As Acura’s premier sport sedan, the 2015 TLX offers more power and drivetrain choices than ever before, with two all-new direct-injected engines, two completely new advanced transmissions, and Acura’s next-generation precision handling technology – Super Handling All-Wheel Drive™ (SH-AWD®).
The TLX is available in both all-wheel-drive and front-wheel drive layouts. Front-wheel drive models come standard with Acura Precision All-Wheel Steer (P-AWS) and can be equipped with either the 2.4-liter 4-cylinder, or 3.5-liter V6 engines. The TLX SH-AWD, with next-generation Super Handling All-Wheel Drive, is available only with the V-6 engine.
The TLX’s two new Direct Injection (DI) engines combine power and efficiency. The 2.4-liter DOHC i-VTEC 4-cylinder engine produces a peak 206 horsepower and 182 lb.-ft. of torque. It has more horsepower and substantially more torque—particularly in the mid-range—than the same-sized engine that powers the TSX sedan. Even though the TLX is larger and heavier than the outgoing TSX 4-cylinder, it actually posts superior EPA fuel-economy ratings of 24/35/281 mpg city/hwy/combined.
A new 3.5-liter direct injected i-VTEC® 24-valve V-6 engine replaces the 3.5-liter and 3.7-liter engines in the TL. The new powerplant gains 10 horsepower (290 peak horsepower) and 13 lb.-ft. or torque (267 lb.-ft.) compared to the 3.5-liter V-6 in the TL sedan. To boost fuel efficiency, Variable Cylinder Management (VCM) automatically deactivates three of the engine’s six cylinders under light engine loads. TLX SH-AWD models also add a new automatic idle-stop feature to further improve fuel efficiency.
The front-wheel drive TLX with V-6 and P-AWS has an EPA fuel-economy rating of 21/34/251 mpg city/hwy/combined; the TLX SH-AWD is EPA rated at 21/31/251 mpg city/hwy/combined.
To make the most of these powerful, refined and efficient new engines, the TLX features two highly advanced new transmissions. 2.4-liter TLX models have a standard 8-Speed Dual-Clutch Transmission (DCT) featuring Sequential SportShift, the world’s first transmission of this type to be paired with a torque converter. The DCT, with its closely-spaced ratios, ultra-quick shifts and automatic downshift rev-matching, gives the 2.4-liter TLX an aggressively sporting feel. The torque converter provides exceptionally smooth operation in stop-and-go situations, plus it offers off-the-line torque multiplication for substantially improved initial acceleration that a DCT alone cannot equal.
3.5-liter TLX models are equipped with an all-new 9-speed automatic transmission featuring Sequential SportShift, which is substantially lighter than the 6-speed automatic in the previous TL. The transmission is engineered to handle the V-6’s substantial power output, and its closely spaced gear ratios enhance performance and fuel efficiency. No competitive vehicle in the segment offers as many transmission ratios.
A new generation of Acura’s acclaimed Super Handling All-Wheel Drive™ is standard in the TLX SH-AWD. SH-AWD progressively distributes torque not only between the front and rear axles, but also between the left and right rear wheels. Using torque vectoring to help turn the vehicle, SH-AWD creates a more responsive, neutral and predictable platform while providing outstanding all-weather confidence and control. In the TLX, torque-vectoring effectiveness has been greatly enhanced, benefiting responsiveness, agility and stability.
Front-wheel drive models feature the latest version of Acura’s Precision All-Wheel Steer™ (P-AWS), which, like SH-AWD, is designed to help give the TLX greater agility and handling balance.
TLX POWER TRAINS
2015 TLX 2.4 I4 (2WD) 206hp/182tq
Aluminum-alloy in-line 4
206hp @ 6,800
182hp @ 4500
Chain drive, DOHC,
Drive by wire
8-speed (DCT) Dual Clutch Transmission with torque converter and Sequential SportShift paddle shifters, Grade Logic and Shift Hold Control
24 city / 35 highway
2) 2015 TLX 3.5 V-6 (2WD, or SH-AWD) 290hp/267tq
290hp @ 6,200
267tq @ 4,500
Belt drive, SOHC,
i-VTEC® 24-valve with VCM® Variable Cylinder Management (cuts cylinders at low throttle)
Horsepower @ rpm (SAE net)
9-speed automatic transmission with Sequential SportShift paddle shifters, Grade Logic and Shift Hold Control
2WD, or optional SH-AWD
21 city / 34 highway (2WD) 21 city / 31 highway (SH-AWD)
Direct-Injected 2.4-liter Inline 4-cylinder Engine
The TLX’s new Direct Injection (DI) 2.4-liter DOHC i-VTEC 4-cylinder engine brings a host of intelligent technology to its segment. The engine’s i-VTEC system combines VTC (Variable Timing Control), which continuously adjusts the intake camshaft phase, with Variable Valve Timing and Lift Electronic Control (VTEC), which changes valve lift, timing and duration of the intake valves. A new Direct Injection (DI) system, dual-stage intake manifold and other technologies combine to produce up to 10-percent more torque as compared to the same sized engine that is standard in the TSX Sedan, with greater power available over the entire operating range. Peak power (206 horsepower) is also higher than that of the TSX engine, with the peak arriving at 6,800 rpm instead of 7,000 rpm.
Fuel economy ratings are exceptional, due in part to efficient Direct Injection, a new combustion chamber design, offset cylinder bores and a range of friction-reducing technologies. The TLX equipped with the 2.4-liter engine and standard 8-speed dual-clutch transmission has an EPA fuel-economy rating of 24/35/281 mpg city/hwy/combined. That’s a significant increase over the smaller TSX sedan, which was rated at 22/31/261 when equipped with an automatic transmission.
