1 (edited by Wanabgts May 28, 2019 10:17 am)

Topic: Slot.it M8D Preparation, full build.

Alright guys, this will be a long one so will likely come in several installments.

This will be how to prepare a FAST Slot.it Mclaren M8D. However the same principals can be applied to all of their sidewinder cars with similar success.

I am prepping another car for a club member so decided to document all the stages of the build. Hopefully there will be enough detail here so that you can replicate the results for yourself.


Prepping plastic cars is pretty time consuming, the first thing you need to do is strip it all the way down to the chassis and bare motor pod. If the chassis and motor pod are not flat, any amount of tuning is going to yield marginal results. As you can see from the photos, this car was far from flat on either the chassis or the pod.




After this, the next step will be flattening the chassis. Steps for this in post #2....


Re: Slot.it M8D Preparation, full build.

The first step to flattening the chassis is to make sure there is no low lying areas on the bottom of the chassis. I take a 600g nail file and just run it across the bottom surface of the chassis to reveal any low spots.

I have found that especially cars that have had axle height screws installed in the bottom, tend to have a high ridge around them. You will want to remove any very low points like this to ensure the chassis ends up flat.


Next you need a flat plate. I use a galvanized storm drain plate I got from home depot for $7 bucks. So it doesn't rust over time. Luckily all those magnets you have taken out of cars are now useable again!

Simply stick the chassis down on the plate using many magnets. Make sure you don't have it on top of anything that will crush, and that you are not pushing the chassis one way or another, or else it will end up tweaked when your done!

I also stuck down the motor pod using all three of the magnet locations.

You want to remove the bushings from the pod when putting in water, as they tend to oxidize. The easiest way I have found on these is to just stick your allen through, turn the bushings sideways, and pry it out. Be careful it doesn't go flying!


Once you have it all prepped on the plate, it goes in oven safe dishware. As per the usual process. Preheat the oven to 230* and boil some water in a separate pot. Once the water is boiling pour it into the dishware over the chassis (i never pour directly on it, but more in the corner of the dish). Immediately after this, stick it in the oven and turn it off. Leave sit overnight (8hrs). The key here is to cool it very slowly, don't open the oven and check etc. Just wait.


The next update will be prepping the motor pod for installation of the motor and bushings. As already shown in the motor pod thread here. So may be repetitive, but I figure it will be nice having it all in order!


Re: Slot.it M8D Preparation, full build.

Great stuff Zack! Thank you!

Re: Slot.it M8D Preparation, full build.

The first step on pod prep. All the new Evo6 chassis have 6 pod mounting points, I have never had success with the cars using any more than the 4 main screws. I believe this is because the chassis's are somewhat flexible, and by having these wings on the pod it will actually help the car lift the inside tire off during cornering. Something you don't want if you looking for maximum grip at the back of the car.

To make sure they are not interfering with the handling, I simply cut them off and sand the pod flat.





After that is done I remove the magnet locking tabs on the middle two slots. I end up only installing around 2g of weight on the pod, but I want it to be as low as possible. So removing these tabs lets the ballast sit right down in the bottom of the pod.





I smooth this out a bit with the tip of a file before gluing the ballast in. More on that in the next post!


Re: Slot.it M8D Preparation, full build.

Alright time to finish up this motor pod!

As I said in the previous thread about preparing the pod. I have found that installing the motor, even with screws, tends to make the pod twist yet again. So I have found it the best practice to open up both ends of the motor holder on the pod. Insert the axle in the pod to help set mesh, and then simply glue the motor in place.

Also in the previous thread you will see I take a small amount of material off of the bushing holders, so that a small portion of the bushing is protruding. This helps alleviate binding. I believe gluing the bushings in after they are aligned can help, but this can be tricky to do right, so I recommend skipping it.

This is the lead that I use in the pod, I bought 5 rolls of it for $9 dollars on Amazon. I believe it was advertised as fishing gear. Anyway, I fold up three layers of it which weighs about 1 gram and then glue it into the prepped slots in the pod.

You may be able to use adhesive lead here, but I think the Shoe Goo actually helps stiffen the pod. So I don't use it here.


This is what it should look like when your done!


Re: Slot.it M8D Preparation, full build.

Next up is wheels and tires.

On most of the Slot.it cars, I usually move the rear wheels to the front of the car. The stock wheels are only 8mm wide, and this just doesn't cut it most of the time.

On the McLaren, because of the extremely low ride height. When you get the body float where you want it the tires tend to rub in the front. So I cut about 1mm total diameter off of them on the truer. Coating them in nail polish afterwards also helps with any potential rubbing not bleeding much speed.

*****DISCLAIMER***** If you don't own a proper tire truer, I recommend getting one. NOTHING has helped me more when trying to build smooth, fast cars. This particular one is a Scaleauto, and while has some disadvantages like not being very good with plastic wheels, one thing I like about it is that is it very easy to match the diameter of multiple tires. Take a break buying cars and buy a proven truer, its worth it.



