2003 Acura RSX -- Powertrain

The two engines offered in the Acura RSX incorporate a host ofinnovative features designed to deliver a cutting-edge combination ofperformance, fuel efficiency, and low emissions. Most apparent is thei-VTEC "intelligent" valve-control system, a technology that combinesVTC (Variable Timing Control)-which continuously adjusts camshaftphase-with Variable Valve Timing and Lift Electronic Control (VTEC)-- which changes valve lift, timing, and duration. Combining thesetwo systems results in impressive horsepower and high torque withoutstanding fuel economy and low exhaust emissions. In addition, theRSX's transversely mounted engine block has been rotated 180 degrees,bringing the exhaust manifold closer to the catalyst for improvedlight-off and reduced emissions at start-up.

The RSX engine is an all-aluminum, 2.0-liter inline four-cylinderdesign that uses 16 valves, a dual-stage intake manifold, and thei-VTEC system (VTC on intake cam shaft only) to deliver 160horsepower at 6500 rpm and 141 lb-ft. of torque at 4000 rpm.

The 2.0-liter 4-cylinder in the high-performance RSX Type-S modeladds a high-performance version of the new i-VTEC system and a fixed,high-volume intake manifold. These features help boost output to 200horsepower at 7400 rpm and 142 lb-ft. of torque at 6000 rpm.

In keeping with Acura's proven commitment to the environment, boththe RSX and Type-S engines meet strict Low Emission Vehicle-II(LEV-II) standards.

The RSX comes with either a quick-shifting 5-speed manualtransmission or an electronically controlled, 5-speed automatictransmission with Acura's Sequential SportShift system. Inspired bythe transmissions used in Formula One race cars, SequentialSportShift allows the driver to shift the forward gears semi-manuallyor enjoy the shifting ease of a conventional automatic.

The RSX Type-S is available exclusively with a new short-throw6-speed manual transmission. Designed to be compact and lightweight,the 6-speed has also been engineered to provide the lightning-quickshift action of a race car transmission. Multiple synchronizers(triple cone on gears 1 and 2, double cone on gears 3-6) help reduceshifting load for a light, responsive feel. The Type-S also includesa short-throw clutch with a torsion mechanism that considerablyreduces gear rattle.

Powertrain At A Glance


  • RSX 2.0 Liter, DOHC, 4-cylinder engine produces 160 horsepowerat 6500 rpm and 141 lb-ft. of torque at 4000 rpm
  • Type-S engine produces 200 horsepower at 7400 rpm-at 100horsepower per liter, one of the highest specific outputs of anyproduction engine in the world-and 142 lb-ft of torque at 6000rpm
  • Latest-generation i-VTEC "intelligent" valve-control systemadding VTC (Variable Timing Control) to VTEC
  • Computer-controlled Programmed Fuel Injection (PGM-FI)
  • RSX engine utilizes dual-stage intake manifold
  • Direct Ignition System
  • 110,000-mile tune-up intervals

Emissions/Fuel Economy

  • RSX delivers estimated EPA fuel economy of 27/33 mpg(city/highway)
  • RSX Type-S delivers estimated EPA fuel economy of 24/31 mpg(city/highway)
  • Both engines meet strict Low Emission Vehicle-II (LEV-II)standards

5-Speed Manual Transmission (RSX)

  • Quick, light shifting effort
  • 5-speed design for excellent performance
  • All-new design created expressly for RSX

5-Speed Sequential SportShift Automatic Transmission (RSX)

  • Quick-response 5-speed Sequential SportShift allowssemi-manual operation
  • Full driver-selectable control in SportShift mode-transmissionwill not shift unless directed to do so by driver
  • Wide-ratio design carefully matched to engine's power band forimproved performance and efficiency
  • Second-gear "hold" function in SportShift mode for improvedtake-off on snow or other slippery surfaces
  • Easy gear selection through fewer gate positions (5), whichmakes finding the desired gear more intuitive
  • Grade Logic Control for reduced gear "hunting" when driving onsteep hills
  • Linear solenoid direct-acting control (world's first) forreduced shift shock and improved shift smoothness andresponsiveness

6-Speed Manual Transmission (Type-S)

  • Exceptionally short throws for "race car" shift feel
  • Close-ratio 6-speed helps improve performance and fuelefficiency
  • Advanced clutch torsion mechanism to reduce rattlingnoise
  • Hydraulic damper integrated with master cylinder for reducedpedal vibration
  • Short clutch-pedal stroke for effortless shifting
  • Advanced friction material for improved clutchoperability

Noise, Vibration, and Harshness (NVH)

  • Aluminum block with cast-in iron liners for light weight anddurability
  • One-piece crankshaft carrier with ferrous main bearing capsfor improved rigidity and durability
  • Four engine mounts: two high-rigidity rubber mounts, twohydraulic mounts for reduced engine vibration
  • Lightweight alloy pistons and forged steel connectingrods
  • Maintenance-free serpentine accessory drive with autotensioner
  • Maintenance-free silent-chain camshaft drive

The innovative Variable Valve Timing and Lift Electronic Control(VTEC) system made its debut on the Acura NSX supercar, deliveringabundant low-rpm torque, exhilarating high-rpm power, and outstandingfuel efficiency.

