Tuesday, April 3, 2012

Convert the Carrera Ferrari 458 Italia to N-Digital

I have three Carrera slot cars that have been converted to Ninco N-Digital. In all three cases I installed the N-Digital decoder chip leaving the existing Carrera guide assembly in tact. I removed all the Carrera electronics, noise suppression components and wiring between the guide lead wire plug and the motor terminals. I then replaced the Carrera Molex-type plug with one of my own that allows me to plug the decoder chip in and out. This worked fine and I believe that the modestly powered, smooth running Carrera drive train is well suited to the N-Digital system. The only nuisance that I had to deal with was sanding that big thick Carrera guide flag down so that it would tolerate the narrower Ninco slot. And yes, I am aware that Carrera makes a smaller guide flag for non-Carrera tracks, however, I feel that the smaller flag is also too thick for Ninco track -- just my opinion.

Regardless, I recently found a mysterious package on my front door step that contained a brand new Carrera Ferrari 458 Italia. I really don't care how it got there. I just knew that this car needed to be running on my N-Digital track ASAP. The Ferrari 458 Italia is another Pininfarina body design so you know that it looks superb from any angle – I can't resist that. Anyway, this time I decided to try something different in the conversion process. Instead of using the stock Carrera guide assembly, I decided to install a B-Nova guide adapter for Carrera (which, interestingly, was also included in the package) that would allow the use of the Ninco ProRace suspension guide. This particular car has already been expertly reviewed elsewhere in the slot car forums, so I will concentrate strictly on the N-Digital conversion process and performance characteristics that relate to N-Digital operation.

Below is the car and all components required for this conversion: the N-Digital decoder chip, the B-Nova guide adapter for Carrera and the Ninco ProRace suspension guide.
The following photo shows the stock Carrera [analog] chassis out-of-the-box. What I see, from left to right, is the usual Carrera self-centering guide assembly, the PCB that hosts the reversing switch, the plugs that connect the guide to the PCB and the PCB outputs to the motor terminals and, finally, the three noise suppression capacitors across the motor terminals and the motor can. All of these items must be removed.
At this point it is important to mention a characteristic of the Carrera guide assembly on this, and I believe, a few other Carrera GT type cars. Note in the following two photos that the ride height of the car causes the guide flag to sit very high, almost half way out of the slot. The Carrera guide flag is relatively deep, so de-slotting may not be an issue, however, this will not afford the best electrical contact which very likely will be a problem in digital operation where control data are obtained through the rails via the braids. I have seen at least one novel solution to this problem in the slot forums, however, I am not concerned about it here because the combination of the B-Nova adapter and the Ninco ProRace suspension guide will solve this problem for me. The primary reason for installing the B-Nova adapter is to enable the use of the Ninco ProRace suspension guide, which provides superior performance on Ninco/N-Digital track. The fact that the B-Nova adapter helps with this issue is an incidental plus. This will become clear a little later.
Removing the Carrera guide assembly is straight-forward: first pull the guide flag straight down and out of the guide assembly. Then remove the two screws at the top of the assembly, just in front of the front axle, and it will pop out of the chassis. Next, remove the single screw holding the reversing switch PCB in place and it will come away from the chassis. Finally, with a medium wattage pencil-tipped soldering iron, remove the lead wires and noise suppression components from the motor terminals and can.

Because the N-Digital decoder chip uses push-on clips to connect to the motor terminals, any excess solder on the terminals must be removed. Use the pencil-tipped iron and a "solder sucker" to do this, as shown in the photo below.
Below are all the removed components and the motor. Note the condition of the motor terminals – free of excess solder. And don't throw those plug assemblies away. They make great quick disconnect cables for cars with lights that get power from the N-Digital decoder chip.
Next I installed the B-Nova for Carrera guide adapter. This is also a straight-forward process that is documented elsewhere in the slot car forums by the B-Nova creator, so I will not go into detail here. Quite simply, the adapter consists of a "resizing ring" and an "adapter ring" that contains the guide post holder. The resizing ring is glued into the guide assembly hole in the underside of the chassis. The adapter ring is then pushed into the resizing ring and then glued in place. However, I will mention that the adapter was an extremely tight fit for this particular car that required a small amount of sanding in order to complete the installation. Given the tolerances that we are dealing with here, I don't consider this to be an issue at all.

