2008 Acura TL - Powertrain

OVERVIEW

Two engines are available for the 2008 TL. Under the hood of the TL is an all-aluminum 3.2-liter V-6 with 24 valves and Acura's VTEC® - Variable Valve Timing and Lift Electronic Control. The 3.2-liter V-6 delivers 258 horsepower and 233 lb-ft of torque.

The TL Type-S is powered by a modified version of the 3.5-liter SOHC VTEC® V-6 found in the Acura RL. With more displacement than the standard TL's 3.2-liter engine and a high-flow exhaust system, the TL Type-S boasts 286 horsepower with 256 lb-ft of torque.

Both engines benefit from Acura's groundbreaking VTEC system. This patented technology provides an exceptionally flat torque curve, enhancing high-rpm horsepower without sacrificing low-end torque. The result is an engine with excellent responsiveness at all engine speeds.

The standard transmission in the TL and TL Type-S is an electronically controlled 5-speed automatic. Developed from the RL's 5-speed automatic, this unique transmission has high torque capacity, yet is very compact. It also features Acura's Sequential SportShift system. Inspired by Formula One® racecars, Sequential SportShift gives the driver the flexibility of a self-shifting automatic or the precise control of a manual. The system has been programmed for smoother operation and enhanced gear holding capabilities. In addition, the TL Type-S "rev matches" the engine during manually selected downshifts.

Available only on the TL Type-S is a close-ratio 6-speed manual transmission, a limited-slip differential and a hydraulically-actuated clutch with smoother, more linear engagement.

With Acura's unwavering commitment to the environment, both TL engines meet strict CARB ULEV2 standards. In addition, cold-start emissions are improved thanks to a close-coupled catalytic converter system replete with an under-floor catalyst.

Powertrain at a Glance

TL Engine

  • 3.2-liter SOHC V-6 aluminum alloy engine
  • 258 hp at 6200 rpm and 233 lb-ft of torque at 5000 rpm
  • Variable Valve Timing and Lift Electronic Control (VTEC®)
  • Dual-stage induction system with lightweight magnesium intake manifold
  • Cold-air intake system
  • Computer-controlled Programmed Fuel Injection (PGM-FI)
  • Direct ignition system
  • Unique exhaust manifolds that are cast directly into the head
  • High flow close-coupled catalytic converters plus under floor catalytic converter
  • High capacity 32-bit RISC processor engine control unit
  • 100,000 mile tune-up intervals

TL Type-S Engine

  • 3.5-liter SOHC V-6 aluminum alloy engine
  • 286 hp at 6200 rpm and 256 lb-ft of torque at 5000 rpm
  • Variable Valve Timing and Lift Electronic Control (VTEC®)
  • Dual-stage induction system with lightweight magnesium intake manifold
  • Cold-air intake system
  • High flow, sport tuned exhaust system with quad exhaust tips
  • Computer-controlled Programmed Fuel Injection (PGM-FI)
  • Direct ignition system
  • Unique exhaust manifolds that are cast directly into the head
  • High flow close-coupled catalytic converters plus under floor catalytic converter
  • High capacity 32-bit RISC processor engine control unit
  • 100,000 mile tune-up intervals

5-Speed Automatic Transmission

  • High torque capacity
  • More compact design
  • Sequential SportShift feature allows quicker downshifts and upshifts
  • Computer-controlled Drive-by-Wire™ throttle and automatic transmission for smoother shifts
  • Steering wheel-mounted F1®-style paddle shifters (TL Type-S only)
  • External transmission fluid cooler (TL Type-S only)
  • Advanced shift-hold control limits up-shifts during spirited driving
  • Advanced Grade Logic Control System reduces gear "hunting" when on steep hills
  • Linear solenoid direct-acting control reduces shift shock and improves smoothness
  • Lockup torque converter design for improved fuel economy

6-Speed Manual Transmission (TL Type-S only)

  • Close ratio gear spacing for maximum performance
  • Multi-cone synchronizers (first through fourth gears)
  • Reverse lock-out feature prevents accidental engagement
  • Lightweight high-pressure-cast aluminum-alloy transmission bellhousing
  • Light clutch feel with smooth engagement
  • Advanced clutch torsion mechanism reduces gear noise
  • Helical gear limited-slip differential reduces wheel spin and maximizes acceleration

