Jump to content
nowinaminute

What's the safe limit for DT02/03 gearbox trimming for better airflow?

Recommended Posts

I know this is quite a common mod but is there any kind of general consensus about how much plastic can be cut away?

I've been running at the beach a lot recently and besides the fact that the plastic motor surround does it's best to cremate the motor, it also acts as a sand storage area which not only adds to the motor being stifled but also means there's sand just hanging around in the vicinity of the motor and gearbox just looking for a way in!

  • Like 1

Share this post


Link to post
Share on other sites

Instead of removing and modding, there are other alternatives. I know of people who have used adapters so they could use 29 series brushless motors.

One of these http://smallpartscnc.com/index.php?route=product/product&product_id=203

with one of these in a 6D http://www.tppowereurope.com/Webwinkel-Product-49250081/TP2935.html

Run it with a Hobbywing 10BL120 ESC and you have one seriously hardcore sandrail. It may be a "puny" 29 motor, but it has more power than a lot of 3674 motors out there.

  • Thanks 1

Share this post


Link to post
Share on other sites

what kind of motor you have in the car? if its a cheap brushless motor it wil get hot.

I like the castle motors they stay very cool, I have a 5700kv castle motor in my gf-01 dumptruck and that car weight 2 kilogram I run that car on the beach and even on a hot summer day the motor stay cool about 35celsius/ 95 farenheit.

I had a 5700 cool rc motor in the dump truck and that runs hot 85 celsius /185farenheit.

I know the castle motors are not cheap but they are much better then the cheap brushless motors, I would say put in a castle motor with some high temp silicone sealent between te motor and gearbox and you are good to go, then you don't have  to chop the gearbox.

And you get much better runtimes with a castle motor In my dumptruck with the castle motor I get 30 minutes of runtime, and with the cool rc it was 20 minutes of runtime both had the same kv rating and I used the same battery.

Share this post


Link to post
Share on other sites
5 hours ago, dannymulder said:

what kind of motor you have in the car? if its a cheap brushless motor it wil get hot.

I like the castle motors they stay very cool, I have a 5700kv castle motor in my gf-01 dumptruck and that car weight 2 kilogram I run that car on the beach and even on a hot summer day the motor stay cool about 35celsius/ 95 farenheit.

I had a 5700 cool rc motor in the dump truck and that runs hot 85 celsius /185farenheit.

I know the castle motors are not cheap but they are much better then the cheap brushless motors, I would say put in a castle motor with some high temp silicone sealent between te motor and gearbox and you are good to go, then you don't have  to chop the gearbox.

And you get much better runtimes with a castle motor In my dumptruck with the castle motor I get 30 minutes of runtime, and with the cool rc it was 20 minutes of runtime both had the same kv rating and I used the same battery.

It's cheap but it's only 3100kv and doesn't get anywhere near as hot in any other RC including my GF01. In fact, I usually run a 3900KV "finned 380" In the dump truck and it still runs cooler than the full size 540 in the DT02.

I can't say I've had the same luck with Castle motors. I have a CM36 of the same KV (5700) and it's the hottest running motor I own pound for pound. I know that cheaper motors are less efficient buy I've never experienced the kind of differences you have. There should only be about a 10% difference worst case, it's hard to make a truly terrible brushless motor. I have a 3600KV castle which DOES run cooler than any similar KV cheapo but I can't think of any cheap motors I've had that run twice as hot at a similar KV.

With those temps you've experienced, the cheap motor would appear to be 60% less thermally efficient which would put it below brushed motor territory. 

I also find you can't really get a suitable final drive ratio for such a fast motor in the DT02 which again causes heat. I find 5700KV to be excessive for these platforms personally. I also have a 4600KV Tekin but again, I find it runs pretty hot vs a lower KV motor regardless of brand.

Share this post


Link to post
Share on other sites

I'd probably start with drilling some holes, test and repeat until there are just enough holes cut to drain the sand. Am interested in what others have done.

Share this post


Link to post
Share on other sites

I'm going to try cutting enough away to fit a clip on (spot of glue too i think) cooling fins and maybe a fan.

