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Old 07 Oct 2010, 02:50 pm
Join Date: Aug 2007
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Default TSX: 2009 Acura TSX - Powertrain


The new TSX's size, weight and total performance work in balance. The result is a car that is comfortable for five passengers, yet agile and responsive for performance driving. The same balanced thinking applies to the TSX powertrain. With an advanced in-line 4-cylinder powerplant, TSX offers strong acceleration, combined with low overall weight and compact packaging. Fuel efficiency is also a strong point.

An advanced, all-aluminum 2.4-liter DOHC i-VTEC® in-line 4-cylinder engine produces 201 hp and 172 pound-feet of torque (MT), and incorporates Acura's i-VTEC® "intelligent" valve control system that features Variable Valve Timing and Lift Electronic Control (VTEC®) combined with Variable Timing Control™ (VTC™). Though peak horsepower is virtually unchanged versus the previous generation engine, peak torque output has risen by 8 lb-ft. In addition, the engine's torque curve has fattened considerably. Horsepower, for example, is up five percent at 4,400 rpm. The result is stronger throttle response and better acceleration just about everywhere in the engine's operating range. To achieve these power gains, the engine has a higher compression ratio, new valve timing, and intake and exhaust flow improvements. A new aluminum and resin composite intake manifold reduces weight over the previous aluminum design, while better insulating the engine's incoming airflow from under-hood heat.

Though engine performance has improved, the powerplant delivers better fuel economy and has reduced emissions. A rear-mounted exhaust layout, close-coupled catalytic converter and advanced Programmed Fuel Injection (PGM-FI) team to help the TSX meet strict EPA 2 - Bin 5, and CARB LEV II Ultra Low Emission Vehicle standards (LEV-2 ULEV).

2009 TSX
Engine DOHC i-VTEC® I-4
Displacement 2.4-liter (2354 cc)
Compression ratio 11.0:1
Fuel type Premium Unleaded, 91 octane
Horsepower @ rpm 201 @ 7000
Torque @ rpm (lb-ft) 172 @ 4400 (MT); 170 @ 4,300 (AT)
Transmission 6 MT 5 AT
EPA estimated mileage (city/highway/combined) 20/28/23* 21/30/24*
Emissions certification CARB LEV-2 ULEV

*Based on 2009 EPA mileage estimates. Your actual mileage will vary depending on how you drive and maintain your vehicle.

The 2009 TSX comes with a choice of two transmissions - a standard 6-speed close-ratio manual transmission or a Sequential SportShift 5-speed automatic. The manual gearbox has a lightweight magnesium alloy case and multi-cone synchronizers providing a light, quick action with very short shift throws. To provide more spirited driving, the manual transmission now includes more performance-minded ratios for second and third gears.

The 5-speed Sequential SportShift automatic has a new straight-style shift gate (versus the previous TSX's serpentine-style gate design) with Drive and Sport positions that provide fully automatic operation. The transmission can be shifted manually via new steering wheel mounted F1®-style paddle shifters at the driver's option. Also new with SportShift is the ability to use the paddle shifters to make gear changes while in Drive, whereas previously this would only occur when in Manual mode. When using SportShift in Drive, the gear changes are made per driver command, but after a short time (with no further gear change input) the 5-speed automatic transmission returns to its normal Drive mode operation. Working in combination with the Drive-by-Wire™ Throttle System, the Sequential SportShift transmission's shift logic results in quick, smoothly controlled shifts. Grade Logic and Shift Hold Control work in automatic mode to keep the transmission in the gear that's ideal for the driving situation. Further improving performance and drivability is a revised torque converter lock-up assembly.

Long 100,000-mile tune-up intervals and a standard Maintenance Minder™ system, which automatically monitors the vehicle's unique operation condition to indicate to the driver when maintenance is required, help to lessen the cost of ownership. The Maintenance Minder™ system is designed to ensure that important service issues are addressed in a timely manner, and eliminate unnecessary maintenance procedures to help reduce environmental impact and operating expenses.

Powertrain at A Glance


  • 2.4-liter, DOHC, i-VTEC® 4-cylinder engine generates 201 horsepower at 7,000 rpm with 172 lb-ft of torque at 4,400 rpm (MT); 170 lb-ft of torque at 4,300 rpm (AT)

  • i-VTEC® "intelligent" valve-control system combines Variable Timing Control™ (VTC™) with VTEC®

  • Drive-by-Wire™ Throttle System

  • Computer-controlled Programmed Fuel Injection (PGM-FI)

  • Dual balance shafts for exceptional smoothness

  • Direct ignition system

  • Lightweight alloy pistons and high-strength connecting rods

  • 100,000-mile tune-up interval (may vary with driving conditions)

Emissions/Fuel Economy

  • Estimated mileage of 21/30/24 mpg* (city/highway/combined, 5 AT) and 20/28/23 mpg* (city/highway/combined, 6 MT)

  • EPA TIER 2 - BIN 5, CARB LEV II ULEV emissions standards

  • Rear-facing exhaust ports, close-coupled catalytic converter and under-floor converter provide fast catalyst light-off for lower and cleaner emissions

*Based on 2009 EPA mileage estimates. Your actual mileage will vary depending on how you drive and maintain your vehicle.

