Honda Automobiles: Honda Civic Si

The new Si Coupe and Si Sedan return the sporty Si model name to the Civic lineup for the first time since model year 2015. To the sophisticated Civic Coupe and Sedan exterior, the Civic Si models add aggressive and athletic exterior features that are visually exciting as well as aerodynamically functional. In front are a distinctive gloss-black “solid wing” grille and headlight surrounds, unique Si badging, a racing-inspired fascia with a larger lower air intake. Unique 18-inch aluminum alloy wheels, low-profile 235/40R18 tires and a subtly longer and lower stance define the Si as a special breed of Civic. While in back, a decklid wing spoiler (elevated on the Si Coupe), unique rear fascia, center exhaust outlet with bright hexagonal finisher and Si badging further identify the new model as performance art.

The new front and rear fascias, together with the rear spoilers and the Civic’s already extensive underbody aerodynamic tailoring, helps the Civic Si slip through the air with minimal lift and drag at higher speeds. Lighting on both Si models includes LED daytime running lights (DRL), projector-beam headlights and fog lights, and LED taillights. Based on the Civic EX-T, the new Si models also feature a high level of premium features including an acoustic windshield, a one-touch power moonroof with tilt feature, heated power side mirrors, Smart Start/Entry, a Walk Away Auto Lock® feature, and more.

Key Body and Exterior Features 

  • Advanced Compatibility Engineering™ (ACE™) body structure with crash stroke front frame design*
  • Acoustic-glass, flush mounted windshield
  • Acoustically sealed unibody
  • Full underbody covering*
  • Projector-beam halogen headlights with Auto-On/Off
  • LED daytime running lights (DRL)*
  • LED taillights*
  • Honda LaneWatch™
  • One-touch power moonroof with tilt feature
  • Smart Entry and Push Button Start/Stop
  • Decklid wing spoiler
  • Civic Si badges on decklid and grille
  • Center exhaust outlet with chrome finisher*
  • 18-inch alloy wheels
  • 235/40R18* all-season tires (summer tires available)

* First for Civic Si

Exterior Dimensions
The 2017 Civic Si Coupe exterior dimensions relate similarly to those of the Civic EX-T Coupe, and both cars share their 106.3-inch wheelbase and 70.8-inch overall width with the EX-T Sedan and Si Sedan. In comparison to the EX-T Coupe, at 177.4 inches overall, the new Si Coupe is 0.5-inch longer due to its restyled front and rear fascias, and at 54.7 inches, it is also 0.2-inch lower due to its lower-profile 18-inch tires. The Civic Si Coupe’s wheel track is fractionally narrower at 60.5 inches front, 61.2 inches rear.

The 2017 Civic Si Sedan shares several key exterior dimensions with the Civic EX-T Sedan, including its 106.3-inch wheelbase and 70.8-inch overall width. From here on, the new Civic Si Sedan exterior differs subtly in its other measurements: its 182.8-inch overall length is 0.5-inch longer than the Civic EX-T Sedan, due to its unique front and rear fascia designs; and the lower-profile 18-inch tires make the Si Sedan 0.2-inch lower in overall height at 55.5 inches. The Civic Si Sedan’s wheel track is fractionally narrower at 60.5 inches front, 61.2 inches rear.

Key Exterior Specifications – Civic EX-T Coupe to Civic Si Coupe Difference

Key Exterior Specifications – Civic EX-T Sedan vs. Civic Si Sedan Difference

(See the Specifications and Features section for all data.)

Advanced Compatibility Engineering™ (ACE™)

As in all 2017 Civic models, Honda’s proprietary Advanced Compatibility Engineering™ (ACE™) body-structure enhances occupant protection and crash compatibility in frontal collisions in the Civic Si Coupe and Si Sedan. ACE utilizes a network of connected structural elements to distribute crash energy more evenly throughout the front of the vehicle, thus reducing the forces transferred to the passenger compartment. ACE channels frontal crash energy to both upper and lower structural elements, including the floor frame rails, side sills and A-pillars.

