reprinted from Automotive Engineering, December 1995
Honda has added a high-performance model to its Integra range. Appropriately designated "R," the car's B18c, dual overhead camshaft, 16-valve, VTEC, 1797-cc engine has been tweaked to produce 149 kW (JIS net) at 8000 rpm and 181 N·m torque at 7500 rpm on an 11.1:1 compression ratio, using premium grade, unleaded gasoline. Specific output is 83 kW/L, a remarkably high value for a naturally aspirated engine. At the engine's maximum allowable rpm, piston speed reaches 24.4 m/s.
In this engine, Honda's VTEC (variable valve timing/lift) technology is applied to both the intake and exhaust valves, switch-over to the high-speed cam occurring at 5700 rpm. Comparisons of the R and the normal DOHC VTEC are as follows:
|Intake opens (deg. BTDC)||15||10|
|closes (deg. ABDC)||45||40|
|Exhaust opens (deg. BBDC)||45||40|
|closes (deg. ATDC)||10||7|
The R engine's internal modifications include lightweight, low-friction pistons; lightweight, high-rigidity connecting rods; fully balanced forged steel crankshaft; thinner-stem valves; dual valve springs; and high-temperature-resistant, platinum-tipped spark plugs. Intake air is now taken from the fender well, instead of the normal VTEC's engine compartment. The intake manifold's opening has been enlarged from 65 to 70 mm, the throttle body enlarged by 2 mm to 62. The 4-2-1 collector exhaust has smoother flow characteristics.
The Integra R is available with a close-ratio manual five-speed transmission only. A helical-gear type limited slip differential is standard. The body has been stiffened by the addition of four tubular crossmembers, and the suspension firmed up with stiffer springs, shock absorbers, and harder bushings. Lightweight aluminum wheels are shod with 195/55R15 84V tires. Some 65 kg of mass has been shed from the normal DOHC VTEC in the R conversion, to which 25 kg has been added for stiffening and aerodynamic improvements, attaining a net reduction of 40 kg.