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Old 02 Oct 2008, 11:00 pm
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Default 2005 Honda Odyssey Powertrain

Advanced Technology for Economy and Performance

Torrance, Calif. - Aug 31 —


The Odyssey powertrain uses the latest innovations to achieve the highest levels
of performance, fuel economy and low emissions in the minivan segment. Honda's
long and successful history introducing state-of-the-art engine technology continues
with the introduction of Variable Cylinder Management on select models and numerous
other features for 2005.

The Honda Odyssey's engine is an advanced 3.5-liter SOHC 24-valve 60-degree
V-6 aluminum-block-and-head design that is compact, light and powerful. A wide
variety of technologies have been engineered to provide 255 horsepower, a broad
and flat torque curve, very low emissions, high fuel efficiency, and instantaneous
throttle response.

Two engine configurations are available - one with a VTEC valvetrain
and one with an i-VTEC valvetrain that includes cylinder deactivation. The VTEC
valvetrain and on LX and EX models optimize cylinder filling efficiency across
the engine's entire operating range. Additional aids to efficiency include a
low-restriction intake and exhaust systems, a 10.0:1 compression ratio, and
roller-type rocker arms. New technology includes a drive-by-wire throttle system
and a sophisticated engine management system that can determine when the vehicle
needs an oil change.

On Touring and EX with Leather models, an "intelligent" i-VTEC
valvetrain automatically de-activates three of the six cylinders during cruising
to enhance fuel economy. When full power is needed during acceleration and other
situations, the engine operates on all six cylinders. Uniquely, Odyssey models
with the i-VTEC valvetrain simultaneously provide the highest fuel economy with
the most power and the longest driving range in the minivan segment.

The Odyssey's engine also provides excellent environmental performance, meeting
California's LEV2-ULEV criteria as well as complying with the Federal Tier 2-Bin
5 emission requirements. High-density catalytic converters are placed directly
below the engine's cylinder heads in both banks, boosting performance during
cold startups. A high-level of emission control performance is also aided with
a third catalytic converter positioned downstream from the two high-density
catalytic converters. To further enhance emission performance inside the engine,
high-atomization multi-hole fuel injectors are used along with four air-fuel
sensors that provide highly precise fuel control and help achieve nearly complete

The Odyssey's compact 5-speed automatic transmission provides ultra smooth
and efficient operation characteristics with the adoption of a direct control
shift system that works with the drive-by-wire throttle control.

What's New for 2005

  • 255-horsepower (+15 hp) SOHC VTEC V-6 with 250 lb.-ft. torque (+8 lb.-ft.)

  • Available 255-horsepower SOHC i-VTEC V-6 with 250 lb.-ft. torque

  • Variable Cylinder Management (VCM) system on i-VTEC engine for high fuel

  • Drive-by-Wire Throttle Control System

  • Active Control Engine Mounts and Active Noise Control on the i-VTEC engine
    minimizes engine vibrations

  • Compact engine design with the exhaust manifold integrated into the cylinder

  • Federal Tier 2 Bin 5 emissions, LEV2 ULEV California emissions

  • High-flow capacity exhaust system

Odyssey Powertrain Versus the Competition

2005 Honda Odyssey
2004 Honda Odyssey
2004 Toyota Sienna
2005 Chrysler Town & Country
2004 Nissan Quest
Engine and Displacement
3.5L V-6
3.5L V-6
3.3L V-6
3.3L V-6,

3.8L V-6
3.5L V-6
180 / 215(3.8L)
Torque (lb-ft)
210 / 245 (3.8L)
Fuel Type

Regular Unleaded
Premium Unleaded

Premium Unleaded
Variable Cylinder Management
Not Available
Not Available
Not Available
Not Available
4AT, 5AT
EPA Estimated Fuel Economy, City/Highway, mpg



19/26 (3.3L)

18/25 (3.8L)
19/26 (4AT)

Emissions Rating







Throttle Control

* Based on 2005 EPA mileage estimates. Use for comparison purposes
only. Actual mileage may vary.