 

Crash Stroke
The ACE structure used on the Civic Si features a crash stroke technology developed by Honda engineers in the company’s advanced safety research laboratory in Raymond. Ohio. With this crash stroke structure, in a frontal collision the lower section of the front vehicle frame hinges to direct the engine down and rearward, helping direct crash energy into the vehicle’s floor while also minimizing cabin intrusion. This crucial piece of safety engineering effectively adds 80mm (3.2 in) of additional energy-absorbing “crash stroke” to the front of the vehicle.

Besides helping the Civic Si receive the highest ratings in the rigorous federal crash tests, the crash stroke structure enabled designers to develop the Civic Si’s body design to feature a short front overhang and short hood-line for a unique and exciting appearance, excellent outward visibility and improved handling. (See the Safety and Driver Assistive section for more information.)

High Body Rigidity
The high bending and torsional rigidity of the 2017 Civic Si Coupe and Si Sedan body structures (+25 percent over previous Civic Si) allows for fine-tuning of the vehicles’ suspension systems for superior handling performance. The stiff body structure allows the chassis to work more effectively and reduces the suspension action needed to control body motion. Another benefit of the rigid body structure is a quieter and more comfortable ride for passengers, with less Noise, Vibration and Harshness (NVH) felt over a wide range of driving conditions.

The localized lateral stiffness of the Si Coupe’s rear body is 4.6 percent stiffer than in the Si Sedan, primarily due to the differences in the rear body design, and this has significant dynamic benefits.

Some key body structure features include:
Under the Hood

  • A lower stiffener, located behind the engine on the front bulkhead, improves handling

In the Unibody

  • Certain connection areas where the A-pillars meet the floor sills, and the B-pillars meet both the floor sills and roof rails, reduce idle vibration and booming
  • Large body panels are shaped using computer aided engineering (CAE) to reduce booming
  • Gussets positioned inside the rear quarter areas of the unibody reduce road noise
  • An internal rear structural ring stiffens the unibody for improved handling
  • Short-pitch welding places spot welds 20mm (0.8 in) apart in critical areas of the unibody, compared to 40mm to 45mm (1.6 in to 1.8 in) traditional spacing, increasing stiffness and durability

Underneath the Vehicle

  • The floor pan is made of 590-MPa high-strength steel to provide a lighter yet stronger overall structure
  • Floor cross-members positioned under the driver and front passenger’s seating area improve ride comfort
  • A lateral cross-member and damper structure, located between the rear wheels, improves handling
  • A cross-car brace, located at the front of the vehicle, improves handling

Aerodynamics
The Civic Si combines athletic and sporty styling with advanced aerodynamic features to provide a unique and exciting blend of design and functionality. Compared to the Civic EX-T models on which they are based, key aerodynamic details for the Si Coupe and Si Sedan includes unique front and rear fascias, front chin spoiler, and decklid mounted wing spoiler. Above and beyond the Civic Coupe and Sedan’s inherently efficient aerodynamics, the new Civic Si aero package directly reduces coefficient of lift (CL) for improved high-speed dynamic performance.

As with the other current Civic models, computational fluid dynamics (CFD) was used to measure aerodynamic efficiency during the design phase, followed by scale-model wind tunnel testing and finally by full-scale wind-tunnel testing. Two critical aero gains from this process include a reduction in engine-room and underbody drag (CdA), which helps improve both fuel efficiency and interior quietness.

Specially shaped components at the front of the vehicle guide airflow through the radiator and into the engine’s cold-air intake, while channeling the remaining airflow over, around and under the vehicle. Along with the narrower A-pillars and flush-mounted glass, these contribute to the Civic’s efficient passage through the air. The relaxed slope of the Si Coupe’s rear roofline and rear window further improves aerodynamic efficiency.

Underbody Airflow
Along with the other current Civic models, the new Si Coupe and Si Sedan feature the flattest underbody of any gasoline-powered Honda production vehicle. A molded under-panel is positioned directly beneath the front fascia, smoothly starting the rearward flow of air underneath the vehicle. An aluminum under-tray is positioned underneath the engine and transmission and features a duct that allows ambient cooling airflow to the hydraulic engine mount. Dual acoustic fiber side under-panels extend from behind the front wheels to just ahead of the rear wheels, further smoothing the airflow as it travels rearward, while also reducing wind noise in the passenger cabin.