You may have seen my DT03 on the beach, and the mess of the gears after. Silicone around the casings is a good idea.

The beach DT03 ran 3s with a 4300kv Goolrc motor and now fitted the Castle 3800kv, the Castle is night and day better than the Goolrc,  both in power and temps (but still going to add fins etc)

  • Like 1

Share this post


Link to post
Share on other sites
2 hours ago, Wooders28 said:

I'm going to try cutting enough away to fit a clip on (spot of glue too i think) cooling fins and maybe a fan.

You may have seen my DT03 on the beach, and the mess of the gears after. Silicone around the casings is a good idea.

The beach DT03 ran 3s with a 4300kv Goolrc motor and now fitted the Castle 3800kv, the Castle is night and day better than the Goolrc,  both in power and temps (but still going to add fins etc)

Yes I remember that lol.

The biggest help I've found for sand ingress with cheap motors is to go around where the cables exit the can with silicone, they aren't very well sealed there at all. The paper gasket thing can help stop it getting in the gearbox but it depends of the motor can even pass it through anyway, some designs don't allow that to happen.

Knock on wood, I haven't had much trouble with sand getting into the actual gearbox itself yet whilst using a "ventless" motor (im not going to call it sealed lol) but I live in fear lol. 

The main thing that has nudged the temps up is that I've been running those DIY sand tyres in soft sand a lot including a lot of uphill driving. It makes the motors get way hotter than when I drive on flat and firmer sand. 

Probably doesn't help that I'm running the 19t pinion either but it was all I had at the time.

I honestly haven't tried 3s with the sand tyres yet, I'm not sure it's even necessary with the amount of kick it has already, it can already flip onto it's roof even in soft sand which never happened with the standard tyres but I would certainly like to improve airflow a little if I was going to try.

It's not exactly scorching as it stands anyway, only about 60-65 degrees after a full pack but I always like to keep it as low as I can whilst still performing how I want so if I can improve on that and get more headroom just by taking some plastic away, I'm up for it!

Like you say, regardless of motor quality and running temp, it's always nice to be able to improve matters for free.

  • Like 2

Share this post


Link to post
Share on other sites
13 hours ago, DK308 said:

Instead of removing and modding, there are other alternatives. I know of people who have used adapters so they could use 29 series brushless motors.

One of these http://smallpartscnc.com/index.php?route=product/product&product_id=203

with one of these in a 6D http://www.tppowereurope.com/Webwinkel-Product-49250081/TP2935.html

Run it with a Hobbywing 10BL120 ESC and you have one seriously hardcore sandrail. It may be a "puny" 29 motor, but it has more power than a lot of 3674 motors out there.

I tried one of those a couple of years back and a few other smaller motors such as DR mad thrust. One of them was something crazy like 75mm long. But I honestly couldn't see much advantage all else being equal. Very powerful for their size but they seemed to get just as warm as any other motor.

Maybe it helps when they are in planes and boats where you have water cooling or very effective air cooling? 

I still use a motor like that in my Grasshopper sometimes, reduces the unsprung mass and runs plenty cool in that car but I found them to be no more thermally efficient than a conventional size 1/10 motor. Ymmv. 

Share this post


Link to post
Share on other sites
6 hours ago, nowinaminute said:

 

I can't say I've had the same luck with Castle motors. I have a CM36 of the same KV (5700) and it's the hottest running motor I own pound for pound. 

Maybe you had a bad 5700kv castle motor,  I used to buy cheap brushless motors then i bought a second hand sct with the 5700 castle motor in it and I was surpriced that it runs so much cooler and have longer runtimes, even better then my hobbywing motors, but the hobbywing motor are the older  quicrun models I don't know how the new models are.

 I have done the same thing to my mst-mtx 1, with the stock 3000kv motor I put in a larger pinion gear 32 tooth 0.6 mod instead of a 24 tooth stock pinion gear because the car was realy slow and the motor  gets hot, then I put in a 3800kv castle 1410 sct motor  and the car was faster and the motor stays cold, If I want I can ran the car on 3S without overheating.

so I have good experience with the castle motors, I still use cheap brushless motors only in light weight cars, the 5700kv cool rc motor is now in my grasshopper/zahhak fusion car and its fine in it max temp 70 celcius, but that cars weights about 850 grams, in cars that are 1.5 or more kilograms I use now castle motors.

