The problems with my McLaren
In getting a car ready for the clubs upcoming CanAm series I looked to my tried and true Slot.it McLaren M8D’s that I ran in the clubs Slot.it McLaren CanAm series back in 2019. During that series I had one car that was running quick with best laps in the 3.7 range. I had another McLaren I was using as a mule to try set up changes looking for any possible improvement. I used this car as a starting point for the updated CanAm series rules.
This CanAm series would run rules similar to the 1:1 CanAm series with almost unlimited rules. This means racers would be able to use any tire, wheel, guide, weight or most anything else in order to get the car to run as fast as possible.
In working on my test McLaren M8D I discovered a few issues that would make this car a little more difficult to modify than I had anticipated. Here is a list of the issues and what I was able to do to work through them.
Interior
Issue – The interior weight is 2.8 grams and although it’s not much it is still located high in the body and can upset the handling of the car.
The first thing I had planned on doing was to replace the plastic interior with a lightweight Lexan version. I thought it would be easy to find a Slot.it Lexan replacement interior but was unable to find one or one that looked like it would work. Unfortunately, I was unable to find a suitable replacement and had to run the stock interior.
Front Wheels and Chassis Height
Issue – The stock 15” front wheels with narrow 8mm front tires work fine but the chassis height set-up is not ideal.
The 15” wheels fit inside the wheel wells of the body with no problem but I was unable to get the wheel height adjusted to get the correct chassis height without the tires contacting the body in the wheel wells. To allow me to get the chassis lower and not have the wheels to fit inside the wheel wells without rubbing I used Slot.it 14” front wheels. Unfortunately, I was unable to get the 14” wheels low enough to touch the track even the front axle in its lowest position. The axle was rubbing on the lower grub screw holders. To fix this I ground down the two front axle grub screw holders on the chassis. This allowed the axle to go lower and get the smaller front wheels to contact the track and give them enough clearance within the wheel wells.
Now that I have the wheels, chassis and body working together I needed to grind down the McLaren wheel inserts to fit inside the smaller 14” wheels. Once done it was time to paint them and get them installed.
Rear Wheels
Issue – The small lip on the bodies rear wheel wells limits the rear track to around 59.5mm
Since this series is for the most part unlimited, I had plans to use a wider wheel and/or tire combination on the McLaren for better traction. I tried multiple options including NSR wheels and tires and various Slot.it wheels and tires but none would allow me to get a good fit within the 59.5mm width limitation. These limitations also limited me from using a lighter magnesium Slot.it wheel or a superlight drilled NSR wheel. In this case I had to stick with the stock super short hub aluminum wheel and a Slot.it F30 tire in the 10mm width and 20mm diameter. So much for lighter or wider rear wheels.
Axles
Issue – No issue, just wanted to run a lighter axle and reduce the rotating weight.
I replaced the solid 48mm axles with 54mm hollow axles that were cut down to the 48mm width.
Guide Wire Clearance
Issue – The guide screw and motor wires on the top of the guide make contact with the body and impede the free movement of the guide.
The front of the car is so low the motor wires coming out of guide make contact with the front of the McLaren body. I looked at grinding down the front of the guide to give additional space between the guide and the body. By griding down the front of the guide there was not enough room for the brass eyelets. In light of this, I used a grub screw to hold the motor wire to the guide. The final thing I did was to use the thinner and more flexible NSR motor wires. All three of these changes together gave the space for the guide to move freely.
Motor Wire Clearance
Issue – The top of the motor and the motor wires come in contact with the interior and the body.
With the interior out of the car I was able to see that the top of the motor and the motor wires were contacting the body of the car. Unfortunately, there are no other motor configuration options for this model so it has to run with a short can motor in the sidewinder configuration.
Changing the motor pod from a 0.5mm offset to a 1mm offset helped the issue but the clearance is still very tight. The other change made was to resolder the motor wires under or level with the motor wire tabs using a lighter and thinner NSR motor wire. This thin and highly flexible motor wire also helped to free up the guide a little more. I also used some hot glue to hold the motor wires in place so they would make as little contact with the body and the interior as possible.
Conclusion
At the end of the day, I wasn’t fully satisfied with the changes I was able to make to the McLaren M8D. My goal was to make a more competitive car and get one that would run quicker than my other McLaren that ran fast laps of 3.7 seconds. I have not had the car on the track yet so let’s see how it goes. Update to follow.