I finally went brushless on my Big Block MERV.

[zedorda]

I bought one of those cheap GoolRC 540 size brushless motors that is finned with just 380 size guts. I had a Sidewinder 3 SCT esc in my spare parts bin. Which forced me to sacrifice one of the battery bays for it. At least the 2s batteries it uses are small and pocketable. I won't be able to do a full proper test till tomorrow but the little I could do around the house gives me high hopes.

The motor I bought:https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

[sayoda]

Looks good!

[zedorda]

I also switched to 7132R Rear Suspension Arm Set that adds 10mm to the wheel base. I believe these are just the rear 1/16 Summit arms. One kewl thing I noticed as soon as they were completely installed. They move the rear wheels out of the way of the battery bays.

The arms I bought:https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1



Next addition will be Duratrax Bandito ST 2.2 Tires on JConcepts Rulux Rims. Hopefully they aren't too tall I couldn't find the OD measurement for the tires in the ST style but I think they should be around 3".

[zedorda]

Received my Rulux rims and Bandito tires and glued them up into wheels. I think they are just the right size but not real heavy like most 1/10th rim/tire combos some try to use.







Tires pictured: https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Rims pictured: https://www.jconcepts.net/shop/rulux...wheel-22-black

[Black-n-red]

When you added the rear Summit arms was there any other parts needed? Like the push rod & toe links.


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[REAP3R]

Nice swap over, I'll be one to say dont sneeze at some of the "Cheapo" things there are, bought a Hobbywing 120A ESC to throw in my slash and it works great, also grabbed a Readytosky 2.4ghz radio system too.......amazon ftw

[Jake483]

I made a bracket for the esc that slides into the stock location. I made out out of angle aluminum from the hardware store. You have to mount it sideways but still fits in the body.
https://imageshack.com/i/pnoXlEmLj

[Squeegie]

When you added the rear Summit arms was there any other parts needed? Like the push rod & toe links.


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No other parts necessary.

I did it to my MERV 6 years ago and haven't had a problem!

[Black-n-red]

No other parts necessary.

I did it to my MERV 6 years ago and haven't had a problem!

Thanks for the reply. I’ll be ordering some here shortly.


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[zedorda]

Thanks for the reply. I’ll be ordering some here shortly.


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Sorry I never got back to you on that. Squeegie is right I didn't need anything additional just had to do some adjustments to other parts to get everything back to straight.

[zedorda]

I have played with the current BL setup for long enough to want more torque. So I thought I would try another inexpensive option. I wanted the same basic size just without the fins and alittle higher Kv. I found this one at 4300kv for a similar price.

https://www.banggood.com/Racerstar-3...r_warehouse=CN



This one has a substantial increase to torque and top speed. I wasn't even able to hit speed without losing control on pavement using 23/55 gearing with 3s. Whole system was only warm to the touch as pictured. No fans or heatsinks with an outside temp of 84F. I really like this setup for now but I am getting a 20T pinion to slow her down alittle

[zedorda]

I thought I would include the specs sheet that came with the motor and some calculations of the tested setup and what it will be with the 20T pinion. Cross your fingers, I hope it fits.