4-Cylinder Engine Block, Crankshaft and Pistons
The TLX’s 2.4-liter engine has a lightweight die-cast aluminum block with a single main-bearing cradle design that creates a rigid assembly to help minimize noise and vibration. Cast-in iron cylinder liners provide long-lasting durability. Each journal on the forged-steel crankshaft is micropolished to reduce internal friction. To improve smoothness throughout the rpm range and help lower noise levels, the engine is fitted with an internal balancer unit. Consisting of a pair of chain-driven counter-rotating shafts located in the lower block and integrated into the oil pan, the balancing system helps quell the inherent second-order harmonic vibrations that normally impact inline 4-cylinder engines.
To reduce piston-sliding friction, the cylinder bores are offset by 8.0 mm from the crankshaft. This gives the connecting rods a more favorable angle during each power stroke, which reduces side loading on the pistons and in turn, improves efficiency. The engine features a forged crankshaft for high rigidity and low friction. Lightweight pistons have a carefully optimized skirt design to minimize reciprocating weight, and reduced weight minimizes vibration and increases operating efficiency. The piston crowns are dished, to help maintain stable combustion and to optimize distribution of the stratified fuel charge from the direct injector in each cylinder. This close control over the combustion process boosts overall operating efficiency.
4-Cylinder Dual-Stage Intake Manifold
To maximize power output, the 2.4-liter engine has a dual-stage intake manifold has two different intake runner lengths that are selected based on the operating conditions. An actuator and a set of four butterfly valves control the intake runner switching process. At low engine speeds, the long runners are used to improve low-end torque. At higher engine speeds the system switches to the short intake runners for greater high rpm power. The result is intake tuning that is optimized for the engine’s entire operating range.
2.4-liter Engine Cylinder Head and Valvetrain
The lightweight cylinder head is made of pressure-cast aluminum alloy, with exhaust passages cast directly into the cylinder head. This eliminates the need for a traditional separate exhaust manifold and allows the close-coupled catalytic converter to be mounted directly to the cylinder head.
A silent-chain drives the dual overhead cams and features a double-arm tensioner design that reduces operating friction. The cam drive is designed to be maintenance free throughout the life of the engine.
To help boost fuel efficiency and power, the combustion chamber shape and valve angles have been optimized. The included valve angle is a narrow 35 degrees, which decreases the surface-to-volume ratio and helps create a flatter, more compact combustion chamber that reduces unburned hydrocarbon emissions. With this combustion chamber shape and the precise control of direct injection, the compression ratio set at 11.6:1.
The cylinder head features a new “tumble port” intake design. In combination with the new combustion chamber and piston crown shape, the design’s high level of airflow tumble helps create a homogenous fuel mixture for low fuel consumption and high airflow for high power output.
2.4-Liter Engine i-VTEC Valve Control System
The TLX’s direct-injected 2.4-liter DOHC 16-valve i-VTEC engine uses an advanced valve-control system to combine high power output with high fuel efficiency and low emissions. The system combines VTC (Variable Timing Control), which continuously adjusts the intake camshaft phase, with Variable Valve Timing and Lift Electronic Control (VTEC), which changes valve lift, timing and duration of the intake valves.
At low rpm, the VTEC intake valve timing and lift are optimized for high torque and low fuel consumption.. As engine rpm builds past 4,900 rpm, the VTEC system transitions to a high-lift, long-duration intake cam profile for superior high-rpm engine power.
The “intelligent” portion of the system is its ability to continuously vary the timing of the intake cam relative to that of the exhaust camshaft. This helps boost power and also provides a smoother idle (allowing idle speed to be reduced). The intake cam timing is varied based on input from sensors that monitor rpm, timing, throttle opening, cam position and exhaust air-fuel ratio. The result is increased fuel efficiency and lower NOx emissions.
3.5-liter V-6 Engine
The TLX 3.5-liter i-VTEC® V-6 is closely related to the 3.5-liter V-6 that powers the RLX and MDX. It has a die-cast lightweight aluminum alloy block with cast-in-place iron cylinder liners, a smooth-firing 60-degree V-angle, and compact overall dimensions. As in the 2014 Acura RLX and MDX, the TLX powerplant combines Direct Injection with i-VTEC and Variable Cylinder Management (VCM) to give the TLX impressive fuel economy ratings and overall performance. A wide range of improvements, including revised intake and exhaust ports and new valve timing, help make the 3.5-liter V-6 more powerful than the 3.5-liter V-6 engine it replaces. The aluminum-alloy 24-valve engine produces 290 horsepower at 6,200 rpm and generates 267 lb-ft of torque at 4,500 rpm — gains of 10 horsepower and 13 lb.-ft., respectively. Torque has also improved throughout the entire operating range, with the most substantial gains at low rpm, aiding the TLX’s responsiveness.
The new V-6 contributes to a 17-percent increase in the EPA highway fuel-economy rating of the 2015 TLX with front-wheel drive, and a 19-percent gain in the TLX SH-AWD, when compared with the 2014 TL. The TLX V-6 equipped with the standard 9-speed automatic transmission and Precision All-Wheel Steer has an EPA fuel-economy rating of 21/34/251 mpg city/hwy/combined. The TLX SH-AWD has a rating of 21/31/251 mpg city/hwy/combined.
V-6 Engine Block and Crankshaft
With its 60-degree V-angle, the TLX’s available V-6 engine has compact overall dimensions that allow efficient packaging within the vehicle. The V-6 has a die-cast lightweight aluminum alloy block with cast-in-place iron cylinder liners. Made with a centrifugal spin-casting process, the thin-wall liners are high in strength and low in porosity. The block incorporates a deep-skirt design with four bolts per bearing cap for rigid crankshaft support and minimized noise and vibration. The 3.5-liter V-6 uses a high-strength steel crankshaft for minimum weight. A cooling control spacer positioned in the water jacket surrounding the cylinders helps control warm-up and operating cylinder liner temperatures to reduce friction.