Emissions/Fuel Economy

  • Meets CARB ULEV2 standard
  • TL EPA fuel economy 18/26* mpg (city/highway)
  • TL Type-S EPA fuel economy 17/26* mpg (AT) and 18/27 mpg* (MT)
  • High flow close-coupled catalytic converters
  • High capacity 32-bit RISC processor engine control unit

*Based on 2008 EPA mileage estimates, reflecting new EPA fuel economy methods beginning with 2008 models. Use for comparison purposes only. Do not compare to models before 2008. Your actual mileage will vary depending on how you drive and maintain your vehicle.

Noise Vibration and Harshness (NVH)

  • Highly rigid aluminum-alloy engine block with cast-in iron cylinder liners
  • 60-degree V-angle design for inherently smooth operation
  • Dual-mass flywheel (6 MT) reduces driveline noise and vibration
  • Automatically tensioned, maintenance-free serpentine belt accessory drive

ENGINE ARCHITECTURE

TL's 24-valve 3.2-liter V-6 features all aluminum alloy construction and an inherently smooth running 60-degree V angle. The TL's cold-air intake system combines with Acura's sophisticated dual-stage intake manifold and 3-rocker VTEC® variable valve timing system, an 11:1 compression ratio, and a high-flow exhaust system to make it one of the most powerful engines in its class. The 3.2-liter delivers exceptional smoothness, refinement, and low emissions. To reduce weight, the intake manifold and valve covers are made of lightweight magnesium and the oil strainer is constructed of a lightweight composite.

The 3.5-liter V-6 in the TL Type-S is based on the engine in the groundbreaking RL and it incorporates many of the refinements and improvements that have been developed in other Acura powerplants. The 3.5-liter shares the 3.2-liter V-6's 60-degree V angle, compact dimensions, weight saving use of magnesium, and also uses hollow camshafts to further save weight.

ENGINE BLOCK

Both the TL's 3.2-liter V-6 and the TL Type-S 3.5-liter V-6 feature die-cast lightweight aluminum alloy blocks with cast-in-place iron cylinder liners. The thin-wall liners are made with a centrifugal spin casting process, which ensures high strength and low porosity. The rough outer surface bonds the liners securely to the surrounding aluminum block thus enhancing liner-to-block rigidity and heat transfer. For rigid crankshaft support and minimized noise and vibration, both engine blocks incorporate a deep-skirt design with four bolts per bearing cap, and both are heat-treated for greater strength.

CRANKSHAFT/ PISTONS/CONNECTING RODS

The TL's 3.2-liter V-6 features robust bottom-end construction. The forged crankshaft is specially counterweighted to offset the heavy-duty 11:1 compression ratio pistons. The connecting rods are made of forged-steel for added strength and durability.

The TL Type-S features much of the same internal construction. The forged crankshaft and pistons are the same as used with the RL. Added reliability is possible thanks in part to an oil jet system that sprays cooling oil on the underside of the piston crowns to keep temperatures in check. Special steel connecting rods are forged in one piece and then the crankshaft ends are "snapped." This process creates a bearing cap that is a perfect fit for the rod it is mated to, and a lighter and stronger rod overall.

CYLINDER HEADS / VALVES

Cylinder heads play an important role in improving power and emissions performance. Both the TL and TL Type-S feature single overhead camshaft (SOHC) cylinder heads made from pressure-cast, low-porosity aluminum that helps keep overall engine weight down. A key feature of the heads is an integrated tuned exhaust manifold that is part of the head casting. This method improves compact packaging, enhances exhaust flow, and allows the optimal positioning of the primary close-coupled catalytic converters. To ensure positive sealing, the TL and TL Type-S apply a three-layer head gasket like that of RL. A single Aramid-fiber reinforced belt drives the overhead camshafts. The TL Type-S heads also feature hollow camshafts to save weight.

VTEC® (VARIABLE VALVE TIMING & LIFT ELECTRONIC CONTROL)

Acura's VTEC® (Variable Valve Timing and Lift Electronic Control) gives the TL and TL Type-S engines strong low speed torque and crisp throttle response while enhancing high-rpm power.