(Right-click and open in a new tab if hard to read)
----------------------------------------------------------------
Differential Ratio: 2.6
Transmission Ratio: 1.9384615384615385
Other Ratio: 1
Spur Tooth Count: 55
Pinion Tooth Count: 23
Total Voltage: 12.00
Motor KV: 4300
Tire Diameter (inches): 3.62
Tire Ballooning (inches): .20
Motor Current Draw: 75
Motor Coil Resistance: .0075
Spur/Pinion Ratio: 2.39 : 1
Total Ratio: 12.05217 : 1
Tire Circumference (inches): 12.63 inches (320.78 mm)
Rollout: 1.05:1
Total Motor Speed: 49181.25 RPM
Vehicle Speed: 48.8 mph (78.39 km/h)
Effective KV Value: 4098.44
KT constant: 0.31 oz-in/A
Motor Torque: 0.12 ft-lbs
Final Torque: 1.48 ft-lbs
Final Power: 900 watts (1.2 HP)
------------------------------------------------------------------
Differential Ratio: 2.6
Transmission Ratio: 1.9384615384615385
Other Ratio: 1
Spur Tooth Count: 55
Pinion Tooth Count: 20
Total Voltage: 12.00
Motor KV: 4300
Tire Diameter (inches): 3.62
Tire Ballooning (inches): .20
Motor Current Draw: 75
Motor Coil Resistance: .0075
Spur/Pinion Ratio: 2.75 : 1
Total Ratio: 13.86 : 1
Tire Circumference (inches): 12.63 inches (320.78 mm)
Rollout: 0.91:1
Total Motor Speed: 49181.25 RPM
Vehicle Speed: 42.44 mph (68.17 km/h)
Effective KV Value: 4098.44
KT constant: 0.31 oz-in/A
Motor Torque: 0.12 ft-lbs
Final Torque: 1.7 ft-lbs
Final Power: 900 watts (1.2 HP)
------------------------------------------------------------------
The first motor in the thread for comparison.

Differential Ratio: 2.6
Transmission Ratio: 1.9384615384615385
Other Ratio: 1
Spur Tooth Count: 55
Pinion Tooth Count: 23
Total Voltage: 12.00
Motor KV: 3930
Tire Diameter (inches): 3.62
Tire Ballooning (inches): .20
Motor Current Draw: 68.3335
Motor Coil Resistance: .0095
Spur/Pinion Ratio: 2.39 : 1
Total Ratio: 12.05217 : 1
Tire Circumference (inches): 12.63 inches (320.78 mm)
Rollout: 1.05:1
Total Motor Speed: 44608.77 RPM
Vehicle Speed: 44.27 mph (71.11 km/h)
Effective KV Value: 3717.4
KT constant: 0.34 oz-in/A
Motor Torque: 0.12 ft-lbs
Final Torque: 1.48 ft-lbs
Final Power: 820 watts (1.1 HP)



Yes I do my calculations with 4v cells because 4.2v doesn't last long in RL. I also do them with limited tire ballooning because I try not to drive on balloons

Values exported from - https://scriptasylum.com/rc_speed/top_speed.html
These are RAW values without things like wind resistance or road bumps so take them with a grain of salt.

[zedorda]

I never did use the 20T pinion. It would of just increased the clicking I been getting from the rear diff. Now I guess I need the Hot Racing metal diff at least for the rear. Unless anyone else has another solution possible.

[starluck rc]

I made a bracket for the esc that slides into the stock location. I made out out of angle aluminum from the hardware store. You have to mount it sideways but still fits in the body.
https://imageshack.com/i/pnoXlEmLj

Same idea I came up with. It’s a shame the Sidewinders got slightly bigger. The old version fits perfectly between those tabs.

[zedorda]

I been driving my MERV with this setup for a bit now and even toyed with using 2 batteries. I just zip-tied the ESC to the battery when I tried it. I have to say I found I liked it a lot better with just the single battery. The weight is much more balanced and I traction roll less. Using a 2s battery also slowed it down enough without changing the gearing but I am back to using the 3s mostly. Now that I am more use to the power and got my throttle control under control.

[Red13]

I installed the extended rear suspension arms and the front of both my tires are facing inwards by a lot. How did you adjust and straighten yours?

[McCreary]

I installed the extended rear suspension arms and the front of both my tires are facing inwards by a lot. How did you adjust and straighten yours?

Page 24 of the owner's manual covers toe and camber adjustments.

https://m.traxxas.com/sites/default/...-OM-EN-R04.pdf

[Red13]

Thank you very much!!!

[McCreary]

Thank you very much!!!

You're welcome.
Traxxas makes adjustable aluminum toe links(part #7138). They make fine tuning the toe in/toe out a lot easier than the stock toe links.