V-6 Pistons/Connecting Rods
Designed with “cavity-shaped” crowns, the V-6 engine’s pistons help maintain stable combustion and contribute to optimized combustion. Ion-plated piston rings help reduce friction for greater operating efficiency. The compression ratio (relative to the 2014 TL 3.5- and 3.7-liter engines) has risen from 11.2:1 to 11.5:1. Heavy-duty steel connecting rods are forged in one piece and then the connecting rods are “crack separated” to create a lighter and stronger rod with an optimally fitted bearing cap.
V-6 Cylinder Heads and Valvetrain
Like other Acura V-6 powerplants, the TLX engine’s 4-valve cylinder heads are a single-overhead-camshaft design, with the cams driven by the crankshaft via an automatically tensioned toothed belt. Made of low-pressure cast, low-porosity aluminum, each cylinder head incorporates a laminar flow intake design that improves combustion efficiency by creating a more homogeneous fuel-air mixture. An integrated exhaust manifold cast into each cylinder head reduces parts count, saves weight, improves flow and optimizes the location of the close-coupled catalyst.
V-6 i-VTEC with 2-Stage Variable Cylinder Management™ (VCM®)
The TLX SOHC V-6 combines Variable Cylinder Management (VCM) with Variable Valve Timing and Lift Electronic Control (i-VTEC), which changes the lift profile and thus timing and lift duration of the intake valves. A switching mechanism allows the engine to operate with the lift and duration optimized for either low or high-rpm operation. The rear cylinder bank closes all intake and exhaust valves to minimize pumping losses on the cylinders which are still firing, increasing overall engine efficiency.
The “intelligent” portion of the system is its ability to vary valve operation based on the driving situation and engine rpm. At low rpm, the i-VTEC intake valve timing and lift are optimized (low lift, short duration) for increased torque, which allows a wide range of 3-cylinder operation. As engine rpm builds past 5,000 rpm, the i-VTEC system transitions to a high-lift, long-duration intake cam profile for superior high-rpm engine power.
V-6 VCM Operation — To help improve the fuel efficiency of the TLX engine, Acura’s Variable Cylinder Management (VCM) is used. The system cooperates with Active Control engine Mounts (ACM) to allow the engine to operate with three cylinders in a wide range of situations to maximize fuel efficiency and reduce emissions. When greater power is needed, the system switches seamlessly to 6-cylinder operation.
During startup, aggressive acceleration, or steep ascents — any time high power output is required — the engine operates on all six cylinders. During moderate-speed cruising and at low or moderate engine loads, the system operates just the front bank of three cylinders.
The VCM system can tailor the working displacement of the engine to match the driving requirements from moment to moment. Since the system automatically closes both the intake and exhaust valves of the cylinders that are not used, pumping losses associated with intake and exhaust are eliminated and fuel efficiency gets a further boost. The system combines maximum performance and maximum fuel efficiency — two characteristics that don’t typically coexist in conventional engines.
VCM deactivates specific cylinders by using the i-VTEC (intelligent Variable Valve-Timing and Lift Electronic Control) system to close the intake and exhaust valves while the Electronic Control Unit (ECU) simultaneously cuts fuel to those cylinders. The spark plugs continue to fire in inactive cylinders to minimize plug temperature loss and prevent fouling induced from incomplete combustion during cylinder re-activation.
The system is electronically controlled, and uses special integrated spool valves in the cylinder heads. Based on commands from the system’s Electronic Control Unit, the spool valves selectively direct oil pressure to the rocker arms for specific cylinders. This oil pressure in turn drives synchronizing pistons that connect and disconnect the rocker arms.
The VCM system monitors throttle position, vehicle speed, engine speed, automatic-transmission gear selection and other factors to determine the correct cylinder activation scheme for the operating conditions. In addition, the system determines whether engine oil pressure is suitable for VCM switching and whether catalytic-converter temperature will remain in the proper range. To further smooth the activation or deactivation of cylinders, the system adjusts ignition timing and throttle position and turns the torque converter lock-up on and off to seamlessly transition between three and six cylinder modes.
V-6 SH-AWD Idle Stop System
To help improve fuel efficiency, TLX SH-AWD models come equipped with a new Idle Stop capability. When the system is active and certain operating conditions are met, the TLX engine will automatically shut off when the vehicle comes to a stop. When the driver releases the brake pedal after a stop, the engine automatically restarts and the TLX is ready to accelerate.
The system is engineered to operate smoothly and seamlessly. When stopped, a special cold storage evaporator in the air conditioning system helps maintain a comfortable cabin temperature even in warm weather. The TLX’s active engine mounts help smooth the restart. Idle Stop operation is fully integrated into the operation of the TLX’s Brake Hold system and its available Adaptive Cruise Control (ACC) with Low Speed Follow.
V-6 Active Control Engine Mounts and Active Sound Control
A powerful 28-volt Active Control Engine Mount system (ACM) is used to minimize the effects of engine vibration as the VCM system switches cylinders on and off. The 28-volt ACM is a key factor in the VCM’s broad range of operation in the new TLX. Sensors alert the Electronic Control Unit (ECU) to direct ACM actuators positioned at the front and rear of the engine to cancel engine vibration using a reverse-phase motion. In the cabin of the TLX, an Active Sound Control (ASC) system further mitigates low frequency noise that can occur during 3-cylinder operation. (See Interior section for more information.)
There are two different Active Sound Control profiles available in the TLX. When the Integrated Dynamics System (IDS) is in the ECON or Normal setting, the ASC is tuned for maximum interior quietness. When the IDS Sport or Sport+ mode is selected, the ASC allows a more aggressive interior engine and exhaust note.