At low speeds, the intake valves have lower lift and are open a shorter period of time during cylinder filling. At high rpm where breathing is critical, the valves switch to a high-lift, long-duration mode to deliver improved volumetric efficiency.

Both engines continue to use the 3-rocker-arm VTEC® system, which allows each of a given cylinder's intake valves to be controlled by its own low-speed camshaft lobe. By comparison, with 2-rocker VTEC®, both intake valves in a given cylinder are controlled by a single low-speed cam lobe. With different low-speed cam profiles for each intake valve, 3-rocker-arm VTEC® allows for staggered valve opening and lift, which promotes swirl in the combustion chambers, thereby improving efficiency. With better air/fuel mixing in the cylinders, burn speed and combustion stability are improved.

When engine rpm reaches 4700 rpm (4950 rpm in the TL Type-S), the powertrain control module (PCM) electronically triggers the opening of an electric spool valve that routes pressurized oil to small pistons within the intake valve rocker arms. These pistons slide into position to lock together the three intake rocker arms in each cylinder which then follow a single high-lift, long-duration cam lobe. With the engine's intake valve lift and opening duration continuously adjusted to suit the engine speed, the TL benefits with a broad torque curve and superior peak power. Although similar in design, the two engines feature different cam profiles, with the TL Type-S having higher lift and longer duration.

COLD-AIR INDUCTION SYSTEM

Cool air is more dense than hot air which allows an engine to make more power by packing-in more oxygen per given volume. To capitalize on this, the TL and TL Type-S use a special cold-air induction system as standard equipment. Ambient air is picked up through an inlet in the left front fascia and fed by a duct directly to the engine air intake. Depending on vehicle speed, this system supplies the engine with air that is as much as 15 degrees (F) cooler than typical engine compartment air.

DUAL-STAGE INTAKE MANIFOLD

The TL and TL Type-S feature a lightweight magnesium dual-stage intake manifold. Working in concert with VTEC®, this manifold improves low-speed torque without sacrificing high rpm power. The manifold is divided into two banks with three cylinders fed by each bank. The powertrain control module (PCM) controls butterfly valves located between each bank. At low engine speeds the valves are closed; each separate bank of the manifold is tuned to maximize the flow and resonance effect of the incoming air. This effect creates pressure waves, which are amplified within each half of the intake manifold at certain rpm ranges. These waves increase cylinder filling and torque through the lower part of the engine's rpm range. On the TL Type-S, funnel-shaped intake ports-similar to those used on racing engines-are built in at the uppermost end of the intake runners to improve airflow.

Since the benefits of this resonance effect fade as engine speeds rise, the butterfly valves open at 4,000 rpm to interconnect the two halves of the intake manifold plenum, thereby increasing its overall volume. With each cylinder drawing intake air from the full plenum chamber, the inertia mass of air rushing down each intake passage helps draw in more charge air than each cylinder would normally ingest. The effect greatly enhances cylinder filling and torque produced by the engine when at higher revs.

DIRECT IGNITION AND DETONATION-KNOCK CONTROL

Optimum ignition spark timing is crucial to engine power and efficiency, and timing varies based on the engine's load, rpm, temperature, and other factors. The powertrain control module (PCM) continually monitors engine functions to determine the best spark timing. An engine block-mounted acoustic detonation-or knock-sensor "listens" to the engine; based on this input, the PCM retards the ignition timing incrementally to prevent potentially damaging detonation. Iridium alloy-tipped sparkplugs are paired with an individual coil unit positioned directly above each plug thus requiring no service prior to 105,000 miles of use.

PROGRAMMED FUEL INJECTION (PGM-FI)

The Programmed Fuel Injection (PGM-FI) system tracks several engine inputs, including throttle position, intake air temperature, water temperature, intake manifold pressure and monitors the exact state of the exhaust gas. Based on these inputs, PGM-FI knows calculates when to trigger and how long to keep open the high efficiency multi-hole fuel injectors that deliver fuel to each cylinder.

