Radical Sportscars SR3 XX User manual

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V1.0

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TABLE OF CONTENTS
Introduction ........................................................................................................................................5
1. Introduction To Your Car..................................................................................................................6
1.1 Cockpit Layout...........................................................................................................................6
1.2 Steering wheel Layout ................................................................................................................6
1.3 Engine Bay Layout .....................................................................................................................7
1.4 Front Suspension Layout..............................................................................................................7
1.5 Rear Suspension Layout..............................................................................................................8
1.6 Electrical Hardware Location.......................................................................................................8
1.7 PDM status window..................................................................................................................10
1.8 Reverse Lever Location..............................................................................................................11
2. Running Your Car .........................................................................................................................12
2.1 Pre-Session Checks...................................................................................................................13
2.2 Driver controls.........................................................................................................................14
2.3 Adjusting the Seat and Pedals...................................................................................................16
3. New Car Shakedown....................................................................................................................17
3.1 Shakedown Guide...................................................................................................................17
3.2 Bedding In The Brakes..............................................................................................................19
4. Tyre Management.........................................................................................................................20
5. Workshop Car Maintenance..........................................................................................................21
5.1 Lifting Your Car .......................................................................................................................21
6. Car Setup.....................................................................................................................................23
6.1 How To Set Up The Car............................................................................................................23
6.2 Corner Weights.......................................................................................................................23
6.4 Hankook Setup Sheet...............................................................................................................24
6.6 Hankook Drop Heights.............................................................................................................25
6.7 Dampers.................................................................................................................................26
6.8 Wet Weather Set-up ................................................................................................................27
7. Car Servicing ...............................................................................................................................28
7.1 Filter Servicing.........................................................................................................................28
7.2 Gearshift Actuator Setup...........................................................................................................28
7.3 Wheel Speed Sensor Setup.......................................................................................................29
7.5 Balancing The Throttle Bodies....................................................................................................29
7.8 Coil Plug Order.......................................................................................................................29
7.6 Servicing The Gear Drive Unit...................................................................................................30
7.7 Filling THe Gear Drive Unit With Oil..........................................................................................31
7.8 Radical Spin Safe Clutch Setup (if fitted)....................................................................................32
7.9 Checking The Starter Motor After A Spin....................................................................................33
7.10 TPMS setup...........................................................................................................................34
8. Troubleshooting ............................................................................................................................35

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8.1 Non starting............................................................................................................................35
8.2 Charging Issues.......................................................................................................................36
8.3 Gearshift Issues .......................................................................................................................37
9. Reference Material........................................................................................................................38
9.1 Dry Sump Layout......................................................................................................................38
9.3 Engine And Gear Drive Unit .....................................................................................................39
9.4 Suspension Components...........................................................................................................40
9.5 Braking System........................................................................................................................41
9.6 Torque Guide..........................................................................................................................42
9.7 Engine Control Parameters........................................................................................................44
9.8 Common Parts.........................................................................................................................44
9.9 Fluids .....................................................................................................................................45
9.10 Gear Ratios...........................................................................................................................45
9.11 Roll Bar Sizes........................................................................................................................46
9.12 Component Lifing...................................................................................................................47
9.13 Service Schedule ...................................................................................................................47
9.14 Repacking Driveshaft Grease ..................................................................................................48
9.15 Replacing Caliper Seals .........................................................................................................48
9.16 standard pre-race/ test CheckList.............................................................................................49
Hankook Setup Sheet .....................................................................................................................53
10. Version History ...........................................................................................................................54

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INTRODUCTION
Dear Radical Owner,
Thank you for purchasing your Radical SR3
Since its launch in 2001 we have continually developed, refined and improved the SR3 into a truly unique
Sportscars. Now in its 4th generation the, SR3 has sold over 1300 units cementing its place as the wor
most widely produced and successful prototype style Sportscar.
If properly maintained your SR3 will give you an amazing driving experience, every time you head down the
pit lane. Although your car has been built and thoroughly inspected at the Peterborough factory prior to you
reading this, please take the time to read through this manual to expand your knowledge of the car. This
manual aims to guide you through every aspect of running and maintaining your car.
You will find any further help and support via our website www.radicalsportscars.com or alternatively please
contact your local dealer. Parts and consumables can be purchased through our online store, whilst any race
series information, sales or technical advice you may need is just an email away.

