Bomber ESC/Motor

[lamar2626]

Hey all,

I recently purchased a new bomber and before running upgraded it to have a Mamba Max Pro with a Castle 3800kv motor. My bomber is only going to be used for u4 and bashing which is why I went uncensored. I also upgraded the pinion only to a 14t. The thing hauls but I expected it to go a little faster on 3s. It topped out at 21mph. Is my gearing off? Also, i ran for about 35-40 mins and the motor felt pretty warm. It wasn't to the point I couldnt hold my finger against it, but it felt a little too hot to not be concerned. Thanks for any input!

[DowntownScience]

If you can hold your finger to it you're good. 14t spur with the stock 64t spur is definitely not overgeared. That is how mine is now. How long are the straights going to be?

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[lamar2626]

Have you ever raced at APR? I'd guess about 100ft? the speed isnt that big of a deal, i just though 3800kv would have me moving about 30 lol

[DowntownScience]

Originally Posted by lamar2626

Have you ever raced at APR? I'd guess about 100ft? the speed isnt that big of a deal, i just though 3800kv would have me moving about 30 lol

I haven't but plan to! I think you'd be safe going to at least a 16 tooth pinion. That would be 4:1.

Running a very similar setup to you. Top speed isn't super high but acceleration is pretty amazing. I think that is what you are looking for on the track.

No point in gearing it for 30 mph if none of the straights are long enough to take advantage of that top end. You'll be accelerating and decelerating a greater portion.

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[svt923]

Originally Posted by lamar2626

It wasn't to the point I couldnt hold my finger against it, but it felt a little too hot to not be concerned. Thanks for any input

The finger test is basically meaningless with brushless motors. Around 130-140* the motor becomes too hot to touch but it is a perfectly safe operating temp. There is no cause for concern until the motor gets above 160*.

You aren't going to be able to distinguish what temp range you are in at those levels by touch so get a temp gauge. They are pretty cheap and your fingers will thank you.

[QDRHRSE]

From what I've observed 21mph is haulin ass with a Bomber. I hope mine moves like that when I'm done.

[84yoda]

Originally Posted by lamar2626

Have you ever raced at APR? I'd guess about 100ft? the speed isnt that big of a deal, i just though 3800kv would have me moving about 30 lol

APR?

Phil says his does 28 mph. 3100kv, 3s and 20t pinion. Not sure how accurate his phone gps is though.

[DowntownScience]

20t seems like it would get really hot! 3.2 to 1 is like short course gearing!

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[DowntownScience]

I downloaded DigiHUD for Android to see what speed my Bomber was going. Found a way to secure my phone to the Bomber with a velcro strap and ran it up and back on the street a few times.

I hit 19.89 mph geared 14/64

Powered by a 13.5T (around 3300kV) Hobbywing sensored brushless motor on 2S.

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[neonsnow78]

is a Novak activ8 and HD8 2200kv overkill or good for rock racing? curious.....

[DowntownScience]

2200kv is going to be better for crawling than rock racing unless on 3s. My .02

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[neonsnow78]

yes it would be on 3s, i wouldnt be crawling with it. i got my scx for crawling lol. i just want something durable and not worry about heat or anything.

[DowntownScience]

Originally Posted by neonsnow78

yes it would be on 3s, i wouldnt be crawling with it. i got my scx for crawling lol. i just want something durable and not worry about heat or anything.

Should be a good place to start then!

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[ostewart]

I run a Roc 412 2300kv on 3s, geared 16/64 and it's a great speed without heat issues. Could probably go to 18/64 without issue.

[DeathVirus]

Originally Posted by 84yoda

APR?

Phil says his does 28 mph. 3100kv, 3s and 20t pinion. Not sure how accurate his phone gps is though.

On 3s mine did 27.5mph on hi and 13.5mph on low using phone GPS. This is with a Sidewinder 3+vanguard 3150kv with 14t pinion running on Proline Hyrax 2.2's. I run the CC BEC as well to keep the ESC cooler without resorting to using an ESC fan. Was 94F outside and ESC got up to 140F, motor 127F and battery 97F after a 20min bash. Seems to be the sweet spot.

It crawls pretty well. In low even with that sensorless motor it felt smooth like a brushed motor but with power and wheel speed of brushless.,

[drkuhar]

Whats everybody opinion of the castle sidewinder 1410-3800 and gearing it down to the 11/68. I just bought a crawl master 13 and geared it at that per holmes website but with how I drive in yard with the kids (stampede and slash) I'm afraid I'm going to trash that motor. Would that brushless run ok at that gear ratio.

[E. Bryant]

I'm currently running a Castle Sidewinder ESC with the SCT 1410-3800 motor and factory gearing, and it works fine on either 2S or 3S (depending upon your level of trigger finger control on that particular day).

Eventually, I'll swap out this system for a sensored setup with a motor more in the 3000 kV range, but that's a want and not an immediate need.

[DeathVirus]

Originally Posted by lamar2626

Have you ever raced at APR? I'd guess about 100ft? the speed isnt that big of a deal, i just though 3800kv would have me moving about 30 lol

I don't know what's going on with that setup or what tires you're running but I run a sidewinder 3+vanguard 3150kv motor. Since it's sensorless I put the 2spd kit on it with the .93 gearing. Wearing Proline Hyrax 2.2's it ran 27.5MPH on GPS. It's a bit more speed than I liked so I swapped the gearing to 1.08 and it still GPS'd at 24MPH. That's all on 3s with a 14t pinion and 64t spur.