Surprisingly some of the alloy wheels even aren't that true in places. So I quickly run a file over the mounting surfaces to make sure there are no high spots.


The wheel I have chosen for the back of the car is the Thunderslot 14.85x10mm wheel. This is the only 10mm wide AIR wheel that fits on the back of the car with no rubbing. So I recommend it.

A lot of the time you can get the wheel right on the axle with a little force, the thunderslot axles are just slightly smaller than the slot.it ones. I found this chucking reamer on Amazon which is 3/32 of an inch. It was about 5 bucks.

Holding it with vise grips and twisting the wheel on shaves off just enough for a perfect fit on the Slot.it axle....




On the rear tires I simply true them down until they are perfectly round, and no more. With these wheels the spur gear will be pretty low. So mounting the tires so that minimal rubber has to be removed is best.

Re: Slot.it M8D Preparation, full build.

Last steps are to clearance and trim the body for float, and mount it all up.

I use a light sanding bit and a hand file for most of the work. In general, I have found that the more you can free up the body from the chassis, the more grip you will be able to generate.

I start by removing the body to chassis tabs along the outside of the body.


I then sand in the areas shown, using the chassis to test how much clearance is there. Be careful and go slowly as to not sand through the body. The rear section is to clear the motor movement with lots of pod and body movement. You will need to test fit this when the car is all back together and make sure you have taken enough off.


When mounting the body I use a Slot.it Brass Flat head screw in the front. This allows you to finely tune how much "body roll" you get on the chassis. I find that somewhere around a 1/4 turn out from snug is best usually.

On the rear I use the stock washer and tapered screw, and also leave it about 1/4 turn loose.



Again, I test fit the body to the chassis often during this process. To make sure the proper movement is allowed without interference to the wheels and tires/chassis.

8 (edited by Wanabgts May 29, 2019 9:16 am)

Re: Slot.it M8D Preparation, full build.

FINAL ASSEMBLY!!! You almost have a fast car now!

First thing, I omit the front bushings from the axle. I have found they cause signficant binding, and on a lot of cars actually keep you from being able to get the guide all the way down. Instead just use the upper and lower front axle screws.

I also add another 3g or so between the pod and right up by the guide, see pics for placement.

Take these out if they are still in there after this work....

Next, I recommend cutting the motor shafts. This can be done before the motor is glued or after. Just cut them enough they can't interfere with the tire. The tires grow a decent amount on an AIR wheel, and any rubbing will cause you problems.


I also use Slot.it Soft braid on all these smaller cars. They are just so light in the front that even the stock braid when fluffed tends to hold the car at a higher ride height.


I keep the braids completely flat, and the pod snug when setting the front axle height. I usually set it so the wheels are full touching which on the copper tape will mean they are just barely on the track surface.

For the pod screws, I run washers on the front screws and NONE on the back. DO NOT OVER TIGHTEN the rear screws without washers or they will crush the chassis.

Settings again in summary for STARTING: From SNUG, never fully tighten.
Front body screw -1/4
Rear body screw -1/4
Front pod screws -1/4
Rear pod screws -1/2
Final weight should be between 61.5 and 63.5 G.

Voila, you have a fast slot.it Mclaren. You may need to tweak the screw settings or clearance more as needed.


In general if you keep these principles I think you will have a fast car:
It should be as low as possible, wide as possible, and as free moving as possible.

Hopefully this helps some folks,

Re: Slot.it M8D Preparation, full build.

Thanks for taking the time to post this Zack!

Re: Slot.it M8D Preparation, full build.

There goes the rest of my free time.  Nice post!

"Big Smooth"

Re: Slot.it M8D Preparation, full build.

Excellent post, Zack! It's not often a racer will share his "secrets," but you have done us all a favor.

12 (edited by Wanabgts May 29, 2019 4:30 pm)

Re: Slot.it M8D Preparation, full build.

Not a problem, I hope it helps some of you. I have no problem helping people in the club out, helping each other out is part of what's fun about being part of one.

After all, you now know what to do....but you still have to do it better than me!


Re: Slot.it M8D Preparation, full build.

Wow, super cool Zack.  Excellent write up. What I don't understand is when I do these same tweaks the results are not the same as when you or others do them. I thought I used to know how to make a car work pretty well but lately the results just aren't there, so I take my hat off to you.


Race cars are neither beautiful nor ugly. They become beautiful when they win.

Re: Slot.it M8D Preparation, full build.

reek455 wrote:

Wow, super cool Zack.  Excellent write up. What I don't understand is when I do these same tweaks the results are not the same as when you or others do them. I thought I used to know how to make a car work pretty well but lately the results just aren't there, so I take my hat off to you.


I think the key is just to really take your time with it. I probably spend 30m just fitting the body.

In some cases not having a track may be helping, i don't get impatient and just start driving it!

Thanks for the compliment Rico, racing these with you should be a blast. I still can't believe how fast you got the Alpha to go!!