The RSX features the latest version of this remarkable enginesystem: i-VTEC. The "intelligent," i-VTEC system adds new VTC(Variable Timing Control) to VTEC to provide continuously variablecamshaft timing-taking the concept of variable valve timing to newheights. In short, i-VTEC = VTEC + VTC. Not only does i-VTEC providea substantial performance increase across a broad power band, itboosts fuel economy while also reducing engine emissions.

VTEC (Variable Timing and Lift Electronic Control)
The innovative VTEC system adjusts the lift and opening duration ofthe valves to help the engine produce both abundant low-rpm torqueand excellent high-rpm power. At low rpm, VTEC adjusts valve timingand lift for optimum cylinder filling. In addition, the timing of theintake valves is staggered and their lift asymmetric-creating a swirleffect within the combustion chambers. The result is increased burnspeed with improved combustion stability. As engine rpm builds, VTECtransitions to a high-lift, long-duration cam profile for improvedhigh-rpm engine output.

The RSX uses two variations of VTEC, a new streamlined version forthe RSX, and a high-performance version for the Type-S.

The 160 horsepower RSX employs a new version of VTEC to boostperformance and reduce emissions that applies variable timing andlift to the intake valves only. Additionally, the RSX system isfurther simplified by utilizing only two rocker arms per pair ofintake valves (instead of the usual three). During low rpm operation,intake air is drawn almost exclusively through the primary intakevalve, thereby creating a very strong swirl effect to maximizecombustion. At 2,200 rpm, the secondary rocker arm engages theprimary rocker causing both intake valves to open for the same liftand duration, substantially increasing airflow into the cylinder andboosting performance.

The 200 horsepower RSX Type-S uses the same high-performance VTECdesign as the NSX, a three rocker arm system that varies the lift andduration of both the intake and exhaust valves for maximum poweroutput. At lower rpm, the valves follow low lift, short durationcamshaft profiles to help boost low-end torque. Above 5,800 rpm, theintake and exhaust valves are operated by high-lift, long-durationcam profiles, for maximum high rpm horsepower.

When combined with VTC, both versions help the RSX engine producea remarkably broad and smooth power band with exceptional torque andhorsepower.

VTC (Variable Timing Control)
The i-VTEC system adds VTC (Variable Timing Control) to VTEC forcontinuously variable camshaft phasing across the engine's entirepower band. As engine rpm builds, a VTC actuator-controlled by anengine-control unit that monitors cam position, ignition timing,exhaust oxygen content, and throttle position-advances or retards theintake cam throughout the 50 degree range, optimizing engine outputand reducing emissions.

During typical operation, the intake camshaft timing is almostfully retarded at idle to help provide more stable idling whilereducing exhaust emissions (NOx). As rpm increases, the intakecamshaft is advanced, opening the intake valve sooner and providingadditional valve overlap. This results in increased fuel economy (byreducing pumping losses) and a further reduction in exhaust emissions(by creating a large, internal exhaust gas re-circulation effect).

Also, to generate additional power throughout the rev range, theintake camshaft is continuously varying the amount of advance orretard, instantly adjusting to provide additional power as requiredby the driver.

The RSX engine uses an aluminum cylinder head and adouble-overhead-cam, four-valve-per-cylinder valvetrain incorporatingthe new i-VTEC system. A generous "squish" area around the combustionchambers yields increased gas turbulence for faster flame propagationand excellent efficiency. The camshafts are operated by asilent-chain drive that helps provide smooth, refined performancewhile also being maintenance-free.

The RSX engine features a compact aluminum block with cast-in ironliners-a design known for its light weight, high rigidity, andexcellent durability. The block has a one-piece aluminum crankshaftcarrier, which has ferrous-carbon inserts in the bearing caps foradditional strength. The Type-S version also incorporates a stiff,cast-aluminum oil pan. The crankshaft is a highly rigid, forged-steeldesign that uses a special micro-polished surface finish for reducedfriction and increased durability.

In addition, the Type-S engine uses high-strength connecting rodsand crankshaft as well as high-compression cast-aluminum pistons.

In the RSX, the transversely mounted engine block has been rotated180 degrees, bringing the exhaust manifold closer to the catalyst forimproved light-off and reduced emissions at start-up.

On the 160 horsepower RSX engine, a dual-stage intake manifoldutilizes two intake runners for each cylinder, one longer than theother. Below 4600 rpm, only the longer of the two runners deliversair to the cylinder-taking advantage of the inertia effect of thelong intake path. Above 4600 rpm, however, a rotary valve in the boreof the short runner opens to allow the passage of additional air tothe cylinder. This has the effect of boosting midrange and high-rpmpower by utilizing the inertia effect at both low and high rpm.

On the Type-S powerplant, a short, high-performance single-stagemanifold is used to help boost high-rpm power.

Both RSX engines are equipped with a Programmed Fuel Injection(PGM-FI) system. The system monitors throttle position, enginetemperature, intake-manifold pressure, atmospheric pressure,exhaust-gas oxygen content, and intake-air temperature. It controlsfuel delivery by four newly developed, multi-holed injectors mountedin the cast-aluminum intake manifold. The ECU also tracks theoperation of the engine with position sensors on the crankshaft andboth camshafts.

