The 2019 RDX takes an entirely new approach to performance with its new direct-injected and turbocharged 2.0-liter 16-valve DOHC VTEC ® inline-4 engine, segment-first 10-speed automatic transmission and available next-generation Acura Super Handling All-Wheel Drive™ (SH-AWD®) torque-vectoring all-wheel-drive system.
The new 2.0-liter turbo engine is mated to a new smooth and responsive Sequential SportShift 10-speed automatic that is closely related to the unit introduced on two-wheel-drive versions of the 2018 Acura RLX performance luxury sedan. The new automatic transmission takes greater advantage of available engine torque while maximizing smoothness and efficiency during highway cruising.
With peak output of 272 horsepower (SAE net) at 6,500 rpm and 280 lb.-ft. of torque (SAE net) from 1,600 to 4,500 rpm – versus 252 lb.-ft. at 4500 rpm for the previous V6 – the DOHC 2.0-liter engine produces greater torque (+28 lb.-ft.) at a much lower engine speed and across a broader range engine speed than before. Combined with the new 10AT, with its 53-percent wider overall ratio range, the new turbocharged engine delivers incredibly smooth, linear and virtually lag-free power along with superior fuel efficiency.
The RDX is available with efficient front-wheel drive, or with a new generation of Acura’s acclaimed SH-AWD system. Replacing the AWD with Intelligent Control System™ on the second-generation RDX, the new SH-AWD system is one of the most advanced torque-vectoring AWD technologies in its class. Under most circumstances, SH-AWD can send up 70 percent of available engine torque to the rear wheels and 100 percent of that torque to either the left or right rear wheel helping RDX put the newfound torque to the pavement with both outstanding stability and agility.
The Drive-By-Wire™ throttle, 10-speed transmission and available SH-AWD™ are all tied into the RDX’s new four-mode Integrated Dynamics system, controlled from the prominent drive mode dial on the vehicle’s center console. With Comfort, Sport, Sport+ and Snow modes, the Integrated Dynamics system allows drivers to select desired dynamic performance characteristics. Additionally, Active Sound Control (ASC), variable-ratio electric power steering (EPS) and, on Advance grades, the four-wheel Active Damper System are integrated in the system (see Chassis section for additional details).
What’s New
The following powertrain features are new for the 2019 Acura RDX:
- VTEC Turbo® 2.0-liter, DOHC direct-injected inline-4 engine
- Computer-controlled Direct Injection (DI) with high-flow fuel injectors
- Low inertia mono-scroll turbo system with electric wastegate
- 10-Speed Automatic Transmission with Sequential SportShift
- Electronic shift-by-wire gear selector
- Acura Super Handling All-Wheel Drive™ (SH-AWD®) (available)
- 4-mode Integrated Dynamics System
Key Powertrain Features
Engine
- VTEC Turbo® 2.0-liter, DOHC direct-injected inline-4 engine
- 272 horsepower at 6,500 rpm (SAE net)
- 280 lb.-ft. torque at 1,600-4500 rpm (SAE net)
- VTEC® valvetrain with Dual VTC
- Low-inertia mono-scroll turbo system with electric wastegate
- Computer-controlled Direct Injection (DI) with high-flow fuel injectors
- 9.8:1 compression ratio
- Super lightweight, high-rigidity steel crankshaft
- “4-into-1” exhaust manifold integrated into cylinder-head casting
- Sodium-filled exhaust valves
- Forged steel connecting rods
- Drive-by-Wire™ throttle system
- Maintenance Minder™ system optimizes service intervals
- 100,000 +/- miles tune-up interval
- Premium Unleaded fuel recommended
Emissions/Fuel Economy Ratings
Emissions Ratings
- LEV3-SULEV30
Anticipated EPA Fuel Economy Ratings (city/highway/combined)
- 2.0-liter turbo, 10AT, FWD: 22/28/24 mpg*
- 2.0-liter turbo, 10AT, FWD, A-Spec: 22/27/24 mpg*
- 2.0-liter turbo, 10AT, SH-AWD®: 21/27/23 mpg*
- 2.0-liter turbo, 10AT, SH-AWD®, A-Spec: 21/26/23 mpg*
Sequential SportShift 10-Speed Automatic Transmission with Paddle Shifters
- Electronic shift-by-wire gear selector
- Sequential SportShift automatic transmission allows semi-manual operation
- Steering wheel-mounted paddle shifters
- Cooperative control between Drive-by-Wire throttle and transmission
- Advanced shift-hold control limits upshifts during spirited driving
- Grade Logic Control reduces gear “hunting” on various road gradients
Two Available Drive Systems
- Front-wheel drive
- Super Handling All-Wheel Drive System™ (SH-AWD®) with dynamic torque vectoring
*Based on projected 2019 EPA mileage ratings. Use for comparison purposes only. Your actual mileage will vary depending on how you drive and maintain your vehicle, driving conditions and other factors.