V-6 Long Range Remote Engine Start with Vehicle Feedback
The 3.5-liter TLX with Advance Package provides the ability to start the vehicle’s engine remotely. This enables drivers to start their TLX, thereby activating the climate control system and heated/ventilated seats before they enter the vehicle — perfect for hot or cold days. The remote is designed to have a range of operation of up to about ½ mile. To start the engine remotely, the owner presses the LOCK button on the remote and then holds the ENGINE button for a few seconds. When the engine is started remotely, the wipers, lighting and audio systems remain off, and the security system remains set. The engine will run for up to 10 minutes after remote starting, and then shut off automatically if the owner doesn’t reach the vehicle within that time. When the owner does get to the TLX within 10 minutes, the engine will keep running while the owner unlocks the vehicle.
This system also provides feedback to the owner to confirm whether the engine is running or the vehicle is locked. The remote has three LED indicators: amber, green and red. To confirm engine start, the owner presses the LOCK button and then holds the ENGINE button for a few seconds. The amber indicator will flash while the remote communicates with the vehicle. If the engine is running, the green LED will then light for one second. If the engine is not running, the red indicator will light for one second. To verify whether the vehicle is locked, the owner presses the LOCK button once. After the amber light comes on, either the green or red LED will light for one second to indicate that the vehicle is locked or not, respectively. And if the red LED flashes three times, the vehicle is out of the remote’s range.
This system can provide owners with the comfort of a pre-warmed and de-fogged/defrosted vehicle on a cold winter morning — or a pre-cooled interior on hot days. Plus, it adds the convenience and confidence of knowing that their vehicle is securely locked, even far beyond the range of a typical remote.
Common Engine Features
Cold-Air Induction System
To maximize power output, the TLX has a cold-air intake system that picks up engine induction air from the grille area at the front of the vehicle, which is typically about five percent cooler than the air in the hot engine compartment. Cooler intake air has greater density, which allows the Direct Injection system to add proportionately more fuel for enhanced power output.
Direct Injection System
Both 4-cylinder and V-6 TLX engines feature efficient direct injection. The system features a compact, high-pressure, direct-injection pump that allows both high fuel flow and pulsation suppression, while variable pressure control optimizes injector operation. A multi-hole injector delivers fuel directly into each cylinder (not to the intake port, as in conventional port fuel injection designs), allowing for more efficient combustion and greater power output.
The multi-hole injectors help create the ideal stoichiometric fuel/air mixture in the cylinders for good emissions control. Theoretically, a stoichiometric mixture has just enough air to completely burn the available fuel. Based on the operating conditions, the direct-injection system alters its function for best performance. Upon cold engine startup, fuel is injected into the cylinders on the compression stroke. This creates a weak stratified charge effect that improves engine start-up and reduces exhaust emissions before a normal operating temperature is reached. For maximum power and fuel efficiency, fuel is injected during the intake stroke once the engine is fully warmed up. This helps create a more homogeneous fuel/air mix in the cylinder. This improves volumetric efficiency, and the cooling effect of the incoming fuel improves anti-knock performance.
Drive-by-Wire™ Throttle System
The TLX Drive-by-Wire™ throttle system replaces a conventional throttle cable with smart electronics that “connect” the accelerator pedal to a throttle valve inside the throttle-body. The result is less under-hood clutter and lower weight, as well as quicker and more accurate throttle actuation. Plus, a specially programmed “gain” rate between the throttle pedal and engine offers improved drivability and optimized engine response to suit specific driving conditions.
Acura’s Drive-by-Wire throttle system establishes the current driving conditions by monitoring throttle pedal position, throttle valve position, engine speed (rpm) and road speed. This information is used to define the throttle control sensitivity that gives the TLX’s throttle pedal a predictable and responsive feel that meets driver expectations.
Three different throttle profiles are available in the TLX. When the Integrated Dynamics System (IDS) is in the ECON mode, the system uses a gradual profile that encourages fuel savings. In Normal mode, the throttle profile balances economy and performance for all-around driving. When the Sport or Sport+ mode is selected, the system switches to a more aggressive throttle map to enhance responsiveness.
Direct Ignition and Detonation/Knock Control
The TLX’s Electronic Control Unit (ECU) monitors engine functions to determine the best ignition spark timing. Engine block-mounted acoustic detonation/knock sensors “listen” to the engine, and based on this input, the ECU can retard the ignition timing to prevent potentially damaging detonation. An ignition coil unit for each cylinder is positioned above each spark plug’s access bore.
The exhaust manifolds of both TLX engines are cast directly into the aluminum cylinder heads to reduce weight, decrease parts count, and create more underhood space. The result of this casting design is that the primary catalytic converters are positioned much closer to the combustion chambers, enabling extremely rapid converter “light-off” after engine start. A significant weight savings is realized by eliminating traditional exhaust manifolds.
Both 2015 TLX engines meet the tough EPA Tier 2/Bin 5 and CARB LEV II ULEV emissions standards, and are certified to this level of emissions performance for 120,000 miles. A number of advanced technologies are factors in the emissions performance. The unique cylinder head-mounted close-coupled catalytic converters light off more quickly after engine start up, and a 32-bit RISC microprocessor within the Electronic Control Unit (ECU) boosts computing power to improve the precision of spark and fuel delivery.
Both engines feature Programmed Fuel Injection (PGM-FI) that continually adjusts the fuel delivery to yield the best combination of power, low fuel consumption and low emissions. Multiple sensors constantly monitor critical engine operating parameters such as intake air temperature, ambient air pressure, throttle position, intake airflow volume, intake manifold pressure, coolant temperature, exhaust-to-air ratios, as well as the position of the crankshaft and the camshafts.