Below is the underside view of the installed adapter. The height of the guide assembly above the slot is determined by how far the adapter ring is pushed into the resizing ring. In this case, the adapter ring is flush with the resizing ring.
And the Ferrari 458 Italia chassis, ready to receive the Ninco ProRace guide and N-Digital decoder chip, and showing the top side of the B-Nova adapter.
I always lubricate the guide post holder, all axle bushings, the exposed motor armature bushings and the gears. This car had grease in the axle bushings so I did not add any oil there. Also, the gears were well greased so I did not add any grease there either.
Below we see the Ninco ProRace suspension guide installed and the decoder chip connections made to the guide and the motor terminals. A small square double-sided adhesive foam rubber pad (provided with the decoder chip) is used to keep the chip in place.
And finally, the completed conversion, waiting only for the body to be screwed back on.
Comparing the guide assembly height of the converted car shown in the following two photos to the photos of the stock Carrera setup shown above, we now see a perfect "tripod" stance and a guide that is well planted...
...with the added benefit of the suspension effect of the Ninco ProRace guide.
With the conversion complete it was time to put the car on the track. My other three Carreras (an Audi R8 LMS, NASCAR COT and Porsche Spyder LMP) are all competent N-Digital runners. I was hoping that the chosen approach to this conversion would yield at least comparable results – if not better.

The Ferrari 458 Italia has two magnets: a large bar magnet located mid-chassis just in front of the motor; and a medium bar magnet located in front of the rear axle under the pinion. Each magnet has a thin metal bar which is presumably a spacer that can be used to raise the height of the magnet above the rails slightly. I am assuming that the smaller magnet in the rear could also be installed in place of the larger magnet in the middle. I don't have a way to measure magnetic down force but it is obvious that the sum of the two magnets' force is considerable. It is also obvious that this particular setup affords a reasonable level of flexibility in adjusting the down force and, therefore, handling characteristics in magnet driving.

--- Mid-chassis ---               -------- Rear --------
First, some perspective on lap times. My home N-Digital track is about 60' of lane length. Mostly R2 turns, short straights and one straight that is about 10' long. The fastest lap recorded is 6.18 seconds by a Ninco Acura LMP2 with the magnet. I run LMP and NASCAR with magnets. They typically run in the mid to upper 6 second range. Everything else is no-mag. NC-5 equipped Ninco GT's run in the upper 7 to low 8 second range. 18K rpm low-torque FC-130 type motors in a variety of cars run anywhere in the mid 8 to mid 9 second range. I run the NINCO 1 cars no-mag in 'professional' profile with lap times in the low-to-mid 8 second range. The previously mentioned Carrera Audi R8 LMS runs in the low 9 second range in 'amateur' profile.

So, for the purpose of testing, I ran the car in four different configurations of magnet for 25 laps each. First with both magnets in place. Next with the the larger mid-chassis magnet removed and smaller rear magnet in place. Then with the mid-chassis magnet in place and the rear magnet removed. And finally with no magnet. In all cases the magnets had the spacer bar on top allowing the magnet to assume its lower position. With magnets on board the 'professional' throttle profile was used. For no-mag the 'amateur' profile. The data for each 25 lap test run were used unaltered – even with de-slots, because I believe that this is representative of the actual performance that can be expected. The resulting lap times are shown in the table below.
The lap times for full and rear magnet running on my track are very good. About the same as the Carrera NASCAR and LMP that I run this way. My personal feeling is that the car handled better and drove more realistically with only the rear magnet in place. The effect of the mid magnet alone was relatively mild. Very close to running no-mag but its effect was still noticeable. And without at least the mid magnet in place, I was not able to run the car reliably in 'professional' throttle profile. However, I think that the real benefit of the B-Nova adapter/Ninco ProRace guide combination is apparent in the no-mag lap times. The recorded times are typically about 4/10ths faster than that of the Carrera Audi R8 LMS which, as previously noted, was converted using the stock guide assembly. The way to verify this is to install the B-Nova adapter/NincoProRace guide combination in the Audi, which I will do eventually.
My purpose here is to answer two questions: 1.) is the Carrera Ferrari 458 Italia a good choice of car to convert to N-Digital? And, 2.) does installing the B-Nova guide adapter to allow the use of the Ninco ProRace suspension guide provide a measurable benefit to the conversion result?

The answer to the first question is really personal and subjective. Regardless, it is a resounding yes! I like the appearance of the car. And its performance, both with and without magnet, on my N-Digital track is very good. The Carrera GT cars are obvious candidates for a N-Digital racing class. They can run competently both with and without the magnet, run well in either of the available N-Digital throttle profiles (except as noted), and have a great deal of flexibility in magnet racing setup without having to tinker with the car.

Based on the recorded lap times, the answer to the second question (at this point at least) is also yes. This car is ideal for no-mag digital racing, where in my opinion, control and handling will consistently trump brute force speed and power – certainly on my type of track. I ran the Ferrari 458 Italia and the Audi R8 alternately for a considerable number of laps. There is less front end bouncing, smoother power through the turns and generally a better feeling of control with the Ferrari 458 Italia as configured.

In conclusion, if you're an N-Digital user and you run no-mag, get one of these cars and set it up this way. I think that you will be very pleased by the result. Certainly enough to consider the Carrera GT's as a N-Digital racing class. And if you run with magnets, I think the flexibility afforded by the magnet set-up will give you lots of options to optimize performance on your N-Digital track.

by Michael Ashton