krillin

Hi. I just recently ordered an ECXSmash (to start with). I wanted to upgrade to a 2.4GHz radio but that means that I'd have to replace the ESC since the smash has a 2-in-1 esc/receiver. I noticed that Hobbypartz.com had some combo specials for motor+ESC. I ended up purchasing a GT3B transmitter along with a EZRUN 7800KV motor with 25a ESC.
This is where I am a bit confused. I read that lower KV usually meant more torque, less speed; and higher KVmeans more speed, less torque. I didn't really care about doing wheelies but I liked the idea of having a high speed; so I decided to go with the higher KV motor. But now I am reading here and there that the lower KV should have been the way to go? Also, that the high KV motor will give me less run time which is actually important to me as well. Did I make the mistake of ordering the 7800kv motor when I should have ordered a 5200kv motor?

I apologize for the stupid questions; I just got into the hobby...

nitrosportsandrunner

its more common to go with the 5000ish kv motor on 1/18 models, but nothing wrong with using the higher kv. It will reduce runtime some, but not a ton.
It will require use of a smaller pinion. and using a temp gun to check temps on initial setup is a good idea.

If I recall, the smash is basically a modified losi mini-t chassis. I think alot of the mini-t upgrades can fit it.

krillin

Thanks for the reply. So other than the runtime and heat, are there any other disadvantages? Is a 7800kv motor less likely to wheelie compared to the 5200kv? My order has already shipped so there is nothing Ican really do unless Ijust place a new order for a lower kv motor.

westoakmech

If you gear it low it enough it will probably stil wheelie. Also will depend on battery selection. A 2s lipo will be more likely to wheelie than a nihm. I have the smash also, got it for my daughter. I am running a 7.4 lion battery out of an old helicopter. It will wheelie on the carpet with stock gearing, and stock motor. As mentioned you will need to keep an eye on temps with that high kv motor. I would start with a pretty low gear to start off with and work up from there. I am not sure what the stock gearing is for sure. I think you will have to buy some pinions that have a grub screw, pretty sure the stock ones will not stay on a brushless motor. Good luck, and let us know how it works out.

krillin

I just received my smash this morning in the office and was pretty excited. The kit I ordered came with the NIMH battery pack and peak charger. I charged the battery right away and happened to put it in the truck to try it out a few minutes ago before seeing this post. I didn't get a chance to really run the car around a whole lot but the truck seems pretty peppy. It makes me wonder if I should have waited on the motor and esc combo... but I wanted to ditch the AM radio and go with the ever so popular 2.4ghz GT3B.

I've never played around with gearing on RC cars before so I'll have to read up on pinion sizes and stuff. The motor I ordered is 12T 7800KV. I was debating whether to just purchase the 18T 5200KV motor to use instead. It feels like such a waste of shipping because the motor is so cheap as it is. I've already paid for shipping on this one and I'd have to be responsible for shiping it back AND also paying shipping for the new motor; so I'd probably just end up keeping both. :P

I also ordered the programming card for the ESC. I was doing a bit of reading and saw a setting for 'PUNCH'. I am assuming if I set it to the lowest that it may give me a noticeable control with wheelies; maybe also loosening the gear mesh? Again, I am not really interested in popping wheelies. Any more comments? Thanks!

westoakmech

Yes punch control wil reduce how hard it hits on take off, kinda like a delay. I think, if remember correct the higher the number the more punch control.

krillin

Sounds good. I'll check it out. Do you think I should get a lower KV motor?

krillin

Ahh. Yeah I just don't want to punch it and end up cartwheeling 30 feet. lol :P

FenDogz

I have an ECX smash and enjoy it. I bought the toro motor 4300kv and ESC combo from hobbypartz and its amazingly fast. I use a 3 cell 1600 lipo. Its a willy machine. I can't imagine how fast that 7300kv motor is going to be. All losi mini t parts fit. I got the aluminum spur gear for the mini t on it.

krillin

Cool. I got home from work not too long ago. I can't run the truck outside since it's raining though. :P
I tried running it in my living room but I don't have enough space. Does anyone know if reverse and forward have the same amount of power? I almost seems like reverse is stronger but it could be me. /shrugs

FenDogz

You'll need to program the esc. You can lower the reverse and give the Throttle more punch. Every esc has different settings so you need to find out what are your settings and program it to your liking.

mrbonez

one thing to keep in mind when changing the pinions on the smash is the motor mount plate . if you look at it you will notice you can NOT adjust the gear mesh as the motor mount plate has no slot cut as the mini t plate does no worries tho . just grab a motor plate from a losi mini t and it will bolt right up and your all set . also most of the mini t hop ups will fit your smash . the only thing i noticed to be different is the servo tie down. it is a separate piece on the mini t and on the smash the breast plate is all one piece with the servo tie down other then that its exactly the same as the mini t . sorry but i am terrible at explaining thing

krillin

Yeah, I've read about that. I actually went to two LHS in my area and none of them had the motor plate. Iguess Imay have to get it online.

