FERRARI 488 GT3 Racing Car User Manual
- June 13, 2024
- Ferrari
Table of Contents
488 GT3 Racing Car
User Manual
488 GT3 Racing Car
DEAR iRACING USER,
Congratulations on your purchase of the Ferrari 488 GT3! From all of us at
iRacing, we appreciate your support and your commitment to our product. We aim
to deliver the ultimate sim racing experience, and we hope that you’ll find
plenty of excitement with us behind the wheel of your new car!
The Ferrari 488 GT3 race car is powered by a twin-turbo, 3.9L, V8 engine that
produces over 550 horsepower. Raced in multiple series around the world
including the IMSA Weathertech Series, Blancpain GT and Endurance and Pirelli
World Challenge.
This classic mid-engine car from Ferrari is known for incredibly well balanced
handling, superb brakes and raw power – nothing else sounds quite like a
Ferrari V8 engine at full throttle.
The following guide explains how to get the most out of your new car, from how
to adjust its settings off of the track to what you’ll see inside of the
cockpit while driving. We hope that you’ll find it useful in getting up to
speed.
Thanks again for your purchase, and we’ll see you on the track!
DOUBLE WISHBONE FRONT SUSPENSION MULTI-LINK REAR SUSPENSION
LENGTH
4633mm
182.4in| WIDTH
2045mm
80.5in| WHEELBASE
2713mm
106.8in| DRY WEIGHT
1283kg
2829lbs| WET WEIGHT
WITH DRIVER
1406kg
3100lbs
---|---|---|---|---
TWIN-TURBO 90° V8
Introduction
The information found in this guide is intended to provide a deeper
understanding of the chassis setup adjustments available in the garage, so
that you may use the garage to tune the chassis setup to your preference.
Before diving into chassis adjustments, though, it is best to become familiar
with the car and track. To that end, we have provided baseline setups for each
track commonly raced by these cars. To access the baseline setups, simply open
the Garage, click iRacing Setups, and select the appropriate setup for your
track of choice. If you are driving a track for which a dedicated baseline
setup is not included, you may select a setup for a similar track to use as
your baseline. After you have selected an appropriate setup, get on track and
focus on making smooth and consistent laps, identifying the proper racing line
and experiencing tire wear and handling trends over a number of laps.
Once you are confident that you are nearing your driving potential with the
included baseline setups, read on to begin tuning the car to your handling
preferences.
GETTING STARTED
Before starting
the car, it is recommended to map controls for Brake Bias, Traction Control
and ABS adjustments. While this is not mandatory to drive the car, this will
allow you to make quick changes to the driver aid systems to suit your driving
style while out on the track.
Once you load into the car, getting started is as easy as selecting the
“upshift” button to put it into gear, and hitting the accelerator pedal. This
car uses a sequential transmission and does not require a clutch input to
shift in either direction. However the car’s
downshift protection will not allow you to downshift if it feels you are
traveling too fast for the gear selected and would incur engine damage. If
that is the case, the gear change command will simply be ignored.
Upshifting is recommended when the shift lights on the dashboard are fully
illuminated in red. This is at approximately 7100rpm.
LOADING AN iRACING SETUP
Upon loading into a session, the car will automatically load the iRacing
Baseline setup [baseline.sto]. If you would prefer one of iRacing’s pre-built
setups that suit various conditions, you may load it by clicking Garage >
iRacing Setups > and then selecting the setup to suit your needs.
If you would like to customize the setup, simply make the changes in the
garage that you would like to update and click apply. If you would like to
save your setup for future use click “Save As” on the right to name and save
the changes.
To access all of your personally saved setups, click “My Setups” on the right
side of the garage.
If you would like to share a setup with another driver or everyone in a
session, you can select “Share” on the right side of the garage to do so.
If a driver is trying to share a setup with you, you will find it under
“Shared Setups” on the right side of the garage as well.
Dash Pages
The dash display in this car is non-adjustable and features a single page to
display critical vehicle information.