Engine Architecture and Features
Cylinder Block and Crankshaft
The RDX’s turbocharged inline-4-cylinder engine uses a lightweight die-cast aluminum block with reinforced main bearing caps to minimize weight. Centrifugally cast iron cylinder sleeves enhance durability. Each journal on the crankshaft is micropolished to reduce operating friction.
Pistons and Connecting Rods
The RDX’s engine has pistons with “cavity-shaped” crowns that help maintain stable combustion and contribute to improved efficiency. The lightweight pistons have a carefully optimized skirt design to minimize reciprocating weight, which minimizes vibration and increases operating efficiency. The pistons are cooled by oil jets directed at the underside of each piston crown. Special cooling channels in the pistons also help keep operating temperatures in check. Ion-plated piston rings help reduce friction for greater operating efficiency. Lightweight, high-strength steel connecting rods are heat-forged in one piece and then “cold cracked” to create a lighter and stronger rod with an optimally-fitted bearing cap.
Cylinder Head and Valvetrain
The direct-injected 2.0-liter VTEC Turbo® has a lightweight, low-pressure die-cast aluminum alloy double overhead cam (DOHC) cylinder head. With the exhaust manifold cast directly into the cylinder head, the use of a separate—and heavy—cast iron exhaust manifold is eliminated, reducing weight and simplifying assembly. The manifold is also liquid cooled to help keep heat in check and has a “4-into-1” design for improved fuel efficiency and responsiveness.
A low-friction, silent chain drives dual overhead cams that, in turn, activate four valves per cylinder. The cam drive is maintenance free for the life of the engine. To further reduce weight, thin-wall hollow camshafts are used.
To benefit fuel efficiency, emissions and power, the turbo engine utilizes sodium-filled exhaust valves. A hollow chamber within the valve contains sodium that is cooled by the exhaust port cooling jacket. Since the chamber is close to the valve head, the sodium helps to cool the entire valve; and since the valve is internally cooled, it doesn’t need the enriched fuel mixture that is generally used in turbo engines to help cool exhaust valves. The resultant leaner mixture reduces emissions, and increases fuel efficiency and power.
The engine uses an advanced valve control system to combine high power output with high fuel efficiency and low emissions. The system combines intake and exhaust Variable Timing Control (dual VTC), which continuously adjusts the intake and exhaust camshaft phasing, with Variable Valve Timing and Lift Electronic Control (VTEC), which changes valve lift, timing and duration of the exhaust valves.
The cam timing is varied based on input from sensors that monitor rpm, timing, throttle opening, cam position and exhaust air-fuel ratio. The result is increased fuel efficiency, lower emissions and optimum drivability.
The cylinder head includes small 12-millimeter (M12) sparkplugs, down from the more common 14-millimeter (M14) size, to save space and weight. The head also includes direct-injection multi-hole wide-range fuel injectors with a small-diameter bore. High-pressure direct injection optimizes fuel atomization, allowing for more efficient combustion. To provide a high-tumble intake charge that further enhances combustion efficiency, both the intake port and piston crown have special designs.
Dual Variable Timing Control (Dual VTC)
Dual VTC adjusts cam timing for the optimal balance of power and efficiency. Based on a range of sensor information, VTC adjusts an oil control valve which acts as a hydraulic actuator that can vary the position of each camshaft sprocket relative to the cam it drives. Under light loads, valve overlap can be increased to reduce pumping losses and improve fuel efficiency. When engine speed is low and the engine’s workload is high, such as during initial acceleration, the amount of overlap is increased to boost the scavenging effect, which improves torque and responsiveness. When engine speed and workload are high, such as during full-throttle acceleration, the amount of valve overlap is reduced to increase engine output by improving both intake efficiency and exhaust scavenging.