DRIVE-BY-WIRE THROTTLE (DBW) CONTROL SYSTEM™

The TL and TL Type-S engines both feature an advanced Drive-by-Wire™ throttle system technology that eliminates the need for a conventional throttle cable. With the driver's throttle pedal movements interpreted electronically, the precise relationship between pedal movement and throttle butterfly valve opening can be varied to suit the driving conditions. The system monitors various parameters such as pedal position, throttle position, road speed, engine speed and gear selection. These inputs are then used to set the moment-to-moment relationship between the pedal position and throttle-body butterfly opening. By altering the amount of "gain" between the pedal and butterfly valve, significant improvements in drivability, response, and fuel efficiency are possible.

The DBW system also allows the Vehicle Stability Assist (VSA) with traction control to be fully integrated with engine function. In the TL Type-S the DBW is programmed to "blip" the throttle during downshifts with the Sequential SportShift automatic transmission for faster and smoother downshifts.

HIGH-FLOW EXHAUST SYSTEM WITH CLOSE-COUPLED CATALYZERS

To reduce weight and move the engine's two primary catalytic converters as close as possible to the combustion chambers, the TL and TL Type-S exhaust manifolds are cast directly into the cylinder heads. A 900-cell per-square-inch (600-cell per-square-inch in TL Type-S) high efficiency catalytic converter mounts directly to the exhaust port of each cylinder head for extremely rapid converter light off after the engine starts. This unique mounting system has the added benefit of eliminating traditional exhaust header pipes for a significant weight savings.

To ensure optimum flow and reduce backpressure, a hydroformed 2-into-1 collector pipe carries spent exhaust gases down to a 350 cell per-square-inch secondary catalytic converter located under the passenger cabin.

After the catalytic converter, the TL Type-S exhaust flows through two underfloor mufflers and dual rear silencers to reduce backpressure.

The TL Type-S features a high-flow exhaust system with 14-percent better flow than the TL, with larger pipes through much of its length. Tuned for an aggressive sound befitting the high-performance image of the TL Type-S, the system also features exhaust tip with large quad outlets (two on each side).

EMISSIONS CONTROL

This generation TL has met tight CARB ULEV2 emissions standards since its introduction in 2004. For 2008, the TL Type-S also meets this standard.

By integrating the exhaust manifolds into the cylinder head, the primary catalysts can be mounted very close to the engine. This ensures quick converter "light off" after engine start up, key to meeting the low emissions standard. Additionally, a 32-bit RISC microprocessor in the powertrain control module (PCM) boosts computing power for more precise fuel and spark delivery. High efficiency multi-hole fuel injectors deliver fuel to each cylinder as well as to direct fuel around the intake valve stem for improved atomization, which helps to further reduce emissions, particularly just after start-up.

NOISE, VIBRATION AND HARSHNESS (NVH) CONTROL

The TL and TL Type-S engines have 60-degree V-angles and compact, rigid and lightweight die-cast aluminum-alloy block assembly. A rigid forged-steel crankshaft, die-cast accessory mounts, and a stiff cast-aluminum oil pan also contributes to the overall smoothness of both engines. The induction system and the lightweight exhaust system of the TL and Type-S have been tuned to create a refined, sporty engine sound at large throttle openings and high rpm.

100,000-MILE TUNE-UP INTERVALS

With long-lasting components like iridium alloy-tipped spark plugs and a space-saving, self-tensioning serpentine accessory drive belt, the TL and TL Type-S are exceptionally low maintenance automobiles. Under normal operating conditions, the engines require no scheduled maintenance until 100,000 miles, other than periodic inspections and normal fluid and filter replacements. The first scheduled tune-up includes water pump inspection, valve adjustment, replacement of the timing belt and new spark plugs.

MAINTENANCE MINDER™

The TL and TL Type-S have a Maintenance Minder™ system that constantly monitors the vehicle's operating condition to indicate to the driver when maintenance is required. If required, maintenance alerts are presented via a dash prompt when the ignition is first turned on, not while driving (to prevent driver distraction). The system monitors engine operating conditions such as fluid temperatures and engine revolutions to determine the proper service intervals.

A Multi-Information Display (MID) is located below the speedometer in the dashboard instrument cluster. The MID indicates the remaining percentage of engine oil life, and then indicates when service is due with a "wrench" icon. A percentage-based countdown to the next service is displayed when the car is within 15-percent of the end of the service interval. An alphanumeric code is displayed to indicate the specific type of service that is required. If the service is missed, the MID indicates past-due mileage to express the urgency of the required service to the driver.