LIGHTING INDICATORS
LEFT OF SHIFT LIGHT CLUSTER
PINK LIGHTS Wheel lockup indicators for the left side, one is mild, two is
severe
RIGHT OF SHIFT LIGHT CLUSTER
PINK LIGHTS Wheel lockup indicators for the right side, one is mild, two is
severe
LEFT LIGHT STACK
ALT | Low battery voltage warning light |
---|---|
LIGHTS | vehicle external lights on/off indicator |
SPARE LH | Indicates if the spare LH is being used in the real car |
LH IND. | Indicates if the LH indicator is illuminated |
RIGHT LIGHT STACK
FUEL | Low fuel pressure warning indicator, illuminates under 5 Bar (72.5 psi) |
---|---|
OIL | Low oil pressure warning indicator |
SPARE RH | Indicates if the spare RH is being used in the real car |
RH IND. | Indicates if the RH indicator is illuminated |
DASH CONFIGURATION
TOP ROW
D2 | Selected dashboard page (non-adjustable) |
---|---|
RPM METER | Engine RPM displayed as a bar graphic |
SECOND ROW
T WAT | Engine water temperature (°C or °F) |
---|---|
T GBX | Gearbox oil temperature (°C or °F) |
LG RED BOX | Currently selected gear |
LAPTIME | Current lap time |
THIRD ROW
P FUEL | Fuel pressure (Bar or psi) |
---|---|
P GBX | Gearbox oil pressure (Bar or psi) |
DIFF | Difference to best lap time |
FOURTH ROW
TC 1 | Current traction control 1 setting (combined with TC2 for GT3 spec.) |
---|---|
TC 2 | Current traction control 2 setting (combined with TC1 for GT3 spec.) |
PBX | PBX mode, for managing failures in the real car, non-adjustable |
PBX | PBX mode, for managing failures in the real car, non-adjustable |
SPEED | Road speed (km/h or mph) |
FUEL | Remaining fuel (Litres or US Gallons) |
FIFTH ROW
MIX | Current engine map setting |
---|---|
PED | Current throttle map setting |
REC | Recovery mode for managing failures in the real car, non-adjustable |
ABS | Current ABS setting |
BRK F | Applied brake pressure to the front calipers (Bar or dapsi) |
BRK R | Applied brake pressure to the rear calipers (Bar or dapsi) |
BAL | Current forward brake bias as % |
PIT LIMITER
When the
pit limiter is active a large green box that includes the current road speed
will display across the top of the dashboard while the left and right
indicator lights will also illuminate.
SHIFT LIGHTS
1 GREEN | 6350 rpm |
---|---|
2 GREEN | 6550 rpm |
3 GREEN | 6750 rpm |
4 GREEN | 6850 rpm |
1 YELLOW | 6950 rpm |
ALL RED | 7100 rpm |
FERRARI 488 GT3 | ADVANCED SETUP OPTIONS | TIRES & AERO
ADVANCED SETUP OPTIONS
This section is aimed toward more advanced users who want to dive deeper into
the different aspects of the vehicle’s setup. Making adjustments to the
following parameters is not required and can lead to significant changes in
the way a vehicle handles. It is recommended that any adjustments are made in
an incremental fashion and only singular variables are adjusted before testing
changes.
Tires & Aero
TIRE SETTINGS (ALL FOUR)
COLD AIR PRESSURE
Air pressure in the tire when the car is loaded into the world. Higher
pressures will reduce rolling drag and heat buildup, but will decrease grip.
Lower pressures will increase rolling drag and heat buildup, but will increase
grip. Higher speeds and loads equire higher pressures, while lower speeds and
loads will see better performance from lower pressures. Cold pressures should
be set to track characteristics for optimum performance. Generally speaking,
it is advisable to start at lower pressures and work your way upwards as
required.
