High revving power, quick shifting precision and tenacious grip describe the Civic Si powertrain. The 16-valve 2.0-liter engine uses Honda’s i-VTEC "intelligent" valve control system that combines Variable Timing Control (VTC) to continuously adjust camshaft phase with Variable Valve Timing and Lift Electronic Control (VTEC) that adjusts 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 utilizes VTEC and VTC for both intake and exhaust valve control to produce 197 horsepower (11) at 7800 rpm and 139 lb-ft. of torque (11) at 6200 rpm. The air intake system and the exhaust system are tuned to provide a deep sound and resonance, adding a level of performance feedback more commonly found on racecars. Further refinement is found in the drive-by-wire throttle body for smooth acceleration response and a chain driven balancer unit in the oil pan minimizes engine vibration.
The Civic Si is available exclusively with a 6-speed manual transmission. Designed to be exceptionally compact and lightweight, this 6-speed has also been engineered to shift with extremely short and precise throws. A final drive ratio of 4.76:1 promotes aggressive acceleration while a tall 6th gear provides for relaxed highway cruising. The short-throw clutch has an innovative torsion mechanism that considerably reduces noise. Multiple synchronizers are utilized, and 5th and 6th gears feature single carbon synchronizers for a direct shift feel.
Most vehicles have open differentials that send power to usually just one wheel in a corner, resulting in wheel spin and less potential for applying throttle and acquiring faster acceleration. The helical type limited slip differential (LSD) in the Civic Si improves acceleration and cornering performance by insuring that both front wheels receive an optimum level of torque at all times. In a straight line, both wheels are better utilized to put the engine’s power to the ground with minimal wheel spin. During hard cornering, the LSD transmits more torque toward the outside wheel to bias more power to the tire with the most grip and facilitates the outside wheel’s longer travel distance relative to the inner wheel. Primary benefits include the ability to accelerate harder exiting corners and enhances the vehicle’s responsiveness to throttle inputs in corners.
The 2006 Civic is available as either a sedan (Civic Hybrid, Civic Sedan) or a coupe (Civic Si, Civic Coupe). All models follow the "Advanced Personal Compact" design theme that incorporates a sweeping roofline and ultra-fast windshield rake that highlights the vehicle’s advanced one-motion profile, low and wide stance, and superior aerodynamic performance. The sedan and coupe each have 100 percent unique sheetmetal and unique proportions such as wheelbase, height and windshield angle. Wheel openings on both minimize the gap between the tire and the body to some of the lowest levels in the industry of just 1.9 inches front and 1.7 inches rear (a reduction of 0.7 inches front and 1.2 inches rear, respective to the 2005 Civic Sedan).
As the performance leader for the lineup, the Civic Si conveys an aggressive attitude that speaks to the performance potential underneath that also carries over into the Civic Coupe. The steeply raked windshield creates a 21.9-degree angle that is even sleeker than the 23.9 degree rake in the Acura NSX supercar. The long trunk deck, with its frontward sloping bumper, accents the forward motion conveyed by the overall vehicle shape. A trapezoidal lower body with short front and rear overhangs further convey a powerful stance.
The Civic Hybrid styling sets the direction for the Civic Sedan with a technologically sophisticated and refined presence derived from a monoform design, long wheelbase and short front and rear overhang. The steeply raked windshield on the sedan forms a 23.9-degree angle.
The Civic is built on an all-new version of Honda’s Global Compact Platform. The solid unit body of the Civic was designed from the outset to define a new standard for torsional and bending rigidity in the compact segment. The new Global Compact Platform implements advanced body construction technologies for enhanced safety, better rigidity, improved ride comfort and a quieter cabin. With 50 percent total high strength steel content and advanced new structural engineering, torsional rigidity increases by 35 percent.
Body construction now includes Honda’s Advanced Compatibility Engineering (ACE) Body Structure that enhances frontal collision energy management through a network of load bearing structures in the front of the vehicle. Conceived around "real world" safety, this newly developed front-end frame structure incorporates new upper and lower frame members to significantly enhance energy dispersion in a frontal collision. The ACE concept differs from traditional crash designs that channel a high percentage of collision force through a vehicle’s two lower channels in a collision (useful only if the frames of the two vehicles connect). The ACE design with its polygonal front structure helps reduce the potential for misalignment with the frame of the opposing vehicle. These features are designed to increase compatibility between vehicles of different size categories for enhanced occupant protection in the event of a collision.
Honda’s commitment to safety extends to pedestrians as well as vehicle occupants. To help reduce pedestrian injuries in the event of a collision, the Civic’s hood and fender areas are designed to deform if contacted by the head of an adult or child pedestrian. Energy-absorbing collapsible hood supports, wiper arms and fender mounts are designed to allow substantial deformation in an impact.
