Big Rock Upgraded Motor not performing

[NitroK]

My Big Rock 3s blx stock spectrum motor finally gave out. Upgraded to surpass rocket 3670 2650kv motor with 18T pinion. Still running stock 100A ESC. Significant performance drop in top speed and acceleration. Serviced the diffs, slipper and changed all bearings. Could it be slipper clutch related due to the increase in torque?

 

[cancelthefuture]

My Big Rock 3s blx stock spectrum motor finally gave out. Upgraded to surpass rocket 3670 2650kv motor with 18T pinion. Still running stock 100A ESC. Significant performance drop in top speed and acceleration. Serviced the diffs, slipper and changed all bearings. Could it be slipper clutch related due to the increase in torque?

A whole lot of speed is lost to the KV drop. You need to gear way way up to make up for it. Run a speed calculator to figure out exactly how much, but also 3670 motor is gonna be asking a lot of that ESC. That motor is better served by 4s and a 120-150 amp ESC.

 

[slick2500]

Looks like you need to gear up more. With the 2650kv motor and a 18t pinion you are slower than stock.

-edit- I just realized I put 54 instead of 57 for the spur but it's still slower either way.

Stock

With your new motor.

A whole lot of speed is lost to the KV drop. You need to gear way way up to make up for it. Run a speed calculator to figure out exactly how much, but also 3670 motor is gonna be asking a lot of that ESC. That motor is better served by 4s and a 120-150 amp ESC.

He should be okay with the BLX100. But yeah that motor is better suited for 4s.

Specification:
KV:2650KV
Max Voltage:21V
Max Amps:80A
Max Power:1600W
Rotor Poles:4
Number of Turns:3D
No Load Current:3.2A
Max RPM:60000

 

[NitroK]

Figured out why the performance was so bad with the new motor. The slipper clutch needed to be tighten a bit more than my old motor setting. Runs well now. Top speed dropped but got lots of torque at low and mid range.

Will take it out bashing soon to confirm if there is any significant difference with the new bigger but lower KV motor.

 

[slick2500]

Figured out why the performance was so bad with the new motor. The slipper clutch needed to be tighten a bit more than my old motor setting. Runs well now. Top speed dropped but got lots of torque at low and mid range.

Will take it out bashing soon to confirm if there is any significant difference with the new bigger but lower KV motor.

I would still up the pinion a few more teeth, start with a 20t.

 

[cancelthefuture]

Figured out why the performance was so bad with the new motor. The slipper clutch needed to be tighten a bit more than my old motor setting. Runs well now. Top speed dropped but got lots of torque at low and mid range.

Will take it out bashing soon to confirm if there is any significant difference with the new bigger but lower KV motor.

Oh yeah that would do it. Adding more torque definitely can get eaten up by the slipper, I found that with the Vendetta I put a 4074 motor into. If you ran it a bit on the looser setting it might be worth putting in new pads, or even considering the Center Diff module from the 4s cars.

 

[NitroK]

Oh yeah that would do it. Adding more torque definitely can get eaten up by the slipper, I found that with the Vendetta I put a 4074 motor into. If you ran it a bit on the looser setting it might be worth putting in new pads, or even considering the Center Diff module from the 4s cars.

Going to try a few different pinion options (as suggested by others) to get the optimum balance of torque/speed while keeping the temperature down on 3s. I mainly use it for bashing...mud being my favorite.

The Mojave 4s center diff is a great upgrade to consider. Next on my to do list is 17mm hex and better tires.

 

[Saladshooter]

Going to try a few different pinion options (as suggested by others) to get the optimum balance of torque/speed while keeping the temperature down on 3s. I mainly use it for bashing...mud being my favorite.

The Mojave 4s center diff is a great upgrade to consider. Next on my to do list is 17mm hex and better tires

You should consider a fan for the motor if you are going to up the pinion.... mud is hard on things and will generate heat.

 

[parcou]

My Big Rock 3s blx stock spectrum motor finally gave out. Upgraded to surpass rocket 3670 2650kv motor with 18T pinion. Still running stock 100A ESC. Significant performance drop in top speed and acceleration. Serviced the diffs, slipper and changed all bearings. Could it be slipper clutch related due to the increase in torque?

I changed up my BR 3S to a Hobbystar 3670 3050kv with a 15T pinion. My goal was to keep it about the same but run cooler. It runs great, BUT I did swap the ESC to a Firma 130A, which is my tipping point to keep it level.

Glad the slipper fix it but do watch the temps on the motor/ESC

 

[NitroK]

Quick update
Took the BR out for a shakedown bash today on the 3670 2650kv 18T. Much better power and smoother acceleration compared to stock motor. Top end is less but not that significant when bashing (very noticeable when on road). I was averaging not more than 75% throttle most of the time. Ran a full 5600 3s pack...temperature was 42C / 107F.

On the second pack, the rear right drive shaft u-join came out. More torque = more breakage where its exponentially higher when you don't have tools on hand

Slipper clutch needs a bit more tightening. Gonna try 19T and 20T pinion next. CVD driveshaft upgrade may be necessary if u-joints keep popping out