The 2017 Honda Civic Si marks a significant turning point in its lineage, embracing a turbocharged engine for the first time in its history. This bold move elevates the Civic Si Coupe and Sedan, injecting a new level of performance and efficiency into these beloved sporty models. Building upon the foundation of the 1.5-liter 16-valve DOHC direct-injected turbocharged engine found in other Civic trims, the Si variant is meticulously enhanced to deliver a more thrilling driving experience. Boasting 205 horsepower at 5700 rpm and a robust 192 lb-ft of torque, available across a wide band from 2100 to 5000 rpm, the 16 Honda Civic Si engine represents a substantial leap forward compared to its naturally aspirated predecessors. This translates to a remarkable increase of 31 horsepower and 25 lb.-ft. of torque over other 1.5-liter turbocharged Civic models, setting a new benchmark for compact sports cars.
This strategic shift to a smaller displacement, turbocharged engine in the 16 honda civic si represents a departure from the previous generation 2015 Civic Si, which housed a naturally aspirated 2.4-liter engine. Despite a 36-percent reduction in displacement, the new 1.5-liter engine is engineered to be lighter, more compact, and significantly more fuel-efficient. Through the implementation of a sophisticated, electronically controlled, intercooled turbocharging system, the 16 honda civic si achieves the same peak horsepower figure as its predecessor, but at a considerably lower and more accessible rpm. More crucially, the turbocharged engine delivers a decisive advantage in peak torque across a much broader rpm range. The outcome is a powertrain that is exceptionally responsive, perfectly aligning with the Civic Si’s core mission of providing a fun and engaging driving experience.
Honda remains committed to the purist driving ethos of the Si, retaining the exclusive availability of a 6-speed manual transmission in the 16 honda civic si. This dedication to driver control and tactile engagement is further enhanced by an all-new gearbox that offers smoother shift action and optimized gear ratios, carefully calibrated to complement the power delivery characteristics of the new turbocharged engine. To ensure optimal power transfer to the road, the 16 honda civic si continues to feature a helical limited-slip front differential as standard equipment, a feature that has been a hallmark of the Si’s performance pedigree.
The 16 honda civic si engine adheres to stringent EPA Tier3/Bin125 and CARB LEV 3/ULEV125 emissions standards. The enhanced efficiency of the new engine and transmission, coupled with improvements in aerodynamics and a significant reduction in rolling resistance, results in substantial gains in both performance and fuel economy compared to the 2015 Civic Si 2.4-liter. EPA fuel economy ratings demonstrate impressive improvements across the board:
- +6 mpg City (a 27% increase)
- +7 mpg Highway (a 23% increase)
- +7 mpg Combined (a 28% increase)
These advancements underscore Honda’s commitment to delivering both exhilarating performance and responsible efficiency in the 16 honda civic si.
Key Powertrain Specifications & Features
The heart of the 16 honda civic si is its Turbocharged 1.5-liter, DOHC direct-injected inline-4 engine, packed with cutting-edge technology:
- Dual Variable Timing Control (VTC): Optimizes valve timing for enhanced performance and efficiency.
- Low inertia mono scroll turbo with electronic waste gate: Ensures rapid boost response and precise control.
- Computer-controlled Direct Injection (DI) with multi-hole fuel injectors: Maximizes combustion efficiency and reduces emissions.
- 10.3:1 compression ratio: Optimized for turbocharged performance.
- Lightweight, high rigidity steel crankshaft: Contributes to engine durability and smooth operation.
- Drive-by-Wire throttle system: Provides precise and responsive throttle control.
- Maintenance Minder™ system: Optimizes service intervals, reducing ownership costs.
- 100,000 +/- miles tune-up interval: Long-lasting reliability and reduced maintenance.
- 205 horsepower at 5700 rpm (SAE net): Exhilarating power output.
- 192 lb-ft. torque at 2100-5000 rpm (SAE net): Broad torque curve for responsive acceleration.
- Premium Unleaded recommended fuel: Optimized for high performance.
Emissions/Fuel Economy Ratings
The 16 honda civic si achieves an impressive balance of performance and environmental responsibility:
- EPA Tier3/Bin125 and CARB LEV 3/ULEV125 Emissions compliant: Meets stringent emissions standards.
- U.S. EPA fuel-economy ratings (city/highway/combined): 28/38/32 mpg: Exceptional fuel efficiency for a performance vehicle.
Transmission/Drivetrain
The 16 honda civic si drivetrain is engineered for driving enthusiasts:
- 6-speed Manual Transmission: Provides ultimate driver engagement and control.
- Helical Limited-Slip Differential: Maximizes traction and cornering performance.