Both TLX engines make use of friction-reducing technologies designed to improve engine efficiency. The outer skirts of lightweight aluminum pistons feature a special coating that reduces overall friction as the pistons move within the cylinder bores. Plateau honing further lowers the friction level between the pistons and the cylinders by creating an ultra-smooth surface. Plateau honing is a 2-stage machining process that uses two grinding processes instead of the more conventional single honing process. This also enhances the long-term wear characteristics of the engine.
Sequential SportShift 8-Speed Dual-Clutch Transmission (DCT) with Torque Converter
To maximize performance and fuel efficiency, the 2.4-liter TLX has a standard 8-Speed Dual-Clutch Transmission (DCT), the world’s first transmission of this type to be paired with a torque converter. In the 8-speed DCT, one clutch controls the odd gears while the other clutch controls the even gears. This arrangement allows gear changes with a much smaller interruption in power to the wheels, resulting in millisecond-quick shifts. In addition, the DCT’s efficient power transmission and wider overall ratio range contribute to the TLX’s substantial gain in fuel efficiency compared to the outgoing TSX 4-cylinder.
Compared to a conventional manual transmission, the operation of the clutches and shifting mechanisms are electronically controlled, eliminating the need for a clutch pedal or manual shift lever. The DCT with its closely spaced ratios, ultra-quick shifts and automatic downshift rev-matching, gives the TLX 4-cylinder an exhilarating and sporty feel. The DCT transmission in the TLX also features a steering wheel-mounted paddle shifter system that lets the driver take manual control of transmission gear selection, further heightening the driving experience.
The ultra-thin torque converter complements the efficient operation of the DCT by providing exceptionally smooth operation in stop-and-go situations, plus it offers off-the-line torque multiplication for improved initial acceleration that a DCT alone can’t equal. In an aggressive standing-start launch, the torque converter substantially improves acceleration in the first 1.4 seconds, or about the first 60 feet (as compared to a DCT alone).
Sequential SportShift 9-Speed Automatic Transmission
2015 TLX V-6 models are equipped with an all-new 9-speed automatic transmission featuring Sequential SportShift. The Sequential SportShift 9-speed automatic is 66 lbs. lighter than the 6-speed automatic in the previous TL, with more closely spaced gear ratios and 25 percent faster gear shifts that enhance performance and fuel efficiency.
The console-mounted shift lever is replaced with a fully electronic, shift-by-wire gear selector. Park, Neutral and Drive are selected with the push of a button. Reverse is selected by pulling back a dedicated switch. Indicator lights near the buttons indicate the mode selected. As an added safety feature, if the vehicle is brought to a stop in Drive, the system will automatically select Park if the driver’s seatbelt is unbuckled and the driver’s door is opened. A steering wheel-mounted paddle shifter system lets the driver take manual control of transmission gear selection.
Front Wheel Drive
The TLX offers front wheel drive, paired with either a 4-cylinder or V-6 engine. With its efficient and lightweight design, the TLX front wheel drive system makes a significant contribution to overall fuel efficiency.
The latest version of Acura’s Precision All-Wheel Steer™ (P-AWS) is standard on all front-wheel drive TLX models, and helps give the TLX best-in-class dynamic performance at all speeds. The system is complemented by Agile Handling Assist, which employs the anti-lock brake system to individually brake either the left or right rear wheel to reduce yaw delay (the period between steering wheel input and the rotation of the body) to improve corner traceability and balance.
Super-Handling All-Wheel Drive™ (SH-AWD®)
The TLX SH-AWD features a new hydraulically controlled iteration of Acura’s acclaimed Super Handling All-Wheel Drive™ (SH-AWD®), which progressively distributes optimum torque not only between the front and rear axles, but also between the left and right rear wheels. Like its P-AWS counterpart, the TLX SH-AWD system is complemented by Agile Handling Assist (See above and Chassis section for more information.)
The benefits of the SH-AWD system are superior all-weather handling and neutral, accurate steering under power that is unmatched by front-drive, rear-drive or conventional all-wheel-drive systems.
By rotating the outside rear wheel faster than the front axle while cornering, SH-AWD uses torque vectoring to create a yaw moment to help turn the vehicle through the corner — reducing understeer and improving controllability. With cornering forces more evenly distributed between front and rear tires, overall cornering power is increased — on wet or dry roads.
Vehicles with high power ratings using conventional front or rear drive systems often employ a limited-slip differential to help maintain traction when under power. By linking inside and outside drive wheels, these systems tend to resist turning and can increase understeer. Conventional AWD systems similarly work to link the inboard and outboard tires as well as the front and rear axles, which can create resistance to turning. Using torque vectoring to help turn the vehicle, SH-AWD delivers more responsive, neutral and predictable handling performance while providing outstanding all-weather traction and control.
Controls and Parameters — The SH-AWD system works in cooperation with the TLX’s Vehicle Stability Assist™ (VSA®) system and Agile Handling Assist to optimize torque distribution for superior handling and traction utilization. The Electronic Control Unit (ECU) provides information on engine torque, airflow and transmission gear-ratio selection, while the VSA ECU provides wheel-speed data. The SH-AWD ECU also monitors steering angle, steering angle rate of change, lateral G-forces, vehicle yaw rate and hydraulic clutch pressure for the right and left rear axle shafts. Drive torque is calculated from ECU information, and then the acceleration situation, wheel spin, lateral G-force, steering angle and steering angle rate-of-change are used to determine the front-to-rear torque distribution and the torque split between right and left rear wheels.
SH-AWD operating parameters include:
Up to 90-percent of available torque can be transferred to the front wheels during normal cruising.
In hard cornering and under acceleration, up to 70-percent of available torque can be directed to the rear wheels to enhance vehicle dynamics.