6-Speed Manual Transmission

  • Close-ratio 6-speed manual transmission

  • Compact, rigid, lightweight transmission case and bellhousing

  • Multi-cone synchronization on all gears for light shifting effort

  • Revised ratios for second through sixth gears

  • Precise and light shift

  • Short clutch pedal stroke with light effort

  • Compact clutch with low inertia for quick acceleration

Sequential SportShift 5-Speed Automatic Transmission

  • Sequential SportShift via F1®-style steering-wheel mounted paddles

  • 5-position straight shift gate

  • Advanced Grade Logic Control for reduced gear hunting when driving on steep hills

  • Linear solenoid direct-acting control for reduced shift shock and shift smoothness and responsiveness

  • Drive-by-Wire™ cooperative control facilitates quicker shifts

  • Lockup torque converter design delivers superior fuel economy

  • Shift Hold Control

Noise, Vibration and Harshness (NVH)

  • Lightweight and durable aluminum cylinder block with cast-in iron cylinder liners

  • One-piece aluminum crankshaft carrier for improved strength

  • Chain-driven balance shafts mounted on lower block in oil pan

  • Maintenance-free silent-chain camshaft drive

  • Maintenance-free serpentine accessory drive-belt assembly with auto-tensioner


The 2009 TSX's 2.4L engine features Acura's i-VTEC® "intelligent" valve control system. Featuring Variable Valve Timing and Lift Electronic Control (VTEC®) combined with Variable Timing Control™ (VTC™), the system provides power characteristics like those of a V6 without sacrificing the light weight or fuel efficiency of an inline four. A new VTEC® design uses three reduced-thickness aluminum rocker arms that operate a pair of intake and exhaust valves for each cylinder. At low rpm, the valves follow low-lift, short duration camshaft profiles to help boost low-end torque. Above 5000 rpm, the intake valves are operated by high-lift, long-duration camshaft profiles, for maximum high-rpm horsepower.

VTEC® lets the engine develop strong low-end torque along with exceptional high rpm power by varying valve lift and duration based on key engine parameters. To further refine powerplant operation, the TSX engine features the "intelligent" i-VTEC® system which adds Variable Timing Control™ (VTC™) to VTEC®. This provides continuously variable, computer controlled camshaft timing. In total, the TSX's i-VTEC® system provides performance, efficiency and emissions benefits by allowing the intake valve lift and valve timing to be continuously adjusted to suit the engine's operating parameters.

Variable Timing Control™ (VTC™)

The TSX's intake camshaft timing is continuously adjusted to suit engine operating conditions by a system called Variable Timing Control™ (VTC™). An integral part of the TSX's i-VTEC® system, the new TSX employs revised VTC™ parameters to enhance power output, fuel economy and emissions performance with its precise control of cam timing.

Camshaft position, intake manifold pressure and engine rpm are simultaneously monitored by the powertrain control unit (PCM), which then commands a VTC™ actuator to advance or retard the intake camshaft timing. The intake camshaft is almost fully retarded at idle to deliver a more stable idle and reduced hydrocarbon (HC) emissions. As engine RPM builds, the intake camshaft is progressively advanced so the intake valves open sooner and valve overlap increases. This reduces pumping losses, which increases fuel economy and further reduces exhaust emissions due to the creation of an internal exhaust-gas recirculation effect.


The TSX cylinder head is constructed of pressure-cast aluminum alloy and features four valves per cylinder actuated by dual overhead camshafts (DOHC). The cams are driven by an automatically adjusted silent-type chain. The chain system is maintenance free and runs in an oil bath for maximum durability. The combustion chambers have large "quench" areas to promote faster flame propagation and more complete burning, thus helping to reduce carbon monoxide (CO) and hydrocarbon (HC) exhaust emissions. Larger intake and exhaust valves and revised ports contribute to improved breathing. An increase in compression ratio from 10.5 to 11.0:1 is a significant contributor to the TSX's greater torque output.


TSX's forged-steel crankshaft has micropolished journals to reduce friction and improve long-term durability. The die-cast lightweight aluminum cylinder block has cast-in iron cylinder liners that are made using a unique spin casting, centrifugal process. New-design pistons use special low-friction rings to reduce power loss. For maximum rigidity and minimal noise and vibration, the cylinder block is a 2-piece design that supports the five main bearings with a single cast-alloy bed-plate assembly.