Lateral strakes located ahead of each wheel and tire (8.5 inches wide in front, and 3.5 inches wide in the rear) help deflect airflow around the tires for additional aerodynamic efficiency gains.

T-Direction Welding
Applied to the forward edge of the front door hinge pillars, just behind the front wheel openings, a “T-direction welding” technique helps the 2017 Civic earn top ratings in the rigorous IIHS Small Overlap Frontal collision test. Instead of using lateral overlapping welded joints on the hinge pillars, which would be negatively affected by the wheel moving rearward and striking the pillar in an offset frontal collision, the hinge pillars instead use a longitudinal welded seam designed to withstand sheer forces generated in such a collision.

Class-leading Forward Visibility
The narrow A-pillar section on the 2017 Civic Si helps provide a class-leading 84.3 degrees of forward visibility (the angle made by drawing lines from the driver’s eye point to the outboard edges of the A pillars). Safety performance is maintained through the pillars’ shape, the precise design of load pathways during a frontal collision or rollover, and the use of 1500 MPa hot-stamped ultra-high-strength steel for the A-pillars.

High-Strength Steel
Multiple steel grades are used in the Civic Si’s body construction to help achieve excellent overall vehicle dynamics, optimize safety performance, and lower NVH. Materials range from five different grades of steel, including premium hot-stamp steel and ultra-high-strength steel used in the unibody, to aluminum for the front bumper beam. All were chosen to achieve the best combination of strength, rigidity, dynamic performance and light weight. Fully 63 percent of the Si Coupe body structure is composed of high-strength steel, while 64 percent of the Si Sedan body structure is composed of high-strength steel.

Body Materials

Noise, Vibration and Harshness (NVH) Countermeasures
The latest Civic platform takes noise, vibration and harshness (NVH) countermeasures to the next level, positioning it at the top of its competitive set. Both Civic Si models feature strategically placed body sealants (see below). Additional NVH enhancements on all models include acoustic separators inside the A- and B-pillars, while a sound-insulating acoustic windshield (see below) further aids overall cabin quietness. (See the Interior section for more information.)

Engine Compartment Isolation
Measures to isolate sound and heat emanating from within the engine compartment include dedicated front, side and rear hood seals, strategically placed heat baffles, a hood insulator panel, an engine undercover, and dedicated insulation within the instrument panel. Inside the vehicle, a one-piece molded insulated carpet liner adds further to exceptional heat isolation and noise reduction for the 2017 Civic SI.

Acoustic Windshield
Special laminated acoustic glass is used for the Civic Si windshield to help reduce noise entering the cabin. Tuned specifically to attenuate wind-noise frequencies, the windshield glass uses an outer layer of 2.0mm safety glass, a 0.7mm thick middle layer of acoustic polyvinyl butyral (PVB), and a 1.8mm safety-glass inner layer for a total thickness of 4.5mm. This helps the Civic Si place at the top of its class in wind-noise performance. The windshield also incorporates UV light-absorbing technology. In addition, flush-mounted 4.0mm tempered front door glass and 3.5mm tempered rear door glass help reduce wind noise in the cabin. The one-touch power moonroof with tilt feature uses 3.5mm tinted and tempered glass.

Sound-absorbing Undercovers
A special baffle plate located beneath the center of the floor pan and felt fender inner liners further attenuates wind and road noise.

Body Sealing
The 2017 Civic Si has an unprecedented level of body sealing to dramatically reduce the levels of noise inside the vehicle. Throughout the unibody are 9.2 sq. in. (coupe) to 9.3 sq.in. (sedan) of weld seals and other sealers to reduce vibration and the transmission of noise.