The Civic conveys an aerodynamic presence on the surface, but many aerodynamic improvements exist in areas that may not be as obvious. All models feature a chin spoiler and multiple under covers that reduce air turbulence near the engine, rear wheels and rear bumper. The Civic Si manages airflow even further and features a rear wing spoiler that creates meaningful and intentional downforce at high speeds, along with a brake cooling strake (a small fin ahead of the front wheel) that directs air across the brake rotor like a dedicated brake duct. The Civic Hybrid and Civic Coupe models use a lip spoiler on the trunk that cleans up the airflow behind the vehicle. The Civic Hybrid has an enhanced undercover for even cleaner aerodynamics. In order to accommodate the steeply raked windshield and its significant surface area, opposable windshield wipers are used that cover more surface area than typical wipers and the blade bodies have a flat design that makes air flow push the wiper blades firmly against the glass.
Honda has a tradition of making its vehicles fun-to-drive with responsive suspension tuning and refined road manners. Precise and sharp handling performance also contributes to accident avoidance maneuverability. The 2006 Honda Civic chassis delivers higher levels of sportiness and ride comfort with improvements in three key areas - enhanced suspension geometry with larger wheels and tires, a longer wheelbase, and a new generation 4-channel anti-lock braking system. The changes add up to a new Civic that is even more responsive and sporty in demanding situations while also maintaining a smooth and quiet ride.
The all-new MacPherson strut front suspension design incorporates new geometry with a high caster angle for straight line stability along with improved toe-control dynamics for sharp and responsive steering. Changes to steering angles, bushings, material rigidity, and spring and shock tuning result in amazingly linear suspension movement at the upper limit of vehicle dynamics and flatter cornering.
The all-new multi-link double wishbone rear suspension design benefits from a new design that facilitates a longer damper stroke and improved positioning of the damper itself. The additional rebound stroke allows the vehicle to soak up bumps and harsh road surfaces with quietness and ease. The damper is mounted closer to the wheel for a more favorable 1.1:1 lever ratio (the relationship between the suspension movement and the distance that the damper actually travels). The previous relationship was 1.7:1. The more direct relationship means the forces acting on the shock do not become magnified and the intended tuning provides maximum benefit throughout a wider range of suspension travel. These changes combined with sport-oriented spring and damper tuning greatly increase the overall sporty feel of the vehicle and increase the feeling of coordination between the front and rear suspensions (a surprisingly uncommon trait in many vehicles.
The steering systems feature quick gear ratios for sharp and sporty transitions. Previously a high-mounted steering gearbox, the new steering system is now located lower in the vehicle to improve suspension geometry for a more direct feel and quick response. The Civic Si and Civic Hybrid feature a sport-oriented speed sensitive Electric Power Steering (EPS) that increases power assist at low speeds and reduces power assist at high speeds. The Civic Coupe and Civic Sedan use a speed sensitive hydraulic power steering system. All models have a tilt and telescope steering wheel.
Larger wheels and tires contribute to the Civic’s improvement in ride and handling. The Civic Si uses Michelin’s all-season Pilot HX MXM4 tire in size P215/45 R17 (also available is a new Pilot Exalto high performance summer version as a factory option) and 17x7 inch alloy wheels. A dealer installed 18-inch tire and wheel package is available. The Civic Hybrid features P195/65 R15 low rolling resistance tires with lightweight and aerodynamic 15x6 alloy wheels. The most popular LX and EX trim levels for sedan and coupe have P205/55 R16 tires and 16x6.5 inch wheels (the EX has alloy wheels and the LX has steel wheels with covers). The DX sedan and coupe ride on P195/65 R15 tires with 15x6 steel wheels with covers.
All Civics are equipped with a new 4-channel anti-lock braking system (ABS) with Electronic Brake Distribution (EBD). Disc brakes are used on the front and rear wheels on Si and EX models; rear drum brakes are used on Hybrid, LX and DX models. The 4-channel ABS with EBD independently modulates braking power at each wheel, as opposed to the more common 3-channel system that modulates the front wheels independently and the rear wheels with equal braking force. Electronic Brake Distribution proportions brake power to the rear wheels based on vehicle weight distribution. The new 4-channel capability allows the rear wheels to react independently while cornering, representing a significant enhancement to the ABS system’s ability to influence vehicle stability and safety. Further additions to the braking system include a new ABS control module (that applies the new 4-channel features) and a brake booster that improves pedal feel. Bottom line, the Civic stops with greater authority and added control.