Programmed Fuel Injection (PGM-FI) uses an array of sensors to constantly monitor a number of critical operating variables, including throttle position, intake air temperature, water temperature, ambient air pressure (altitude), air flow, air/fuel ratio, along with the position of the crankshaft and camshafts. Highly vaporized-style fuel injector nozzles reduce the typical size of fuel droplets, which improves air/fuel atomization and flame propagation inside the combustion chambers.


The TSX's induction system has been reworked to increase airflow volume by nine percent and to create a more aggressive, linear engine sound. The revised inlet design allows cool ambient air to be picked up at the front of the vehicle, and then routed though a high-flow filter assembly. The single-stage lightweight plastic intake manifold has fixed-length intake runners that are tuned in length, diameter and shape to provide an optimal blend of low-rpm torque and high-rpm response. The new manifold incorporates new 48 mm intake runner (up 6 mm from the previous design runners) along with a new throttle-body with a 4 mm larger inlet opening.


To help boost engine torque, the TSX has a new high-flow, low back-pressure exhaust system that contributes to a 15-percent increase in exhaust flow over the previous TSX. Large-diameter pipe sizes throughout the exhaust system increase flow; beyond the under-floor catalytic converter, the exhaust system passes through a pre-chamber under the second-row floor, and then splits just behind the rear axle to feed into free-flowing dual silencers and chrome exhaust tips.


In place of a conventional mechanical throttle linkage, the TSX uses a Drive-by-Wire™ Throttle System. A DC motor controls the throttle butterfly position in the intake tract. This allows the ratio between pedal movement and throttle motion to be altered to suit the driving conditions. The system monitors throttle pedal position, throttle butterfly position, road speed, engine speed and engine vacuum. This information is used to define the throttle control sensitivity. The system also alters response based on the calculated road slope, providing more throttle gain uphill, and less downhill, and also reduces changes in gain on curvy roads to make the car easier to control.

The drive-by-wire throttle system works with the Sequential SportShift 5-speed automatic transmission to make shifts smooth and quick. With coordination of the throttle opening and the transmission's shifting functions, shift shock and delay are reduced.

Emissions Control

In addition to the TSX engine gaining torque, the 2.4-liter engine has lower emissions. The 2009 TSX is compliant with California Air Resources Board (CARB) LEV II ULEV standard, which is one of the toughest emissions regulations in the United States. TSX also achieves EPA TIER 2 - BIN 5 regulations emissions compliance.

The in-line 4-cylinder engine is designed with emissions performance in mind, employing VTC and a unique i-VTEC® cylinder head promoting internal exhaust gas recirculation, which helps reduce NOx output. Newly designed fuel injectors likewise help reduce hydrocarbons after starting, while a Linear Air/Fuel sensor positioned in the exhaust system just upstream of the catalyst improves air/fuel mixture control.

The exhaust manifold is integrated into the cylinder-head casting in the rear of the transversely mounted engine. This allows the catalytic converter to be positioned very close to the cylinders for swift light-off after a cold engine start. A secondary catalytic converter is positioned under the passenger compartment floor, shortly downstream.


The TSX engine has an array of features designed to reduce noise, vibration and harshness (NVH). The pressure-cast cylinder block has a bed-plate type main bearing cap that results in a highly rigid assembly, which helps to resist vibration. Two balance shafts further smooth the inherent vibration commonly found with a large-displacement in-line 4-cylinder engine layout, and a self-adjusting silent-type camshaft chain and serpentine accessory drive belt also reduce NVH.


Features like a self-adjusting silent-type camshaft chain, long wearing platinum-tipped spark plugs and a precision-engineered valvetrain, all contribute to the TSX's low maintenance needs. Aside from routine fluid changes and inspections, the first scheduled engine tune-up is not required for 100,000 miles or more (may vary with driving conditions).

Maintenance Minder SYSTEM

A standard Maintenance Minder™ system automatically monitors the vehicle's operating condition. The driver is alerted via a message on the Multi-Information Display (MID) when maintenance is required. The system helps eliminate unnecessary service stops, while ensuring that the vehicle is properly maintained.

The Maintenance Minder™ system monitors operating conditions such as coolant and oil temperatures along with engine speed, and then determines the proper service intervals. Depending on the engine operating conditions, oil change intervals can be extended to a maximum of 10,000 miles, potentially sparing the owner considerable money and inconvenience over the life of the vehicle. The system can be reset manually by the owner, and monitors all normal service parts and systems, including oil and filter, air-cleaner, tire rotation, automatic transmission fluid, coolant, spark plugs, timing belt, brake pads and more. Maintenance alerts are presented on the instrument cluster when the ignition is first turned on, and not while driving.


