Upgrade Motor for Losi Tenacity DB

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Wraith405

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Guys, I am having some issues identifying a good motor to go into my Losi Tenacity DB. The stock Dynamite Fuze 3800kv is very strong, but really hard on my 3S Batteries. Here's the changes I've made to the buggy. I am using SMC TrueSpec 3S batteries, 50C, 5000mah. I definitely don't feel like I am driving it too hard.

1. I've upgraded the wheels and tires to true 1/8 buggy wheels, using the M2C adapter kit
2. I've geared the pinion down from the stock 16T, down to a 12T, and then down again to an 11T robinson racing pinion. Tried a 10T, literally doesn't fit it's too small.
3. Changed the ESC timing down from 15 degrees stock to 0 degrees.

I'm thinking something 1/8 scale, that I can then gear back up a little. Maybe something around 4068 size, since the I'd have to modify the chassis to get anything longer than about 70mm in there. Maybe around 3000-2650 kv?

Anybody have any ideas? Has anybody had good luck with the Hobbystar motors from amazon? Or maybe changes I can make to the buggy to lower the amp drain on my batteries?
 
Are the 1/8 buggy tires/wheels about the same overall diameter as the stock ones? What is happening to your 3S batteries?
 
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The 1/8 wheels are very slightly larger but much more aggressive tread. That’s why I moved down again to the 11T pinion.
What’s happening to my batteries is that they are overheating. 130 F degrees and higher. This makes them start to swell up a little.
 
Could try a hobbystar 3665 or 3670. I run a 3100kv 3665 in my stampede 4x4 and it does pretty good on 3S. I run it off a HW Max10 sct. I first tried the HW 3660SL 3200kv (came as a combo with the esc) and it ran hot and caused the esc to run pretty hot.
 
The 1/8 wheels are very slightly larger but much more aggressive tread. That’s why I moved down again to the 11T pinion.
What’s happening to my batteries is that they are overheating. 130 F degrees and higher. This makes them start to swell up a little.
I would take the pinion off and double check that the drive train rolls freely. You might have a bad bearing. Also, make sure that the gear mesh isn't too tight and try using a lower ESC timing.
 
I would take the pinion off and double check that the drive train rolls freely. You might have a bad bearing. Also, make sure that the gear mesh isn't too tight and try using a lower ESC timing.

Already did this. I took the center diff apart, checked all the gears, it seems fine. I replaced the two bearings on either side of the center diff, both were okay but I replaced them anyways. With the motor pinion removed, everything rolls freely. I can't feel or hear any binding anywhere.

As far as the ESC timing goes, it was set at 15 degrees stock, but I turned it down to 0 when I first got the truck and the motor itself was overheating. The motor is fine now for the most part. I got a cheap little heatsink and fan and installed those as well. Motor is often only 150-160 degrees after a hard bash and that seems fine to me.

I heard from reddit that running the truck in grass is likely whats causing my problems, but I don't really have anywhere else other than my yard and local parks to run it. If it can't handle short cut grass, what's the point? Not everybody has dirt tracks or BMX parks to run in.
 
The stock motor SUCKS......
I replaced mine with a cheap off ebay 3674 2650kv motor. I also had the heatsink and fan off the arrma kraton 4s. The motor is a cool as a button now. The stock esc has no issues pushing it either.
 
The stock motor SUCKS......
I replaced mine with a cheap off ebay 3674 2650kv motor. I also had the heatsink and fan off the arrma kraton 4s. The motor is a cool as a button now. The stock esc has no issues pushing it either.
Did you have issues fitting the 3674 can did you have issues closing the body
 
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