Note: All values subject to change.

SOHC VTEC 3.5-Liter V-6 Engine Highlights

(LX and EX models)

  • 255 horsepower @ 5750 rpm (+15 hp)

  • 250 lb.-ft torque @ 5000 rpm (+8 lb.-ft.)

  • New Drive-by-Wire Throttle Control System

  • Uses regular unleaded gas

  • Federal Tier 2 Bin 5 emissions, LEV2 ULEV California emissions

  • Close-coupled catalytic converter

  • High-flow exhaust

i-VTEC 3.5-Liter V-6 Engine with Variable Cylinder Management (VCM)

(EX with Leather and Touring models)

Above features plus:

  • 250 lb.-ft torque @ 4500 rpm

  • Variable Cylinder Management

  • Active Control Engine Mount System

  • Active Noise Control (see Interior section)

  • Dual-Stage Intake Manifold

Engine Architecture

The Honda Odyssey's engine is a transverse mounted 3.5-liter, SOHC, 24-valve,
60-degree, V-6, aluminum-block-and-head design that is compact, light and powerful.
A long list of technologies has been engineered to provide 255 horsepower, a
broad and flat torque curve, ultra-low emissions, high fuel efficiency and instantaneous
throttle response. The VTEC valvetrain optimizes cylinder filling efficiency
across the engine's entire operating range.

The i-VTEC engine further extends fuel economy while maintaining the same power
as the regular VTEC engines. Low-restriction intake and exhaust systems, a 10.0:1
compression ratio and roller-type rocker arms also aid efficiency.

Engine Block

The Odyssey's 3.5-liter die-cast engine block is made from heat-treated
aluminum to maximize block rigidity and to minimize weight. A deep-skirt configuration
rigidly supports the crankshaft, minimizing noise and vibration. Thin-wall,
centrifugally-cast iron liners help reduce overall length and weight. Each liner's
rough as-cast exterior surface bonds securely to surrounding aluminum during
the manufacturing process to increase strength and enhance heat transfer.

Lightweight and Compact Construction

The Odyssey engine features lightweight and compact construction through the
use of serpentine belts to drive engine accessories, a lightweight and high-strength
timing belt, and an integrated die-cast aluminum exhaust manifold help make
the engine more compact and lightweight. The compact and lightweight components
contribute to improved packaging and reduced weight for enhanced fuel economy
and performance.

Integrated Exhaust Manifold

The exhaust manifold is integrated and unified with the cylinder head. High-density
catalytic converters have been placed directly under the cylinder heads on each
side, which is a design that vastly reduces combustion-gas heat loss and ensures
quick activation of the catalytic converters for better purification during
cold starts. An additional catalytic converter under the floor cleanses exhaust
gases even further.

Crankshaft/Connecting Rods/Pistons

A forged-steel crankshaft is used for maximum strength, rigidity and durability
with minimum weight. In place of bulkier, heavier nuts and bolts, connecting
rod caps are secured in place with high-tensile-strength fasteners that screw
directly into the connecting rod. Short-skirt, cast-aluminum, flat-top pistons
are notched for valve clearance and fitted with full-floating piston pins.

Cylinder Head Construction

The Odyssey utilizes innovative cylinder heads that include tuned exhaust manifolds
as an integral part of the casting. Made of pressure-cast, low-porosity aluminum,
these lightweight components improve overall packaging, enhance exhaust flow
and permit optimal positioning of the close-coupled catalytic converters.

Unlike many minivans, the Odyssey has four-valve combustion chambers, the best
approach to optimum performance with excellent fuel efficiency and very low
emissions. Valves are clustered near the center of the bore to minimize combustion
chamber volume and to provide ample squish area. A 10.0:1 compression ratio
helps maximize thermal efficiency, power output, and fuel mileage. A fiberglass-reinforced
toothed belt drives one centrally located camshaft per bank. Head gaskets are
made of high-strength materials to contain combustion pressures.