The Electronic Control Mount System is used to minimize the effects of engine vibration. At low engine speed, a vacuum-controlled front engine mount allows additional engine movement, so that less low-frequency vibration is transmitted to the body. At higher rpm, the mount stiffens so that the mass of the engine is properly restrained for better handling.


A close-ratio 6-speed manual gearbox is one of two standard transmissions in the TSX. With precise and light shifting action, the manual transmission is designed to compliment the TSX's sporting side. Compared to a 5-speed transmission, the 6-speed gearbox allows for closer ratio staging. This enables the engine to operate closer to its power peak during acceleration for better performance.

A high (numerically low) top gear ratio allows for a relaxed cruising rpm and fuel efficiency. For 2009, the TSX 6-speed manual gearbox has new ratios for second through sixth gears for better performance with the revised engine.

The compact, highly rigid transmission case is cast of magnesium alloy to reduce weight by about seven pounds relative to a comparable aluminum unit. Additionally, the highly rigid casting helps damp out noise and vibration. Multi-cone synchronizers on first through fourth gears reduce and smooth shifting effort.

The low-effort clutch pedal design has a broad engagement band for progressive engagement and smoother launches.


The TSX has a standard Sequential SportShift 5-speed automatic transmission with F1®-style paddle shifters and Grade Logic Control to maximize acceleration, fuel economy and driver control.

Automatic mode

A console mounted, 5-position shift gate makes operation of the transmission simple. When in this mode the transmission operates automatically in the "D" position, selecting among the five forward gear ratios based on the driving conditions. When in automatic mode, the transmission incorporates an advanced Grade Logic Control and Shift Hold Control, both of which work to reduce gear "hunting" on hills and through turns.

Grade Logic Control reduces shift frequency and improves vehicle speed control by altering the transmission's shift schedule when traveling uphill or downhill. The transmission computer continuously compares throttle position, vehicle speed and acceleration/deceleration with a map stored in the computer memory. The Grade Logic Control System determines when the TSX is on an upslope or down slope. The shift schedule is then adjusted to automatically hold the transmission in a lower gear for better climbing power or increased downhill engine braking.

When the throttle is quickly released and the brakes are applied, as might be the case when decelerating for a corner, Shift Hold Control keeps the transmission in its current (lower) ratio. This helps provide added engine braking, and ensures that abundant power is immediately available at the corner exit.

Manual mode

New for 2009, TSX is equipped with steering-wheel mounted paddle shifters. The steering-wheel mounted Sequential SportShift F1®-style paddle shifters are activated when a fingertip pull of the right paddle commands an upshift or a pull of the left paddle commands a downshift. A digital display in the tachometer face indicates which gear the transmission is in when the steering wheel paddles are active.

The steering wheel paddles can operate in both the "D" and "S" transmission positions. When in "D," a touch of a paddle shifter temporarily places the transmission in manual mode (but without gear holding at redline). After comparatively steady-state cruising conditions are detected, the transmission returns to full automatic operation. In "S," engaging a paddle enables gear holding, which allows only driver-commanded shifts, with the exception of automatically shifting to first gear at a stop, even if not driver-selected.

When first placed in "S" mode, the transmission will automatically shift between first, second, third and fourth gears until a paddle shifter is activated. When a paddle shifter is activated, the transmission goes into full manual mode.

Manual mode protective features

An array of protective features is active when the transmission is in manual mode to help protect the engine and drivetrain from damage. The Powertrain Control Module (PCM) will cut off fuel flow to the engine if there is a possibility of over-revving in a gear, as might occur if the driver is late in commanding an upshift. To prevent over-revving while downshifting, the transmission will not execute a driver-commanded downshift that would send the engine beyond redline in the lower gear. Even if the driver allows the vehicle to come to a stop in a high gear, the transmission will automatically downshift to first gear to prevent lugging away from a stop in a high gear.

Cooperation between 5-Speed Automatic Transmission & Drive-by-Wire Throttle System

With the TSX's electronically controlled automatic transmission and Drive-by-Wire™ Throttle System, the function of the engine and transmission are closely choreographed for faster, smoother shifting. As a result, shift shock is reduced significantly during upshifts and downshifts.


To provide good fuel economy while maintaining a high level of drivability, the 5-speed automatic transmission includes an active lockup torque converter. With the precise control afforded by a linear solenoid and assist spring, the system features a wide range of speed and throttle settings in which lockup can be engaged in the top four gears. This results in excellent fuel economy in both city and highway driving.


To provide better fuel efficiency, a special low-friction clutch disc is used for all five gears.

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