HEADLINES

2005 Acura TL Powertrain - Part 1

OVERVIEW

The TL is powered by an aluminum-alloy 3.2-liter V-6 that uses advanced Acura technology to provide an exceptionally high level of power and refinement. The VTEC V-6 generates 270 horsepower and 238 lbs-ft of torque. The TL engine delivers outstanding city and highway fuel economy when paired with the Sequential SportShift automatic transmission. In terms of emissions performance, it meets CARB LEV-2 ULEV requirements, a much tougher standard than either of its predecessors.

The TL offers an available 6-speed manual transmission at no extra cost. With short shift throws, closely spaced ratios and slightly shorter (higher numerically) overall gearing, the 6-speed manual transmission is targeted at drivers interested in extracting the maximum performance-and hands-on fun-out of the most powerful V-6 engine in the class. A helical gear-type limited-slip differential is applied as standard equipment in the 6-speed manual transaxle, providing maximum grip and handling stability under heavy acceleration.

Engine Comparison:

2005 Acura TL
2005 BMW 530i
2005 Infiniti G35
2005 Lexus ES 300
2005 Mercedes-Benz C320
Engine
3.2-liter SOHC VTEC V-6
3.0-liter DOHC I-6
3.5-liter DOHC V-6
3.3-liter DOHC V-6
3.2-liter SOHC V-6
Horsepower @ rpm
270 @ 6200
225 @ 5900
260 @ 6000
225 @ 5600
215 @ 5700
Torque @ rpm (lbs-ft)
238 @ 5000
214 @ 3500
260 @ 4800
240 @ 3600
229 @ 4600
Standard transmission
5 AT
5 MT
5 AT
5 AT
6 MT
EPA estimated mileage City/ Highway
20/29
19/29
18/26
20/29
17/25

POWERTRAIN AT A GLANCE

Engine

  • 3.2-liter, VTEC V-6 engine produces 270 horsepower at 6200 rpm and 238 lbs-ft of torque at 5000 rpm
  • Intake-side three-rocker VTEC (Variable Valve Timing and Lift Electronic Control)
  • 11.0:1 Compression ratio
  • High flow cold air induction system
  • High flow exhaust system with closed coupled and under floor catalytic converters
  • Dual-stage tuned intake manifold
  • Drive-by-Wire Throttle System™
  • Computer-controlled Programmed Fuel Injection (PGM-FI)
  • Direct ignition system
  • Serpentine accessory belt
  • Maintenance Minder system which optimizes service intervals
  • 105,000-mile tune-up interval

Emissions/Fuel Economy

  • Compact in-head exhaust manifolds
  • High flow close-coupled catalytic converters plus under floor catalytic converter
  • High capacity 32-bit RISC processor engine control unit
  • Meets CARB LEV-II ULEV standard, which cuts NOx by 75% compared to LEV-I LEV
  • EPA mileage of 20/29mpg (City/Highway, 5 AT) and 20/29 mpg (City/Highway, 6 MT)

6-Speed Manual Transmission

  • Close ratio spacing for maximum performance
  • Lightweight high-pressure-cast aluminum-alloy transmission housing
  • Multi-cone synchronizers are used on first through fourth gear
  • Reverse lock-out feature prevents accidental engagement
  • Advanced clutch torsion mechanism reduces gear noise
  • Helical gear limited-slip differential reduces wheel spin and maximizes acceleration

5-Speed Sequential SportShift Automatic Transmission

  • Quick-response Sequential SportShift allows semi-manual operation
  • Coordination between Drive-by-Wire Throttle System and transmission makes for quicker, smoother shifts
  • Intuitive 5-position shift gate
  • Advanced shift-hold control limits Up-Shift during aggressive driving mode
  • Lockup torque converter design for superior fuel economy
  • Advanced Grade Logic Control System reduces gear "hunting" when driving on steep hills
  • Linear solenoid direct-acting control reduces shift shock and improves smoothness

Noise, Vibration & Harshness (NVH)

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

ENGINE ARCHITECTURE

The TL 3.2-liter VTEC 24-valve, V-6 features aluminum-alloy construction and has a compact, smooth firing 60-degree V-angle. A cold-air induction system coupled with Acura's sophisticated dual-stage intake manifold, 3-rocker VTEC system, increased compression ratio, close-coupled catalytic converters and high flow exhaust delivers the highest horsepower in its class, combined with exceptional smoothness and extremely low emissions.

ENGINE BLOCK

The lightweight die-cast aluminum-alloy block has cast-in place iron cylinder liners. These thin-wall liners are made using a centrifugal spin casting process that ensures high strength and low porosity. With rough outer surfaces, these liners bond securely to the surrounding aluminum, enhancing liner-to-block rigidity and heat transfer. For rigid crankshaft support and minimized noise and vibration, the block incorporates a deep-skirt design with four bolts per bearing cap. The block assembly is also heat-treated for greater strength.

CRANKSHAFT / PISTONS / CONNECTING RODS

The crankshaft is based on that of the previous generation TL Type-S. The counterweights have been adjusted to accommodate the slightly heavier high compression pistons. With taller, reinforced crowns, these pistons reduce the squish volume (the mixture trapped between the pistons and the cylinder head) and raise the compression ratio (relative to the Type-S) from 10.5:1 to 11.0:1. The connecting rods are made of forged steel.

CYLINDER HEADS / VALVES

Cylinder heads are an important factor in improving power and emissions performance. A key feature of the TL cylinder heads is the integrated exhaust manifold that is part of the cylinder head casting. Made of pressure-cast, low-porosity aluminum, the heads help keep overall engine weight down. Each cylinder head feeds directly into a close-coupled catalyst. To ensure positive sealing, the TL applies a three-layer type head gasket like that of the MDX sport-utility vehicle and NSX. A single Aramid-fiber reinforced belt drives the overhead camshafts.

VTEC™ (VARIABLE TIMING & LIFT ELECTRONIC CONTROL)

Acura VTEC™ (Variable Timing and Lift Electronic Control) gives the TL engine strong low speed torque and response coupled with class-leading high rpm horsepower. The TL VTEC system has two distinct modes of operation for the engine's 12 intake valves. At low speeds, the intake valves have low lift and are open a comparatively short period of time during cylinder filling. At high rpm where breathing is critical, the valves switch to high-lift, long duration mode to deliver the best volumetric efficiency possible. The VTEC changeover point occurs at 4700 rpm, and takes just 0.1 second; it's undetectable to the driver.

In the TL, the VTEC system continues to be the 3-rocker type, which allows each of a given cylinder's intake valves to be controlled by its own low-speed cam 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 VTEC allows for staggered valve opening and lift. This promotes swirl in the combustion chambers, which improves efficiency. With better mixing in the cylinders, burn speed and combustion stability are improved. When engine rpm reaches 4700 rpm, the powertrain control module (PCM) triggers the opening of an electric spool valve that routes pressurized oil to small pistons in the intake valve rocker arms. These pistons slide into position to lock together the three intake rockers in a given 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 operating engine speed, the TL benefits with a broad torque curve and superior peak power.

COLD-AIR INDUCTION SYSTEM

Cool air is denser than hot air and allows an engine to make more power by packing more oxygen per given volume. To capitalize on this fact, the TL has 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 to the engine air intake. Depending on vehicle speed, this system supplies the engine with ambient air that is much as 15 degrees F. cooler than typical engine compartment air.

A low-restriction induction system improves breathing in the TL and provides an aggressive sound under acceleration.

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