Variable Valve Timing and Lift Electronic Control (VTEC™)

Standard on all models, the Odyssey's innovative Variable Valve Timing
and Lift Electronic Control (VTEC) is one key to maximizing engine output across
the engine's full operating range. The high-rpm induction lobes of the
camshaft provide additional valve lift to help increase peak horsepower. Ordinary
engines have fixed valvetrain parameters - the same timing of valve lift
and overlap whether the tachometer needle is struggling to climb out of the
low-rpm range or screaming at the redline. The VTEC approach, however, has two
distinct modes so that operation of the intake valves changes to optimize both
volumetric efficiency (breathing) and combustion of the fuel-air mixture. In
order to achieve the optimum volumetric efficiency in the lower portion of the
engine's operating range, rocker arms are programmed to follow cam lobes that
provide low lift and reduced duration (shorter time open with less valve lift).

At 4600 rpm, the Odyssey's powertrain control module commands the VTEC system
to switch intake valve operation to the high-rpm mode. In response, an electric
spool valve opens to route pressurized oil to small pistons within the intake-valve
rocker arms. These pistons then slide to lock the three rocker arms provided
for each cylinder together. As a result, both intake valves follow a central
high-lift, longer-duration cam lobe. The switching process takes place instantaneously
and is undetectable by the driver. The extra lift and longer duration provide
the added air and fuel the engine needs to produce high peak horsepower and
a broader torque band. Instead of a peaky engine, the Odyssey has a powerplant
that provides excellent performance at any engine speed.

i-VTEC with Variable Cylinder Management™ (VCM™)

Honda's innovative VTEC technology has evolved once again: the i-VTEC* engine
(the "i" is for intelligent) in the 2005 Odyssey features a Variable
Cylinder Management (VCM) system that switches between six- and three-cylinder
combustion. When high output is required, such as during startup and acceleration
or when climbing hills, the engine operates on all six cylinders to deliver
superior performance. During cruising and at low engine loads, the system idles
one bank of three cylinders, thus achieving outstanding fuel economy. Further,
the idled cylinders remain sealed, alleviating the pumping losses associated
with intake and exhaust and giving fuel economy a further boost.

Variable Cylinder Management helps maximize fuel economy by making the Odyssey's
available i-VTEC V-6 engine effectively run on only three cylinders when the
power needs are minimized, yet it can still seamlessly provide the full power
of all six cylinders during acceleration or other high power situations. When
full power is needed, i-VTEC instantly opens the valves and sends fuel to three
more cylinders with output reaching as much as 255 horsepower. Honda's
VCM system allows for maximum performance and maximum fuel economy - two
characteristics that rarely co-exist at this level of extremes. Other minivans
may offer high fuel economy and others may offer engines tuned for horsepower,
but only the Odyssey delivers class-leading levels of both.

* Of special note, Honda's 4-cylinder i-VTEC technology
uniquely employs VTEC + Variable Timing Control (VTC) for superior performance
and fuel economy. Honda's intelligent V-6 technology uniquely employs
Variable Cylinder Management (VCM) for performance and fuel economy.

VCM Operation

The Odyssey's i-VTEC V-6 engine (available on EX with Leather and Touring
models) features a Variable Cylinder Management (VCM) system that improves fuel
economy by idling three of the Odyssey's six cylinders during cruising
and deceleration. VCM deactivates the rear bank of cylinders by using the VTEC
(Variable Valve-Timing and Lift Electronic Control) system to close the intake
and exhaust valves while cutting fuel at the same time.

The rear bank of cylinders was chosen for deactivation because the front bank
is best positioned for cooling performance. Idling the rear bank also helps
to maintain the temperature of the catalytic converter beneath the cylinder
heads, helping to maintain optimum environmental performance.

