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Competitive Production car racing has changed over the last couple of years with the advent of the Demon chassis and also lighter motors. Due to these innovations the overall weight of 1/32 production cars has decreased markedly, this has led to cars which are far nimbler in the handling department and also due to the weight loss, faster accelerating. The days of the heavy Proddy car are over ! This article is based on the building of the 2002 Nat’s winning car and the many since that have been built by AB for discerning racers.
Recent (some may say Bizarre) changes have been made by BSCRA in regard to chassis bracing. This page has been modified to reflect these changes.
To get an idea of the weight differences in motors here are some figures for current motors;-
Super 16D - 36 grams, Mura Super wasp - 25 grams, Proslot Super Wasp - 24 grams,
RJR Hornet -22 grams, JK Falcon 22grams.
As the motor is the heaviest component in the car it greatly affects the handling characteristics, especially as it is at the back of the chassis, causing a “pendulum” type moment of inertia when the car is cornering. The lighter the motor, the less the effect. This is why less correctional weight needs to be added when using Hornets or indeed the intro motor, the JK Falcon.

So when building the car, bear in mind that weight and balance are key.
It’s all very well building a light car, but it also must be strong, or as strong as it needs to be to race it. There is only so much bracing allowed by the rules and overdoing chassis bracing will either render the car illegal in terms of the race rules or make it heavier or stiffer than it needs to be, both of which will not enhance the handling. The Demon is essentially a fairly strong chassis, if the car takes a heavy hit to the side, it is possible to bend the pan section (this is however easy to straighten with a bit of bending) and likewise, if the car takes a wall shot head on, or a smack up the back, the centre section, or guide plate may bend, but experience has shown that if you brace it as per the following pictures the centre section will only bend just in front of the motor, and the guide plate may tweek slightly, both of which are easy to “tweek out”.
A LITTLE NOTE ON GEARING MOTORS!
Virtually ALL competitive Proddy cars in the last few years have had Hornet motors. These motors, especially the 42 degree timed variety are fast and very “Revy”. When gearing these motors never go bigger than a 7 tooth pinion, (favourite gearing is 7/37) and on very short tracks even a 6 tooth pinion can be used (6/35 is about right). These motors need to rev to stay cool and perform at their maximum potential. So be warned - The only thing you can use a Hornet for on an 8t pinion is to make toast! BSCRA rules now allow the Proslot Super Wasp and although slightly heavier than the Hornet it is a very competitive motor. Gear this in much the same fashion as the RJR hornet.

Initial Preparation
Ensure the chassis is flat. Put it on a sheet of glass or a flat metal plate / tech. block and if necessary manipulate the chassis until it sits dead flat on the block.
The Build
Remove the supplied 1.5mm dia piano wire tie connecting the chassis parts and bend the “pan tabs” flat (these act as Skids for the front of the chassis - the front wheels are decoration only..
You can use either 0.55 wire or 0.046 wire for the front axle. 0.046 is easier to bend correctly and also tends to deflect better in accidents. Should you wish to use 0.046 you should follow the first steps utilising the 0.046” Sonic ferrules on the chassis pan holes, this will also give you a chassis with minimal “pan sway”. This is a distinct advantage on tighter tracks as it really helps to keep the car from being “back endy” in the tight corners.
If you elect to go the 0.055” route start at ( 3).

7) Before soldering in the pin tubes, it is an idea to elongate the pin tube holes so the tubes will sit a little higher in the chassis pan, this will enhance body mounting by giving more “body” to put the pins through. Only use short tubes as illustrated. Full width tubes are hassle to bend around obstructions, add weight and prevent easy straightening of the pans if required.
8) Using 0.062” or 0.055” wire, bend the one piece rear brace as illustrated, this is a bit of a faf, but you will get it right after a couple of attempts!
Solder it in place
9) Align and solder in the rear axle oilite bearings.
Now we have done all the main chassis work, put the chassis back on the block and ensure it is flat, also ensure the guide tongue is parallel to the horizontal plane.
11) Take chassis into kitchen and scrub liberally with kitchen cleanser to remove all traces of acid flux and crud. Rinse and dry.
12) Set up rear axle, use thin teflon spacers, one each side of the outer faces of the rear bearings (these cut friction loss and prevent any other spacers or the gear etc. trying to grind their way through the oilite bearings) then fit the gear “boss inwards” as shown - this gives a narrower motor angle and helps gear mesh).
13) Offer up motor with pinion loose fitted and check motor shaft length, trim as necessary.
14) Solder pinion to motor shaft.
15) Align motor for gear mesh and solder to motor brace upright, go for a “light contact mesh with no trash”. Turn chassis upside down and solder as shown.
NOTE;- When soldering in Hornet Motors you should bear in mind that the magnets are “bonded” into these motors and that there are no magnet clips. It is therefore important that you DO NOT get the can (or the area of the can behind the magnets) hot. If you do, you run the risk of overheating the adhesive and ending up with a loose magnet.
16) Fit guide flag (this one is a standard TWP guide) and use thin teflon washers both side of the guide tongue. Use a proprietary Guide nut to ensure a good fit with no wobble.
17) Arrange your lead wires to your own preference. I always use the method illustrated as this saves weight and ensures the wires (i) stay where you put them and (ii) the guide centres correctly. The black stuff is “shrink insulation” (AB Lead wire tidy). This is shrunk on the cable and then glued to the upstop centre rail with Evostick. (This is legal, using a soldered guide lead holder is not).
18) Run in your gears;- lubricate rear axle bearings, motor bearings
and gears with Activ8. Hook up you car to a power supply and run at around 6 volts. While it is spinning, lightly apply pressure to the rear axle to cause a “Load” on the motor and gears, run like this for 3-5 minutes. Disconnect power supply and reverse polarity so motor is running backwards. At NO MORE than 6 volts run this way, applying light pressure again to the back axle for a maximum of a minute. It is not advisable to run high timed motors backwards for periods of more than 1 minute as they run far hotter backwards than forwards. Turn of power, reconnect the correct way and run at 6 volts for a further 3 minutes (this will cool the motor).
You will notice that the chassis is set up with Polymer rear wheels, this is no coincidence, These hubs are great as they tend to deflect in an accident, protecting the rear axle and alignment of the chassis. Using these will help save you from bent axles and bent chassis + they are light and tough. This set-up generally works best with “Fish tyres” such as JK B, but in high grip conditions, “if the front is falling out”, use Alpha Supernatural which has slightly less grip. Set the car up to be just slightly “loose” in the back end.

Total all up weight of this example is 98 grams.
Weight set-up depends on the track you race on. You should never need more than a few small rectangles of lead and this can be moved back and forth between pin mounts to find the right set-up for you. Attach lead using Evo-stick ( that way it won’t fall off if you hit anything!)

Ensure your car is as “wide as possible” on the rear track (note the 2 additional anodised aluminium spacers on the off-side.)
Enjoy your racing!

Use JK Polymer hub wheels. These are both light and tough + they deflect in accidents, helping to absorb shock and prevent/minimise chassis and rear axle damage.

It has been found that on fast tracks and segmented race formats, it is an idea to “tweek” the centre section of the chassis in front of the motor so the pans at the back run approx. 0.5mm higher than the centre section. This helps prevent the pans “decking out” on low tyres.