HOT AIR PRESSURE
Air pressure in the tire after the car has returned to the pits. The
difference between cold and hot pressures can be used to identify how the car
is progressing through a run in terms of balance, with heavier-loaded tires
seeing a larger difference between cold and hot pressures. Ideally, tires that
are worked in a similar way should build pressure at the same rate to prevent
a change in handling balance over the life of the tire, so cold pressures
should be adjusted to ensure that similar tires are at similar pressures once
up to operating temperature. Hot pressures should be analysed once the tires
have stabilised after a period of laps. As the number of laps per run will
vary depending upon track length a good starting point is approximately 50% of
a full fuel run.
TIRE TEMPERATURES
Tire carcass temperatures, measured via Pyrometer, once the car has returned
to the pits. Wheel Loads and the amount of work a tire is doing on-track are
reflected in the tire’s temperature, and these values can be used to analyze
the car’s handling balance.
Center temperatures are useful for directly comparing the work done by each
tire, while the Inner and Outer temperatures are useful for analyzing the
wheel alignment (predominantly camber) while on track. These values are
measured in three zones across the tread of the tire. Inside, Middle and
Outer.
TREAD REMAINING
The amount of tread remaining on the tire once the car has returned to the
pits. Tire wear is very helpful in identifying any possible issues with
alignment, such as one side of the tire wearing excessively, and can be used
in conjunction with tire temperatures to analyze the car’s handling balance.
These values are measured in the same zones as those of temperature.
AERO CALCULATOR
The Aero Calculator is a tool provided to aid in understanding the shift in
aerodynamic balance associated with adjustment of the rear wing setting and
front and rear ride heights. It is important to note that the values for front
and rear ride height displayed here DO NOT result in any mechanical changes to
the car itself, however, changes to the rear wing angle here WILL be applied
to the car. This calculator is a reference tool ONLY.
FRONT RH AT SPEED
The Ride Height (RH) at Speed is used to give the Aero Calculator heights to
reference for aerodynamic calculations. When using the aero calculator,
determine the car’s Front Ride height via telemetry at any point on track and
input that value into the “Front RH at Speed” setting. It is advisable to use
an average value of the LF and RF ride heights as this will provide a more
accurate representation of the current aero platform rather than using a
single corner height.
REAR RH AT SPEED
The Ride Height (RH) at Speed is used to give the Aero Calculator heights
to reference for aerodynamic calculations. When using the aero calculator,
determine the car’s Rear Ride height via telemetry at any point on track and
input that value into the “Front
RH at Speed” setting. It is advisable to use an average value of the LR and RR
ride heights as this will provide a more accurate representation of the
current aero platform rather than using a single corner height.
WING SETTING
The wing setting refers to the relative angle of attack of the rear wing, this
is a powerful aerodynamic device which has a significant impact upon the total
downforce (and drag!) produced by the car as well as shifting the aerodynamic
balance of the car rearwards with increasing angle. Increasing the rear wing
angle results in more total cornering grip capability in medium to high speed
corners but will also result in a reduction of straight line speed. Rear wing
angle should be adjusted in conjunction with front and rear ride heights,
specifically the difference between front and rear ride heights known as
‘rake’. To retain the same overall aerodynamic balance it is necessary to
increase the rake of the car when increasing the rear wing angle.
FRONT DOWNFORCE
This value displays the proportion of downforce acting at the front axle for
the given wing and ride height combination set within the calculator
parameters. This value is an instantaneous representation of your aero balance
at this exact set of parameters and
it can be helpful to pick multiple points around a corner or section of track
to understand how the aerodynamic balance is moving in differing situations
such as braking, steady state cornering and accelerating at corner exit. A
higher forwards percentage will
result in more oversteer in mid to high speed corners.
