(continued)
Improving upon 40 years of rotary designs, the Renesis engine boasts side intake
and exhaust ports with nearly 30 percent more intake area and twice as much
exhaust area than previous rotary engines. The efficiencies gained through
larger intake and exhaust ports exclude the need for forced induction, a feature
found on the last rotary-powered sports car from Mazda, the vaunted third
generation RX-7.
The RX-8’s normally aspirated 1.3-liter engine might appear diminutive to the
untrained eye when compared to large-displacement V-8s or heavyweight V-10s or
V-12s. However, through the incredible efficiencies of a rotary powerplant, an
advanced three-stage intake system and an electronic throttle, the Renesis
engine delivers smooth, linear power on a grand scale.
The 2005 RX-8 does not sacrifice emissions for power, though. Through
improvements to the port design, overlap between the intake and exhaust ports
has been eliminated, greatly reducing exhaust emissions, improving fuel economy
and allowing the car to meet the strict Bin 5-A Federal emissions
classification. The effort made by Mazda engineers to improve emissions is a
prime example of the concern for environmental impact maintained throughout the
development process.
The RX-8 benefits from placing the powerplant low and far back in the engine bay
in what Mazda calls an advanced front-midship layout, which lowers the center of
gravity and improves vehicle balance. In addition, the fuel tank is placed ahead
of the rear axle, and all seating is within the wheelbase and track of the car.
Combined, these factors contribute to a perfect 50/50 vehicle weight
distribution, low yaw-inertia movement and superb handling characteristics. With
such excellent balance, it is little wonder the RX-8 feels right at home on even
the most challenging race tracks or negotiating a tight freeway onramp.
Fit for the Track
The RX-8’s comfort on the track is not overlooked by the motorsports community.
The same Renesis engine found in production RX-8s is used in the Pro Formula
Mazda series, a popular open-wheel racing format run on the nation’s most
demanding race tracks. Pro Formula Mazda is widely regarded as a training ground
for developing drivers looking to build a career in motorsports. That this
popular series uses a showroom-stock, non-modified Renesis engine is a testament
to the power, reliability and light weight of the RX-8 powerplant.
The RX-8 also campaigns in the Grand American Road Racing Association’s Grand Am
Cup Sports Touring division. The Sports Touring division consists of production
cars driven straight from the showroom to the race track with limited racing
modification. Here, the superb handling characteristics and near-bulletproof
Renesis engine already have taken the RX-8 to victory circle twice in 2004, and
all indications point to return visits.
Suspension and Steering
The RX-8 uses a newly developed aluminum double-wishbone front suspension,
reducing unsprung weight over the use of steel components. By mounting the upper
and lower arms on a highly rigid sub-frame, the long arms ensure linear
alignment changes throughout the jounce and rebound of the front wheels. All
wheels receive mono-tube gas-filled shock absorbers designed with large-diameter
internal pistons and valving, which offer excellent road feedback and a smooth
ride.
An electric-assist rack-and-pinion power-steering system transmits just the
right amount of road information back to the driver. Mazda engineers have chosen
to pursue their own path by using an electric motor for steering assistance –
rather than a conventional power-steering pump. The electric motor provides
additional assistance at low speeds to ease parking and reduces steering
assistance at higher speeds to provide greater road feel, responsiveness and
feedback.
Styling
The trend of innovation in the engine bay and suspension continues to the RX-8’s
styling with a unique "freestyle" four-door design. Mazda has broken the notion
of sports cars as cramped coupes by effectively demonstrating that a true sports
car does not need to sacrifice space or convenience. With ample passenger room
for four full-size adults and enough trunk space for a weekend’s worth of
luggage or two full-size golf bags, a new era of sports car design has arrived.
The RX-8’s body shell, due to the advanced design of the rear-hinged rear
"freestyle" doors, provides a large door opening (front doors open to 67 degrees
and rears open to a near-perpendicular 80 degrees), making for easy adult-sized
ingress and egress. This also is advantageous when securing a baby or small
child in the back seat.
The styling of the Mazda RX-8 is made up of taut muscular lines, suggesting the
look of an athlete in motion. The muscular design maintains classic sports car
proportions while adding a Zoom-Zoom edge that is unmistakably Mazda. Integrated
throughout the exterior is the unique triangular rotor design, which clearly can
be seen in the front fascia, head lamps, hood and rear bumper valence. RX-8’s
exterior dimensions are virtually identical to the Porsche 911, yet it still
manages to seat four adults and offers sufficient rear-seat room to install a
rear-facing child seat.
The RX-8’s exterior styling presents a genuine sports car form, while the
interior boasts a comfortable and intelligently designed cabin. An extremely low
cabin floor allows the seats to be mounted low in the chassis, which, along with
a low instrument cluster and hood, enhance driver visibility. Mazda designers
concentrated on the shape of the front seat backs and the rear seat cushions to
ensure adequate rear-seat knee room. Front seat slide-rails are positioned to
allow maximum leg room for rear-seat passengers.
The rotary design element is carried through the interior of the RX-8 in
creative ways, appearing in the seats, center console, shift knob and emergency
brake. The cabin also evokes a sense of style and high-end quality. Mazda’s
design team examined every aspect and component of the interior and has created
an elegant, performance-minded atmosphere. Through the use of advanced ergonomic
research, Mazda engineers determined improper seating posture to be a cause of
driver fatigue and built in optimum support in the front seats to help
counteract discomfort. In addition, the soft blue lighting used in the RX-8’s
instrument cluster was found to minimize eye fatigue and strain.
Safety
When designing the RX-8, safety was given as much consideration as performance.
For Mazda, the safety process incorporates both accident avoidance and accident
protection. In practice, this approach to safety means the RX-8 can avoid many
dangers and protect occupants in the unfortunate event of a collision. In a
recent rollover test performed by the National Highway Traffic Safety
Administration (NHTSA), the RX-8 was the only car of the 68 tested vehicles to
receive a five-star rating.
Mazda engineers incorporated numerous active and passive safety elements
throughout the car. Active safety features, which require input from the driver,
include the use of large ABS-equipped disc brakes on all wheels as well as
precise steering and suspension systems. Dynamic Stability Control (standard on
manual transmission cars with Sport Package, optional on RX-8s with automatic
transmissions) provides a superior level of handling that can be disabled
safely when driving and road conditions allow.
Passive systems, or those that take effect automatically without driver
intervention, also are present throughout the RX-8. Despite the absence of a
center B-pillar, the RX-8 has an exceptionally rigid body, a feat accomplished
through the use of a series of locking pins, which hold the doors together and
tie each door directly into the roof and floor. Integrating the frame components
helps dissipate crash energy through the vehicle’s structure.
More standard passive systems on the RX-8 include front airbags, seat-mounted
side-impact airbags and side-curtain airbags. Additionally, the front end and
engine bay have ample crumple zones, the front seats are designed to minimize
whiplash injuries, the brake pedal is designed to break away in the event of a
collision of sufficient force to protect feet and legs and all four seating
positions are fitted with three-point seatbelts. Consideration even was given to
pedestrian protection as the RX-8 is fitted with Mazda’s "shock-cone" hood
design that yields more to the impact of a pedestrian onto the hood than a
standard design, yet is strong enough to not deform in normal use.
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