iRacing FORMULA iR-04 User manual

iRACING FORMULA iR-04
USER MANUAL

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Introduction »5
Tech Specs »4
A Message From iRacing »3
Getting Started »5
Pit Limiter »7
Dash Pages »7
Loading An iRacing Setup »6
Shift Lights »8
Dash Configuration »7
Tires & Aero »10
Front »13
Aero Calculator »12
Aero »11
Left/Right Rear »16
Tire Settings »10
Left/Right Front »15
Chassis »13
Rear »17
ADVANCED SETUP OPTIONS
GENERAL INFORMATION
Table of Contents
CLICK TO VIEW A SECTION

DEAR iRACING USER,
Congratulations on your purchase of the iR-04! 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 iRacing Formula iR-04 has been developed in conjunction with the global effort to massively increase
the participation of motorsport worldwide. Following the introduction of a second-generation entry-level
open-wheel formula in 2022, the iRacing Formula iR-04 benefits from the same level of analysis, detail, data,
and testing as our members have come to expect while the genericized model allows for use by national
clubs world-over without manufacturer conflicts. iRacers have their choice of the GT2 and GT3 versions of
the Ford GT.
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!

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POWER
UNIT
CHASSIS
iRACING FORMULA iR-04 // TECH SPECS
DOUBLE WISHBONE PUSHROD
SUSPENSION FRONT AND REAR
INLINE-4
LENGTH
4467mm
175.9in
DISPLACEMENT
2.0Liters
122.0CID
WIDTH
1738mm
68.4in
TORQUE
226Nm
167lb-ft
WHEELBASE
2745mm
108.1in
POWER
178bhp
131kW
DRY WEIGHT
581kg
1281lbs
RPM LIMIT
7275RPM
WET WEIGHT
WITH DRIVER
665kg
1466lbs

