Toasted HPI 15t Firebolt in one run...

So I've gone through some motors in this GP real fast so far...
I'm running just a Traxxas XL5 and a Venom 8000 mah 2s Lipo. I knew the stocker would not last.
My latest attempt in hopes of a cheap mild motor that would run fairly cool was the HPI FCirebolt. I had read a lot of good things about it. Indeed it actually did punch pretty nice with this motor. The problem was that it was smoking before my pack was up. I ran it pretty hard at a BMX park. I think doing a few smallish hill climbs did it in. It still runs, but seems pretty slow now. I think I killed it.
Are there any mild brushed motors that will run cool in this rig on 2s? I've run brushless in nearly everything recently, but I wanted to keep this guy on the slower side to keep the breakage down. Everytime I drove my Slash 4x4 it broke. That got old real fast.

I like the EZRUN systems and had good luck with them in the past. How do you think the 17.5 turn 2400kv motor on a 60 amp would do?
I'm thinking about this or the 9 turn. I know the 9 turn is going to end up sending this rig to the grave...

Oh and I already have the mod 1 gears and just ordered the steel shafts from CPE. :)

-Brandon
 

Brian34

Well-Known Member
What size pinion gear are you running ? Are you using the MOD 1 pinion and spur gears ? What kind of connectors are you using on your battery pack and motor ? I don't know much about Lipo packs, but that seems kind of much for a brushed motor.
 

MonsterBrit

Well-Known Member
Sounds to me like you had your pinion/spur gearing waaaay off.

15T brushed motors are okay and fast but they have nearly crap-all torque compared to say a 27T or so. That means running the same pinion as the stocker will stress the motor, especially if you've been driving it hard up ramps and such. Moral of the story is stop regularely on a first run and check your temperatures at the motor, esc, battery and if you can access it the pinion. Ideally get a temp gun like the Nitro guys use. They are very handy and way more accurate than "ow **** that's hot" or "meh it doesn't feel so bad" ;)

Still, you probably won't have so much of a problem with the 3300kV EZRun. I run one in my Wheely King and it barely even breaks a sweat :) They are a nice flexible system with a range of options.
 

william g

Retired
Moderator
Sounds to me like you had your pinion/spur gearing waaaay off.

15T brushed motors are okay and fast but they have nearly crap-all torque compared to say a 27T or so. That means running the same pinion as the stocker will stress the motor, especially if you've been driving it hard up ramps and such. Moral of the story is stop regularely on a first run and check your temperatures at the motor, esc, battery and if you can access it the pinion. Ideally get a temp gun like the Nitro guys use. They are very handy and way more accurate than "ow **** that's hot" or "meh it doesn't feel so bad" ;)

Still, you probably won't have so much of a problem with the 3300kV EZRun. I run one in my Wheely King and it barely even breaks a sweat :) They are a nice flexible system with a range of options.
I agree, your gearing way out, or to tight a mesh would cook any motor.

Grab a temp gun, it's a 20-25 dollar investment that will save you headaches and it's cost in the long run.

.
 

Brian34

Well-Known Member
I have a Traxxas Velineon 3500KV in my GP. It flies pretty good, and I'm running Clodbuster tires. If you are running the stock RedCat tires, your truck is gonna be a rocket.
 

spliffnwesson

Well-Known Member
My HPI Sprint 2 Drift came with the 15T Firebolt. The car is pretty light (without battery pack) but drifting runs the motor at high rpm's, or at least how I drive which to me seems how everyone else does it. Anyway, with the stock gearing the motor gets quite warm, actually a tad on the hot side but doesn't burn my finger.

I do have a Turnigy infrared thermometer I got from HobbyKing.com, but I forget I have it and/or forget to actually use it.
Except a few times on my 2WD Slash before/after I installed an FLM alum trans case.

HPI's site lists that motor as stock for 4WD cars and 2WD stadium/sc trucks.
It's also listed as an option part for the Crawler King, 2WD WK, and several touring/drift cars.

Basically, it's not the motor you wanted to put in there.
Especially without re-gearing.

I have a Great Planes S-600 19T (made for airplanes) in my stretched 4x4 WK with locked rear diff and it's been amazing. It'll handle 7.2v-8.4v, so 2s will be no problem. I run it on 6cell nimh packs cuz it's a muddin truck. 7 cells or a 2s kicks it into high gear. The only thing about it is the size of the can. It's fatter and longer than a 540, so you'd have to check the specs. Another great thing about it, is it's only $15.99 so it's cheap to replace. I've been running mine for over a year, through water, mud, watery-mud, dirt and dust and it's still going strong.
 
Well I'm running pretty close to stock gearing which was probably the problem. I had the mesh set nice and loose. I wanted to go brushless eventually anyway. I should have kept my velineon system, but this ezrun should do fine.

Oh, I actually almost grabbed one of those s600 motors. I've heard a lot of good things about them.
 
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