Share this post


Link to post
Share on other sites
1 hour ago, nowinaminute said:

Probably doesn't help that I'm running the 19t pinion either but it was all I had at the time.

Ran a selection ,but 20T on both motors with 3s was good, although tried 16t with the Goolrc,  and it just didn't satisfy the speed bug. 

 

1 hour ago, nowinaminute said:

I honestly haven't tried 3s with the sand tyres yet, I'm not sure it's even necessary with the amount of kick it has already, it can already flip onto it's roof even in soft sand which never happened with the standard tyres

You'll need nose weight for 3s, although the Goolrc wasn't too bad, so you could control back flips on the throttle, the Castle was brutal, and I'm back to the angle iron bumper for its next sand run (whenever that might be, maybe a speed run attempt before then)

Share this post


Link to post
Share on other sites
4 minutes ago, Wooders28 said:

Ran a selection ,but 20T on both motors with 3s was good, although tried 16t with the Goolrc,  and it just didn't satisfy the speed bug. 

Do you have an adjustable motor mount?

I guess if you could run the 4300 on 3s and 20t I should be ok running a 3100. 

Maybe I should just man up lol

Did you use sand tyres though? They seem to make quite a difference to motor load.

Share this post


Link to post
Share on other sites
3 hours ago, nowinaminute said:

Do you have an adjustable motor mount?

Nope,  just leave a bolt out! 

Try it, you'll find the motor can't actually move further away, as it hits the casing 😏

(Figured with a new gear set being a fiver, it was worth a try 🙄)

2019-09-12_06-48-14

I'll bung in a 16t and take a pic,  not the best mesh in the world, but it worked 🤷‍♂️

3 hours ago, nowinaminute said:

Maybe I should just man up lol

Saying nothing.....🙊😂😂

 

3 hours ago, nowinaminute said:

Did you use sand tyres though? They seem to make quite a difference to motor load.

Yep, 2.2" intimidator's on FTX Mauler wheels.

2019-07-16_03-11-27

 

Share this post


Link to post
Share on other sites

Goolrc 4300kv 3s , no nose weight ,soft sand (just seemed to bounce on the hard sand) -

 

Castle 3800kv 3s , some nose weight, harder sand than the Goolrc (maybe need to swap the motor on the same day?) - 

 

 

 

Share this post


Link to post
Share on other sites
1 hour ago, Wooders28 said:

Try it, you'll find the motor can't actually move further away, as it hits the casing 😏

I like your style lol

1 hour ago, Wooders28 said:

Saying nothing.....🙊😂😂

It's only a £10 motor I suppose....

1 hour ago, Wooders28 said:

Yep, 2.2" intimidator's on FTX Mauler wheels.

ok, that helps, at least we're on the same page!

54 minutes ago, Wooders28 said:

Goolrc 4300kv 3s , no nose weight ,soft sand (just seemed to bounce on the hard sand) -

Are you giving it the same aggression with the throttle as you are in the Castle video? If so, that does seem awful laid back for 3s brushless, even a cheapy. It even sounds less eager! Perhaps it was a little too much KV for the gearing and was bogging down a little and staying in the lower RPM/higher amp range? I'm guessing the threshold for that happening would be lower on a cheaper motor. I feel like my 3100 pulls harder but it's pretty much impossible to tell without comparing both in the same vehicle in the same circumstances.

54 minutes ago, Wooders28 said:

Castle 3800kv 3s , some nose weight, harder sand than the Goolrc (maybe need to swap the motor on the same day?) - 

You can even hear that has more get up and go. I guess the sand consistency could make a difference. Soft sand is notorious for making things bog down but I don't think the other motor was delivering the goods either way. 