- *First for Civic Si: Highlighting key advancements in the model.
Engine Architecture and Features: Turbocharged 1.5-Liter In-Line 4 Cylinder
The 16 honda civic si debuts the first-ever turbocharged engine in the Si model line. While related to the 1.5-liter turbocharged engine in the 2017 Civic EX-T Coupe and Sedan, the Si powerplant undergoes substantial upgrades to unleash an additional 31 horsepower and 25 lb.-ft. of torque. Equipped with direct injection, a low-inertia high-flow mono scroll turbo system featuring an electrical waste-gate, and dual Variable Valve Timing Control (VTC), the turbocharged 16 honda civic si engine rivals the horsepower and torque of much larger engines.
Compared to the larger, naturally-aspirated 2.4-liter engine in the previous generation Civic Si (model year 2015), the 16 honda civic si engine delivers the same peak horsepower (205) but at a significantly lower and more accessible 5700 rpm (compared to 7000 rpm). Furthermore, the new Si generates 18 lb.-ft. more peak torque (192) and sustains it across a much wider engine speed range. Peak torque in the 16 honda civic si arrives at a mere 2100 rpm—less than half the engine speed (4400 rpm) of the previous 2.4-liter engine.
Specifically engineered for direct injection and turbocharging, the 16 honda civic si powerplant is meticulously designed to deliver exceptional torque output from 2,100 rpm to 5,000 rpm. This broad torque plateau maximizes responsiveness and acceleration without demanding high engine revs. This readily available power is a defining characteristic of the 16 honda civic si, contributing to its immediate power delivery and inherently fun-to-drive nature.
The turbocharged 1.5-liter engine in the 16 honda civic si is designed to operate on premium unleaded fuel and is officially rated at 205 horsepower at 5,700 rpm and 192 lb.-ft of torque between 2,100 and 5,000 rpm (SAE net). The EPA fuel economy ratings for the Civic Si are 28/38/32 mpg1.
Cylinder Block and Crankshaft
The 16 honda civic si 1.5-liter inline four engine features a lightweight die-cast aluminum block with individual reinforced main bearing caps to minimize weight. Cast-in iron cylinder liners ensure long-lasting durability. Each journal on the lightweight forged-steel crankshaft is micropolished to reduce internal friction, enhancing efficiency and longevity.
Pistons and Connecting Rods
The pistons in the 16 honda civic si engine are designed with “cavity-shaped” crowns to promote stable combustion and improve overall efficiency. These lightweight pistons feature an optimized skirt design to minimize reciprocating weight, reducing vibration and increasing operating efficiency. Twin oil jets cool the pistons from underneath, while a cooling gallery within each piston provides superior heat resistance. Ion-plated piston rings further minimize friction for enhanced operating efficiency. Lightweight, high-strength steel connecting rods are heat-forged and “crack separated” to create lighter, stronger rods with optimally fitted bearing caps.
Cylinder Head and Valvetrain
The direct-injected 16 honda civic si engine utilizes a lightweight DOHC cylinder head crafted from pressure-cast aluminum alloy. The exhaust port is integrated directly into the cylinder head, eliminating the need for a traditional separate exhaust manifold. Compared to other 1.5-liter Civic turbocharged engines with a 10.6:1 compression ratio, the 16 honda civic si features a slightly lower 10.3:1 ratio. This adjustment allows the engine to reliably operate at a higher maximum boost pressure of 20.3 psi, compared to 16.5 psi in the Civic EX-T.
A low-friction, silent-chain drives the dual overhead cams and four valves per cylinder. This cam drive is maintenance-free for the engine’s lifespan. Thin-wall hollow camshafts further contribute to weight reduction.
To optimize fuel efficiency, emissions, and power, the turbo engine incorporates sodium-filled exhaust valves. A hollow chamber within the valve contains sodium that is cooled by the exhaust-port cooling jacket. As the chamber approaches the valve head, the sodium effectively cools the entire valve. This internal cooling reduces the need for enriched fuel mixtures, which were traditionally used in turbo engines to cool exhaust valves. The leaner mixture resulting from this technology reduces emissions, improves fuel efficiency, and contributes to increased power output in the 16 honda civic si.
The cylinder head utilizes smaller M12 sparkplugs to save space and weight. It also features direct-injection multi-hole fuel injectors with a small diameter bore. Higher-pressure direct injection optimizes fuel atomization for more efficient combustion. The intake port and piston crown are specially designed to create a high-tumble intake charge, further enhancing combustion efficiency in the 16 honda civic si.
