Articles

How-To Convert Your 1/24-Scale Losi 4WD To Brushless

Posted:  Friday, April 01, 2011
Written By:  Gary Katzer
Copyright:© 2011 Horizon Hobby, Inc.

We've been big fans of the Losi 1/24-scale Micro Rally Car and Micro SCT since we first laid eyes on them. These vehicles bring a lot of fun to the table thanks to the solid platform that handles quite well straight from the box. In today's day and age one of the first questions people have regarding any new vehicle is: can you convert it to LiPo power and how will it stand up to the additional stress—and the Micro Rally Car and Micro SCT are no exception.

We've taken one of our 1/24-scale Micro Rally Cars and merged it with one of the Losi Xcelorin Brushless systems to see exactly what is needed to perform this conversion. We've put everything together for you to follow along, both in video and written form. In the end we think you'll agree this is one fun project.



The right tools for the job

Before you begin, you'll need to make sure you have the right tools and components. You'll need:

  • #00 Screwdriver (P/N DYN2826)
  • Servo Tape (P/N PAR8044)
  • Parts Tray (P/N LOSB1603)
  • Losi Xcelorin Brushless System (P/N LOSB9594- 8750Kv Combo; LOSB9595- 10250Kv Combo)

If using the Stock Transmitter:
Losi 3-wire servo and 27MHz Receiver Combo (LOSB0830)

If using a Spektrum Transmitter:
Losi 3-wire Servo (P/N LOSB0814)

Disassembly process

  1. Disconnect the servo from the receiver board and remove the receiver crystal.
  2. There are seven screws that hold the two chassis halves together. One in the front, four on either side of the chassis towards the side and two towards the back. Remove these and set them aside; you'll need these later.
  3. Once the screws are removed the two halves of the chassis should pull apart with little effort. Note that the servo may come off in the top half of the chassis or it may stay in the bottom. Either way remove the servo from the chassis at this time.
  4. With the chassis cover removed the ESC/Receiver board is exposed. There are four screws that hold the board to the chassis at each of the four corners of the board. Remove these four screws.
  5. Disconnect the motor from the plug that connects it to the ESC and route the battery plug out of the battery tunnel.
  6. Turn the chassis over. There are two screws that hold the plastic motor guard in place. They will need to be removed. You will not re-use this piece later.
  7. You can also remove the three screws that hold the motor mount to the chassis that can also be removed at this time.
  8. Once the motor and motor guard have been freed from the chassis, you can remove the ESC's plug from the chassis. You should notice some hot glue on the tabs that keep the switch in place. You should be able to use a pair of needle nose pliers to pop this glue off with little effort.
  9. Carefully pull one of the retainer tabs back as you push up on the switch from the bottom of the chassis. It will take a little work but the switch will come free. You may set the ESC/Receiver board off to the side as it is no longer needed.
  10. Remove the two motor screws that hold the motor to the motor mount. Slide the pinion off of the motor's output shaft at this same time. You will need the pinion during the reassembly process.
  11. At this point you should have a bare chassis without any electronics installed in it.

Reassembly Process

  1. Using the screws removed from the original motor attach the new brushless motor to the motor plate.
  2. lide the pinion onto the output shaft of the motor.
  3. Reinstall the motor mount into the chassis. Leave the three screws loose until you have properly set your gear mesh.
  4. Transfer the servo saver and arm from the original 5-wire servo to the new 3-wire servo. Make sure the servo is set to a neutral position before doing this.
  5. Select a mounting location for the ESC on the chassis. You may want to snip off one of the standoffs that was used for the original ESC and Receiver. Note: if you do this, it is irreversible!
  6. Route the battery plug into the battery tunnel. You have two options for this, towards the front or rear of the tunnel.
  7. You can install the new ESC's switch into the old switch's position if you wish. You will need to carefully remove the shrink wrap from around the switch to allow it to fit.
  8. Using servo tape, mount the ESC to the chassis.
  9. Connect the motor leads to the ESC making sure the colors match.
  10. Install the new servo into the chassis. Make sure that the servo arm properly engages the bellcranks and the servo sits as flush as possible on the chassis.
  11. Route the ESC and Servo leads out of the top deck. The openings previously used for the servo lead and crystal work well for this application.
  12. Carefully slide the chassis top deck into place. Be aware you may have difficulty getting the top deck reinstalled if the servo is not sitting flush on the bottom of the chassis. The motor wires can also cause an obstruction.
  13. Once the chassis halves are together reinstall the 7 screws you removed earlier.
  14. Mount the Receiver to the top of the chassis.
  15. Plug the servo and ESC into their proper ports.
  16. Bind the receiver to your transmitter. If using the 27MHz receiver, find a location on your chassis to mount the antenna to and reinstall the crystal you removed earlier.
  17. If you are going to use a LiPo battery, make sure you use the programming card included with the Xcelorin ESC to set the proper voltage cutoff to prevent damaging your battery due to overdischarging it.

Testing

I've always enjoyed driving both the Micro Rally and Micro SCT. They're just so much fun, even in stock form. I opted to install the 8750Kv motor for this test instead of the 10250Kv system. I just cannot believe that it's possible for these to go any faster with the 10250 system as with a 2S LiPo this car is flat-out silly fast. Cornering becomes a bit more challenging with this much power and I highly suggest turning your steering rates down until you adjust to just how much faster this conversion goes.

This was a blast of a project to work on and was absolutely worth the time and effort. I'd estimate the total time to convert this over to brushless was close to an hour, give or take a couple minutes. I couldn't be happier with the final results as I now have a micro rocket ship of-sort. While we used the Micro Rally car for this conversion, the steps are identical if you have one of the Micro Short Course Trucks. If you have one or the other, you'll absolutely want to give this conversion a try.





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