drive motor. Don't worry to much about 2 pole VS 4 pole. In short a 2 pole (Traxxas Vxl) is softer on take off, than a 4 pole (Castle 3800). You can control the speed with gearing, within reason. Lol, even on 2S, you will be looking for ways to slow it down for more control. Brushed looses alot of energy through heat generation. BL, brushless, is much more effecient than them, leading to longer run time. No contacting parts inside the motor other than the bearings.

I forgot to mention, the Traxxas VXL setup, has a 50% training mode on it. It's stil quick, but full throttle is limited to 50%.

tvmax

edubRC you mention sending motors back to Traxxas. How do you go about this? Do you contact them about returning?

Overdriven

iTrader: (18)

I'll stay out of the motor talk but you mentioned strengthening the body. Aftermarket bodies from Proline are generally a little thicker and tougher than stock Traxxas bodies. A trick I do to extend the life of a beat up body is using 2 liter soda bottles. Simply cut a nice rectangle to span between the two body posts and extend forward and in back of them about an inch. I use a piece on top of and under the body so you'll have three layers. Drill through all three layers near the corners of the rectange pieces and two holes in between the posts. Use small screws and nuts to clamp the layers together. Using Shoogoo between the layers will bind them together better. Drill the body post holes and you're done. For the front, if you cut the rectangle out of the soda bottle the right way it will follow the curve of the body better and be less noticable. Adding a rollbar in the center of the chassis to support the cab of the body during a rollover will also help the body last longer.

Edit: Some guys use Sheetrock/spackle mesh tape to reinforce bodies along with shoogoo, especially in the corners of the bed, corners of the cab and where the cab meets the bed. This can help prevent cracking in these areas to a certain extent but it also helps the body stay together when it does crack.

Maxximize

I remember having an issue with my 2wd Stampede overheating back in the day when I ran high MaH 8.4v NiMH packs. The longer run times at higher voltages were not kind to that little motor There were no brushless motors in those days, so I was limited on what I could do. My truck had a 20 turn stinger motor with no internal fan, so naturally it ran even hotter. I added a good quality heat sink to it and geared it down slightly, maybe 1 or 2 teeth I think. With the heat sink alone it ran quite a bit cooler, and the lower gearing seemed to help too although it was slower of course. You could always try a heat sink, they are pretty cheap so it's worth a shot. Also being a 4x4 Stampede, you have one advantage I didn't in the motor placement. Since it sits on top of the chassis, if you put a heat sink on it you could also try cutting a hole in the wind shield and the tail gate on the motor side like you do on nitro trucks to get some air in there. My buddy did the heat sink thing and ran one of my cut up T Maxx shells on his original brushed E Maxx back in the day and it helped with his overheating issues on higher power batteries, so he ended up cutting holes in all his bodies.

I'd like to add to the body strengthening part of things too. +1 for the Proline bodies firstly, the best bodies out there by far! thicker than any others I've used and made from actual Lexan. a second to Proline is Parma. I use 3m aluminum foil tape on the inside of my older and thinner bodies to help hold them together when they start to deteriorate, works like a charm. I have a 13 year old Parma beater T Maxx body that is still together with that stuff all over the inside of it. And believe me that body has been to hell and back, and has been used and abused on 2 other people's trucks before I inherited it. By the way, nice trick with the soda bottles Overdriven, I'll remember that one! Yet another use for shoe goo in the RC world. My buddies dad used to save all the trimmings from new truck bodies, now I know why

edubRC

iTrader: (56)

I just sent the broken parts with a sheet of paper stating the problem with the part. (ie: "I bought this Stampede for my son over xmas and the motor just stopped working...")--> you can put something like this. They did not ask for any paperwork or anything. Just send the broken parts, a sheet of paper explaining the problem and your return address. It takes about 4 weeks to get the parts back. I have done this a few times for various parts over the last few years and I have always gotten new parts back.

2uzferunner03

Traxxas vxl system is now 4 pole.

Overdriven

iTrader: (18)

I usually forget to save the trimmings from new bodies but they can be useful for a variety of things. Thanks for the compliment. I have a nephew who started when he was about 5 so finding ways to extend the life of bodies was needed. If you use shoogoo between the layers of Lexan you can actually remove the nuts and bolts used to sandwich everything totether once the shoogoo is fully cured. Shoogoo is some pretty versatile stuff.