2012 Lexus LFA rate

16
Engine protection mechanisms
The LFA’s 1LR-GUE engine generates a maximum output of 412 kW (553 HP) at
8,700 rpm and delivers 90% or more of its peak torque of 354 ft•lbf (480 N•m,
48.9 kgf•m) between 3,700 and 9,000 rpm. The engine features a number of
protection mechanisms to ensure longevity and maintain peak performance.
A number of driving restrictions will be in place until the total mileage shown on the
odometer exceeds 310 miles (500 km). This break-in period serves not only to
protect the engine, but also to preserve the transmission, suspension and the vehicle
as a whole. It is recommended that during this time the owner become familiar with
the LFA and avoid high-load driving maneuvers.
One engine protection mechanism in place beyond the break-in period is the limiting
of maximum engine speed when the engine is cold. When the vehicle is cold started,
various components within the engine begin to warm up and expand at different rates.
Forcing the engine to operate at high speeds in this condition can cause accelerated
engine wear. For this reason, the maximum engine speed is limited when manually
shifted driving modes (SPORT, NORMAL, WET) are selected and restricted to a set
range when AUTO mode is selected.
This engine speed limitation does not indicate a malfunction with the vehicle. Warming
the engine up by driving, rather than extended idling, is recommended.

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Operating the driving mode selector switch
■
■Selecting a driving mode
The automatically shifted AUTO mode or
a manually shifted SPORT, NORMAL or
WET mode can be selected. The driving
mode selector switch will automatically
return to its original position after being
operated.
AUTO NORMAL
AUTO
SPORT
WET
Turn switch to SPORT
Operate paddle
shift switch while driving
Turn switch to WET Press AUTO driving mode buttonPress AUTO
driving mode button
Turn switch to WET
Turn switch to WET Turn switch to SPORT
Turn switch to SPORTPress AUTO driving mode button

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■
■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)

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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.

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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

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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.

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■
■Torque tube
Employing a torque tube to unite the front-mounted engine with the rear-mounted
transaxle creates an outstanding level of powertrain rigidity.
This aspect is essential in order to extract the most performance out of a vehicle. A
rigid powertrain reduces parasitic losses that occur from unwanted engine movement
and input from the wheels, allowing a greater amount of power to be sent to the road
and a more direct response.
Torque is transferred by means of an input shaft housed within the torque tube. This
fast-spinning shaft is mounted using rubber insulators with integrated bearings to
ensure quietness.
Torque tube
Rubber dampers with integrated bearings
Input shaft
Front counter gear Input shaft
A front counter gear is employed,
allowing the engine to be placed
closer to the ground. The engine
crankshaf t axis is lower to the
ground than the input shaft axis.
Crankshaft axis
Front counter gear

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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