Overcoming Obstacles to Other Manufacturers' Cars in N-Digital

Converting other (than Ninco) manufacturers' cars to N-Digital is arguably the easiest process of the all the major digital slot car systems. This is primarily because the N-Digital decoder chip is very compact and there are no external components, such as a sensor, that often require modification to the chassis in order to be installed. I have never encountered a car that could not be "chipped" to the N-Digital system, although a few did require some minor internal body and chassis modifications such as a little filing or sanding here and there.

However, once the N-Digital chip has been successfully installed it's not a good idea to start celebrating right away. That's because there are other obstacles to performance of some non-Ninco cars that are inherent in the N-Digital system. Most notable are the road surface anomalies that are inherent in the N-Digital track pieces such as lane change sections. The rails of Ninco track are raised above the actual road surface higher than all other track systems and there are many gaps between rail sections in the digital track pieces. There are places where the leading edge of the rails is raised to the point that it causes the oncoming guide to literally bounce up and out of the slot. An example of this is shown in the photo below of an N-Digital double lane change curve track piece, highlighted by the red arrows.

These sections cause cars from certain manufacturers such as Revell/Monogram, MRRC and especially Scalextric to de-slot even at very low speed. The rails can be depressed to a certain extent but not enough to eliminate the problem. I have also tried to fabricate a tiny ramp in front of the leading rail edge but this was also ineffectual.

Now I run cars almost exclusively without magnets. So getting cars from manufacturers such as those previously mentioned to perform well is already a challenge because their cars are designed to run with the magnet in place. Truing wheels and/or tires does not seem to help this particular problem, nor did adding weight to keep the nose down. And I prefer to maintain all cars as close to stock condition as possible. Plus I just don't have the time, skill or equipment to perform some of the innovative modifications that you see elsewhere in these forums. Therefore, I must either forego these manufacturers' cars or find a solution that is simple, requiring no modification to the car, yet is able to overcome this problem.

Interestingly, the Ninco cars -- or more specifically -- the Ninco guides, are not affected by these gaps and bumps at all. This is true of all Ninco guides: standard, suspension and ProRace guides. I can only surmise that there is something subtle about the geometry of the Ninco guide that makes it perfectly suited to the relative bumpiness of Ninco track in general and the N-Digital sections specifically.

My experience is that cars with a fixed (non-suspension) guide and fixed front bushings instead of an axle "slot" have the most problems on Ninco track. Based on my own self-imposed restrictions I can't do anything about the bushings but I can replace the guide. And based on the performance of the Ninco guides they would be the obvious choice.

I recently converted a Revell/Monogram Corvette Grand Sport and a MRRC Ford MKIV to N-Digital. After removing the magnet, lubricating all the usual friction points and installing the N-Digital decoder chip, these cars could not complete a single lap at even medium speed without de-slotting, most often on the lane change curve shown above. So, I decided to replace their stock guides with Ninco guides. This was not inherently difficult, however, because of certain characteristics of the two cars, some modification to the Ninco guides was required.

The following photo depicts a comparison between the stock guides and the Ninco guides that replaced them:

First lets look at the swap of the MRRC guide. In its stock form the MRRC guide had some vertical play because the guide post holder is relatively short. This did not help performance in stock condition but could be put to good use with a Ninco guide. Also, the low profile nose section of the Ford MKIV required a short guide post. This meant that the only Ninco guide that would fit would be the standard type. And the retaining "knob" on the top of the guide post had to be filed down in order to fit under the nose (see the following two photos below). But there was still enough vertical play to allow a spring from the suspension type guide to be employed with the Ninco #80104 standard guide which achieved the goal of having a suspension type guide installed. It turned out to be ideal.

As can be seen below, the front end of the Ford can pop up by approximately 6 mm before the guide flag loses contact with the slot.

While at the same time the car's stance seems very good with the guide being well planted. This is aided by the use of Ninco ProRace braids, which are quite flexible while still maintaining excellent electrical contact.

Next is the Revell/Monogram Corvette Grand Sport. The R/M Classics are a real challenge. They have a front-mounted motor chassis design, fixed guide and fixed front bushings that allow absolutely no vertical movement of the front axle. On top of all that is the R/M braid that has a metal clip that presents a hard ridge where the leading edge of the guide housing meets the track rail. Without some modification this car just can't be driven on an N-Digital track!

The good news is that there is plenty of room in the Corvette's nose for the "true" Ninco #80106 suspension guide. However, the diameter of the Ninco guide post is slightly too wide for the R/M guide post holder. It was not difficult to narrow the Ninco guide post's diameter by gently pulling a narrow band of high grit sand paper back and forth all around the post as shown below. Sanding, checking, sanding, checking... Only a small reduction was necessary before the guide post fit perfectly, snug but with easy vertical movement by the spring.

It is apparent in the following photo that the Ninco suspension guide has significant vertical movement in this car. Because of the fixed front bushings, I feel that the car benefits greatly from this high range of movement, but for those who tend to frown upon this sort of set up the guide post can be easily shimmed with one or more nylon washers/spacers.

Once again, in spite of the larger vertical range of movement, the car's stance looks correct and the guide is well planted. Ninco ProRace braids are also used here.

Following the installation of the Ninco guides in both cars the effect on handling was dramatic. Both cars had no problem negotiating the lane change curve section at pretty high speed and handling improved markedly all around the track. They will never achieve fastest lap times for the track but they are now fun to drive as opposed to being just frustrating before the guide swap. Can other things be done to improve performance? Of course. If you have the time and wherewithal these cars can be transformed into respectable no-mag runners on any type of track. But if you have an N-Digital track and you would like to include cars from these other manufacturers, a simple guide change is the single most effective tuning trick that can be employed. I believe that this simple guide swap alone could be the difference that allows certain cars that were previously unsuitable for N-Digital to be real candidates. It could open up a whole class of cars that were previously avoided by N-Digital users.

By Michael Ashton

To download a PDF version of this article click here

Update...
Since this article was first published, I went back and replaced the Ninco ProRace guide that was originally installed in the Revell-Monogram Corvette Grand Sport with the Hobby Slot Racing (HSR) suspension guide. My experience with the HSR guide has been quite good. It displays the same ability to effectively navigate the bumps, gaps and other anomalies of the Ninco track in general, and the N-Digital track sections in particular. The advantage of this guide is that its guide post diameter is slightly narrower than that of the Ninco guides. So for cars that would normally require the sanding of the Ninco guide post to reduce its diameter (such as RM), the HSR guide is the perfect replacement with no additional work required.

Below is the HSR Suspension guide installed in the Corvette Grand Sport. Guide flag geometry looks similar to the Ninco ProRace guides. The HSR guide post is slightly shorter than the Ninco which allows vertical travel to be restricted a little more. The screw and washer allow the guide to accomodate a fairly wide range of guide holder height.

There are a number of tuning tricks that can help turn non-Ninco cars into respectable performers on an N-Digital track. I believe the one that virtually always results in an immediate measurable imrovment in performance and handling is the guide/braid change.

by Michael Ashton