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1. INTRODUCTION TO YOUR CAR
1.1 COCKPIT LAYOUT
1.2 STEERING WHEEL LAYOUT
ECU Data Port
Aim Data Port
Fire Extinguisher
Master Switch
Brake Bias
Rainlight
Start/Stop
Extinguisher Button
PDM Power
Main Lights
Ignition Switch
Radio button
Marker button
Display
Menu/Left button
Right button
Neutral button
Flash button
Memory/ OK button
View/ Quit button
Page dial

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1.3 ENGINE BAY LAYOUT
1.4 FRONT SUSPENSION LAYOUT
Air box
Water swirl pot
Rear Light Connector
Fuel pump out
connection
Gear Drive Unit
Oil catch tank
Dry sump oil tank
Rear air jack
Rocker
Top Wishbone
Track rod
Upright
Lower Wishbone
Roll Bar
Pushrod
Spring/Damper

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1.5 REAR SUSPENSION LAYOUT
1.6 ELECTRICAL HARDWARE LOCATION
On the right-hand side of the SR3 cockpit you will find an access panel, behind this are the following items:
oECU
oBarometric pressure sensor
To remove the ECU, undo the 4 bolts holding the plate on, then the two bolts in the bracket for the ECU. Then
pull the silver clip upwards to an upright position. The connecting hairbrush can then be rotated off the ECU.
To refit repeat these steps in reverse. This should not be removed unless there is an issue or the engine is
being returned for rebuild.
Rocker
Top Wishbone
Pushrod
Upright
Lower Wishbone
Roll Bar
Driveshaft
Spring/Damper

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On the left-hand side of the SR3 cockpit you will find an access panel, behind this are the following items:
oPDM
oCharging module (24V charging option)
oAuxiliary battery (24V charging option)

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1.7 PDM STATUS WINDOW
On the PDM is a status window which shows the operation of the PDM. On the right-hand side of this
window is the power (ON) and status (STS) lights. When the unit it powered on these should always be
green. The LEDs numbered from 1-32 are the individual status lights for the PDM outputs. When the output is
turned on the light will be green. If there is a fault with any output the light will go red.
On the SR3-XX from chassis number 1288 onwards the outputs correspond to the below table:
Status light
Max output
Function
1
20A
Starter Motor Relay excitor
2
20A
Fuel Pump
3
20A
ECU main
4
20A
Paddleshift Compressor
5
15A
Water Pump
6
15A
Radiator Fan
7
15A
ECU Lambda
8
15A
ECU Coil Pack
9
15A
ECU Injector
10
15A
not used
11
15A
TPMS
12
15A
Brake Light
13
15A
Left hand Main Beam
14
15A
Right hand Main Beam
15
15A
Radio
16
15A
Transponder
17
10A
Charging Relay excitor
18
10A
not used
19
10A
not used
20
10A
Rain Light
21
10A
Tail light
22
10A
Charging Relay excitor
23
10A
24V Charging Module
24
10A
not used
25
10A
not used
26
10A
Left hand DRL
27
10A
Right hand DRL
28
10A
Touchpad
29
35A
12 Auxillary power
30
35A
Steering wheel
31
35A
not used
32
35A
not used

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1.8 REVERSE LEVER LOCATION
The reverse lever is loca as shown below:
The lever moves a gear in the Gear Drive Unit putting the output drive into reverse.
To engage reverse gear the car must be stationary and in neutral. Push the lever forwards until the gear is
fully engaged. Put the gearbox into first gear as normal and carefully reverse.