Drive-by-Wire™ Throttle System
The RDX’s Drive-by-Wire™ throttle system replaces a conventional throttle cable with smart electronics that electronically “connect” the accelerator pedal to a throttle valve inside the throttle body. The result is less under-hood clutter and lower weight, as well as quicker and more accurate throttle actuation. Acura’s Drive-by-Wire™ throttle evaluates the current driving conditions by monitoring throttle pedal position, throttle valve position, engine speed (rpm) and road speed. This information is used to define the throttle control sensitivity that gives the RDX’s throttle pedal a predictable and responsive feel that meets driver expectations.
There are three throttle profiles available in the RDX. When the Integrated Dynamics System is in the Snow setting, the drive-by-wire system uses a gentle profile aimed at maintaining traction in slippery road conditions. Both Comfort and Sport modes share the same response profile, designed to offer a natural driving feel. In Sport+ mode, the drive-by-wire system shifts to a more aggressive profile to enhance throttle response.
Direct Injection System
The RDX’s engine features a direct-injection system that enables increased torque across the engine’s full operating range along with high fuel efficiency. The system features a compact, high-pressure, direct-injection pump that allows both high fuel flow and pulsation suppression, while variable pressure control optimizes injector operation. Multi-hole injectors deliver fuel directly into each cylinder (not to the intake port, as in conventional port fuel injection designs), allowing for more efficient combustion.
The multi-hole injectors help create the ideal stoichiometric fuel/air mixture in the cylinders for good emissions control. Theoretically, a stoichiometric mixture has just enough air to completely burn the available fuel. Based on the operating conditions, the direct-injection system alters its function for best performance. Upon cold engine startup, fuel is injected into the cylinders on the compression stroke. This creates a weak stratified charge effect that improves engine start-up and reduces exhaust emissions before a normal operating temperature is reached.
Once the engine is fully warmed, fuel is injected during the intake stroke for maximum power and fuel efficiency. This helps create a more homogeneous fuel/air mix in the cylinder that is aided by the high-tumble intake port design. This improves volumetric efficiency, and the cooling effect of the incoming fuel improves anti-knock performance.
Low Inertia Mono Scroll Turbo System with Electric Wastegate and Intercooler
The RDX’s turbocharged powerplant features a mono scroll IHI turbocharger with small-diameter, low-inertia turbine for maximum responsiveness. The mono scroll housing design helps the turbo build boost even at relatively small throttle openings and low engine rpm. The electrically-actuated wastegate allows boost pressure to be precisely controlled.
A large, low-restriction intercooler is positioned low in the front of the car where it receives unobstructed airflow. The intercooler helps reduce the temperature of air entering the engine, increasing its density for greater performance. Intake air travels from the air filter, to the turbo compressor, on to the intercooler, then to the engine’s intake ports. To reduce weight, the turbo system is plumbed with rigid, lightweight resin-composite inlet pipes.
Direct Ignition and Detonation/Knock Control
The RDX’s Electronic Control Unit (ECU) monitors engine functions to determine the best ignition spark timing. An engine block-mounted acoustic detonation/knock sensor “listens” to the engine, and based on this input, the ECU can retard the ignition timing to prevent potentially damaging detonation. The inline-4-cylinder engine has an ignition coil unit for each cylinder that is positioned above each spark plug’s access bore.
Idle-Stop System
To help improve fuel efficiency, the RDX is equipped with Idle-Stop capability. When the system is enabled and certain operating conditions are met, Idle-Stop will automatically shut off the engine when the RDX comes to a stop. The engine is automatically restarted when the driver releases the brake pedal after a stop, or pushed the accelerator pedal if the brake hold is active.
The system is engineered to operate smoothly and seamlessly. When stopped, a special cold storage evaporator in the air conditioning system helps maintain a comfortable cabin temperature even in warm weather. Idle-Stop operation is fully integrated into the operation of the RDX’s Brake Hold system and its Adaptive Cruise Control (ACC) system.