FenDogz

I just drilled the hole longer until it meshed.

krillin

Idon't own any power tools. :P
There is a home depot across the street though.

krillin

So I ended up completing my motor+electronics swap.  This thing is really fast (makes me wish I had a radar gun laying around).  I was afraid that the 7800kv motor would be overkill, but I set the punch control low so it helped out a lot with the wheelies.  I noticed my tires and bumpers are getting eaten up quick, which brings me to my next question:

I was looking at picking up spare tires, body, bumpers.  Those items altogether add up to $50+.  The truck itself can be bought for mid-50's brand new.  Would it make sense to just buy a second truck and use it as spare parts?  The only thing that bothers me about this is that I would have a lot of extras that I feel would go to waste.  Unless someone can recommend better wheels/tires and body that would fit with this truck.  Thanks!

onestillme

Iam going to upgrade aluminum for my spur and pinion. What "t" would be a good start for both? Iordered the toro 5###k brushless set for it. Iam just running a 1600 nimh battery not sure how much difference that makes. Thanks,

update;sorry should mention im not racing with it just some normal basement. parking lot bashing mostly so want more durability of engine than for speed.

rcav8or

My Feedback: (5)

I know this was a while ago, but I've got just about the same set up as you have, maybe I can cast some light. I just finished my 3rd one today, one for myself, one for my grandson, and one for my daughter - the family that rc's together, sucks the bucks out of grandpa's wallet!

Mine and my daughters have the 6100 toro brushless combo, while my grandson's has the 5050. I am running the stock spur, at 60 teeth, with a 15 tooth pinion, my daughter has the stock 60 with 13 teeth, and the grandson has the stock 60 spur with 14 teeth. All the programming is identical, with all settings default, except 1)brake/reverse type, which I have set for #3, forward/brake/reverse, so that you can hit reverse any time. I don't like the 2 second delay of neutral, because the grandson is too impatient, when it stops, if he has to wait 2 seconds, he blips the throttle, and has to wait another two seconds, time after time. He does know not to slam full reverse from full throttle. He's 5, I should mention. I also have 4) punch control set to #1, high, which stops the automatic wheelie from standstill. Without punch, I can literally full throttle, spin up on one rear wheel, and spin around 4 or 5 times, before tumbling to the ground! Really cool to watch, really bad on the car! I am still playing with 5) Drag Brake, have tried both 10%, and 20%. I like having some, because the Smash is so sprightly with the brushless set up, if I just release to neutral, it flat spins, sometime 360, sometimes 180, sometimes 540, making it impossible to just turn gracefully! The Drag Brake seems to help in that department, and I'm going to continue to experiment. I am running the 1600 nimh battery, but intend to go to LiPo's soon. I was thinking 2C, but after seeing several people here, using 3C, I might opt for that. I am fairly new to electric, but I'm now flying several Blade heli's, and now three cars, so might be worthwhile investing in a good charger, and LiPo management system.

As you can guess, with our setups, mine is the fastest, but just a little bit faster than the daughters, and the grandson's is just a tad bit slower than both ours. It comes down to driving finesse!

I was told by our LHS owner (an EXCELLENT source for car questions!!), NOT to go with the metal spur gears - he said that they tend to kick off metal filings, which isn't good. He said you'd virtually never strip a spur, and the give is good for the car. I trust him on that. He also recommended changing to the metal gear set, and I'm using the metal spider and ring gears, but not the metal pinion. I want that to be the weak point, and so far, after a LOT of hard experimenting, no sign of fatigue or failure. I DID have to file a bit on the "planetary" gears (spiders), on the post, to get them to spin freely. But once I did, they work great. The plastic spiders stripped out the first day, about the third run. Again, this was running hard, and laughing my tail off! I am planning on getting some more pinion gears, and spur gears, and getting the best arrangement I can.

I used a Dremel tool on all 3 motor plates, and they came out perfectly fine - saved 3 "custom" plates at $15 each, since I can't find a single Mini-T adjustable plate, any where. Perhaps ebay, but I don't go there, very often. I just took a compass, and using the one outside hole, marked the other hole arc, and dremeled away, slowly.

Oh yeah, I put an infrared thermometer gun on the motors, and none are running very hot, no matter how hard I work them. However, before I filed the posts on the spiders, it was catching, and that motor got too hot to the touch, very quickly - can't tell the temperature, uncomfortable to touch, though, because I couldn't find the gun. But, it was hot enough to make me find the problem!

The only other mod I made so far, is on mine, I have the oil filled shocks - makes a WORLD of difference, and when I get a few bucks back in the wallet, I'll upgrade the other two. Theirs bounce really bad if they hit a rock, often going into a cartwheel, and mine just bumps over them, without bouncing a 2nd time. Well worth the bucks.

EDIT Oh yeah, forgot one more upgrade - all 3 have ball bearings on all 4 corners. You wouldn't think they'd do THAT much, but I did the grandsons and mine first, and my daughter's was slower than both - when I changed hers, she moved into 2nd...

These things are GREAT! Hope I've passed on a little experience...