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2. RUNNING YOUR CAR
Upon delivery of your new car it is recommended you check the following items:
oIf the car has been shipped, be sure to check the tracking of the front and rear wheels, it is possible
that the securing straps may have been overtightened and pulled the car out of alignment.
oMake sure the master switch was not
oCheck that the driver is comfortable in the car. The seat can be adjusted forwards and backward by
loosening off the 3 bolts either side of the seat. The pedals stops can also be adjusted. If the pedal
adjustment is not enough a short pedal box is available, please contact your local dealer for more
information.
oRemove the fire extinguisher safety pin prior to starting the car.
oCheck all fluid levels; coolant, brake, clutch and engine oil. Fluid specifications can be found on page
38.
oEnsure there is a sufficient amount of fuel in the car. We strongly advise a minimum of 98 RON
octane.
Minimum Fuel Octane Rating
RON (Europe)
MON
PON or R+M/2 (USA)
95
87
91
96
88
92
98
90
94
100
91
96
105
95
100
For further information on fuel please contact [email protected]
To ensure the reliability of your car and engine we would strongly recommend following this procedure every
time you start running your SR3:
Dry crank ing - in
neutral, by pressing the starter button for a few seconds before turning the ignition on. Keep an eye on the
dash to check for oil pressure being displayed.
Warm ing up the car - Check the water level, then start the engine and allow it to idle until the water gets
above 80oC and the oil has started to warm up. The oil will take longer to heat up than the water meaning
you will need to switch the engine off when water reaches 80oC and allow the engine to rest for a short time
whilst the water cools down before running up the engine again to get the oil up to temperature. Optionally
you can use an engine oil pre-heater to warm the oil prior to starting the engine, for more information please
contact our stores department.
Oil Check - When the oil temperature is over 50oC raise the RPM to 4,000 for 5 seconds to fully scavenge
the oil, then switch the engine off. Using the dipstick, check the oil level; the oil level should be in between the
minimum and maximum marks of the dipstick. If the car requires oil, it is recommended to follow the same
process of holding the RPM at 4,000 for 5 seconds, to re check the oil level.

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2.1 PRE-SESSION CHECKS
Despite all the thorough checks which are carried out on all our cars before they leave the factory, it is
important you also do some basic checks before you take the car to the track for the first time.
oTorque the centre lock wheel nuts to 260lb/ft. Fit the safety retaining clips.
oUse the tyre guide to get a rough idea on cold starting tyre pressures and ensure these are set
correctly.
oDouble check the fire extinguisher system is set to active (electrical specification) and the pin is out of
the lever.
oEnsure the mirrors are all in the correct position for the driver
oDependent on weather conditions, you may need to blank off the side-pod intakes in order to
maintain recommended engine running temperatures. Running outside these temperature ranges can
he harmful to the performance of your engine.
Target engine running temperatures:
Parameter
Temperature
Oil Temperature (EOT)
90° 110°C
Water Temperature (ECT)
70° 90°C

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2.2 DRIVER CONTROLS
STAR TING THE CAR
To start the car, turn on the master isolator switch and the touchpad will light up. Press master switch button
on the touchpad and the Steering wheel and ECU will power up. Press the ignition button to turn it on and
finally you can press start/stop button to startup the car. The starter will automatically run for up to 2 seconds
until the rpm is above 500rpm.
IMP OR TANT NOTE
As with any race car, it is important to put the car in neutral and release the clutch when stationary. This will
significantly reduce clutch wear. Ensure the car is always started in neutral.
P ADDLESHIFT CONTROL S
oTo pull away, depress the Clutch, hold the neutral button in and shift down to get to first (remember
the engine is from a motorbike). Once you have pulled away in first gear you can then shift up as
normal all the way to 6th.
oThe SR3 is fitted with an auto blipper and automatic ignition cut. This allows you to flatshift up the
gearbox and means you do not have to blip the throttle on the way down.
oThe paddleshift system has safety controls that can override paddle requests to help prevent damage
to the gearbox caused by overrevs. Because of this, the system may deny shift requests if the RPM is
too high for a downshift or you are still applying throttle whilst trying to downshift. These safety
overrides are explained in more detail in the Radical Data Manual.
oWhen stopping the car and wanting to select neutral remember it is between first and second gear.
To select neutral when the car is traveling at low speeds or has stopped; hold the neutral button and
shift down from second, or up from first.
The gear order is shown below:
1 →N →2 →3 →4 →5 →6
IMPORTANT:
Remember the engine is not designed to run backwards, if you have a spin make sure you depress the
clutch. Without a Radical Spin Safe Clutch fitted, If the engine runs backwards without the clutch
depressed it will damage the starter motor. Never restart the car if you did not depress the
clutch. If the starter spins backwards, the starter motor and starter clutch need to be inspected back at the
pits to ensure there has been no damage.
If you have a Radical Spin Safe Clutch fitted this will automatically disengage the drive to the starter motor
during a spin but to be safe it is still advised that the driver depressed the clutch as well.

