Civic Si Powertrain
The 2006 Civic Si incorporates a host of innovative features designed to deliver a cutting-edge combination of performance, fuel efficiency, and low emissions. Most apparent is the i-VTEC "intelligent" valve-control system, a technology that combines VTC (Variable Timing Control) - which continuously adjusts camshaft phase-with Variable Valve Timing and Lift Electronic Control (VTEC) – which changes valve lift, timing, and duration. Combining these two systems results in impressive horsepower and high torque with good fuel economy and low exhaust emissions.
The Civic Si engine is a dual overhead cam (DOHC) all-aluminum, 2.0-liter inline four-cylinder design that uses 16 valves, a high-performance version of the i-VTEC system and a specially tuned high-volume intake manifold. The Civic Si produces 197 horsepower at 7800 rpm, up from 160 horsepower at 6500 rpm and torque increases from 132 lb-ft. at 5000 rpm to 139 lb-ft. at 6200 rpm. At nearly 100 horsepower per liter, it has one of the highest specific outputs of any production engine in the world.
In keeping with Honda's proven commitment to the environment, the Civic Si engine meets strict Low Emission Vehicle-2 (LEV-2) tailpipe emissions standards. Engine, fuel tank and catalytic converter modifications made for 2006 have lowered evaporative emissions by 75 percent to achieve a LEV-2 Evaporative Emissions rating.
The Civic Si is available exclusively with a short-throw 6-speed manual transmission. The final gear ratio is a low 4.765:1 that complements the additional horsepower and provides enhanced acceleration. Designed to be compact and lightweight, the 6-speed has also been engineered to provide the lightning-quick shift action of a racecar transmission. Synchronizers (triple cone on gears 1 and 2, double cone on gears 3 and 4, and single cone carbon on gears 5 and 6) help reduce shifting load for a light, responsive feel. The Si also includes a short-throw clutch with a torsion mechanism that enhances clutch refinement in terms of engagement and feel.
Civic Si Powertrain At-A-GlanceAluminum block with cast-in iron liners for light weight and durability
16-valve DOHC i-VTEC "intelligent" valve-control system
Lightweight alloy pistons and forged steel connecting rods (11.0:1 Compression Ratio)
One-piece crankshaft carrier with ferrous main bearing caps for improved rigidity and durability
High performance camshafts
Performance-tuned intake manifold
Drive-by-wire throttle control
Computer-controlled Programmed Fuel Injection (PGM-FI)
Direct Ignition System
Chain-driven balancer unit mounted in oil pan
Torque rod engine mount system consists of an upper and lower torque rod, a hydraulic body mount and a front beam stopper
Maintenance Minder system
Maintenance-free silent-chain camshaft drive
Maintenance-free serpentine accessory drive with auto tensioner
Emissions/Fuel EconomyEstimated EPA fuel economy of 22/31 mpg (city/highway)
Low Emission Vehicle-2 (LEV-2) emissions
6-Speed Manual TransmissionExceptionally short throws for "racecar" shift feel
Low final gear ratio for quick acceleration (4.765:1)
Advanced clutch torsion mechanism enhances clutch engagement
Hydraulic damper integrated with master cylinder for reduced pedal vibration
Short clutch-pedal stroke for effortless shifting
Advanced friction material for improved clutch operability
Helical type limited slip differential
Source: Honda PR