The Idle-Stop feature can be turned on/off via a button on the center console, located to the left of the electronic gear selector array. The system will automatically turn itself off in certain circumstances, including:
- If the driver’s seatbelt is not fastened
- If the engine coolant and/or transmission fluid temperature is too high or low
- If the vehicle comes to a stop again before vehicle speed reaches 3 mph
- If the transmission is in a position other than “D”
- If the battery state of charge is low, or the battery temperature is below 14°F
- If the climate control system is on and the outside temperature is below -4°F
Close-Coupled Catalyst
The RDX engine’s exhaust manifold is cast directly into the aluminum alloy cylinder head to reduce weight and complexity, and to position the primary catalytic converter as close as possible to the combustion chambers. A high-efficiency converter mounts directly to the exhaust port of the cylinder head for extremely rapid converter activation after engine startup.
Emissions Certification
The RDX engine is engineered for low emissions and is certified to meet LEV3-ULEV50 standards for 120,000 miles.
100,000+/- Mile Tune-up Intervals
The RDX powerplant requires no scheduled maintenance for 100,000+/- miles or more, other than periodic inspections and normal fluid and filter replacements. The first tune-up includes water pump inspection, valve adjustment and the installation of new spark plugs.
Maintenance Minder™
To eliminate unnecessary service stops while ensuring that the vehicle is properly maintained, the RDX has a Maintenance Minder™ system that continually monitors the vehicle’s operating condition. When maintenance is required, the driver is alerted via a message on the Driver Information Interface (DII).
The Maintenance Minder™ system monitors operating conditions such as oil and coolant temperature along with engine speed to determine the proper service intervals. Depending on operating conditions, oil change intervals can be extended to a maximum of 10,000 miles, potentially sparing the owner considerable expense and inconvenience over the life of the vehicle. The owner-resettable system monitors all normal service parts and systems, including engine oil and filter, tire rotation, air-cleaner, transmission fluid, spark plugs, engine coolant, brake pads and more. To reduce the potential for driver distraction, maintenance alerts are presented only when the ignition is first turned on, not while driving.
10-Speed Automatic Transmission
All RDX models are equipped with a new 10-speed automatic transmission (10AT), the first of its kind in the RDX’s segment. Engineered for high efficiency with low internal inertia and an exceptionally wide ratio range, the 10AT maximizes the RDX’s performance and fuel efficiency. Compared with the previous 6-speed automatic, the 10AT is 30 lbs. lighter and has a 68-percent wider overall ratio range with a 56-percent lower first gear and a 7-percent taller top gear.
The 10AT is designed to be lightweight and compact. It features four planetary gear sets that work together to provide an exceptionally wide ratio spread of 10.147:1 compared with 6.041:1 on the previous-generation RDX’s 6-speed unit. The 10-speed also has substantially faster upshift and downshift performance than the previous generation 6-speed transmission. For greater responsiveness, the 10-speed transmission can make 4-gear direct downshifts: from 10th to 6th, or from 7th to 3rd.
To maximize fuel efficiency and minimize interior noise, the transmission’s 10th gear is exceptionally tall, resulting in quiet and relaxed cruising engine rpm.
Shift-By-Wire Gear Selector
In the 2019 RDX, the conventional shift lever is replaced with a fully electronic, shift-by-wire gear selector. Park, Neutral and Drive are selected with the push of a button. Reverse is selected by pulling back a dedicated switch. Indicator lights on or next to the buttons indicate the mode selected. Also, if the vehicle is brought to a stop in Drive or Reverse, the system will automatically select Park if the driver’s seatbelt is unbuckled and the driver’s door is opened. And steering wheel-mounted paddle shifters lets the driver take manual control of transmission gear selection.
Automatic Modes
The 10-speed automatic transmission can be operated in two fully automatic modes. The D (or “Drive”) mode is ideal for most driving situations and combines fuel efficiency with smooth operation and responsive power when needed. The S, or SPORT mode, is meant for more demanding driving in 1st through 8th gears and features more aggressive shift mapping to keep engine rpm higher for greater acceleration and pulling power.