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STOP P ING THE CAR
Use the start/stop button to turn off the car. Do not turn the car off via the master switch, unless in an
emergency. Keeping the m aster sw itch turned on after the engine has stopped running
allow s the cooling fan and w ater pum p to continue to run to prevent heat soak . After 120
seconds they w ill autom atically turn off and the m aster can be sw itched off.
BR AK E B IAS
The brake bias can be adjusted to suit the drivers needs dependant on the circuit, driving style and weather
conditions. As a starting point, we recommend starting at 57%, which is 7% biased towards the front. During
wet conditions it is advisable to move the bias rearwards at around 5% (see wet setup guide).
R ADICAL SP IN SAFE CL UTCH (IF FITTED)
Radical advises checking the adjustment of the clutch at the start of each day prior to going out on track.
Instruction on this can be found in the Service section of this manual.
Usage notes:
1.
2. other than first
3. Pull away gently if possible
4. Use first gear at low speeds ensuring RPM is in excess of 4000rpm IF POSSIBLE, to ensure full
engagement
department:
[e-mail]

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2.3 ADJUSTING THE SEAT AND PEDALS
The pedals and seat can be adjusted to suit the driver.
Seat Adjustm ent:
The seat is fitted on sliding rails which can be adjusted by loosening the 6 bolts on the seat. There are two
M6 nylocs, one either side at the top of the seat between the chassis, two M6 button heads at the base of the
seat and two M6 cap heads at the front lip of the seat. Once these are loose simply pull the seat forward or
back whichever is desired, then tighten all six fixings.
Pedal Adjustm ent:
The pedals can be adjusted by either loosening the locknuts on the pedal pad, or by loosening the locknuts
on the m aster cylinder pushrods,then turning the rods to move the pedal. The pushrods must be moved
evenly as this will affect the brake bias. The clutch pedal stop must be reset if the pedal is moved.
Measure the gap between the pedal and the stop, once the pedal has been adjusted, move the stop until the
same gap is achieved between the pedal and the clutch stop. The throttle pedal can be adjusted by
lengthening or shortening the throttle adjustm ent bolt. The throttle position must be checked after
adjusting, the TPS should sit at 4% when at idle, you must then make sure full throttle can be achieved
100%+ if not the throttle stop must be adjusted. Also check the tension of the throttle cable if any
adjustments are made.
If any further adjustment is required, pedal extension kits are available. Contact our stores department:
[email protected]
Throttle Adjustment bolt
Throttle Stop
Master Cylinder Pushrods
Clutch Adjustment Rod
Clutch Stop

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3. NEW CAR SHAKEDOWN
At Radical, we pride ourselves on our quality control and rigorous testing procedures that we have in place
for every new car. All new cars are subject to a 100 point post production inspection and track simulation on
our rolling road dynamometer prior to delivery. However, it is not possible to replicate the forces exerted
driving around a race track. The first time you drive your new SR3 around a track is the first time the car has
experienced the G-
procedure is followed for all new cars.
3.1 SHAKEDOWN GUIDE
Warm the car up and complete the pre-session checks. The first track session for a new car is also the first
time the brakes have been used under load. All cast iron brake discs for competition use need to be bedded-
in to ensure heat stabilisation and improve resistance to cracking. Cracks or warping can occur during the
first few heavy stops if careful bedding is not carried out.
Your car comes fitted with carbon metallic brake pads. To bed in the brakes and achieve maximum stopping
power, a film of carbon must be transferred to the discs. Additional notes on brake bedding can be found in
the following section.
To help with brake bedding, initially blank the brake cooling ducts off ¾ to increase temperature build up.
RUN 1 (OUT & IN)
Driver:
oFor the driver this is a good way for you to start to learn about the car. It is important to try and run
through every gear if possible; it is advised to change gear at 5,000 rpm. During this run only use
light pr
Technician:
oRemove the engine cover and check for leaks and for any components rubbing
RUN 2 (3 LAP RUN)
Driver:
oand speed. Be
mindful that the brakes and tyres are still new and
Start to build up brake pressure, and roll some more speed in to the corners. Bring the RPM up to
8,000 before shifting up through the gears.
Technician:
oCheck the tyre pressures
oCheck the running temperatures of the oil and water and adjust any blankings in order to ensure the
car runs at target temperatures
oAgain, remove the engine cover and inspect the engine bay for leaks
oRe-check the wheel nut torque
oAllow the brakes to cool for a few minutes before heading back out on track.