Up to 100-percent of the torque sent to the rear axle can be applied to either the left or right rear wheel, depending on conditions.
SH-AWD System Layout — The TLX SH-AWD is a full-time all-wheel-drive system that requires no driver interaction or monitoring, thanks to a torque-transfer unit that is bolted directly to the front-mounted transaxle. The torque-transfer unit receives torque from a helical gear that is attached to the front differential’s ring gear, and a short horizontal shaft and hypoid gear set within the torque-transfer unit’s case send power to the rear propeller shaft, which in turn transfers power to the rear drive unit.
The TLX’s new, more lightweight (25 percent reduction) SH-AWD rear drive unit is constantly overdriven by 2.7-percent (the previous generation TL system was overdriven by 1.7-percent). The resulting overdrive effect is regulated by left- and right-side clutch packs (located in the rear differential) that independently control the power delivered to each rear wheel. The increased overdrive percentage in the new TLX means that the torque vectoring effect is more pronounced and effective even in corners with a radius of as little as 49.2 feet (15 meters). This means that torque vectoring can be felt more often, such as when accelerating aggressively through a standard corner. Up to 885 lb.-ft. of torque can be delivered to either rear wheel, which gives the system the unique ability to yaw the TLX into turns for superior handling.
Hydraulically operated clutch systems mounted on either side of the hypoid gear that drives the rear axles control the amount of torque sent to each rear wheel and provide a limited-slip differential function when needed. The clutches can be controlled as a pair to alter front/rear torque split or they can be controlled independently to allow 100-percent of available rear axle torque to go to just one rear wheel.
In this new iteration of SH-AWD, a single electric motor powers a pair of hydraulic pumps — one for each clutch pack. An Electronic Control Unit (ECU) controlled linear solenoid valve selectively sends pressure to the clutch packs, which in turn control the amount of power sent to each rear wheel. This new hydraulic system eliminates the magnets, coils and other components of the previous electromechanical SH-AWD system to realize a substantial weight savings
The clutch packs and their friction material are carefully designed to withstand the small amount of continuous slip between front and rear axles created by the 2.7-percent speed differential — all while delivering the durability expected of an Acura product.
Front Cast-Aluminum and Steel Subframe
In a first for Acura, the TLX employs a cast-aluminum and steel “hybrid” front subframe to reduce road surface vibration and shock inputs for a smoother, quieter ride. The new subframe supports the engine, transmission, front suspension and steering system. The front section of the subframe is steel, and the rear section is cast aluminum. The sections are joined with a newly developed friction-stir-welding process to form a single high-strength, lightweight unit that provides ideal ride and handling properties. Altogether, the front subframe, along with a lower arm hydro-bushing, reduces vertical and fore/aft forces felt at front seats by 61 percent and 46 percent, respectively, compared to the previous TL model.
MacPherson Strut Front Suspension
MacPherson strut front suspension with Amplitude Reactive Dampers provides precise and engaging handling performance, a responsive feel for the driver, and luxurious ride quality. Specially tuned hydro-compliance bushings improve resistance to shimmy and while also reducing brake judder, further improving the TLX’s refinement and driving character. All TLX models have a 26.0 mm diameter tubular (hollow) front stabilizer bar.
Rear Steel Subframe
Constructed of high-tensile steel, the rear subframe uses hydraulic mounts, along with increased fitting-point stiffness, to reduce road surface vibration and shock inputs for a smooth ride and low noise. The rear subframe reduces vertical and fore/aft forces felt at front seats by 31 percent and 33 percent, respectively compared to the previous TL model. In addition, on TLX models with Super-Handling All Wheel Drive (SH-AWD), the rear subframe features a 4-point differential mounting system. Its bushing rates are specially calibrated to reduce the transmission of driveline noise and vibration into the vehicle body, while also helping to maintain ride quality.
Multi-Link Rear Suspension
Multi-link rear suspension with Amplitude Reactive Dampers provides optimal handling agility, driver confidence and ride sophistication. Geometry, including rear toe control, is optimized for handling competence, stability and a sophisticated ride in a variety of urban, highway and open road scenarios. The system includes multi-link control arms, control-arm bushings that are optimized for the best blend of noise, vibration and harshness (NVH) isolation and handling precision, and Amplitude Reactive Dampers. Both the 4-cylinder and SH-AWD models have a 24.7 mm diameter rear stabilizer bar, while the front-wheel drive V-6 has a 25.4 mm diameter stabilizer bar.
The TLX body is designed to support the twin goals expressed in the vehicle’s “Red Carpet Athlete” development theme – significantly enhanced luxury appeal, in terms of cabin quietness, ride comfort and styling refinement, and exhilarating and athletic sports-sedan performance – while also achieving class-leading fuel economy and crash safety ratings.
To achieve these sometimes-competing goals, Acura engineers created an all-new body design utilizing advanced materials, including ultra-high-strength steels, aluminum and magnesium, for rigidity, collision performance and weight savings. Special attention was paid to local body rigidity in areas where the body meets up with the suspension, engine and subframes, and to improvements in body sealing and noise insulation.
Vehicle aerodynamics also played a critical role in achieving class-leading fuel economy ratings. The TLX aerodynamics are improved by 15 percent (CdA) over the previous TL and based on internal testing, is the best (lowest) in its competitive class. At the same time, the body also is designed to provide a high level of occupant crash protection incorporating Acura’s latest thinking in advanced body design, including the next-generation of Acura’s Advanced Compatibility Engineering (ACE) front body structure and one-piece hot-stamped-steel door ring, first applied to the all-new 2014 Acura MDX (see SAFETY section for more detail).