The 16 honda civic si turbocharged engine incorporates Variable Valve Timing Control (VTC) to independently adjust the timing of both intake and exhaust camshafts. This variable cam timing optimizes valve timing to suit various driving conditions. Under light loads, increased valve overlap reduces pumping losses and improves fuel efficiency. During initial acceleration at low engine speeds and high engine loads, increased overlap boosts the scavenging effect, enhancing torque and responsiveness. At high engine speeds and loads, such as during full-throttle acceleration, reduced valve overlap maximizes engine output by improving both intake and scavenging.
Direct Injection System
The direct-injection system in the 16 honda civic si engine enables increased torque across the entire operating range and enhances fuel efficiency. The system features a compact, high-pressure, direct-injection pump that provides both high fuel flow and pulsation suppression, while variable pressure control optimizes injector operation. Multi-hole injectors deliver fuel directly into each cylinder, allowing for more efficient combustion compared to conventional port fuel injection designs.
These multi-hole injectors create an ideal stoichiometric fuel/air mixture in the cylinders for optimal emissions control. The direct-injection system adapts its function based on operating conditions to achieve peak performance. During cold engine startup, fuel is injected into the cylinders on the compression stroke, creating a weak stratified charge effect that improves start-up and reduces emissions before reaching normal operating temperature.
Once the engine is fully warmed up, fuel is injected during the intake stroke for maximum power and fuel efficiency. This creates a more homogeneous fuel/air mix in the cylinder, aided by the high-tumble intake port design. This improves volumetric efficiency, and the cooling effect of the incoming fuel enhances anti-knock performance in the 16 honda civic si.
Low Inertia Mono Scroll High-Flow Turbo System with Electronic Wastegate
The 16 honda civic si turbocharged engine utilizes a unique high-flow, high capacity turbocharger for maximum responsiveness. The Mono scroll housing design enables the turbo to build boost even at relatively small throttle openings and low rpm. The electrically actuated wastegate provides precise control over boost pressure. With its lower compression ratio, the 16 honda civic si maximum boost pressure is elevated to 20.3 psi (from 16.5 psi in the Civic EX-T), significantly increasing maximum horsepower and torque.
A large, low-restriction air intercooler is positioned low in the front of the car to receive unobstructed airflow when the vehicle is in motion. Intake air flows from the air filter to the turbo compressor, then to the intercooler, and finally to the engine’s intake ports. The intercooler reduces the temperature of the intake air, increasing its density for enhanced performance in the 16 honda civic si. Lightweight, rigid resin composite inlet pipes are used to plumb the turbo system, reducing weight and carrying intake air to and from the intercooler.
Friction Reducing Technology
The 16 honda civic si engine incorporates friction-reducing technologies to improve engine efficiency. Lightweight aluminum pistons feature a low-friction coating applied in a unique pattern to reduce overall friction as they move within the cylinder bores. Plateau honing, a 2-stage machining process, creates an ultra-smooth surface in the cylinders, further lowering friction between pistons and cylinders and enhancing long-term wear characteristics. Low viscosity 0W-20 oil also minimizes friction. Additional contributors to operating efficiency include a special two-stage oil pump relief valve, low-friction oil seals, a low-drag piston ring design, a low-friction cam chain, and a lightweight crankshaft in the 16 honda civic si.
Drive-by-Wire Throttle System
The 16 honda civic si Drive-by-Wire throttle system replaces a conventional throttle cable with intelligent electronics that connect the accelerator pedal to a throttle valve inside the throttle body. This reduces under-hood clutter and weight while providing quicker and more accurate throttle actuation. A specially programmed “gain” rate between the throttle pedal and engine optimizes drivability and engine response for various driving conditions in the 16 honda civic si.
Honda’s Drive-by-Wire system monitors throttle pedal position, throttle valve position, engine speed (rpm), and road speed to evaluate current driving conditions. This information defines the throttle control sensitivity, giving the 16 honda civic si throttle pedal a predictable and responsive feel that meets driver expectations.
The 16 honda civic si features a drive mode selector on the center console, allowing drivers to choose between NORMAL and SPORT modes. In SPORT mode, the Drive-by-Wire throttle system adopts a more aggressive profile, optimized for performance driving.
Emissions Control
The 16 honda civic si engine meets stringent EPA Tier3/Bin125 and CARB LEV 3/ULEV125 emissions standards and is certified to this level of emissions performance for 150,000 miles.
00,000+/- Mile Tune-up Intervals
The 16 honda civic si powerplant requires no scheduled tune-ups for 100,000+/- miles or more, aside from routine inspections and fluid/filter replacements. The first tune-up includes a water pump inspection, valve adjustment, and new spark plug installation.