When in the D mode (optimized for normal driving), the transmission incorporates an advanced Grade Logic Control System, Shift Hold Control and Cornering G Shift Control – all of which reduce unwanted shifting and gear hunting. The result is smart transmission operation that optimizes fuel efficiency and keeps the transmission in the appropriate gear for driving conditions, generating excellent performance and smooth operation.
While ascending or descending hills, Grade Logic Control alters the transmission’s shift schedule to reduce shift frequency and improve speed control, helping to minimize driver workload. The transmission ECU continually measures throttle position, vehicle speed and acceleration/deceleration to determine when the vehicle is on a hill. The shift schedule is then adjusted – during ascents to hold the transmission in lower gears to boost climbing power, and during descents to provide greater engine braking.
Shift Hold Control keeps the transmission in its current (lower) gear ratio during aggressive driving, as in the case of decelerating at a corner entry. Shift Hold Control leaves the chassis undisturbed by eliminating excess shifting and ensures that power will be more immediately available (without a downshift) at the corner exit. Cornering G Shift Control monitors the speed of each rear wheel independently to determine when the RDX is turning. When the system detects a sufficient speed differential between the rear wheels, it will suppress any unwanted upshifts. This prevents the transmission from upshifting during a corner which could upset the chassis balance, thus requiring downshifting again at the corner exit when the throttle is applied.
Paddle Shifters
The RDX features dual steering wheel-mounted paddle shifters. Particularly useful in mountainous terrain or during spirited driving, the paddles give the driver greater control over transmission operation. On long downgrades, the driver can command downshifts with the paddles that allow increased engine braking to reduce the load on the brakes and help control the RDX’s downhill speed. The RDX A-Spec gets longer, more prominent paddle shifters with metal-style plating.
Paddle Shifter Operation in Drive Mode
While in Drive mode, special transmission logic programming allows the use of the steering wheel-mounted paddle shifters. When the driver operates the paddle shifters, the transmission responds to the driver’s shift command and then returns to its normal fully automatic mode if further paddle shift inputs are not made within a few seconds, depending upon driving conditions. This special logic makes it easy for the driver to command a quick downshift without leaving the convenience of Drive mode. This temporary manual mode can be cancelled at the driver’s will by continued operation of the right-side paddle until the transmission resumes “Drive.”
Paddle Shifter Operation in Sequential Mode (Sequential SportShift)
By selecting the “S” position with the transmission D/S selector button, Sequential mode is engaged. This mode offers automatic operation with more aggressive shift mapping and locks out operation of 9th and 10th gears. A pull on either of the paddle shifters places the transmission in fully manual mode until another mode of operation is selected. A digital display in the instrument cluster indicates which gear the transmission is in. The Drive-by-Wire™ throttle system creates a “blip” of the throttle to help match gear speeds while downshifting.
To prevent harm to the powertrain when the transmission is paddle shifted by the driver, the system will inhibit potentially damaging shifts. As an added safety measure, the Electronic Control Unit (ECU) can also cut off fuel to the engine to prevent over-revving. If fuel cutoff is insufficient to prevent engine over-revving, as might be possible when the vehicle is on a steep downhill, the transmission will automatically upshift to prevent damage. On downshifts, the transmission will not execute a driver command that will over-rev the engine.
For improved stop-and-go performance and to help prevent “lugging” the engine, the transmission will automatically downshift even though the transmission has been left in a higher gear as the vehicle comes to a stop.
Cooperative Control
Both shift performance and smoothness are improved by cooperative control between the Drive-by-Wire™ throttle system and the electronically controlled transmission. The engine is throttled by the engine management system during upshifts and downshifts so the function of the engine and transmission can be closely choreographed for faster, smoother shifting. As a result, the peak g-forces (or “shift shock”) are reduced significantly during upshifts and downshifts.
Drivetrain Architecture and Features
Front Wheel Drive
The RDX offers standard front-wheel drive. With its efficient design and light weight, the RDX with front-wheel drive receives EPA fuel economy ratings1of 22 mpg city, 28 mpg highway, 24 mpg combined (A-Spec: 22/27/24).