Chassis
FRONT
ARB BLADES
The configuration of the Anti-Roll Bar arms, or “blades”, can be changed to
alter the overall stiffness of the ARB assembly. Higher values transfer more
force through the arms to the ARB itself, increasing roll stiffness in the
front suspension and producing the same effects, albeit on a smaller scale, as
increasing the diameter of the sway bar. Conversely, lower values reduce the
roll stiffness of the front suspension and produce the same effects as
decreasing the diameter of the sway bar. These blade adjustments can be
thought of as fine-tuning adjustments between sway bar diameter settings. 10
ARB blade options are available ranging from 1 (softest) to 10 (stiffest).
ARB OUTER DIAMETER
The ARB (Anti-Roll Bar) size influences the stiffness of the front suspension
in roll, such as when navigating a corner. Increasing the ARB size will
increase the roll stiffness of the front suspension, resulting in less body
roll but increasing mechanical understeer.
This can also, in some cases, lead to a more responsive steering feel from the
driver. Conversely, reducing the ARB size will soften the suspension in roll,
increasing body roll but decreasing mechanical understeer. This can result in
a less-responsive feel from
the steering, but grip across the front axle will increase. Along with this,
the effects of softening or stiffening the ARB in relation to aerodynamics
should also be considered, smaller and hence softer ARB’s will result in more
body roll which will decrease control of the aero platform in high speed
corners and potentially lead to a loss in aero efficiency. 3 configurations of
ARB diameter are available and range from small (softest) to large (stiffest).
TOE-IN
Toe is the angle of the wheel, when viewed from above, relative to the
centerline of the chassis. Toe-in is when the front of the wheel is closer to
the centerline than the rear of the wheel, and Toe-out is the opposite. On the
front end, adding toe-out will increase slip in the inside tire while adding
toe-in will reduce the slip. This can be used to increase straight-line
stability and turn-in responsiveness with toe-out. Toe-in at the front will
reduce turn-in responsiveness but will reduce temperature buildup in the front
tires.
FRONT MASTER CYLINDER
The Front Brake Master Cylinder size can be changed to alter the line pressure
to the front brake calipers. A larger master cylinder will reduce the line
pressure to the front brakes, this will shift the brake bias rearwards and
increase the pedal effort required to lock the front wheels. A smaller master
cylinder will do the opposite and increase brake line pressure to the front
brakes, shifting brake bias forward and reducing required pedal effort. 7
Different master cylinder options are available ranging from 15.9 mm / 0.626”
(highest line pressure) to 23.8 mm / 0.937” (lowest line pressure).
REAR MASTER CYLINDER
The Rear Brake Master Cylinder size can be changed to alter the line pressure
to the rear brake calipers. A larger master cylinder will reduce the line
pressure to the rear brakes, this will shift the brake bias forwards and
increase the pedal effort required to lock the rear wheels. A smaller master
cylinder will do the opposite and increase brake line pressure to the rear
brakes, shifting brake bias rearward and reducing required pedal effort. 7
Different master cylinder options are available ranging from 15.9 mm / 0.626”
(highest line pressure) to 23.8 mm / 0.937” (lowest line pressure).
BRAKE PADS
The vehicle’s braking performance can be altered via the Brake Pad Compound.
The “Low” setting provides the least friction, reducing the effectiveness of
the brakes, while “Medium” and “High” provide more friction and increase the
effectiveness of the brakes while increasing the risk of a brake lockup.
CROSS WEIGHT
The percentage of total vehicle weight in the garage acting across the right
front and left rear corners. 50.0% is generally optimal for non-oval tracks as
this will produce symmetrical handling in both left and right hand corners
providing all other chassis settings are symmetrical. Higher than 50% cross
weight will result in more understeer in left hand corners and increased
oversteer in right hand corners, cross weight can be adjusted by making
changes to the spring perch offsets at each corner of the car.
IN-CAR DIALS
BRAKE PRESSURE BIAS
Brake Bias is the percentage of braking force that is being sent to the front
brakes. Values above 50% result in greater pressure in the front brake line
relative to the rear brake line which will shift the brake balance forwards
increasing the tendency to lock up the front tyres but potentially increasing
overall stability in braking zones. This should be tuned for both driver
preference and track conditions to get the optimum braking performance for a
given situation. It is important to note that differing combinations
of master cylinder size will necessitate differing brake pressure bias values,
this is because increasing or reducing the split in master cylinder size
difference between front and rear axles will produce an inherent forward or
rearward bias in brake line pressure.