Additional measures include:

  • Pillar separators seal the hollow A- and B-pillars to reduce the transmission of noise from the floor area into the passenger cabin.
  • Triple door sealing utilizes 360-degree molded door seals to reduce wind noise and improve isolation.
  • New door gap seals at the rear edges of the doors join triple-sealed door openings and lower door-edge seals in keeping wind noise from entering the cabin.
  • Multiple air leak reduction moldings and clips are used at key locations where the side windows slide into the doors, reducing the possibility of audible air leaks occurring in these locations.
  • Along with internal bracing, acoustic hole seals fill open areas inside the door structures, significantly reducing the amount of wind and road noise and vibration that can reach the cabin. The same Thinsulate™ material that is used in the doors is also used to reduce sound transmission through the roof, the body A- and B-pillars, and the rear tray.

Body Features

(See the Specifications and Features section for all data.)

LED Lighting
The 2017 Civic Si incorporates a wide range of light-emitting diode (LED) exterior lighting features. These include standard LED daytime running lights (DRL), LED taillights, LED brake lights, LED license-plate light and LED center high-mounted stop light.

Power Side Mirrors
Power side mirrors have a striking design and their body-colored housings are aerodynamically optimized to reduce wind noise and minimize turbulence. The mirrors are heated for improved efficiency in inclement weather and can be manually folded for greater convenience in tight parking situations.

Honda LaneWatch™
Both Civic Si models include Honda’s LaneWatch™ display that uses a camera located at the bottom the passenger-side exterior mirror to display a wide-angle view of the passenger side roadway on the Display Audio screen. The image appears when the right turn signal is activated, or when a button on the end of the turn signal stalk is pressed. (See the Safety and Driver Assistive section for more information.)

One-Touch Power Moonroof with Tilt Feature
The Civic Si Coupe and Si Sedan both have a one-touch power moonroof with tilt feature that will fully open or close with a single touch of the switch. The moonroof mechanism was purposely designed to provide ample headroom.

Integrated Rear Window Antenna
Bonded onto the rear window is a wire-type antenna that is optimized to help deliver excellent radio reception without the negative impact on vehicle aerodynamics that would be caused by a traditional mast antenna.

Power Windows and Locks
Power windows are standard equipment on both Civic Si models and include auto-up and -down operation on the driver and front passenger’s windows. Power locks are standard, and a customizable auto-locking feature can be configured using the Driver Information Interface and steering wheel-mounted controls.

Smart Entry and Push Button Start/Stop
The new Civic Si Coupe and Si Sedan include the upscale convenience of Smart Entry Push Button Start/Stop. The system simplifies approaching, entering and operating the Civic Si. To gain entry, the driver/passenger simply pulls either of front door handles while the remote in his or her possession. (See the Comfort and Convenience section for more information.)

Windshield Wipers
The Civic Si has variable intermittent windshield wipers. Designed to cover the maximum possible windshield area, the left (driver) and right (front passenger) windshield wipers are 25.5 inches and 18 inches long, respectively. For better appearance, the wipers are hidden low on the front cowl when not in operation. The wiper motor uses a built-in ECU that reduces complexity.

Capless Fueling System
The Civic Si’s capless fueling eliminates the fuel cap, meaning that fueling the vehicle simply requires opening the fuel lid, refueling, and then closing the lid. This smart and easy-to-use design eliminates the need to touch a dirty fuel cap, reduces the possibility of damaging the vehicle’s paint with the fuel cap or tether, or forgetting the fuel cap at the gas station.

Exterior Features

* First for Civic Si

(See the Specifications and Features section for all data.)

Exterior Colors
The 2017 Civic Si Sedan is available in six exterior colors including two metallic colors (Lunar Silver Metallic and Aegean Blue Metallic). Meanwhile the new Civic Si Coupe comes in a choice of seven exterior colors including two metallic colors (Lunar Silver Metallic and Aegean Blue Metallic) and one exclusive pearl color (Energy Green Pearl). All colors reflect the athletic and outgoing character of the new Civic Si models, offering vivid contrasts wherever light plays on the body-panel curves and angles, while also offering an exclusive and upscale appearance.

The 2017 Civic Si exterior colors include:

 

*Coupe Only

The exterior color choices are keyed to a black fabric interior with Si exclusive front seats featuring black/gray carbon-pattern accents and red stitching. (See the Interior section for more information.)