Super-Handling All-Wheel Drive System™ (SH-AWD®)
The RDX is available with the latest generation of Acura’s acclaimed Super Handling All-Wheel Drive™ (SH-AWD®), which progressively distributes optimum torque not only between the front and rear axles, but also between the left and right rear wheels for more precise and exhilarating handling response in all road conditions.
An evolution of the systems offered in the MDX and TLX, the new RDX SH-AWD® rear differential has enhancements to upgrade its torque capacity. Compared to the previous generation RDX, maximum rear axle torque capacity has been increased by 150 percent, and up 40 percent compared to MDX. In normal conditions, up to 70 percent of torque can be sent to the rear axle, and 100 percent of that torque can be distributed to either the left or right rear wheels.
The SH-AWD® system is complemented by Agile Handling Assist, which employs the anti-lock brake system to individually brake either the left or right front wheel to improve corner traceability and balance. (See the Chassis section for more information.)
By rotating the outside rear wheel faster than the front axle while cornering, SH-AWD® uses torque vectoring to create a yaw moment to help turn the vehicle through corners – reducing understeer and improving controllability. With cornering forces more evenly distributed between front and rear tires, overall cornering power is increased – on wet or dry roads.
Vehicles with high power ratings using conventional front or rear drive systems often employ a limited-slip differential to help maintain traction when under power. By linking inside and outside drive wheels, these systems tend to resist turning and can increase understeer. Conventional AWD systems similarly work to link the inboard and outboard tires as well as the front and rear axles which can create resistance to turning. Using torque vectoring to help turn the vehicle, SH-AWD® delivers more responsive, neutral and predictable handling performance, while providing outstanding all-weather traction and control.
Electronic Controls and Parameters
The SH-AWD® system works in cooperation with the RDX’s Vehicle Stability Assist™ (VSA®) system and Agile Handling Assist to optimize torque distribution for superior handling and traction utilization. The Electronic Control Unit (ECU) provides information on engine rpm, airflow and transmission gear-ratio selection, while the VSA® ECU provides wheel-speed data. The SH-AWD® ECU also monitors steering angle, lateral g-forces, vehicle yaw rate and electromagnetic clutch engagement for the right and left rear axle shafts. Drive torque is calculated from ECU information, and then the acceleration situation, wheel spin, lateral G-force and steering angle are used to determine the front-to-rear torque distribution and the torque split between right and left rear wheels.
In hard cornering and under acceleration, up to 70-percent of available torque can be directed to the rear wheels to enhance vehicle dynamics, and up to 100 percent of torque sent to the rear axle can be applied to either the left or right rear wheel, depending on conditions.
SH-AWD® System Layout
The RDX SH-AWD® is a full-time all-wheel-drive system that requires no driver interaction or monitoring, thanks to a torque-transfer unit that is bolted directly to the front-mounted transaxle. The torque-transfer unit receives torque from a helical gear that is attached to the front differential’s ring gear, and a short horizontal shaft and hypoid gear set within the torque-transfer unit’s case send power to the rear propeller shaft, which in turn transfers power to the rear drive unit.
The RDX’s lightweight SH-AWD® rear drive unit (below right) is constantly overdriven by 2.7-percent, with its torque instantly available at all times. The resulting overdrive effect is regulated by hydraulically-operated left and right-side clutch packs located in the rear drive unit that independently control the power delivered to each rear wheel. Up to 2,213 lb.-ft. of torque can be delivered to either rear wheel, providing torque vectoring capability that is effective in corners while also providing a limited-slip differential function when needed.
The hydraulically operated clutches can be controlled as a pair to alter front/rear torque split, or they can be controlled independently to allow 70 percent of available engine torque to go to either rear wheel, which gives the system the unique ability to yaw the RDX into turns for superior handling.
In this iteration of SH-AWD®, an electric motor powers a pair of hydraulic pumps – one for each clutch pack. A pair of linear solenoids controlled by the Electronic Control Unit (ECU) selectively sends pressure to the clutch packs, which in turn control the amount of power sent to each rear wheel.
Powertrain Specification Comparison
Automatic Transmission Gear Ratio Comparison
1. Based on projected 2019 EPA mileage ratings. Use for comparison purposes only. Your actual mileage will vary depending on how you drive and maintain your vehicle, driving conditions and other factors.