Trx4 motor swap - Brushless
 

I’m looking to swap to the hobbywing axe system over castle, for a few reasons. 1 being the waterproofing, and the other being the built in tuneablity. Anyway, I need to know what can size and what kv to get. I like to crawl slow and on rocks and such, tow some weight around (homemade trailer, sticks, rocks, etc.) but still would like some nice speed in the high range, at least more than stock. Maybe 20mph or more. Also, I’m trying to keep this as cool as possible, so if I need a different pinion than stock, let me know.
If anyone has some info, I’d love to hear it. Thanks!

Re: Trx4 motor swap - Brushless
 

i just put a Mamba X and Castle Slate 2850KV in my TRX4 Blazer. On 3s, way faster than stock. This rig has no business going that fast in high gear!! Drag brake needs some tuning as its to abrupt with default ESC settings. Motor got a little hot running around in the grass. I just put a 9t pinion in to slow it down and get better low speed throttle control. I havent tested it yet. Ooh....there is still light outside. i think ill go get some crawling in.

Re: Trx4 motor swap - Brushless
 

ok.with 9t pinion, obviously not as fast as with hte stock 11t. still plenty fast. still no business full throttle in high gear. for crawling, really good. it has great low speed throttle control. in fact, i was crawling in high gear and i didnt event notice! low gear is MUCH louder, high gear is about the same. all in all a great upgrade. The improvements are notciable, but the upgrade is not a neccessity. It didnt transform the rig, just a big refinement.

Re: Trx4 motor swap - Brushless
 

What about temps on a 9t pinion? I’d like to do some towing and stuff like that. Do you think you could slow crawl for a whole batter pack or would it overheat? Mainly just temp questions. Keep me up to date with your rig and let me know!

Edit: also, shouldn’t my temps with a 2200kv motor be a bit cooler than yours when crawling since it has more torque? Or am I understanding this wrong?

Re: Trx4 motor swap - Brushless
 

good questions. I'm not sure about what temp the motor got to with the 11t pinion, but it was uncomfortable to touch. hotter than the stock motor for sure after a similar run. I don't have enough time with the new setup for a comparison.

In theory a lower KV motor will have more torque and less speed. I opted for HH recommendation of higher KV and lower gearing.

Re: Trx4 motor swap - Brushless
 

Would you say your temps were atleast better when geared down?

Re: Trx4 motor swap - Brushless
 

i haven’t run it in similar conditions yet. i will get the chance over the next few days.

Re: Trx4 motor swap - Brushless
 

Okay cool. Let me know for sure, I’d be interested to know. One question tho, is it a 550 can?
I’m looking at the axe 550 3300kv currently...

Re: Trx4 motor swap - Brushless
 

i just got back from a little run time. a mix of walking speed, high speed on thick grass, crawling, technical trails. approx 45 min of use. i found that low is basically useless except for crawling. even for low speed technical "trailing." i think the low speed resolution in low gives me FABULOUS control. that could also be the throttle curve im using. i look forward to finding some harder routes to try out.

motor temp after my session was approx 123F. ESC approx. 109F. Motor is a 540 Castle Slate 2850KV.

I did all of this with my 5 year old son and he was driving his stock TRX4 Sport. obviously his driving preferences are more bashing oriented (full throttle, full left until it flips, then hold the throttle untill it spins back up again). His motor temp was approx 135F but that was after a few min of not driving.

my rig with the 9t pinion is VERY noisy. ill have to play with the mesh some. It is WAAY louder than stock.

Re: Trx4 motor swap - Brushless
 

Good to know. So not overheating really by any means. I think 150 is still safe. Good to know. Sounds like a blast driving around with your son!

Re: Trx4 motor swap - Brushless
 

The smaller 9t pinion allows the motor to rotate faster which in turn lets the motor run cooler and produce more effective torque. As John Holmes always says "gear down, volt up" which means that a 9t pinion with a 3s battery is a good setup. The Axe system in general is not as well liked among crawlers as a Mamba X and 1406-2280 combo. The other strike against the Axe is that it has a proprietary motor connection which means you cannot mix and match ESC and Motor combinations like you can with the Mamba X. Last, the Mamba X is manufactured by Castle Creations which is a US company and I will always buy US before China whenever possible.



Just FYI, TRX4 posts should be placed in the TRX4 specific section below.

Re: Trx4 motor swap - Brushless
 

I originally used a GPM 9t pinion (found on ebay), but it was LOUD!! liKe VERY LOUD. I went ahead an bought a TRAXXAS 9t pinion and the gear noise is now back to stock (maybe a LITTLE louder.) Although both gears have the same teeth and pitch, the TRAXXAS seems to match the spur gear better resulting in less gear noise.

Re: Trx4 motor swap - Brushless
 

The lowest pinion tooth count is 11t with the 550 Axe motors. I’ve got the 3300 in my TRX-6 and have a temperature sensor on the motor. Even after high speed runs, I’ve never gotten over 106F. Crawling stays way lower, even on hot summer days.

FYI: you want to stay with firmware 2.02 for finer low speed control. 2.03 is an abrupt on/off no matter how you tune it.

https://uploads.tapatalk-cdn.com/202...0ce83845bb.jpg

Re: Trx4 motor swap - Brushless
 

I have a 9T pinion on a stock trx4 defender. I was regularly seeing temps of 133 - 137*F on motor & 119*F on the ESC with the 11T pinion ---- but this was just crawling at slow speeds in backyard, Nothing extreme.

With the 9T, temps were around 119*F on motor & 109 on ESC. Thats doing the same type of driving . Full throttle extended runs resulted in 134*F on motor & 119*F on ESC. YRMV.

Re: Trx4 motor swap - Brushless
 

I just put an axe 550 in my trx6. Are you still using the TQi radio system? I cant get the axe ESC to see neutral so it won’t go through the throttle calibration. The light on the receiver is green, ive tried to rebind it, did you have any issues getting yours to calibrate? Maybe i fried the receiver throttle channel some how, i plugged the xl5 back in and it won’t calibrate either. Idk. I think its a transmitter neutral problem. Ive reset the multifunction dial to throttle trim and zeroed it out but no luck.

Re: Trx4 motor swap - Brushless
 

I’m running a 12t pinion stock spur , axe 550 2700kv I’d say it’s perfect slow crawl and top speed, mine doesn’t overheat unless I’m running high gear abusivly lol, my trx6 is 15+ pounds? Ish

Re: Trx4 motor swap - Brushless
 

I’m currently running a tekin rx8 esc with a tekin pro4 hd 4300kv. It is way to fast in high gear. Needs geared down more and maybe a different motor.

Re: Trx4 motor swap - Brushless
 

I’m going to switch the rx8 out to mamba x.

Re: Trx4 motor swap - Brushless
 

The ESC on my TRX4 Sport, puffed out that magic smoke after only 5 days of having it. On it's second time out. :cry:
So I upgraded to the Castle Mamba X ESC and 1406-2280 Motor Combo. I was planning on doing it, just not this soon.
Haven't had a chance to try it out yet. I'll be going out Friday to play with it and then I have a comp on Saturday.
Trail by Fire!! :shock:


https://thumbnails-photos.amazon.com...iL_jRRrECZQix9

https://thumbnails-photos.amazon.com...tar2FM5tr9UkjS

Re: Trx4 motor swap - Brushless
 

If you haven’t already, check out Holmes Hobbies videos regarding programming the Mamba X.

Excellent information and he explains the “why” of each setting.

My Mamba X is set up verbatim to the Holmes videos and the low speed control is excellent.