The Odyssey's spark plugs continue to fire even when the cylinders are
deactivated. This minimizes plug temperature loss and prevents fouling-induced
from incomplete combustion during cylinder re-activation. Further, sparking
in air alone results in higher voltages than in a fuel-air mixture because of
the higher insulation resistance. Therefore, iridium-tipped spark plugs are
used for their high resistance to wear at high voltages.

i-VTEC VCM System Designed for Rapid Switching at Low Engine Speeds

In a conventional VTEC system, hydraulic pressure pushes a single synchronizing
piston, which is in turn pressed back by a return spring. The VTEC system locks
the valvetrain's rocker arms to allow additional valves to open and increase
engine breathing. Such systems require relatively high engine speeds since hydraulic
pressure is used to push the spring. VCM, however, demands switching at low
rpm. This is achieved by creating a hydraulic circuit with two systems, each
capable of providing the hydraulic pressure required to push the synchronizing
piston in the required direction. This design thereby allows switching from
six cylinders to three cylinders in low-speed ranges. To achieve responsive
switching to six cylinders when the driver operates the accelerator pedal, the
system employs a new three-way solenoid spool valve to control the oil pressure
for switching. These enhancements result in highly responsive VCM switching
regardless of engine speed.

VCM monitors throttle position, vehicle speed, engine speed, automatic-transmission
gear selection, and other factors to determine if the vehicle is cruising or
decelerating. During cruising and deceleration, VCM deactivates three of the
cylinders on the rear bank of the engine. To further enhance control, the system
also simultaneously determines whether engine oil temperature is suitable for
VCM switching and whether catalytic converter temperature will remain in the
proper range. While idling the cylinders, the system controls ignition timing,
adjusts throttle position via Drive-By-Wire, and turns the torque converter
lock-up on and off, thereby suppressing torque-induced jolting during the switch
from six to three cylinder operation. The result is a smooth, seamless switch
between three and six cylinder modes that is nearly unnoticeable to the driver.

For cylinder deactivation operation, the synchronizing piston moves to isolate
the valve-lift rocker arms from the deactivated cylinders' rocker arms.
The deactivated cylinder rocker arms are operated by zero-lift cams that deactivate
the cylinders by closing the intake and exhaust valves.

Engine Mounts

Odyssey LX and EX models use a special liquid-filled engine mount and an Electronically
Controlled Mount (ECM) to help absorb vibration from its already smooth V-6
engine. Odyssey EX with Leather and Touring models (with VCM) use an advanced
Active Control Engine Mount system to counteract any vibrations.

Due to the inherent increase in engine vibration when VCM has deactivated the
rear cylinders, an Active Control Engine Mount system (ACM) is used to minimize
the effects of engine vibration. The system uses sensors that alert the Electronic
Control Unit (ECU) to direct ACM actuators to move in synch with the vibration,
thereby eliminating the vibration being transmitted to the passenger compartment.
Additionally, an Active Noise Control system (ANC) works in cooperation with
the ACM. An ANC controller with a microphone detects the booming noise associated
with cylinder deactivation and instructs the audio system's speakers to
emit "anti-noise." See the interior section for more information
on ANC.

Dual-Stage Induction System (i-VTEC Engine)

Designed specifically for the Odyssey's i-VTEC engine, the induction
system works in concert with the valvetrain to significantly boost torque across
the engine's full operating range. Internal passages and two butterfly
valves commanded by the powertrain control module are configured to provide
two distinct modes of operation. The valves are closed at lower rpms. In this
mode, the three cylinders on each bank draw air from only the nearer half of
the manifold's internal chamber, or plenum. The volume of the plenum and the
length of inlet passages are both tuned to maximize the resonance effect, wherein
pressure waves are amplified within each half of the intake manifold at certain
rpm ranges.

The amplified pressure waves significantly increase cylinder filling and the
torque produced by the engine throughout the lower part of its rpm band. Funnel-shaped
intake ports - similar to those used on racing engines - are built
in at the uppermost end of each intake runner to improve air flow.