Almost too much power with the Castle in a way but it's a tricky balance sometimes. When I'm climbing dunes and in more enclosed areas, 2s feels pretty much perfect but when the tides out and you have that massive expanse of sand, the perception of speed instantly falls off and you crave more speed.

When I was at the beach a couple of weeks back, a guy with an X-maxx turned up and he wasn't really that much faster when he was trying to actually adhere to the terrain on the dunes but he also had the option of just hitting the start of the dune, clearing the rest of it completely, landing on the beach and then just blasting off at 50mph. Talk about kicking sand in my face :wacko:. I could keep up when he was trying to obey gravity but on the open beach it was hopeless. I know I wouldn't have kept up even on 3s but it would have been enough for the panic and doubt to set in for a glorious split second of £1000 buyers remorse:D

ze91iRu.gif

I did manage to smoke a guy with a 2wd slash at the beach with my Grasshopper once using a finned 380 on 3s but the victory as short lived. A soon as we hit some bumpier sand the Grashopper assumed it's default upside down position. It felt **** good though!

  • Haha 2

Share this post


Link to post
Share on other sites
47 minutes ago, nowinaminute said:

Are you giving it the same aggression with the throttle as you are in the Castle video?

No, more! You see me stabbing the throttle, trying to get the nose to lift. The castle I dropped the end point down to 75/80% just to try and get the front end to sit in the air nice rather than flip (and yes, I was trying to drive it). I much prefer too much power, as it's easier to dial back than add more! 

I did run the Castle in softer sand, soft enough that the car wouldn't actually move until I punched the throttle to get the tyres to balloon and get grip.

2019-07-16_03-17-01

Anyway.

Fling in a 3s and have fun 🙄😁😁

  • Haha 1

Share this post


Link to post
Share on other sites
On 9/12/2019 at 8:55 PM, Wooders28 said:

Fling in a 3s and have fun

Well, that was interesting lol.

I went back to the beach. It didn't go quite to plan as I got my times wrong and arrived at high tide, doh! There wasn't any decent flat sand and people had been walking all over the soft stuff and leaving deadly mini potholes everywhere so it was tough to find enough space to work with. Why are families so selfish? :lol: It rained earlier in the day too so even the soft sand had a kind of damp mortar like quality rather than the soft fluffy stuff there usually is.

Anyway! First of all, I managed to get some old Pro Line Sand Paws so I slapped them on my DT03 (they would have scrubbed like badword on the Kumamon or Holiday Buggy shell) and jeez, these things have insane grip in the sand. My DIY tyres were pretty good but these things are something else!

Even on 2s it was really difficult to keep the nose down!
 

You certainly notice the difference in weight between a hard body with a bear in the driving seat and lexan! And those tyres were just tenacious!

Between the lack of a decent running space and the tyres, I found it pretty much impossible to use full throttle or get up to speed. I'll have to get some weight in the nose and come back when the tide is out. It might be worthwhile changing to my DIY tyres too for this particular buggy. They seem to be a more conservative compromise in terms of grip. The Pro lines definitely make for less stalling though!

I did try it on 3s, it was more of the same pretty much. It was very difficult to get the power down without flipping. I would have had a play with the EPA given more time. It's definitely exhilarating though! I just wish there had been more space with smooth sand so I could have really opened her up.

I need to take the preload collars off the back too I think, it's way lighter than the hard body '02s so with the same amount of pre-load, it's too bouncy.

As far as temps go, I didn't bother to measure. It got too hot to comfortably touch on 3s but meh. Nothing melted.

I tried to get some video but it's hard to drive and film at the same time when you're dealing with something a little volatile and space is limited!

Here's 2s:
 


And 3s. I struggled to go flat out on 2s so using the full power of 3s was nigh on impossible with the limited amount of smooth ground and trying to film but there's maybe one or two passes where you can at least see there's more power on tap:
 

 

  • Like 5

Share this post


Link to post
Share on other sites

That looks a lot of fun. If you are stashing those little square sticky weights around the front of the car if you can be bothered strip the chassis tub off the transmission and split it you can get an extra 30-40 grams in the voids in the nose, before sticking some more to the outside. 