The system is designed to eliminate unnecessary maintenance procedures, environmental impact and expenses, while ensuring important service issues are addressed. In some cases, oil change intervals can extend to a maximum of 10,000 miles, which could spare the owner considerable money and time over the life of the car. The owner-resetable system monitors all normal service parts and systems, including oil, oil filter, tire rotation, air-cleaner, automatic transmission fluid, spark plugs, timing belt, coolant, brake pads and more.

6-SPEED MANUAL TRANSMISSION

While the TL is available exclusively with a 5-speed automatic transmission, the TL Type-S is offered with an available close-ratio 6-speed manual transmission. The manual transmission incorporates a short-throw shifter assembly and the 6-speed is designed to take advantage of the high power and torque of the TL Type-S engine.

This compact transmission is substantially lighter than the automatic transmission. It features a high-pressure die-cast aluminum-alloy transmission housing to save weight. To further reduce weight and size, special narrow, high-strength steel gears are used, and the shafts are hollow. Close ratio gear spacing helps provide quicker acceleration by keeping engine revs closer to the horsepower peak. Brass multi-cone synchronizers are used in first through fourth gears with a single-cone synchronizer for reverse to reduce shift load and help ensure smooth, precise shifting. A large gear-tooth contact area helps to reduce gear noise and increase strength. A reverse lockout feature prevents the transmission from accidentally being shifted into reverse while the car is moving forward.

CLUTCH AND DUAL-MASS FLYWHEEL

The TL's manual transmission is equipped with a compact clutch unit that is self-adjusting for consistent pedal height, feel, and effort throughout its service life. This innovative clutch system automatically eliminates the slack between the pressure plate and clutch disc thus lowering release loads while maintaining consistent pressure for the diaphragm spring. The clutch mechanism incorporates a clutch feel compensation spring that results in a more linear engagement feel.

To reduce drivetrain shock and limit the torque load on transmission components, the clutch includes a one-way delay valve located in the slave cylinder that restricts return fluid flow during rapid clutch engagement. This makes the clutch engagement more gradual during rapid release.

A dual-mass flywheel helps to reduce noise, cut down the transfer of engine vibration into the cabin, and provide increased comfort during shifting. This unit is divided into two flywheels with a torsion spring and viscous damper sandwiched between the two. This design enhances the durability of the synchronizers, reduces vibration and gear rattle, and reduces the shift load.

LIMITED-SLIP DIFFERENTIAL

When equipped with the 6-speed manual transmission, the TL Type-S features a standard limited-slip differential. This helical-gear-type differential enhances traction during acceleration and reduces understeer in high cornering load situations.

A set of helical gears mounted within the ring gear carrier responds to wheel spin at either front wheel by dividing the torque more equally between the two front wheels for improved traction. This limited-slip system improves traction when cornering and when negotiating slippery surfaces or surfaces where traction is uneven from side to side.

SEQUENTIAL SPORTSHIFT 5-SPEED AUTOMATIC TRANSMISSION

Both the TL and TL Type-S are equipped with a 5-speed automatic transmission. With a 4-shaft design and higher torque capacity, it is a more robust design than its predecessor, yet it is more compact. On the TL Type-S, gear changes can be made with the shifter or via steering wheel-mounted paddle shifters.

Designed for low maintenance and a high level of durability, the TL's automatic transmission requires no scheduled service until 120,000 miles. To provide strong off-the-line acceleration coupled with a relaxed, fuel-efficient cruising rpm, the unit has one of the widest gear ratio spreads of any 5-speed automatic transmission in its class.

Automatic Mode

The Sequential SportShift feature of the automatic transmission can be operated in a conventional fully automatic mode via a front console-mounted gated shifter. When in automatic mode, the transmission incorporates an advanced Grade Logic Control system and Shift Hold Control, both of which work to reduce gear "hunting" and unnecessary shifting.

Shift Hold Control keeps the transmission in its current (lower) ratio when the throttle is quickly released and the brakes are applied (as might be the case when decelerating to enter a corner). Shift Hold Control leaves the chassis undisturbed by excess shifting, ensuring that abundant power is immediately available without a downshift.