Key TLX body features found in this section include:
Rigid, lightweight body
Hemmed rear wheel arch
Ultra-high strength steel
Magnesium steering hanger beam
Advanced Compatibility Engineering (ACE) body structure
Jewel Eye™ LED Headlights
LED fog-, tail-, puddle-, license- and side-mirror lights
Auto-dimming side mirrors
Acoustic glass windshield
Acoustic foam applied to critical body sections
Electric trunk lid and fuel lid release
Expanded View Driver’s Mirror
Exclusive Acura exterior colors (Black-Bronze and Acura Silver Metallic)
Dynamic and Athletic Proportions
With its low and wide stance, the new 2015 TLX possesses a lithe exterior form, taut body surfaces and “just right” proportions for a sports sedan. This sporting character is further defined by shortened front and rear overhangs, dynamically sculpted fender arches, and purposeful character lines. Even the sculpted hood, with its sharply creased bilateral ridgelines, hints at the performance capabilities of the advanced new Acura powertrains it conceals. Meanwhile, the open and airy greenhouse provides commanding sight lines, with slim A-pillars providing improved visibility.
“Just Right” Dimensions
The 2015 TLX’s “just right” body dimensions result from a careful balance of aerodynamic efficiency, interior roominess, dynamic performance, quietness and refinement, and design. Compared to the previous TL, the new TLX has the same 109.3-inch wheelbase, but is 3.8 inches shorter in overall length. This positions it between the smaller ILX entry-luxury sedan and flagship RLX sedan. Despite its more compact exterior footprint, the TLX offers a spacious interior that approaches the previous TL.
In comparison to its competitors, the TLX is longer than the Audi A4, BMW 3 Series, Lexus IS and Mercedes-Benz C-Class. It is also significantly wider than all of its direct competitors, including the Lexus ES and GS, and Mercedes-Benz E-Class.
Track, Front/Rear, in.
Rigid Lightweight Body
Light weight and rigidity are the twin foundations for TLX comfort, handling and safety performance. Light weight is achieved by a combination of advanced engineering and the use of high-strength steel, magnesium and aluminum unit-body components. TLX body rigidity is enhanced by precise engineering, particularly in optimizing key component fitting points (up to 25 percent stiffer) for superior bending stiffness, and the unit-body structure’s torsional rigidity is up 21-percent vs. the previous TL.
In order to improve fuel efficiency and lower emissions, Acura designers merged the TLX’s dynamic styling with a high level of aerodynamic efficiency, with a reduction in frontal area and lower running resistance (the amount of energy that is lost as the car moves along the road and through the air) as key goals.
Most of the running-resistance improvements are achieved via refinements to the TLX’s body design, with even the smallest details calculated and confirmed by the use of sophisticated computational fluid dynamics (CFD), as well as scale wind tunnel and high-precision coast-down testing.
The new TLX is 0.4-inch lower and 1.0-inch narrower, with a slightly longer roofline, than the previous TL model. The result is 1.5-percent less frontal area than the previous TL, along with a 15-percent improvement in aerodynamics (CdA). Slightly narrower 225mm wide tires also replace the 245mm wide tires on the TL, further improving running efficiency. The end result is 16-percent reduction in running resistance compared to the previous TL. Internal testing shows the TLX to be the most aerodynamically efficient car in its class.
Hemmed Rear Wheel Arch
The rear wheel arches on the TLX use a special roll-hemming process that results in a cleaner edge and smoother appearance than on the previous TL model. In simple terms, the wheel-arch “hems” are the curved sheet-metal edges that surround the rear tires. In the new TLX, a special hemming process is used instead of spot welds to join the inner and outer fender sheet-metal on the inside of the fender opening. The result is a reduced tire-to-fender gap which improves aerodynamics, elimination of visible spot-welds and a cleaner appearance.
High Strength Steel
To achieve the high rigidity that promotes a smooth and quiet ride, crisp steering and handling, safety performance and long-term durability, the TLX utilizes six different grades of high-strength steel (HSS) in 52% of its body structure by weight. This high-grade, high-tensile strength steel adds the required rigidity for these positive traits without adding excessive weight, which in turn enhances fuel efficiency and lowers emissions. Altogether, 59-percent of the TLX body is created from a combination of high-strength steel, aluminum and magnesium.
High strength steel uses include:
UISBOR – USIBOR is a boron-alloyed steel with an aluminum-silicon coating that protects against oxidation during the heating, forming and hardening process. This high-strength hot-stamp steel is used for the TLX’s door opening rings, for 5% of the unit body. (See Safety section for more information.)
980 grade HSS – Used in certain key structural points such as the front edges of the door sills, and in the A-pillars and B-pillars, for 2% of the unit body.
780 grade HSS – Used for most structural load paths for ACE™, including the side sills and forward spars of unit body, for 2% of the unit body.
590 grade HSS – Used for the front frame spars, floor and roof supports, for 35% of the unit body.
440 grade HSS – Used in the front bulkhead, and in front and rear energy-absorbing structures, for 5% of the unit body.
340 grade HSS – Sheet steel is used in the roof, for 3% of the unit body.
Aluminum stampings are used in certain key locations to reduce the TLX’s curb weight, which provides benefits in handling, fuel efficiency and emissions reductions. Altogether, the aluminum components comprise 6-percent of the TLX’s body weight, a savings of 27.8 pounds compared to comparable steel components.
Among the aluminum body components are:
Front bumper beam
Rear bumper beam
Front subframe (hybrid aluminum/steel)
Magnesium Steering Hanger Beam
Located behind the instrument panel, a 3-piece magnesium steering-hanger beam replaces the 26-piece aluminum and steel unit in the previous TL model. Its purpose is as a structural attachment point for the steering column, pedals and instrument panel, as well as a structural element that helps the passenger cabin retain its shape in certain collisions. This single robust magnesium component makes up 2-percent of the TLX’s body weight.