Knowing the DT, if it is bouncy because of the speeds could i suggest trying some thicker damper oil? 

How much time do you havw to spend cleaning it after a beach run? 

Share this post


Link to post
Share on other sites
55 minutes ago, ThunderDragonCy said:

. If you are stashing those little square sticky weights around the front of the car if you can be bothered strip the chassis tub off the transmission and split it you can get an extra 30-40 grams in the voids in the nose, before sticking some more to the outside. 

That's the plan, I saw someone on here putting then in the void, maybe you? Just a matter of finding the enthusiasm to strip it down lol.

55 minutes ago, ThunderDragonCy said:

Knowing the DT, if it is bouncy because of the speeds could i suggest trying some thicker damper oil? 

That was my first thought but looking back at slow motion footage, there doesn't seem to be much articulation happening compared to the DT02 with hard body so I thought it might be something to do with the weight difference. I can try it though if reducing preload doesn't help.

It was probably a bit of an unfair test of the suspension anyway, foot prints in sand are a pretty big obstacle for a light 1/10 buggy, especially at such speed. And it had been raining earlier too so although dry, by the time I got there, the sand had a kind of firm shell on the surface vs the totally fluffy stuff I was running the 02 in the other day. Those footprints were the biggest issue I think though. I chose the wrong time of day. Tide fully in meaning people were walking all over the soft stuff.

Cleaning wasn't bad st all. Because it was mostly dry and without salt in, most of it just fell right off and I have no fear of major corrosion. If the tide had been out and I had been on the damp stuff, I would have washed the metal parts with fresh water and put a little oil on but no need this time.

Gearbox was very clean all things considered.

20190914_105146-768x1024.thumb.jpg.9e0546d02b26bc650e36b141b91b4a43.jpg20190914_105117-768x1024.thumb.jpg.4d85554018ada10a5c8b988c63f72234.jpg

  • Like 2

Share this post


Link to post
Share on other sites
On 9/12/2019 at 3:12 PM, nowinaminute said:

I tried one of those a couple of years back and a few other smaller motors such as DR mad thrust. One of them was something crazy like 75mm long. But I honestly couldn't see much advantage all else being equal. Very powerful for their size but they seemed to get just as warm as any other motor.

Maybe it helps when they are in planes and boats where you have water cooling or very effective air cooling? 

I still use a motor like that in my Grasshopper sometimes, reduces the unsprung mass and runs plenty cool in that car but I found them to be no more thermally efficient than a conventional size 1/10 motor. Ymmv. 

Never had any heat issues with the TP motors. The one I suggested is only 65mm long. I've used that particular TP in some different application, and have never had it too hot. 

I still think it's an interesting choice. Other than a select few 3665 and 3674 motors, not sure what else is out there delivering that kind of power.

Share this post


Link to post
Share on other sites
On 9/15/2019 at 12:04 AM, nowinaminute said:


 

 

7/10 , well executed, need a full rotation and drive off for a perfect score....🙄😂😂😂

 

On 9/15/2019 at 12:04 AM, nowinaminute said:

3s. I struggled to go flat out on 2s so using the full power of 3s was nigh on impossible with the limited amount of smooth ground and trying to film but there's maybe one or two passes where you can at least see there's more power on tap:

Tbh, the 2s looked impressive,  looks quicker than mine with the Goolrc on 3s! 

Nose weight needs to be added to get the full use out of power it's got, how much weight tends to be trial and error.

I've gone back to beast mode, for an attempt at cracking 70mph with a 7700kv, but to also try 5s / 6s on the beach with the 3800kv 🚀😬😀

 

2019-09-16_05-00-22

 

8 hours ago, nowinaminute said:

Gearbox was very clean all things considered

Spotless!! 👍

 

  • Haha 1

Share this post


Link to post
Share on other sites
On 9/16/2019 at 5:14 PM, Wooders28 said:

I've gone back to beast mode, for an attempt at cracking 70mph with a 7700kv, but to also try 5s / 6s on the beach with the 3800kv 🚀😬😀

That looks very purposeful! 6s😮😮 mind you, it seems to work in short bursts on road so it should be do-able as long as you're careful. 