Grade Logic Control alters the 5-speed automatic's shift schedule when traveling uphill or downhill, reducing shift frequency, and improving speed control. Throttle position, vehicle speed and acceleration/deceleration are continuously measured, then compared with a map stored in the transmission computer. The Grade Logic Control system then determines when the car is on a hill. If this is the case, the shift schedule is adjusted to automatically hold the transmission in a lower gear for better climbing power or increased downhill engine braking.

Manual Mode

The Sequential SportShift transmission feature can be shifted into manual mode by moving the center console-mounted selector lever laterally to a special gate to the left of the "Drive" position. The TL can then be shifted manually by pushing or pulling the shift lever to change gears. TL Type-S owners can also choose to use F1® style paddle shifters mounted on the steering wheel, which reduces the need to remove their hands from the wheel during spirited driving. A digital display within the tachometer indicates which gear the transmission is in.

TL Type-S models use special gear shift algorithms to deliver quicker, firmer shifts, heightening control and driver involvement. Additionally, thanks to the robust construction of the automatic transmission, downshifts occur over a very wide range. TL and TL Type-S drivers can manually downshift into first gear and TL Type-S drivers enjoy special shift programming for the third-to-second and second-to-first downshifts that increases speed by about 7 mph for even greater flexibility.

To help protect the engine and drivetrain from damage, an array of preventive features are active when the transmission is in manual mode. In first, second, third and fourth gears, the logic changes, and the transmission ECU cuts off fuel flow to the engine if there is a possibility of over revving.

In the rare situation where the fuel cutoff alone is unable to prevent engine over revving (as could happen on a steep downhill) the transmission will automatically upshift itself to prevent engine damage. As a further safety measure, when downshifting, the transmission won't execute a driver-commanded gear change that would send the engine beyond redline in the lower gear. The Sequential SportShift transmission will automatically downshift to first gear as the vehicle comes to a stop, to prevent inadvertently lugging away from a stop in a high gear.

5-POSITION SHIFT GATE

The TL benefits from a 5-position shift gate that simplifies the operation of the transmission. It features a linkage and a speed-controlled reverse lockout solenoid valve to prevent transmission damage. When operated in automatic mode, the transmission lets the driver choose between D (Drive) and L (Low). When moved to the Low position, the transmission downshifts to the lowest possible ratio for the current road speed to provide maximum engine braking. If the vehicle continues to slow, the transmission progressively downshifts to maintain engine braking effect. When it has shifted all the way down to first gear, the transmission won't upshift further unless the driver moves the selector back to the D (Drive) position where normal transmission operation resumes.

ACTIVE LOCKUP TORQUE CONVERTER

The 5-speed Sequential SportShift automatic includes a new generation active lockup torque converter that improves fuel economy while maintaining a high level of drivability. A precise linear solenoid expands the speed and throttle setting range in which lockup can be engaged in the top four gears. This results in a reduction in transmission slippage for an improvement in fuel economy. The torque converter is now calibrated to offer more progressive acceleration than in the past, coupled with better acceleration at large throttle openings. The efficient Sequential SportShift automatic transmission couples with tall overall gearing to deliver 26 mpg on the highway in both the TL and Type-S during using the EPA method, while city mileage is 18 for TL and 17 (AT) and 18 (MT) for the Type-S.

COOPERATION BETWEEN 5AT AND DRIVE-BY-WIRE

With the Drive-by-Wire Throttle System™, the function of the engine and transmission can be closely choreographed for faster, smoother shifting. Upshifts from first to second gear, and from second to third gear, are now more than one-tenth of a second quicker. In manual mode, driver-commanded downshifts are also more than one-tenth of a second quicker. Meanwhile, the peak g-or "shift shock"-has been reduced significantly during downshifts.

Manual downshifts are smoothed in the TL Type-S by shift programming that matches engine revs to gear selection and vehicle speed. When the driver toggles the gearshift lever or paddle shifter for a lower gear, the powertrain control module (PCM) senses the shift and opens the throttle slightly, injecting extra air and fuel into the Type-S engine. This action revs the engine to the speed the transmission will reach in the lower gear, smoothing the gear change while simultaneously speeding up the downshift. The driver feels only a quick downshift, with virtually no driveline shock or hesitation.

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