Honda R engine

The Honda R engine is an inline-four engine launched in 2006 for the Honda Civic (non-Si). It is fuel injected, has an aluminum-alloy cylinder block and cylinder head, is a SOHC 16-valve design (four valves per cylinder) and utilizes Honda's i-VTEC system. The R series engine has a compression ratio of 10.5:1, features a "drive by wire" throttle system which is computer controlled to reduce pumping losses and create a smooth torque curve.

Honda R engine
Overview
Manufacturer	Honda Motor Co Ltd
Production	2006–present
Layout
Configuration	Naturally aspirated Straight-4
Displacement	1.6–2.0 L; 97.3–121.9 cu in (1,595–1,997 cc)
Cylinder bore	81 mm (3.19 in)
Piston stroke	77.4 mm (3.05 in) 87.3 mm (3.44 in) 96.9 mm (3.81 in)
Block material	Aluminum alloy
Head material	Aluminum alloy
Valvetrain	SOHC 4 valves x cyl. with i-VTEC
Compression ratio	10.5:1-10.7:1
RPM range
Redline	6800
Combustion
Fuel system	PGM-FI
Fuel type	Gasoline
Cooling system	Water-cooled
Output
Power output	125–156 PS (92–115 kW; 123–154 bhp)
Torque output	15.4–19.4 kg⋅m (151–190 N⋅m; 111–140 lb⋅ft)

The engine uses many advanced technologies to improve fuel economy and reduce friction. Piston rings are given an ion plating and weight is reduced with plastic and aluminum parts and variable length intake manifolds that maintain ram air at a wide RPM range. The engine also features piston cooling jets, previously available only on high performance engines, and in the ninth-generation 1.8L Civic (2012-2015) the pistons are treated with molybdenum disulfide applied in a polka-dot pattern. The automatic transmission model is rated at California Air Resources Board (CARB) ULEV-2 (Ultra Low Emissions Vehicle) with fuel economy 25 mpg_‑US (9.4 L/100 km; 30 mpg_‑imp) city, and 36 mpg_‑US (6.5 L/100 km; 43 mpg_‑imp) highway. It also uses the same computer (engine control unit) controlled distributorless coil-on-plug ignition as the Honda K-series engines. As of September 2019, the R series engines were only offered outside of Japan.