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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 a control for Brake Bias adjustment. While this is not mandatory, this will allow
you to make quick changes to the brake bias to suit your driving while out on track.
Once you load into the car, getting started is as easy as pulling the “upshift” paddle to put it into gear, and hitting the accelerator
pedal. This car uses an automated sequential transmission and does not require manual clutch operation to shift in either
direction.
Upshifting is recommended when the shift lights on the dashboard are all fully illuminated. This is at 7000rpm.
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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.
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Dash Pages
The dash display in this car is non-adjustable and features a single page to display critical
vehicle information.
DASH CONFIGURATION
PIT LIMITER
When the pit limiter is activated a large green box will appear at the base of the dash display.
Row 1 Left Engine oil pressure (Bar or psi)
Row 1 Center Engine rpm
Row 1 Right Engine water temperature (Celsius or Fahrenheit)
Row 2 Left Engine oil temperature (Celsius or Fahrenheit)
Row 2 Center Currently selected gear
Row 2 Right Road speed (km/h or mph)
Row 3 Left Session best lap as mm:ss:ms
Row 3 Right Session last lap as mm:ss:ms
1 Green 6300 RPM
2 Green 6500 RPM
3 Green 6600 RPM
4 Green 6700 RPM
1 Red 6800 RPM
2 Red 6900 RPM
All Flashing 7000 RPM
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SHIFT LIGHTS
1 Green 6300 rpm
2 Green 6500 rpm
3 Green 6600 rpm
4 Green 6700 rpm
1 Red 6800 rpm
2 Red 6900 rpm
All Flashing 7000 rpm
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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.
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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 require
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 analyzed once the tires have stabilized 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.
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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
FRONT MAINPLANE ANGLE
The relative angle of attack of the front wing. This is a powerful aerodynamic device in terms of balance and total downforce
produced. Increasing the front mainplane angle results in more total cornering capability in medium to high speed corners, a
significant shift forwards in handling balance (more oversteer) and a slight reduction in straight line speed. The front mainplane
angle should be adjusted in conjunction with the rear wing angle as well as the relative difference in front and rear ride heights
known as ‘rake’. Reducing the rake will shift the aerodynamic balance rearwards while increasing it will shift the aerodynamic
balance forwards.
REAR WING SETTING
The relative angle of attack of the rear wing. On this car the primary purpose of the rear wing is to trim the aerodynamic balance
to suit changes made to the front mainplane angle. Increasing the rear wing angle will produce more downforce, more drag and
shift the aerodynamic balance rearwards (more understeer). In both balance and downforce senses it is relatively less powerful
than the front mainplane and will require larger step changes to suit any changes made to the front mainplane. However, it is
relatively more influential in terms of drag. As such, at tracks with long straights it may be beneficial to focus on reducing the rear
wing angle for greater straight line speed to aid in overtaking.
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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.
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.
DOWNFORCE TO DRAG
In absolute terms this number represents the amount of downforce produced per unit drag and thus represents the overall
aerodynamic efficiency of the currently selected wing configuration and at speed ride heights. This can be useful in evaluating
various combinations of wings and rake while keeping an equivalent downforce to drag number. However, it should be noted that
this number only represents the efficiency, not the total downforce produced. As such, it is very possible to create two different
packages that have the same efficiency but very differing levels of performance in terms of mid corner and end of straightaway
speeds.
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.
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Chassis
FRONT
TRANSPARENT HALO COLUMN
This option is visual only. Checking this box will change the center support of the halo from opaque to transparent.
PUSHROD OFFSET
Used to adjust the front ride height by increasing or decreasing the length of the front pushrods. Lengthening the pushrod
will increase the ride height and shortening the pushrod will reduce the ride height. Left and right adjustments are paired and
adjusted as one.
ARB BLADES
The configuration of the Anti-Roll Bar arms, or “blades”, can be changed to alter the overall stiffness of the ARB assembly.
Increasing the number of ARB arms 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 number of ARB arms 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 assembly in relation to aerodynamics should also be considered, softer ARB assemblies 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. 5 configurations of ARB arms are available and range from 1 (softest) to 5 (stiffest).
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DAMPER COMPRESSION STIFFNESSThe bump stiffness setting is a paired adjustment controlling both the low and high
speed compression damping characteristics of the damper. In this case 1 is minimum damping (least resistance to compression)
while 10 is maximum damping (most resistance to compression). Increasing the bump stiffness will result in a faster transfer of
weight to this end 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 damping. High speed compression
damping will increase proportionally to the increase in low speed compression damping which will also result in harsher response
to kerb strikes. At smoother tracks more bump stiffness will typically increase performance while at rougher tracks or ones with
aggressive kerbs less compression damping can result in an increase in mechanical grip at the expense of platform control.
DAMPER REBOUND STIFFNESS
The Rebound Stiffness setting is a paired adjustment to both low and high speed rebound damping characteristics. Increasing
rebound damping will slow down the rate at which the damper extends in both low and high speed situations. A typical low damper
speed situation would be as the car rolls back to level on a corner exit while a high speed situation would be where the suspension
is extending after large kerb contact. 1 is minimum damping (least resistance to extension) while 10 is maximum damping (most
resistance to extension). While high rebound stiffness will result in improved platform control for aerodynamic performance and
overall chassis response it is important to avoid situations where the damper is too slow in rebounding as this will result in the tire
losing complete contact with the track surface which can induce or exacerbate severe oscillations.
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.
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, adjustments to cross weight can be made by making changes to the corner spring rates, air pressures or
alignment at each corner of the car.
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LEFT/RIGHT FRONT
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. For the iR-04 this cannot be easily influenced as individual corner pushrods are
non-adjustable. However, when running asymmetrical setups some difference in corner weights may still be observed.
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 20.0 mm.
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 should be increased to retain the same roll stiffness as previously. Six
options for spring rate are available ranging from 88 N/mm (500 lbs/in) to 175 N/mm (1000 lbs/in). Pushrod offsets must be
adjusted to return the car to the prior static ride heights after any spring rate change.
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
pneumatic 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
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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.
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.
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; more toe-
out results in more straight line stability but increased rolling drag. Generally, it is best to keep to small values here due to the low
power nature of the car.
LEFT/RIGHT REAR
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. Six options for spring rate are available 88 N/mm (500 lbs/in) to 175 N/mm (1000 lbs/in).
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Pushrod offsets must be adjusted to return the car to the prior static ride heights after any spring rate change.
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 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. Generally, it is advised to keep the left and right toe values equal to prevent crabbing or asymmetric handling
behavior; 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
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 30.0 mm while maximum legal rear ride height is 40.0 mm.
PUSHROD OFFSET
Used to adjust the rear ride height by increasing or decreasing the length of the rear pushrods. Lengthening the pushrod will
increase the ride height and shortening the pushrod will reduce the ride height. Left and right adjustments are paired and
adjusted as one.
ARB BLADES
The configuration of the Anti-Roll Bar arms, or “blades”, can be changed to alter the overall stiffness of the ARB assembly.
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Increasing the ARB assembly stiffness will increase the roll stiffness of the rear suspension, resulting in less body roll but
increasing mechanical oversteer. This can also cause the car to “take a set” more quickly at initial turn-in. Conversely, reducing
the ARB assembly stiffness 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. 5
configurations of ARB arms are available and range from 1 (softest) to 5 (stiffest).
DAMPER COMPRESSION STIFFNESS
The bump stiffness setting is a paired adjustment controlling both the low and high speed compression 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 end 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.
DAMPER REBOUND STIFFNESS
The rebound stiffness 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 damper 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.
FUEL LEVEL
The amount of fuel in the fuel tank. Tank capacity is 40 L (10.6 g). Adjustable in 1 L (0.26 g) increments.
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