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RUN 3 (5 LAP RUN)
Driver:
oDuring this run build up to full brake pressure, and use the full rev range before shifting (10,000rpm).
Technician:
oCheck the brake discs,
up sufficiently. Allow the brakes to cool once again and remove the blanking on the ducts for the
next session
oCheck the tyre pressures
oCheck for play in the wheel bearings
oRe-check wheel nut torque for a final time
RUN 4 (NORMAL SESSION)
The car can now be run as normal. After this session is complete it is recommended to spanner check the
whole car, again pay final attention for potential leaks and a give the car a good general inspection. When
spanner checking the car, ensure suspension components are not overtightened as this will restrict the
movement of these components.

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3.2 BEDDING IN THE BRAKES
This procedure should be followed each time new discs are fitted to your car:
oThe brake ducts should be ¾ blanked off in order to allow the brakes to warm up through the bedding in
period, previously bedded pads should be used if possible.
o3 lap run - use the brake lightly (<20bar application) on the slow down lap and allow brakes to cool for
5 mins (be sure to not sit stationary in the pits with the brake pedal depressed)
oNext run 5 laps increase brake pressure to build up temperature in the discs (with a peak of around
40bar). The braking potential of the car will start to fade and any potential vibration will surpass; this is
a sign that the bedding procedure is complete.
odisk becoming aligned for the first time; this is not a process that can be simulated in the build of the car.
It is therefore very important that if the driver feels they have brake judder during this first full heatcycle
they continue to build up brake pressure and heat in the disk. Do not decrease pedal pressure, to do so
has the potential to make the vibration worse.
oComplete a cooling down lap with moderate brake pressure before stopping the car. Allow the brakes to
cool for 15 minutes. Do not apply brakes whilst stationary during the cooling down period.
oWe strongly advise AP Racing thermal paint is used; if so, then only the green paint (430°C) should have
fully turned to white and the orange will have slightly turned (560°C) on the outside edges of the discs
during the bedding procedure. If fitted, brake pressure sensors can be used to monitor the bedding in
procedure.
IMP OR TANT NOTES
With cast iron discs, brake pressures should not exceed 20bar during the out lap, even with pre-bedded
discs. This is to prevent heat shocking which causes the discs to crack, this occurs when the disc is taken from
ambient temperature up to 600°C very rapidly such as heavy braking on the out lap. When stationary never
hold pressure on the brake pedal, this can cause warping and/or the discs and pads to bind.

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4. TYRE MANAGEMENT
The table below shows the suggested running pressures and pressures for race tyres:
oPlease note that the starting pressures are to only be used as a guide; conditions on the day will alter
where you should start your pressures. Hot conditions will increase the pressure rise over the same
period of time
oFit valve caps when running
oTemperature spreads must not exceed 15°C across the front and 10°C on the rear
oMeasure tyre temperature spreads, 3cm in from each edge of the tyres and in the centre, make sure
you are not measuring the temperature of any pickup on the tyre
oAvoid kerbs on the out-lap when the tyres are cold
oIt is important to take advice from your tyre manufacturer to ensure you are following their
recommended setup parameters.
TYRE P ER FOR MANCE ANALYSIS
oDecisions based on handling should always be preceded with thorough examination of tyre working
surface.
oUse the temperatures, pressures, data and driver feedback with the visuals of the tyre to get the best
all round view of car and tyre behaviour.
oMeasure the tyre temperatures and pressures as often as possible straight after a fast lap, get the
driver to do a full pace in-lap, in order to get the best readings.
TYRE CONDITION FEEDBACK
When examining a tyre, always check both sides. The unloaded side can drag
the inner wheel, causing excessive negative camber and overheating in the
inner edge.
When measuring the temperature spreads start from the inner edge then work to
the outer edge.
The picture on the left is an example of a rear tyre in good condition, more
camber can be added if the rear is lacking grip.
This is an example of a well-worn front tyre, judging by the wear indicators and
the level of graining it suggests the car has been suffering with understeer. This
could also be run with more camber. If a tyre is graining on either side, this can
be used to judge whether the right level of camber is being used
Hankook Cold Starting Pressure
Slicks
Wets
22
22
22
22
21
21
22
22
Hankook Hot Pressure
Slicks
Wets
28
28
28
28
28
28
28
28
Outer Edge
Outer Edge