The steering-hanger beam offers several advantages compared to the previous unit:
Simpler construction — Created from just three parts instead of the previous 26 different extrusions and stampings, the new magnesium steering hanger brace offers better construction precision.
Lighter weight — The magnesium steering hanger beam saves 2.7 pounds compared to a comparable aluminum and steel, contributing to the TLX’s superior ride and handling, fuel efficiency and low emissions.
Better fit and finish — The exacting tolerances of the magnesium steering hanger brace in turn allow the instrument panel to fit better, exhibiting higher overall interior quality.
The most comprehensive use of LED lighting on any Acura vehicle is a signature design element of the new TLX. From the dramatic Jewel Eye™ headlights to the convenient new puddle lights and back to the new taillights, the LED lighting provides crisp, bright, energy-efficient and long-lasting illumination that directly improves the driving and ownership experience. A summary of exterior lighting includes:
New LED headlights with incandescent-bulb turn signals
New LED parking and side marker lights
New LED under-mirror puddle lights (Advance grades)
LED front fog lights (Advance grades)
New LED tail and trunk-lid lights with incandescent-bulb turn signals and backup lights
New LED Center High Mount Stop Lights (CHMSL) with integrated cover
LED license-plate lights
Jewel Eye™ LED Headlights
Acura’s signature Jewel Eye™ LED headlights give the TLX with an advanced and appearance while producing superior down-the-road illumination. The headlights utilize an array of high-intensity LED lamps to deliver outstanding light distribution, distant irradiation performance and light characteristics with a wavelength close to the human eye’s luminosity curve. With five “Jewel Eye” lights per headlight, the LED lights provide improved down the road visibility compared to HID and halogen headlights.
On each side of the TLX, the low beams consist of three LED lights, while the innermost LED lights are utilized for high beams. The daytime running light (DRL) function utilizes all five lenses illuminated by LED’s that are clearly and dramatically visible even in bright sunlight. Altogether, they create a dramatic and distinctive appearance with superior lighting capability.
Both the low and separate high beam LED headlights offer outstanding performance in all nighttime driving conditions, including highway, winding roads, intersections, and in inclement weather conditions. The result is that the driver can see further with uniformity, making high-speed nighttime driving easier and less fatiguing.
A summary of LED benefits include:
Outstanding light distribution that surpasses competitors
Excellent distant illumination performance
Clear illumination of the road surface and white lines
High visibility of the entire visible color spectrum (white, red, green, blue and yellow) compared to HID and halogen headlights
Response time when switching between low and high beam is shortened
Light congruity is improved between low and high beams
Using just 65 watts total, the TLX’s LED headlights use 41-percent less power than traditional halogen headlights, contributing to the TLX’s overall operating efficiency.
Besides producing better light characteristics with lower energy usage, the TLX’s LED headlights are longer lasting. With an estimated life expectancy of 10,000 hours, the LED headlights are projected to last five times longer than HID headlights and 10 times longer than traditional halogen headlight bulbs — contributing to less frequent replacement and potential associated cost savings. Further, their compact packaging allow for an improved aerodynamic frontal design.
LED Fog Lights
Included in the Advance Package, LED fog lights are positioned at the lower corners of the TLX’s front fascia for maximum effectiveness and a bold appearance.
LED taillights are part of the TLX’s comprehensive exterior lighting array. Highly stylized to compliment the TLX body design, they are also brighter than traditional incandescent-bulb taillights, with a longer projected lifespan. Use of LEDs allows the addition of a “light pipe” styling element extending across the top of the lenses, contributing to the TLX’s unique blend of design and engineering.
LED Puddle Lights
Included in the standard Smart Entry system, LED puddle lights positioned on the undersides of both side mirror housings enhance convenience when entering or leaving the vehicle. The LEDs automatically illuminate when the TLX detects the key fob approaching, in concert with the automatic interior illumination. The puddle lights also illuminate when the driver puts the TLX in Park and leaves the vehicle, fading off after about two seconds after locking the doors, or 30 seconds if the doors are not locked.
LED Side Mirror Lights
Keying off of the Jewel Eye™ LED headlights, each TLX mirror has LED lights fused into the mirror housing. The LEDs come to life when the turn indictors are activated, providing extra visibility and a high tech appearance.
Auto-Dimming Side Mirrors
Included in the Advance Package, auto-dimming side mirrors use the same activation sensor as the TLX’s auto-dimming inside rearview mirror. The auto-dimming function of all three mirrors helps reduce glare during nighttime driving, especially from the headlights of following vehicles. Mirror glass area is 24-percent greater than on the previous TL model for improved rear visibility.
To reduce noise in the cabin The TLX utilizes a 4.5-mm thick, 3-layer acoustic windshield that consists of two layers of safety glass, separated by a thin acoustic resin center. The windshield reduces wind noise on in the higher frequency ranges, contributing to a luxurious feeling of isolation in the cabin. Also helping to mitigate wind, road and traffic noise in the cabin is 5.0-mm thick front door glass.
Auto Up-Down Side Windows
The 2015 TLX has power front and rear side windows with an auto-open and auto-close feature with anti-pinch.
Advanced Windshield Wiper System
The sleek, flat design of the wiper blades adds to the TLX’s visual appeal. The flat blade design improves aerodynamic performance and reduces wind noise.
Headlights On With Wipers
Laws in some states require drivers to turn on the headlights when the wipers are operating in the rain. The new TLX helps its driver comply with these laws by automatically illuminating the headlights when the wipers are activated for five cycles or more (with headlight switch in AUTO). The headlights will remain illuminated for as long as the rain continues and the wipers are being operated. When the rain stops, the wiper activation also ceases, with the headlights remaining lit until the wipers stop.