Maintenance Minder™ System
To minimize unnecessary service stops and ensure proper vehicle maintenance, the 16 honda civic si incorporates a Maintenance Minder™ system. This system continuously monitors vehicle operating conditions and alerts the driver via a message on the Driver Information Interface (DII) when maintenance is required.
6-Speed Manual Transmission
Continuing the Si’s tradition for enthusiast drivers, the 16 honda civic si is exclusively offered with a quick-shifting 6-speed manual transmission (6MT). This unit delivers a smooth and precise shift feel with exceptional efficiency. Compared to the 6-speed manual in the Civic EX-T, the Si transmission features more rigid bracket mounts to accommodate the engine’s higher horsepower and torque output. Refinements to the shift linkage and selector mechanism result in a precise and smooth gear lever shift action with a 10 percent reduction in stroke.
The 10th-generation Civic 6-speed manual transmission is meticulously engineered for state-of-the-art performance and shift action, incorporating reduced internal friction, tighter internal tolerances, and improved synchronizers. The transmission also features a more rigid aluminum exterior case, higher-capacity ball bearings, stiffer gear shafts, and increased torque capacity compared to the previous Civic Si transmission. A constant-mesh helical reverse gear mechanism significantly reduces noise when reverse is selected. A reverse lockout feature prevents accidental shifts into reverse while the car is moving forward in the 16 honda civic si.
Manual Transmission Gear Ratio Comparison
| Gear Ratio (X:1) | 2015 Civic Si 2.4L | 2017 Civic EX-T 1.5L Turbo | 2017 Civic Si 1.5L Turbo |
|---|---|---|---|
| 1st | 3.267 | 3.643 | 3.643 |
| 2nd | 2.040 | 2.080 | 2.080 |
| 3rd | 1.429 | 1.361 | 1.361 |
| 4th | 1.073 | 1.024 | 1.024 |
| 5th | 0.830 | 0.830 | 0.830 |
| 6th | 0.647 | 0.686 | 0.686 |
| Reverse | 3.583 | 3.673 | 3.673 |
| Final Reduction Ratio | 4.760 | 4.105 | 4.105 |
Powertrain Feature Comparison
| Feature | 2015 Civic Si 2.4L | 2017 Civic EX-T 1.5L Turbo | 2017 Civic Si 1.5L Turbo |
|---|---|---|---|
| Engine Type | L-4 | L-4 Turbocharged | L-4 Turbocharged |
| Displacement (cc) | 2354 | 1498 | 1498 |
| Horsepower @ rpm (SAE net) | 205 @ 7000 | 174 @ 5500 | 205 @ 5700 |
| Torque (lb-ft @ rpm SAE net) | 174 @ 4400 | 167 @ 1800-5500 | 192 @ 2100-5000 |
| Bore and Stroke (mm) | 87.0 x 99.0 | 73 x 89.5 | 73 x 89.5 |
| Compression Ratio | 11.0:1 | 10.6:1 | 10.3:1 |
| Maximum Boost Pressure (psi) | – | 16.5 | 20.3 |
| Fuel Injection | Port | Direct | Direct |
| Programmed Fuel Injection (PGM-FI) | • | – | – |
| Valvetrain | 16-Valve DOHC i-VTEC® | 16-Valve DOHC w/ VTC | 16-Valve DOHC w/ VTC |
| Drive-by-Wire Throttle System | • | • | • |
| Low-Inertia MONO Turbocharger | • | • | |
| Variable Intake Valve Lift | • | – | – |
| Intake/Exhaust Variable Cam Timing | • | • | • |
| Transmission | 6MT | CVT/6MT | 6MT |
| Helical Limited-Slip Differential | • | – | • |
| Front Wheel Drive | • | • | • |
| 100K +/- Miles No Scheduled Tune-Ups | • | • | • |
Fuel Economy and Emissions Ratings
| Ratings | 2015 Civic Si 2.4L | 2017 Civic EX-T 1.5L Turbo | 2017 Civic Si 1.5L Turbo |
|---|---|---|---|
| EPA Fuel Economy Ratings1 (city/hwy/combined) | 22/31/25 (6MT) | 31/42/35 (6MT) | 28/38/32 (6MT) |
| Recommended fuel | Premium Unleaded | Regular Unleaded | Premium Unleaded |
| CARB emissions rating | ULEV-2 | LEV3-ULEV125/ LEV3-SULEV30 | LEV3-ULEV125 |
(See the Specifications and Features section for all data.)
1Based on 2017 EPA fuel-economy ratings. Use for comparison purposes only. Your mileage will vary depending on how you drive and maintain your vehicle, driving conditions and other factors.
