During the summer of 2022, Eugene gave me this MR-03VE chassis to do something fun for the youtube channel. Thank you. With its 102mm wheelbase, I was originally going build an LM car for the stock class. It may eventually become an LM car, but for now it's going to be a more standard 98mm for the 2500 Lipo/3500 AAA class. In this video, I will show the build and choices I've made over the past several months.
So what do we have here? This is an ASF-based MR-03VE brushless chassis with a sensorless GL 3500KV motor. It came with an interesting gimbal style t-plate connected to an LM R246 motor pod (R246-1202). On the top is an MR-03 shock and an LM damper disk system. Front knuckles are R246 -1 camber ones.
Because this is an LM/MML pod, it uses an LM diff which is 2mm wider on each side. I got this popular Nexx Racing ball differential (LM). This is a 64p diff using ceramic balls. The diff action is super smooth. However, the spur gear itself has a lot of lateral play, which disappears when it's spinning. Because of the extra 2mm width of the LM diff, choosing rim offsets will need to account for this difference.
Let's look at the front end. This car has obviously seen some track time and the plastic parts have developed some slop. There's also quite a bit of play with the servo, more so than a new MR-03. Time to take it apart and examine the parts more closely. Removing the bottom plate exposes the servo gears and action. Nudging the servo horn, we can see some play. When I compared this with another MR-03, this is definitely sloppier. We will revisit the internal of the servo later.
I have these extra MR-03 hard suspension arms (MZW433) to replace the more worn out original parts. Since I'm here already, I'm doing the kingpin flip operation too. I've gotten good at this. For a more predictable drive, it's important to verify we got free ball joints. Checking the bottom ball joints too. If there's any binding, squeeze the cups with pliers. With the front end back together. There's a bit less slop now.
Let's do some test runs at home. I've never used ASF or the VE board before, so I want to make sure I can make it work. Eugene didn't mess around. He asked if I had an ASF transmitter, which I didn't, so he gave me an KO Propo EX1UR too. It's got the ASF Mini-Z module in the back. KO has always designed interesting and modular transmitters. There's no throttle endpoints calibration with the MR-03VE board. Instead, you set the EPA on the transmitter to some specific values. I wasn't able to get full throttle until I set the throttle back endpoint to about 50%. Forward needs to be set to 60% or so. The chassis drives very smoothly and quietly. The brushless system behaves like the modern EVO system, but the servo is more like the RTR. It's slower than EVO but it's much quieter.
To try to reduce the steering slop further, I ordered PN delrin gears and brass 4th gear. I'm not sure yet what else might need to changed/upgraded. Since I've previously shared a video dedicated to showing how to upgrade the MR-03 servo, I won't go into details here. Let's fly through the servo upgrade steps.
The next big upgrade was replacing the MR-03VE main chassis with PN2.5W. Since I already have an RTR MR-03 and MR-03EVO, so I figured it will be interesting to try the PN chassis. The conversion is a lot of fun. I did a video on this recently.
So this is what my 2500 Lipo/3500 AAA chassis looks like now. It's got a PN main chassis, upgraded servo, fresh frontend parts, kingpin flip, and a Nexx ball diff.
To convert the wheelbase from 102mm to 98mm, while reusing the same LM pod, I needed the R246-1356 damper plates. Technically, now the motor pod is in an MML configuration. The wheelbase is 98mm but the diff is still 2mm wider on each side. These damper plates and carbon fiber are very smooth!
Because steering still feels sloppy, let's try putting in an one degree toe out tie bar from PN. The PN part is well made, as expected. The toe out bar is barely shorter than the stock tie bar. Stock MR-03 tie bar is 47.8mm long, providing a bit of toe out. Meanwhile, PN's W-1 is 0.5mm shorter at 47.3mm. Is the steering less sloppy? Unfortunately, not really. Inspecting the servo more closely, I think the servo saver is simply too worn out. The additional toe out is beneficial though to match the increased negative camber.
At last, the PN2.5W build is complete! With all the changes under the hood, this should perform better than a stock MR-03VE. This is my high performance AAA Mini-Z build. The only notable thing missing is an upgraded front suspension like PN or Nexx. Even though I spend more time with my GL and Reflex cars, straight up Mini-Z is still a lot of fun.
This is Sammy and thanks for watching!
Music: "Journey to the Stars", Savfk ( • Journey to the Stars b... )