TRACTION CONTROL SETTING
The position of the traction control switch determines how aggressively the
ecu cuts engine torque in reaction to rear wheel spin. 6 positions are
available. Settings 1-5 range from least intervention/sensitivity (position 1)
through to highest intervention/ sensitivity (position 5). Position 6 disables
the traction control completely. Position 3 is the recommended baseline
setting. More intervention will result in less wheelspin and less rear tire
wear but can reduce overall performance if the traction control is cutting
engine torque too aggressively and stunting corner exit acceleration.
THROTTLE SHAPE SETTING
Throttle shape setting refers to how changes in the drivers pedal position
result in changes in provided engine torque. 6 positions exist, position 1
results in a linear torque map relative to throttle position (e.g. 10%
throttle position results in 10% engine torque, 0% throttle position results
in 50% engine torque and so on.). Position 6 emulates a non-linear S-shaped
map similar to a cable throttle which results in reduced fidelity in the
middle portion of the throttle range. Positions 2-5 are hybrids of the
position 1 and 6 throttle mapping styles.
ENGINE MAP SETTING
The fuel map on which the car is currently running. Position 1 is the base map
and produces maximum power but the most fuel usage. Positions 2 through 11 are
for fuel saving under green flag conditions and will reduce engine power
output correspondingly.
The higher the number the better the fuel economy but the lower the power
output. Position 12 is for saving fuel under safety car conditions and is not
recommended for normal usage.
ABS SETTING
The current ABS map the car is running. 12 positions are available but only 10
maps exist. Position 1 has the least intervention/ support while position 10
has the most support. Position 11 is the same as position 10 and position 12
disables the ABS completely. Position 2 is the recommended baseline setting.
More intervention reduces the possibility of and the duration of lockups
during braking but can result in longer braking distances if the system is set
overly aggressive for the amount of available grip.
LEFT NIGHT LED STRIP
Changes the colour of the light strip on the left side of the car. 7 options
are available: Blue, Purple, Red, Yellow, Orange, Green and Off.
RIGHT NIGHT LED STRIP
Changes the colour of the light strip on the right side of the car. 7 options
are available: Blue, Purple, Red, Yellow, Orange, Green and Off.
FRONT CORNERS
CORNER
WEIGHT
The weight underneath each tire under static conditions in the garage. Correct
weight arrangement around the car is crucial for optimizing a car for a given
track and conditions. Individual wheel weight adjustments and crossweight
adjustments are made via
the spring perch offset adjustments at each corner.
FRONT RIDE HEIGHT
Distance from ground to a reference point on the chassis. Since these values
are measured to a specific reference point on the car, these values may not
necessarily reflect the vehicle’s ground clearance, but instead provide a
reliable value for the height of the car off of the race track at static
values. Adjusting Ride Heights is key for optimum performance, as they can
directly influence the vehicle’s aerodynamic performance as well as mechanical
grip. Increasing front ride height will decrease front downforce as well as
decrease overall downforce, but will allow for more weight transfer across the
front axle when cornering. Conversely, reducing ride height will increase
front and overall downforce, but reduce the weight transfer across the front
axle. Minimum legal front ride height is 50.0 mm.
SPRING PERCH OFFSET
Used to adjust the ride height at this corner of the car by changing the
installed position of the spring. Increasing the spring perch offset will
result in lowering this corner of the car while reducing the spring perch
offset will raise this corner of the car. These
changes should be kept symmetrical across the axle (left to right) to ensure
the same corner ride heights and no change in cross weight. The spring perch
offsets can also be used in diagonal pairs (LF to RR and RF to LR) to change
the static cross weight in the car.
