FORMULA KIT CAR
FORMULA KIT CAR – AN INTRODUCTION
Welcome to Greenpower racing with your new kit car, suitable for use in the established Formula 24 and Formula 24+ categories, governed and run by Greenpower.
Before beginning the build of your car, we recommend you read through this manual first, in conjunction with the Greenpower handbook enclosed.
Discuss ideas and learn from others in the Greenpower online forum, packed full of useful advice and information, and encourage any Facebook users in the team to add
Greenpower Racing as a friend, where you can see photos, film footage and more.
This vehicle has been designed to be simple to build in the minimum of time, but a wealth of set up possibilities and innovative developments are possible, and there are no
restrictions on changing mechanical parts, provided you comply with the regulations for the Greenpower season in which you intend to participate. The kit can be stripped
down at the end of each season and rebuilt with new team members the following year, or simply developed to maximise its potential.
Remember that having purchased this kit car you are eligible for free entry to your first season’s racing. When you are confident of a race deadline, you will need to
complete and return the enclosed form a minimum of six weeks before the event, ensure your vehicle and team’s compliance with the regulations, train your drivers, and
you will be ready to go racing…
The team at Greenpower are always there to offer advice on any aspect of the design, build or race process, so please do not hesitate to get in touch with any queries.
Tel: 01243 552305
Whilst the basic kit car is good to get you going in Greenpower racing, the following are available to order as add‐ons for your kit car which will help with vehicle
development or race strategy:
Motor Heat Sink Kit:
Ideal for keeping motors cool in Formula 24 or 24+ racing, particularly if air is ducted over the heat sink. The kit contains; 2x Endplate heat sinks, 4x heat sink retaining
springs, 1x Large wraparound heat sink, 1x Tube Thermal compound, 2x 120mm wraparound heat sink retaining clips.
Foot Switch Control Kit:
Operate the car by foot instead of steering wheel control. Ideal for taller drivers, with easy mounting on existing front end of chassis plate. Kit contains switch, fixings and
24 Volt Battery Charger:
Keep your batteries in top condition after races and over winter using our 1.5amp trickle charger. Simply connect to both batteries as a pair. The charger can be left on
to switch on and off automatically when required.
For prices and to order any of the above by e‐mail to firstname.lastname@example.org or fax to 01243 552305.
The kit car has been designed to require as few tools as possible during the build, through standardising components and fixings wherever possible. You will require the
Chassis/Mechanical: Electrical: Finishing:
‐Metric Spanners (selection)
‐Metric Allen Keys (Selection)
‐3.2mm Drill Bits
‐Small G Clamps
‐Cable Terminal Crimper
‐Tyre Pump with Pressure Gauge
Now that you have the chassis of the car, you will be able to assess the size of area required to build. Ensure you have plenty of clear working space for all the team, and
that all members have appropriate safety equipment for the required tools and are fully briefed.
At this stage consider how the finished vehicle will be transported to events. It will not fit in the back of an estate car, so you will need access to a trailer, van, or similar.
STARTING THE BUILD
First of all, check and identify all the components in the kit against the enclosed parts list. You can lay the steering and drive parts out beside the chassis to help visualise
what goes where. The team can be divided into smaller groups to work on different sections of the car.
FITTING THE FLOOR
The regulations require a solid floor under the whole of the driver, and this is provided as an aluminium sheet (Z45) to be riveted to the underside of the chassis using pop
rivets (F24). Turn the chassis upside down to achieve this, clamping the floor to the lower chassis rails using small G clamps. Mark where you will position the rivets, at
100mm intervals down both chassis rails, and across the cross tubes. It is good engineering practise to space these at equal centres, even though they will not be seen.
Drill and rivet in two positions first at the rear, and work towards the front, and across the cross members.
CAMBER, TRACKING, ACKERMANN AND RIDE HEIGHT
First read the ‘Steering Geometry’ section of the Greenpower Handbook to gain an insight into these topics. You’ll notice that Ackermann angle is built into the design, but
camber, tracking and ride height are all adjustable using the wishbone and steering rod linkages. Research and look at the advantages in different set ups, which will affect
the final position of the wishbones, and also lengths of the steering rods (see below). Remember that the regulations require a minimum of 40mm ground clearance, and
you need to allow for the fact that the car will settle slightly once a driver and batteries are in.
