ECU lexus LFA 2012 Owner's Manual / LEXUS 2012 LFA: INSIDE THE LFA

22
■
■Using the floor mats
The floor mats and installation hardware have been designed specifically for use with
the LFA.
When installing the LFA-specific floor
mats, ensure that the front edge of the
floor mat is securely inserted under the
heel stopper.
After inserting the front edge of the floor
mat securely under the heel stopper,
fix the rear edge of the floor mat to the
carpet using the retaining hooks (clips).
If the floor mats are not securely fixed in
place, they may interfere with operation
of the pedals and increase the risk of an
accident.
The following circumstances may result in the floor mats interfering with operation of the
pedals, increasing the risk of an accident:
• When an all-weather or similar type of floor mat is placed on top of the LFA-specific
floor mat.
• When using floor mats other than the LFA-specific units.
• When using the passenger side floor mat on the driver side.
Heel stopper

23
Ideal driving position
■
■Steering wheel adjustment range
The LFA has a tilt and telescopic steering column that allows you to manually adjust
the longitudinal and vertical position of the steering wheel.
The tilt fulcrum has been placed a significant distance away from the steering wheel
itself in order to minimize the change in steering wheel angle when adjusting its
vertical position. Minimizing the change in steering wheel angle prevents the top of
the steering wheel from moving too far away from the driver.
Meanwhile, the telescopic adjustment allows the steering wheel and column to be
moved as a whole so that the distance between the steering wheel and the paddle
shift switches remains the same.
Highest
position
Lowest position
Telescopic adjustment range:
1.57 in. (40 mm) Tilt range:
2.6°
Tilt fulcrum

Adjusting the steering wheel position
Pull the tilt and telescopic steering lock
r e l e a s e l e v e r d o w n w h i l e m o v i n g t h e
steering wheel longitudinally and vertically
into the desired position. After adjustment,
p u s h t h e l eve r u p a n d c h e c k t h a t t h e
steering wheel is securely fixed in place.

28
■
■Active rear wing
The LFA’s active rear wing operates on a speed-linked schedule in accordance with
the selected driving mode. Control is performed by the ECU (Electronic Control
Unit).
Vehicle speed-linked active control allows for a reduced drag coefficient (Cd value)
when the wing is stowed. The wing is automatically raised to control airflow and
provide an appropriate level of downforce (-Cl value) at higher speeds, contributing
to handling stability.
Depending on the driving mode, the
active rear wing will rise in approximately
5 s e c o n d s w h e n t h e ve h i c l e s p e e d
exceeds 50 mph (80 km/h) or 81 mph
(130 km/h) respectively.
T h e w i n g w i l l a u t o m a t i c a l l y l owe r i n
a p p rox i m a t e l y 7 s e c o n d s w h e n t h e
vehicle slows to 25 mph (40 km/h) or
less.
The dif ference in rising and lowering
speeds is intended to minimize undesired aerodynamic changes due to frequent
operation.
Driving mode
SPORT/NORMAL/WET
Active rear wing operation speed
Raised
Speed [mph (km/h)] Lowered
25 (40) 50 (80)

29
Operating the driving mode selector switch
■
■VDIM
The LFA employs VDIM (Vehicle Dynamics Integrated Management), a dynamic
control program that integrates braking and drive torque control to help ensure
overall vehicle stability and secure handling. VDIM also features vertical acceleration
and roll rate sensors, added exclusively for the LFA. The addition of these sensors
increases the precision and response of road camber estimation on banked roads,
such as “The Carousel” at the Nürburgring, to determine the vehicle’s performance
limits. This prevents excessive intervention on banked roads.
The LFA’s VDIM system allows for two individual control modes selected by the driver
using the driving mode selector switch.
When in SPORT mode, VDIM control is modified in order to enhance driving
pleasure and the driver’s confidence in the vehicle.
When not in SPORT mode, VDIM returns to NORMAL mode, designed to intervene
seamlessly as the vehicle reaches its performance limits, thereby realizing smoother
driving dynamics.
This helps ensure both overall vehicle stability and secure handling.

32
When the driver depresses the accelerator pedal, a signal is sent to the ECU where
it is interpreted and used to control the throttle valve angle. This is all performed
electronically without a conventional cable linkage.
The throttle valves are opened and closed by a pair of electric motors, one for each
bank of cylinders. There are a total of 10 individual throttle valves, one for each
cylinder. This configuration minimizes the amount of air between each combustion
chamber and its corresponding independent throttle valve, promoting instantaneous
throttle action for outstanding engine response.
Furthermore, this drive-by-wire technology is able to tailor specific throttle valve
angle strategies to each available driving mode. Depending on which driving mode
is selected, depressing the accelerator pedal the same amount will result in a different
throttle valve angle. This variable control results in engine characteristics better suited
to the driver’s intentions and driving conditions.
■
■Accelerator pedal mechanism
A f l o o r- m o u n t e d a c c e l e r a t o r p e d a l
allows the fulcrum to be moved closer to
the floor and the driver's heel. Depressing
the pedal actuates a rod, which moves
through a sensor. The pedal has a 1.48 in.
(37.7 mm) stroke and the sensor is able
to precisely detect movement down to
0.03 in. (0.8 mm) in order to provide a
more direct feel.
Pedal stroke
Fulcrum
Accelerator pedal (Position sensor judgment)
Pedal
released Pedal
fully
depressed 0 1.48 (37.7)
Pedal stroke [in. (mm)]
Accelerating