Standard on the RSX is a newly designed, stainless-steel, lowheat-mass exhaust system. The system employs a new, high-densitycatalytic converter for improved light-off performance and reducedhydrocarbons and NOx. Emissions performance is further improvedthanks to the engine's new design, which positions the exhaustmanifold on the rear of the engine-which shortens the distance thatthe exhaust gases must travel to the catalytic converter, resultingin faster light-off and more complete conversion of the exhaustgases. The exhaust system also incorporates an "e-shaped" dual-pathpipe that optimizes the exhaust flow for improved torque and loweremissions.

To help the Type-S produce 200 horsepower the exhaust system hasbeen tuned to further reduce backpressure.

In addition to their outstanding power and response, the RSX engineshave been engineered for class-leading smoothness and refinement. Tothat end, the 2.0-liter four-cylinder employs such NVH-reducingfeatures as highly rigid, ferrous-carbon inserts in the main bearingcaps for added rigidity, a one-piece crankshaft carrier, a silentchain cam drive, and a stiff, cast-aluminum oil pan (Type-S). Fourengine mounts (two liquid-filled) and reinforcements in the enginecompartment help further reduce engine noise and vibrations.

The RSX's first scheduled engine tune-up is required at 110,000 miles(only routine inspections and fluid changes are required up to thispoint). Credit for this longevity goes to long-wearingplatinum-tipped spark plugs, a long-life timing chain, and carefulengineering of the precisely manufactured DOHC valvetrain-whichreliably maintains proper valve tappet clearances until the110,000-mile first tune-up (under normal conditions).

The RSX comes with a 5-speed manual transmission equipped with ashort-stroke shift linkage for superb shifting quickness and feel.For smooth, progressive shift engagement and low clutch-pedal effort,the transmission includes a refined hydraulic clutch unit. Thetransmission also uses a new clutch friction material for improvedperformance, long life, easy engagement, and reduced friction area.

A 5-speed Sequential SportShift automatic transmission is availableas an option on the RSX. Exceptionally lightweight and compact, the5-speed automatic is designed to provide best-in-class performanceand superb fuel economy.

The RSX 5-speed reduces shift shock and improves shiftsmoothness-thanks to a linear solenoid direct-acting control with newcontrol logic. A highly intuitive shift-gate design enhances shiftingease.

The RSX 5-speed automatic is equipped with a Sequential SportShiftsystem similar to the one originally introduced in the NSX sportscar. The SportShift transmission operates as an automatic or putsgear selection in the hands of the driver, much like a manualtransmission. By moving the console-mounted transmission selectorhandle to the left of the "Drive" position into a special SportShiftgate, upshifts and downshifts can be commanded with a quick fore oraft motion. Gear selection is indicated by an LED display locatedbetween the tachometer and speedometer.

To foster the immediate feel of a manual transmission, inSportShift mode the transmission logic commands firmer shifts thatare quicker than in automatic mode. Additionally, the system isengineered to deliver an unusually quick response time to shiftcommands as compared with other semi-manual automatic transmissions.

The Sequential SportShift system parallels the operation of amanual gearbox, but with built-in safety override features. The logicwill not allow a downshift that would cause the engine to over-rev inthe driver-selected lower gear. The transmission will stay in theselected gear until the vehicle approaches a complete stop, and thenwill shift into first automatically. During acceleration, thetransmission will not upshift automatically in SportShift mode;however, should the driver fail to command an upshift in time, theengine ECU will cut off the fuel flow to prevent the engine fromover-revving. If the over-revving continues after the fuel cut, thetransmission will upshift automatically.

To improve powertrain smoothness and reduce gear "hunting" on steepgrades, the 5-speed automatic transmission is also equipped with astandard Grade Logic Control system. Using sensors that monitorthrottle position, vehicle speed, and acceleration/deceleration andthen comparing these inputs with a map stored in the transmissioncomputer, the system is able to determine when the vehicle is on anincline and adjust the shift schedule for improved climbing power ordownhill engine braking.

To provide driving enthusiasts with exceptional control and feel, thehigh-performance RSX Type-S is available exclusively with a new,short-throw, close-ratio 6-speed manual transmission. By employingmultiple large-capacity synchronizers (triple cones on gears 1 and 2;double cones on gears 3-6), the 6-speed offers an exceptionally lighteffort-while an extremely short-stroke shift lever provides the quickand precise shift response normally associated with racecartransmissions.

Despite its high-performance 6-speed design, the RSX transmissionis actually the same weight and is even more compact than the 5-speedmanual transmission in the Integra GS-R. In addition, it employs anew wide-angle, clutch-torsion mechanism with two-stage hysteresis togreatly reduce the gear rattling that plagues many conventional 6-speed transmission designs.

Further refining the transmission's sporty, high-quality feel is ashort-stroke clutch pedal for quicker shifting, a hydraulic damperintegrated with the master cylinder for reduced clutch vibration, anda new clutch-friction material for improved clutch engagement feel.

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