1986 Acura Integra -- DriveTrain

The Integra's DOHC, Programmed Fuel Injection, 4-cylinder engine is a rigid, light, and compact 1.6-liter powerplant, which combines high performance with high efficiency. It incorporates the latest in technological advances including its race-proven combustion chamber and port designs. With its precision die-cast, aluminum alloy block (incorporating integral siamesed cylinder bores) and DOHC head, the entire engine weighs but 94 kg (207 Ibs.) and produces 113 horsepower at 6250 rpm.

The pent-roof combustion chamber, with a compression ratio of 9.3:1, uses four valves, at an included angle of 51°, to maximize valve area (Intake valve diameter is 30 mm x 2, exhaust 27 mm x 2). The spark plug is in the center of each chamber for rapid and uniform flame-front propagation.

Dual overhead camshafts actuate each bank of valves through finger-followers. Both cams are inside the centerlines of the valves, reducing the outside dimensions of the engine and increasing the fulcrum length of the finger-followers for a higher valve lift (9.5 mm intake, 9.0 mm exhaust) relative to cam lobe diameter. Using a patented casting process, the core of each cam is hollow, both shaft and lobes, reducing total weight by 1.2 kg (2.6 Ibs.). The cams are driven by an NBR (synthetic rubber) belt which is temperature resistant and provides higher strength and durability. A multi-core oil cooler is utilized to help maintain optimum lubricant temperature.

The intake and exhaust ports, and their corresponding manifolds, and carefully configured to take full advantage of the Integra' s free-breathing 4-valve design. Each of the equal-length 370 mm intake runners is tuned for increased mid-range torque.

Fuel is provided by means of programmed fuel injection system. It consists of three subsystems: Air Intake, Electronic Control, and Fuel Delivery. The fuel/air ratio is kept at the optimum level by an eight bit microprocessor which analyzes information received from the following sensors:

A) Throttle Angle Sensor--A precision shaft angle transducer monitors exact throttle position. The computer uses this information to determine fuel injection quality during all operating conditions.

B) Crank Angle Sensors (TDC and #1 cylinder)-- The #1 cylinder Sensor tells the computer when to start the sequential injection; and the top dead center (TDC) sensor monitors engine speed.

C) Coolant Temperature Sensor--A thermistor changes resistance as coolant temperature changes; the signal is used to tailor injection duration to different engine conditions.

D) Intake Air Temperature--A thermistor measures intake air temperature and the computer adjusts injection duration to suit conditions.

E) Manifold Air Pressure (MAP) Sensor--A precision vacuum/pressure transducer senses engine load; the computer uses the information to determine the proper basic injector discharge durations.

F) Atmospheric Pressure Sensor--A transducer measures barometric pressure; its information is used by the computer to adjust injector discharge duration.

G) Oxygen Sensor--Monitors oxygen in exhaust gas; the computer uses the signal to adjust injector duration to maintain a stoichiometric air/fuel ratio for efficient NOx control by the three-way catalyst.

Utilizing the information from the various sensors, the correct volume of fuel is injected into each manifold runner sequentially at a specific time just prior to the intake stroke. Fuel is automatically cut off during deceleration and interrupted at 7500 rpm to prevent over-revving.

Idle is electronically controlled and ignition is through a fully transistorized, solid state system. A three-way catalyst is used for exhaust emission control

Two transmissions are available in the Integra line: a standard, fully synchronized 5 speed manual and an optional 4-speed automatic with lockup torque converter.

The standard transmission has been designed for precise driving. Its shift-lever throws are short and crisp.

The automatic transmission is equipped with a fourth gear lockup torque converter which engages according to throttle position and speed. This eliminates slippage and improves fuel efficiency.

. . (5sp. Man.) (4sp. Auto.)
Transmission Ratios 1st. 3.181 2.705
. 2nd. 1.944 1.560
. 3rd. 1.347 1.031
. 4th. 1.033 0.777
. 5th. 0.848 .
. Reverse. 3.000 1.954
Final Drive Ratio . 4.21:1 .

The Integra's refined front-wheel drive system uses equal length driveshafts to reduce torque steer caused by unequal constant-velocity joint angles. The left side shaft is divided into inboard and outboard sections. The inboard section is supported by a bearing and connects to the outboard section by a constant-velocity joint. The length of this outer section matches the length of the short driveshaft, resulting in equal constant velocity joint angles.

The Integra has power assisted rack-and-pinion steering. The steering has ratios of 18:1 and 3.6 turns lock-to-lock. The steering column is adjustable so that the angle can be set for the best driving position.

To match its performance potential, Integra is equipped with four-wheel disc brakes. Power assist is provided by a 9-inch servo unit, and the braking system incorporates a proportioning valve. The 241.3 mm (9.5-inch) diameter front discs are ventilated; the 238.8 mm (9.4-inch) diameter rear discs are solid, and the rear brake calipers incorporate an integral mechanical parking brake. The brake pads are made from new compound which improves wear resistance and anti-fade characteristics. Total brake swept area is 1950 sq. cms (302 sq. in.).

The Integra's suspension is tuned to work in conjunction with performance oriented Michelin MXV 195/60 R14 radial tires. On LS models, they're mounted on light alloy, 5.5JJ x 14 wheels; RS models use 5.5JJ x 14 styled steel wheels with full wheel covers.

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