July 2015

This series of  articles is about tuning the Pioneer Trans-Am models. We are featuring the Camaro but these modifications will also work on both versions of the Mustang as the chassis and interior design are identical. We will start with basic chassis modifications and then include more advanced options if you decide you want to upgrade the original running gear.

Introduction

Our first efforts will focus on achieving good body to chassis float.
In a nutshell, this float is important as it reduces chatter (bouncing) in the corners and under hard acceleration.
Many times when the car comes from the factory with the screws tightened, it can cause some slight chassis warping. Even the slightest amount of flash molding on the body posts or chassis can effect the way your chassis sits. If it is sitting unevenly with one ore more tires not making contact with the track, this really degrades operation.
Having the screws too tight also allows the body to absorb excess vibration.
Pioneer models are a little more advanced than some other brands as they have smooth shoulder screws installed.
These smoother shoulders allow you to back the screws off and there are no threads that might catch on the chassis, preventing the desired effect.

This works only if the body and chassis are independant from one another.
If the chassis or body is rubbing or binding against each otherm then just lossening the screws will not result in the desired amount of true float.

 
And such is the case with these models. Both the Camaro and Mustang are hindered from desired float due to excess pressure/contact. From the chassis edges to the interior tray, there are areas that need some work. Although it appears to be a major project, it really isn't. You can perorm this modification in about an hour or less. Even if you are keeping the stock running gear, this modification does help improve overall operation.

NOTES:
1. I do not lower the body. I have no reason to sacrifice scale appearance for any increase in performance.
2. Full interior will be preserved.
3. The chassis modification alone will improve the model's handling even if you do not perform any other tuning applications.
Tools


The tools I use in the photo above are all you need to get the job done. You will also want some sandpaper if you want to clean your areas up and make them appear a little cleaner. Lighter grit sandpaper is also my choice in sanding the body post surface.

I use 800 grit automotive sandpaper by 3M a fair amount in my tuning. You can buy it individually or it also comes in the variety packs.
Preparations

You need to remove the body from the chassis and all running gear components. Once removed tyou are ready to begin.


Chassis Radiusing
Sanding of the chassis is a very simple process. I call this "radiusing" the chassis. You are simply sanding the outer edges of the chassis until it can be mounted into the body without obstruction.

Here is a video of the process.

Having the body on hand to test as you go is always a good idea. You will notice on the rear that I do not cut into the "fuel tank". I sand just flush of it and it fits cleanly.

When you shape the front, make sure you clear the 2 spoiler mount tabs. The chassis originally slips under them and this can interfer with your float.

You have enough clearance to sand the chassis and still not harm the body mount posts.
Chassis Body Mount Posts
The mounting posts on the chassis sometimes are in need of a quick clean up. There is usually some slight flash molding that needs to be removed from the tops of the posts. If left exposed, it can cause the body not to sit properly and also is another factor in preventing the body to float cleanly on the chassis.

Below is a video of how I clean this and slightly enlarge the mounting holes.
To make sure the chassis does not bind when you install the screws, I enlarge these holes slightly.

As we discussed earlier, the screws in Pioneer models come with a smooth shoulder that really helps you achieve float but only if they do not have excess pressure on them. Slightly enlarging these holes goes a long way in making sure they are not binding.
Interior Sanding
Another important part of eliminating the body to chassis contact is the interior. Although we all like a well detailed slot car, the full interior in these models can interfere with achieving good body float. The issue is the 2 reinforcment ribs that run the length of the interior and the 2 mounting holes that used to be for securing the interior to the chassis.

Out of the box these mounting holes might be an issue. If the lead wires are not routed properly, they can get caught in between the chassis and interior as shown above. Since we do not use screws here anymore it is highly advised to sand this material away.

Above is the stock interior with the areas than need sanding highlighted.

Now you can see the finished interior and notice the areas I sanded. Hopefully these photos and accompying video explain it clearly.
Body Post Clean Up
Another small but important item are the body posts themselves. The tops of these posts sometimes have excess flash molding and/or paint that causes the body to stick to the chassis mounts or in extreme case causes the body to sit unevenly.

The above photo hopefully shows you the goal. All you are doing is simply cleaning the top of the post to make sure it is free of excess flash molding or paint.
Although this next step is not really related to body float, since you have the body off it's a quick task to accomplish.

Using the same 800 grit sandpaper, you want to make a few passes on the INSIDE of the fender wells. In a few cases I have noticed some very fine flash molding. This can cause slight contact between the body and tire depending on your setup. I usually just sand until the paint is cleaned away and that indicates a clean area.

Summary
This is one of those tuning sessions where numerous small things combined equal a large improvement in performance. Something else to considor: Changing to aftermarket parts in the running gear ALONE isn't going to work any magic. Ignoring these steps will still leave your car too tight and you won't see those performance results you were hoping for. The added appeal is that this tuning has no added cost.

I hope this article helps you improve the overall performance of your models. A smoother running slot car is always more fun to race in my opinion and the satisfaction you get from tuning them just adds to that fun factor.
In our next series we will discuss other performance enhancements so stay tuned.

-Harry
Feel free to contact me anytime about this review or just our hobby in general.



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