With the chassis the right way up again, work can begin on the front end, rear drive system, or both simultaneously. Matching the parts and fixing components to the
drawings, loosely assemble the front wishbones to the chassis, and the stub axle brackets to the wishbones. Do not tighten any of the mounting bolts at this stage.
Assemble the steering column and wheel as shown, and fit steering column bearings (Z11).
With all parts now loosely in place on the front end of the car, the steering rods can be cut to length and fitted once you are happy with your camber and ride height
settings. At least 10mm of threaded rod must be inside each female rod end (Z12), and back nuts must be in place. As the length of the steering rod between steering
brackets affects the front wheel tracking, carefully measure between the wheel rims at front and rear to ensure they are parallel, before measuring the required length of
steering rod. The steering wheel should also be in a central position before measuring and cutting the shorter rod linking steering column to the right hand steering bracket.
Once fitted, all steering components can be tightened – adjustments can always be made later.
Only once the front wheels are fitted can the brake callipers be assembled. Bolt them on as shown, noting that they are not handed so the cable entry differs on each side.
Also note that the callipers’ own brackets are slotted to enable side to side adjustment. Whilst the adjustable brake pads must be as close as possible to the discs, rubbing
causes unnecessary friction that will reduce efficiency – another key point for set up. Route the brake cables to the common lever (Z18) on a smooth but tidy path, ensuring
that neither are stretched when the wheels are on full lock in either direction. Further adjustment is available on the lever.
All wheels on the kit are identical, and only need tyres fitting to be ready to race. Wrap a band of rim tape (Z22) around the inside of the rim before fitting the inner tube
(Z21) and tyre (Z20) to each wheel. Tyres can be inflated to approximately 60 p.s.i. Under inflated tyres can dramatically affect performance, so this must be an area of
focus in setting up the car for racing.
Ensuring spring washers (F3) are in place, fully tighten the brake discs (Z15) onto the two front wheel hubs. The wheels can then be pushed onto the front stub axle
brackets, and fixed in place using washers and screws in the sequence shown.
First, bolt the rear axle brackets (Z7) in place as shown. To these loosely fit the axle bearings (Z27). Assemble the sprocket (Z25) onto its hub and pin to the axle (Z28).
Working through the side of the chassis forward of the rear axle bracket (left hand side), push the axle through the right hand bearing at the required angle, and, once
through sufficiently, the assembly can be slid back through the left hand bearing so an equal amount protrudes each side of the car.
Bolt the motor to its mounting plate with the motor sprocket (Z24) in place. This sprocket should only be locked onto the flat of the shaft with its two grub screw fixings
once both sprockets are perfectly aligned. It is ideal to use a thread locking compound such as Loctite Threadlock on all grubscrews on the car.
SPROCKETS AND CHAIN
Sprocket alignment is another important part of setting up your car for high efficiency running. Use a straight edge against the side of the large sprocket to adjust the
position of the motor sprocket until the teeth are perfectly in line and then lock the motor sprocket in place. The chain can then be fitted, for which the motor may require
hinging up. Once on and the connecting link (Z30) is fitted, the motor can be tightened down but only until the chain can be depressed a few mm under finger pressure. This
will need re adjusting after the first test run. Over tightening of the chain puts unnecessary side loading on the motor shaft.
With sprockets positioned, tighten the axle bearing grub screws onto the shaft, to prevent sideways movement. Bolt the second hub (Z26) to the drive wheel, which does
not require the cone shaped spacer. Only once the hub is fitted to the wheel should you pin the assembly to the axle – this makes for much quicker assembly. The non‐drive
wheel can also be fitted as shown, but this does require the cone shaped spacer and should rotate freely on the axle. Only one wheel drive is required for Greenpower
racing as this is more efficient than a differential which is necessary on road vehicles.
You should now have a rolling chassis which can be pushed around with drivers in to get a feel for the characteristics of the vehicle.
Mounting holes are provided in two places over the shoulder as shown, and to the side of the driver at the base. It is
critical that the harness is adjusted to suit each driver once they are in the car – during races this is checked at every
pit stop, and penalties are incurred if not adjusted correctly. Read the Greenpower Handbook for more details on
The pair of batteries sit behind the driver’s seat, and are retained by a top strap and quick release pins. It is
extremely important that the fixing strap is in position at all times whilst the vehicle is in motion – this strap should
also be insulated with some inner tube, PVC tape or similar. The batteries should be orientated as shown in the
diagram. Check the Greenpower Handbook for tips on maintaining and conserving your batteries – a vital and
expensive part of your race equipment.