SPRING SELECTED/SPRING RATE
This setting determines the installed corner spring stiffness. Stiffer springs
will result in a smaller variance in ride height between high and low load
cases and will produce superior aerodynamic performance through improved
platform control however, they
will also result in increased tire load variation which will manifest as a
loss in mechanical grip. Typically the drawbacks of stiffer springs will
become more pronounced on rougher tracks and softer springs in these
situations will result in increased overall performance. Corner spring changes
will influence both roll and pitch control of the platform and ARB changes
should be considered when altering corner spring stiffnesses in order to
retain the same front to rear roll stiffness and overall balance.
When reducing corner spring stiffness the ARB stiffness (either via blade or
diameter depending on the size of the corner spring change) should be
increased to retain the same roll stiffness as previously. 6 options for
spring rate are available ranging from 180 N/mm (1029 lbs/in) to 330 N/mm
(1886 lbs/in) in 30 N/mm (172 lbs/in) steps. Spring perch offsets must be
adjusted to return the car to the prior static ride heights after any spring
rate change.
LS COMP DAMPING
Low speed compression affects how resistant the shock is to compresion
(reduction in length) when the shock is moving at relatively low speeds,
usually in chassis movements as a result of driver input (steering, braking, &
throttle) and cornering forces. In this case 0 is minimum damping (least
resistance to compression) while 11 is maximum damping (most resistance to
compression). Increasing the low speed compression damping will result in a
faster transfer of weight to this corner of the car during transient movements
such as braking and direction change with increased damping usually providing
an increase in turn-in response but a reduction in overall grip in the context
of front dampers.
HS COMP DAMPING
High speed compression affects the shock’s behavior in high speed travel,
usually attributed to curb strikes and bumps in the track’s surface. Higher
compression values will cause the suspension to be stiffer in these
situations, while lower values will allow the suspension to absorb these bumps
better but may hurt the aerodynamic platform around the track. At smoother
tracks more high speed compression damping will typically increase performance
while at rougher tracks or ones with aggressive kerbs less
high speed compression damping can result in an increase in mechanical grip at
the expense of platform control. 11 is maximum damping while 0 is minimum
damping.
LS RBD DAMPING
Low speed rebound damping controls the stiffness of the shock while extending
at lower speeds, typically during body movement as a result of driver inputs.
Higher rebound values will resist expansion of the shock, lower values will
allow the shock to extend
faster. Higher rebound values can better control aerodynamic attitude but can
result in the wheel being unloaded when the suspension can’t expand enough to
maintain proper contact with the track. When tuning for handling, higher front
low speed rebound can increase on-throttle mechanical understeer (but reduce
nose lift) while lower values will maintain front end grip longer, helping to
reduce understeer, but will allow more splitter lift. Excessive front rebound
can lead to unwanted oscillations due
to the wheel bouncing off of the track surface instead of staying in contact.
11 is maximum damping (most resistant to extension) while 0 is minimum damping
(least resistance to extension).
HS RBD DAMPING:
High-speed rebound adjusts the shock in extension over bumps and curb strikes.
Higher values will reduce how quickly the shock will expand, while lower
values will allow the shock to extend more easily. Despite not having as much
of an effect on handling in result to driver inputs, High-speed rebound can
produce similar results in terms of aerodynamic control and uncontrolled
oscillations if set improperly. 11 is maximum damping while 0 is minimum
damping.
CAMBER
Camber is the vertical angle of the wheel relative to the center of the
chassis. Negative camber is when the top of the wheel is closer to the chassis
centerline than the bottom of the wheel, positive camber is when the top of
the tire is farther out than the bottom. Due to suspension geometry and corner
loads, negative camber is desired on all four wheels. Higher negative camber
values will increase the cornering force generated by the tire, but will
reduce the amount of longitudinal grip the tire will have under braking.