Exhaust System

A low-restriction, high-flow exhaust system is crucial to efficient power and
torque production. The Odyssey features a high efficiency system that incorporates
several key elements that work in concert with the engine's uniquely designed
cylinder heads to help boost performance, reduce tailpipe emissions and trim
weight. Major system components include two close-coupled catalytic converters,
a secondary underfloor catalytic converter, a centrally positioned, high-flow
resonator and a silencer. The close coupled catalytic converters mount directly
to the cylinder head to reduce light off time, thereby allowing the catalyst
to begin cleansing the exhaust as soon possible.

The catalysts, muffling element, and piping are all sized for high flow and
low restriction. High-chromium stainless steel is used throughout the exhaust
system for excellent durability.

Linear air-fuel and oxygen sensors installed in each of the close-coupled catalytic
converters make possible precise control of the air-fuel ratio. These sensors
and the precisely controlled high-atomizing multi-hole fuel injectors help achieve
almost complete combustion, for cleaner emissions. The result is compliance
with California's LEV2-ULEV standards as well as Federal Tier 2-Bin 5 emission


Drive-By-Wire Throttle System

The Odyssey features an innovative drive-by-wire (DBW) throttle control system.
This DBW system replaces a conventional throttle cable arrangement with an all-electronic
system that senses the accelerator pedal position and relays that information
to a computer. The computer then performs the actual throttle activation instantaneously.

The Odyssey electronic throttle control system works by means of a accelerator
pedal sensor, a throttle angle sensor, a control unit built into the power control
module and a DC motor to control throttle opening and provide fail-safe throttle
operation. This system allows for throttle control to be integrated into the
VSA and VCM systems, and also incorporates the cruise control function. To improve
shifting smoothness, the automatic transmission shifting has been enhanced,
and the electronic throttle control system controls the throttle during transmission
shifts. To optimize driving feel, accelerator pedal characteristics are calibrated
to be smooth and linear during start up, and when driving on ice or other low
traction surfaces, and more responsive during acceleration. During cruise control,
throttle operations are smoothed out to maximize idled-cylinder operation. This
not only enhances fuel economy but also helps eliminate unnecessary switching,
making for a smoother ride.

Programmed Fuel Injection (PGM-FI)

Fuel is delivered in sequence and timed to each cylinder's induction stroke
by six injectors mounted on the lower portion of the intake manifold. The Odyssey
features innovative orifice-type injectors instead of pintle-type injectors.
These injectors optimize the fuel spray pattern, and improve fuel atomization
for increased fuel mileage and reduced emissions. A 32-bit, 40MHz central processor
unit (CPU) within the Odyssey's powertrain control module calculates injection
timing and duration after assessing an array of sensor signals; crankshaft and
camshaft position, throttle position, coolant temperature, intake manifold pressure
and temperature, atmospheric pressure, and exhaust-gas oxygen content. The CPU
controlling the Odyssey's Programmed Fuel Injection (PGM-FI), VCM, VTEC valve
train, dual-stage intake manifold, the drive-by-wire throttle, and the transmission
also communicates with CPUs that regulate the Vehicle Stability Assist (VSA)
and meters, and interacts with the ACM.

Direct Ignition and Knock Control

Maintaining the correct ignition timing throughout all operating conditions
is essential to producing maximum power, using fuel efficiently and minimizing
emissions. A powertrain control module (PCM) examines various engine functions
as well as a block-mounted acoustic knock sensor to determine optimum ignition
timing. In the event the engine is supplied with fuel lower in octane than the
specified unleaded premium, the PCM retards ignition timing as needed to forestall
detonation. As a result, the engine constantly operates at the point of peak
efficiency. Spark is supplied to iridium-tipped, long-life spark plugs by six
coil units positioned directly over the plugs in the cylinder-head access bores.