Also included in your kit are 6 pairs of battery terminal post adaptors (Z55), to fit, simply remove and discard the
already fitted screw and replace with a terminal adaptor and the socket head screw provided.
Be sure to fit the slightly thicker terminal to the positive side of the battery.
The red button on the steering wheel acting as the ‘throttle’ or control for the vehicle – it is either on or off, so to slow the vehicle the button is simply released.
Follow the wiring diagram logically starting at the batteries. 110amp cable (Z41/Z42) should be used for all main feeds between batteries, to cut out, isolator and relay.
5.75amp cable (Z40) is low amperage and is used for the cable run to the main push button, and also for the horn and brake light circuits.
The larger cable terminals will require soldering unless a large crimping tool is available. Cables can be run inside the chassis tubes through the slots provided, but rubber
grommets (F25) must be used to prevent chaffing. Tie all excess wire back with cable ties to ensure tidiness and no danger of cables being caught in moving parts.
The horn can be mounted off any suitable M8 bolt, and is shown inside the rear motor compartment in the diagram, operated by a push button in the dash panel.
The brake light has its own plastic bracket for which mounting holes are pre‐drilled in the rearmost crossmember, and is operated by a microswitch (Z34) fixed to the
front left stub axle bracket (Z5). The lever on the microswitch is activated by the actuating arm on the brake calliper.
If you do not have the kit car optional bodywork, you will need to create bodywork of your own to both comply with the regulations, and for aerodynamic purposes.
Research aerodynamics online and also in the Greenpower Handbook. Along either side of the car on the outside, simple sheet material can be fastened to top and bottom
chassis rails, which also provides a surface for the adhesive backed impact foam which fits between the chassis rails on the inside, only requiring cutting to length. Consider
fitting a floor for the battery/motor compartment, remembering that the underneath of a car is as important as the top for aerodynamics. From there, shaped bodywork
for the nose and tail sections can be achieved in a variety of ways – the Greenpower forum contains advice on this.
Note – The regulations require 100mm of foam forward of the front bulkhead. This could be the same polyethylene or polystyrene.
A poorly set up car increases rolling resistance, decreases efficiency, reduces battery life and ultimately is likely to burn out your motor – expensive and demoralising. It is
therefore key to set up your car correctly from the start. In particular look at the following areas:
‐Tracking: Look at the Tracking page of the Greenpower Handbook.
‐Tyre Pressure: All tyres should be equal and to the maximum pressure stated on the tyre.
‐Camber: Assess benefits of negative and positive camber in the Greenpower Handbook.
‐Brakes: Must be effective and comply with the regulations, but should not rub.
‐Drive Alignment: Use the tip in this manual to achieve accurate sprocket alignment.
‐Motor Cooling: Cool motors are efficient. Research cooling methods in the Handbook.
‐Aerodynamics: A very important aspect, not to be overlooked.
When, and only when, your vehicle is complete and complies in all respects to the regulations, and you are sure of insurance cover, should you attempt a test drive. The
driver must be dressed in accordance with the regulations, as well as being firmly strapped in and long hair tucked into the correctly adjusted crash helmet – all items that
will be checked at every pitstop, so worth practising and getting right now. You will need a large area of concrete or tarmac for testing, clear of all obstacles and people.
Push each intended driver around a course to begin with, without power, so that they can get used to the location of the controls. When ready to try a powered run, give
the car a two step push which is allowed at races. Drivers must be taught to release the power before braking, and slow for corners. Start slowly and build speed over a few
test runs for each driver.
RACING – Formula 24
Six drivers are required for standard format four hour races in the Formula 24 category, five of whom must driver for a minimum of 20 minutes and maximum of two hours
during the race. Appoint a member of the team to be in charge of driver strategy. You may switch between your two pairs of batteries at any point during the race, as
many times as you like during the race, but no battery charging is allowed anywhere on the event site. Additional batteries may be used for practice if desired. Full event
rules and regulations specific to each event are sent to all competitors prior to race day, but an example is included in this pack. In particular drivers must be aware of flag
signals, and all team members must be aware of the penalty system. Always remember that race days are fun, but never lose sight of safety and follow all instructions.