36
Shifting
With regards to the drivetrain, the steering wheel-mounted paddle shift switches
command the automated dry single-plate clutch and rear-mounted ASG (Automated
Sequential Gearbox) transaxle. This fully automated configuration allows the driver to
upshift (+) or downshift (-) while keeping both hands on the steering wheel.
When the driver initiates a gear change using the paddle shift switches, the ASG
computer automatically controls and coordinates clutch engagement, engine speed,
torque transfer and gear select and shift operations.
The engine-mounted dr y single-plate clutch and rear-mounted transaxle are
connected via torque tube to provide the direct feel of a manual gearbox.
The ECU manages gear changes to provide intuitive response to the driver ’s
a c c e l e r a t i o n d e m a n d s . D o i n g s o a l l o w s g e a r c h a n g e s t o b e c a r r i e d o u t
instantaneously, providing a nearly uninterrupted flow of power. The engine speed
is computer controlled on upshifts and downshifts in order to ensure smooth clutch
engagement.
Naturally, shifting can be accomplished manually via the paddle shift switches.
However, shifting can also be performed automatically in AUTO mode. Switching to a
different driving mode using the driving mode selector switch or operating the paddle
shift switches will resume manual operation.
When in a manually shifted driving mode, the shift speeds may be tailored to the
driver’s preferences. Using the shift speed selector, the shift speed can be adjusted in
7 stages to a minimum shift time of approximately 0.15 seconds.

37
Shifting
■
■Dry single-plate clutch
A dry single-plate clutch has been adopted to enable a direct engagement feel. The
clutch in the LFA is a hydraulically
actuated unit controlled by the ECU in order to
ensure quick and precise operation.
A pump within the hydraulic power unit generates the hydraulic pressure needed
to operate the clutch. This pump is powered by an electric motor to ensure a stable
supply of hydraulic pressure. In some cases, one can hear the sound of this electric
motor operating prior to the engine starting. This operation provides the hydraulic
pressure needed to disengage the clutch prior to starting the engine.
Because the LFA employs a dry single-plate clutch, it will not exhibit the slow speed
creep associated with a conventional automatic transmission. The driver must normally
depress the accelerator pedal to accelerate, even in ultra-slow speed situations such
as a traffic jam.
Diaphragm spring
Clutch disc The clutch disc is a compact size [9.45
in. (240 mm) diameter] and features
friction material designed specifically
to comply with the engine’s high-output
characteristics. The clutch cover is
c o n s t r u c t e d f r o m a l u m i n u m f o r a
precisely balanced, low-inertia design
that contributes to outstanding engine
response.

39
Shifting
■
■Rear transaxle
The LFA’s gear change mechanism consists of a parallel two-shaft layout often used
in modern manual transmissions. In the LFA, the transmission and differential are
integrated and placed near the rear axle, thus realizing a rear transaxle configuration.
Gear shift and select commands are sent by the ECU to a hydraulically operated shift

mechanism for fast and precise operation.
To ensure ample strength and the ability to handle the engine’s broad torque curve,
various areas throughout the transaxle have been reinforced and high-capacity three-
point contact bearings have been adopted. Furthermore, each synchronizer ring
employs a high-friction carbon material to realize quicker engagement and faster
shifts. Additionally, the teeth of all speed gears have been micro-polished for precise
engagement and reduced gear whine.
The transaxle employs its own oil pump and oil cooling system to ensure a constant
supply of oil at a stable temperature even under demanding endurance conditions.
3rd 6th 5th 2nd 1st
Support bearings
Regarding synchronizers, 1st through 4th gears employ triple-cone units while 5th and 6th
gears are double-cone. A TORSEN
® LSD (Limited Slip Differential) with a specific amount
of preload dialed in has been adopted to ensure excellent traction and handling stability.
TORSEN
® LSD is a registered trademark of JTEKT. 4th

40
■
■Paddle shift switches
I t i s u n d e rs t o o d t h a t d r i ve rs t e n d t o
anticipate downshifts more than upshifts.
To mechanically reflect this phenomenon,
the downshift paddle shift switch (-) has
a comparatively higher force pull than
the upshift paddle switch (+) to foster
a g re a t e r s e n s e o f exc i t e m e n t w h e n
stepping down a gear.

Automatic processes that occur during gear changes
Engine speed control
When the driver commands an upshift, the ECU will automatically lower the engine
speed to facilitate the gear change without requiring the driver to release the
accelerator pedal.
Blipping control
When the driver commands a downshift, the ECU will automatically raise the
engine speed in order match the speed of the transaxle, ensuring smoother clutch
engagement.
Automatic downshift control
The ECU will au tomatically downshif t when the vehicle slows to below a
predetermined speed. This will occur even in a manually shifted driving mode.
Downshift (-) Upshift (+)

50
Braking
The LFA is equipped with an ECB (Electronically Controlled Brake) system.
When the brake pedal is depressed, information on how much force is being used to
depress the pedal and the amount it is depressed is sent to the ECB computer. This
computer takes into account the vehicle’s overall condition using inputs from various
sensors and distributes the optimal amount of brake force to each individual wheel.
The ECB system uses an electric pump to generate hydraulic pressure, thereby
providing braking power without relying on engine vacuum. The use of this
technology ensures a consistent supply of effective braking power.
However, the detail behind the LFA brake system does not end with the ECB system.
Monoblock calipers and CCM (Carbon Ceramic Material) discs are just a few of the
other components that give the LFA its generous braking power. Furthermore, large
brake ducts have been proactively integrated in order to feed the brakes fresh, cold
air to keep them working at their optimum temperature for consistent performance.

Regarding the brake override system:
If the driver depresses the brake and accelerator pedals at the same time or if
the ECU judges that both acceleration and braking commands are being issued,
braking will be prioritized. The system will ignore the signal from the accelerator
pedal, close all throttle valves and provide the appropriate amount of braking force
demanded by the driver’s braking effort.