Excessive camber values can produce very high cornering forces but will also
significantly reduce tire life, so it is important to find a balance between
life and performance. Increasing front camber values will typically result in
increased front axle grip during mid to high speed cornering but will result
in a loss of braking performance and necessitate a rearward shift in brake
bias to compensate.
CASTER
Caster is the vertical angle of the steering axis relative to the side view of
the chassis. Positive caster angle is where the steering axis is leaned
rearwards from this viewpoint, the more caster the larger the total trail of
the contact patch behind the steering axis. More caster angle will result in
the mechanical trail being a larger proportion of the felt steering weight
relative to the tires neumatic trail. This will result in a heavier overall
steering feel but a possible loss in felt feedback from the tire. Increasing
caster angle will also have secondary effects such as an increase in dynamic
camber when turning the wheel through large steering angles which can be
beneficial in chicances or hairpins. As well as this the more caster angle the
greater the jacking effect during cornering which will result in lifting the
inside front wheel while lowering the outside front wheel. This jacking effect
will also result in the unloading and potentially lifting of the inside rear
wheel which can aid in rotation around tight corners.
REAR CORNERS
REAR RIDE
HEIGHT
Distance from ground to a reference point on the rear of the chassis.
Increasing rear ride height will decrease rear downforce as well as increase
overall downforce and will allow for more weight transfer across the rear axle
when cornering. Conversely, reducing ride height will increase rear downforce
percentage but reduce overall downforce while reducing the weight transfer
across the rear axle. Rear ride height is a critical tuning component for both
mechanical and aerodynamic balance considerations and static rear ride heights
should be considered and matched to the chosen rear corner springs for optimal
performance.
Minimum legal rear ride height is 50.0 mm while maximum legal rear ride height
is 90.0 mm.
SPRING SELECTED/SPRING RATE
Similar to at the front axle, stiffer springs will result in a smaller
variance in ride height between high and low load cases and will produce
superior aerodynamic performance through improved platform control at the
expense of mechanical grip. This can be particularly prominent when exiting
slow speed corners with aggressive throttle application. Stiffer springs will
tend to react poorly during these instances especially so on rough tracks
which will result in significant traction loss. Spring stiffness should be
matched to the needs of the racetrack and set such that the handling balance
is consistent between high and low speed cornering. As an example case, a car
which suffers from high speed understeer but low speed oversteer could benefit
from an increase in rear spring stiffness. This will allow for a lower static
rear height which will reduce rear weight transfer during slow speed cornering
while maintaining or even increasing the rear ride height in high speed
cornering to shift the aerodynamic balance forwards and reduce understeer. 6
options for spring rate are available ranging from 190 N/mm (1086 lbs/in) to
310 N/mm (1771 lbs/in). The first portion of the range from 190 N/mm (1086
lbs/in) to 250 N/mm (1429 lbs/in) is in 30 N/mm (172 lbs/in) steps for coarse
adjustment while the next 2 rates are stepped in 15 N/mm (86 lbs/in) steps for
fine adjustment. Spring perch offsets must be adjusted to return the car to
the prior static ride heights after any spring rate change.
COMPRESSION DAMPING
The compression damping setting is a paired adjustment controlling both the
low and high speed damping characteristics of the damper with identical ranges
to those of the front dampers. Increasing the compression damping will result
in a faster transfer of weight to this corner of the car during transient
movements such as accelerating and direction change with increased damping
usually providing an increase in response but a reduction in overall grip
especially at corner exit traction in the context of rear dampers. Excessively
stiff compression damping can cause very poor traction on rough tracks as it
can result in large tire load variation and a reduction in overall grip.
REBOUND DAMPING
The rebound damping setting is a paired adjustment controlling both the low
and high speed damping characteristics of the damper with identical ranges to
those of the front dampers. Increasing rebound damping will slow down the rate
at which the damper extends in both low and high speed situations. As at the
front, high rebound stiffness will result in improved platform control for
aerodynamic performance and overall chassis response but it is important to
avoid situations where the shock is too slow in rebounding as this will result
in the tire losing complete contact with the track surface. This can be
particularly detrimental during braking events and during the initial turn-in
phase though an increase in rebound stiffness can help to ‘slow down’ the
change in pitch of the car as the brakes are applied, potentially increasing
braking stability.