 

On 9/16/2019 at 5:14 PM, Wooders28 said:

Spotless!! 👍

I'm pretty pleased! I was having more trouble with stuff getting in the motor itself than the gearbox. I put some silicone around where the wires go into the motor case but there's a design aspect of the gearbox that can cause problems too. That's why I suggested using that paper gasket thing when you has a lot of sand in yours.

The part of the gearbox where the motor mounts isn't flat, it has reinforcing ribs and the voids line up perfectly with some of the unused screw holes on brushless motors and make a passage for sand to get it's way into the motor because there's a gap between the motor and the plastic prison that wraps around it

20190918_141609.thumb.jpg.46356742dec222895f00de93d882cb8c.jpg

Using the gasket should pretty much prevent it or you can just cover over the spare holes. Another option is to populate the spare holes with little grub screws just to stop sand passing through.

  • Thanks 1

Share this post


Link to post
Share on other sites

I went a bit mental in work today and hacked a massive chunk of plastic away. I didn't even have any proper tools to hand so it's really rough at the moment. I'll tidy it up later.

I basically just copied the most extreme examples I could find around the internet.

3ilj5ih.jpg

I basically tried to make sure I only took away the thin solid side of the "tunnel" and made sure not to encroach into the half where it's actually two separate halves with a void inside.

5xifnqp.jpg

The only question now is have I compromised the rigidity enough for the motor mount to flex and the pinion lose mesh?

  • Like 2

Share this post


Link to post
Share on other sites

Surprise! You don't have to wait for an answer because I took it out after work.

im5OPbg.jpg

There were zero issues because of the plastic removal and I really beat on the buggy today, lot's of fairly big (for a DT03) jumps reaching 6 or 7 foot with quite a few face plants and heavy chassis slaps etc. the transmission appeared to hold up fine!

Annoyingly, the sand was in the same state as last time only worse, every square inch of the soft sand had foot prints and the sand was somewhat compacted and firm instead of being loose and fluffy like I prefer.

bS74JkD.jpg

Removing the pre-load collars at the rear definitely helped to keep the rear wheels on the ground but with such rutted terrain, it wasn't enough once you got over a certain speed.

I guess a combination of nice weather and no wind just means the footprints have built up rather than the sand being blown smooth like it usually is. I don't think they take the tractor out to rake it at this point in the year either. Oh well!

Luckily, the tide was out though so I manged to open her up on 3s on the flat sand. It sure did move! Not a mind alteringly fast top speed but definitely enough to up the fun factor significantly. Massive high speed drifts and power slides, endless rooster tails and the ability to outrun most dogs including a lurcher (he wasn't far off though!)

After that I went to the less walked on dunes over the other side of the beach up on the hill and the sand was much better there, silky smooth and soft. That's where I did a lot of the jumping and other general stress testing. There was no damage apart from the ESC breaking loose from it's mounting tape from all the heavy impacts.

In terms of whether removing the plastic helped with temps, it definitely seemed cooler on 2s. With 3s it's hard to say because it all feels the same to me over about 60 degrees anyway but I can definitely tell you the motor cooled down a lot quicker when idle whether it had just run on 2s or 3s. It should also be easier to fit a heatsink now too.

  • Like 2
  • Thanks 1

Share this post


Link to post
Share on other sites
16 hours ago, nowinaminute said:

I went a bit mental in work today and hacked a massive chunk of plastic away. I didn't even have any proper tools to hand so it's really rough at the moment. I'll tidy it up later.

I basically just copied the most extreme examples I could find around the internet.

3ilj5ih.jpg

I basically tried to make sure I only took away the thin solid side of the "tunnel" and made sure not to encroach into the half where it's actually two separate halves with a void inside.

5xifnqp.jpg

The only question now is have I compromised the rigidity enough for the motor mount to flex and the pinion lose mesh?

 

I had wondered if this could be done.  I thought to cut enough to expose fins of a heat sink. 

Seeing as how yours have survived the dunes, I think I'll follow suit.  

 

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×
×
  • Create New...