Smart Maintenance Tune-Up Intervals

The new Smart Maintenance System allows the Odyssey to become an active participant
in alerting its owner to pending service requirements. This feature takes the
guesswork out of determining how severe or normal road conditions may affect
oil service intervals by displaying the percentage of remaining oil life before
the need for an oil change. Smart Maintenance also monitors driving conditions
and prescribed mileage, and displays corresponding codes that indicate the need
for tire rotation, air cleaner element replacement, automatic transmission service,
a coolant change, and spark plug and timing belt replacement. This system anticipates
soon-to-be maintenance needs and groups them together with those more urgently
required. This allows an owner to take care of everything at one time and reduce
their number of visits to the service department.

The only maintenance necessary is routine inspections and fluid and filter
changes. At 105,000 miles, the valves should be adjusted, the timing belt should
be replaced, the water pump should be inspected and the iridium-tipped spark
plugs should be replaced.

5-Speed Automatic Transmission Overview

The Odyssey features a compact 5-speed automatic transmission that utilizes
a 3-shaft design layout. The SOHC VTEC V6 transmission provides both smooth
startup and outstanding fuel economy when cruising at high speed. The SOHC V6
i-VTEC with VCM transmission makes use of a lower ratio for fourth and fifth
gears, boosting acceleration during high-speed travel. These ratios expand the
range of the three-cylinder mode that dramatically enhances fuel economy, thereby
realizing both powerful acceleration and low fuel consumption.

A lock-up torque converter is provided to maximize fuel efficiency. Torque-converter
lock-up and shift timing are both managed by a PGM-FI ECU that maintains a communications
link with the engine's CPU. Lock-up continues even during downshifting from
fifth to fourth and from fourth to third gear, making continuous fuel cutoff
possible. The specially designed springs used for the lock-up dampers employed
with the VCM system feature a low spring coefficient during three-cylinder mode,
effectively absorbing changes in speed.

Creative use of clutched idler gears permits the transaxle to provide five
forward speeds with little more weight or bulk than a typical four-speed automatic.
A one-way clutch is provided for first gear to smooth upshift quality. An extra-capacity
transmission fluid cooler is offered with the Odyssey's optional tow package
to maintain acceptable lubricant temperatures during heavy-load conditions.

A direct-control strategy provides real-time pressure management of the transmission's
clutches. Various safety and control strategies coordinate engine and transmission
operation. For example, driveline shocks during up- or downshifts are minimized
by momentarily reducing engine torque during the shift. In neutral and park,
engine rpm is automatically limited to 5000 rpm.

For driving through hilly terrain, a Grade Logic Control system monitors throttle
position, vehicle speed, acceleration and deceleration to avoid hunting and
excessive shifting. A lower gear is held for a longer-than-normal period to
provide better climbing ability on hills and more engine braking on downhill
grades. On i-VTEC models, the 2005 Odyssey is equipped with an intelligent cruise
control system that works in combination with the transmission to provide downshifts
from fifth to fourth or from fourth to third as required on downhill grades,
making effective use of engine braking to control the vehicle's speed.


Equal-length, front-wheel half-shafts use a plunger joint at their inboard
end and a ball-type universal joint at the wheel end.

Gear Ratios (VTEC and i-VTEC)

Gear LX, EX (VTEC) EX w/ Leather,

Touring (i-VTEC)
2004 Model
Final Drive Ratio


The ability to haul pop-up campers, medium-sized boats, and recreational vehicle
trailers can be a priority to some minivan owners. Ultimately, the engineers
concluded that a casual or weekend towing capability was most appropriate for
the Odyssey. Customer feedback helped set the towing limit at 3500 pounds for
trailers. The Odyssey's 3500-pound rating is calculated to include up to two
passengers and their cargo.

In support of safe towing, Odyssey's tow hitch and other hardware needed
for the job are factory engineered for dealer installation. The dealer-installed
trailer hitch is a Class III receiver-type design that bolts on with no drilling,
cutting, or bumper-cover modifications. An external transmission cooler and
a separate power-steering fluid cooler is also included along with a harness
to provide electrical power to trailer lights that plug into a connector provided
at the rear of the vehicle.

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