CAMBER
As at the front of the car it is desirable to run significant amounts of
negative camber in order to increase the lateral grip capability however, it
is typical to run slightly reduced rear camber relative to the front. This is
primarily for two reasons, firstly, the rear tires are 25 mm (~1”) wider
compared to the fronts and secondly the rear tires must also perform the duty
of driving the car forwards where benefits of camber to lateral grip become a
tradeoff against reduced longitudinal (traction) performance.
TOE-IN
At the rear of the car it is typical to run toe-in. Increases in toe-in will
result in improved straight line stability and a reduction in response during
direction changes. Large values of toe-in should be avoided if possible as
this will increase rolling drag and reduce straight line speeds. When making
rear toe changes remember that the values are for each individual wheel as
opposed o paired as at the front. This means that individual values on the
rear wheels are twice as powerful as the combined adjustment at the front of
the car when the rear toes are summed together. Generally, it is advised to
keep the left and right toe values equal to prevent crabbing or asymmetric
handling behaviour however, heavily asymmetric tracks such as Lime Rock Park
may see a benefit in performance from running asymmetric configurations of
rear toe and other setup parameters.
REAR
FUEL LEVEL
The amount of fuel in the fuel tank. Tank capacity is 110 L (29.1 g).
Adjustable in 1 L (0.26 g) increments.
ARB BLADES
The configuration of the Anti-Roll Bar arms, or “blades”, can be changed to
alter the overall stiffness of the ARB assembly. Higher values transfer more
force through the arms to the ARB itself, increasing roll stiffness in the
rear suspension and producing
the same effects, albeit on a smaller scale, as increasing the diameter of the
sway bar. Conversely, lower values reduce the roll stiffness of the rear
suspension and produce the same effects as decreasing the diameter of the sway
bar. These blade adjustments can be thought of as fine-tuning adjustments
between sway bar diameter settings. 10 ARB blade options are available ranging
from 1 (softest) to 10 (stiffest).
ARB OUTER DIAMETER
The ARB (Anti-Roll Bar) size influences the stiffness of the rear suspension
in roll, such as when navigating a corner. Increasing the ARB size will
increase the roll stiffness of the rear suspension, resulting in less body
roll but increasing mechanical oversteer. This can also cause the car “take a
set” more quickly at initial turn-in. Conversely, reducing the ARB size will
soften the suspension in roll, increasing body roll but decreasing mechanical
oversteer. This can result in a less-responsive feel from the rear especially
in transient movements, but grip across the rear axle will increase. 3
configurations of ARB diameter are available and range from small (softest) to
large (stiffest).
GEAR STACK
Four options of gear stack are available for selection depending upon track
type. The FiA stack is suitable for almost all track types and should be
treated as the baseline. IMSA Daytona and IMSA Short provide two alternative
options which are targeted for
tracks with longer and shorter straightaways respectively. The Ferrari
Challenge gear stack is an alternate option which emulates nd thru 7th of the
488 Challenge gearbox and is not commonly recommended, though it may be useful
on street circuits due to
its tight spacing of the lower gears.
DIFF PRELOAD
Diff preload is a static amount of locking force present within the
differential and remains constant during both acceleration and deceleration.
Increasing diff preload will increase locking on both sides of the
differential which will result in more understeer when off throttle and more
snap oversteer with aggressive throttle application. Increasing the diff
preload will also smooth the transition between on and off throttle behaviour
as the differential locking force will never reach zero which can be helpful
in reducing lift-off oversteer and increasing driver confidence. Typically
diff preload should be increased when there is noticeable loss in slow corner
exit drive and/or over-rotation during transition between the throttle and
brake in low to mid speed corners.