1997 986 Boxster - Press Release

For Immediate Release - The 1997 Porsche Boxster

Water-Cooled Engine

Boxer engine, horsepower and torque
The Boxster engine is an all new Porsche horizontally opposed (boxer) layout designed to meet stricter emissions, noise and fuel economy requirements. It utilizes water cooling and four valve technologies featured on the 911 GT1 race car. With a displacement of 2.5 liters (151 cu. in.), engine power is 201 bhp (150 kW) at 6000 rpm. Maximum torque is 181 ft.lbs. (245 Nm) at 4500 rpm, with more than 147 ft.lbs. (200 Nm) available between 1750 and 6500 rpm.

Crankshaft
The Boxster engine starts with the forged steel crankshaft running in seven main bearings. The crankshaft and auxiliary shafts driving the camshafts are housed in aluminum/cast iron bearing shells, offering consistent bearing play regardless of temperatures, and reducing mechanical noise.

Connecting rods
Connecting rods are forged steel, broken mechanically at the bottom end for assembly along a dividing line marked by a laser beam. Once the connecting rods are fitted onto the bearings, the crystalline fracture surfaces provide an ideal mating surface. The cracking technique is featured for the first time with the forged connecting rods in the Boxster engine.

Cylinders
The alloy engine block, which is separated down the center, has the three cylinders on each side arranged in an open deck design within the block. The flow of coolant around the cylinders and combustion chambers follows crossflow cooling principles applied by Porsche in the design and construction of racing engines. Coolant flows along the entire width of the cylinder bank and cylinder heads from the intake to the exhaust side. Flow in the new boxer engine extends up and down in two directions on either side, thus ensuring thermal stability. One coolant flow extends around the cylinders inside, a second around the combustion chambers on the outside.

Lokasil casting
For the block, Porsche has used a new Lokasil casting technology. The cylinder liners are made of an alloy made abrasion resistant by adding silicon. Prior to casting, the cylinder liners are fixed in position, then surrounded by a conventional aluminum alloy casting. The advantage of the Lokasil process is that the silicon required is applied only where it is needed.

Integrated dry sump lubrication
The oil sump also forms part of the engine block on the new boxer engine, although it is separated from the crankshaft chamber, a new design known as integrated dry sump lubrication. The advantage of this new system, versus the 911 design with a separate oil tank, is simplification of engine construction, with the number of hoses and tubes reduced to a minimum. On the pressure side, a geared oil pump at the front end of the engine ensures the supply of oil, which then returns to the reservoir from the crankshaft bearings. Oil in the cylinder heads is pumped back by two return pumps. The oil pickup is housed in a reservoir beneath a partition that prevents the oil from flowing to the sides under lateral acceleration by means of baffle plates, keeping oil in the pickup under all driving conditions.

Oil/water heat exchanger
The oil/water heat exchanger mounted to the engine block provides temperature balance. During warm-up, this system warms the oil directly from the coolant, so the engine reaches its operating temperature quickly. Whenever oil temperature exceeds the coolant temperature of approximately 2000 F (900 C) under high load, the heat exchanger process is reversed, with the oil dissipating heat to the coolant.

Fuel injection
Fuel injection and ignition are controlled by the latest Bosch Motronic M 5.2 electronic engine management system. Fuel supply is sequential, through one injector per cylinder, following the engine's firing order. The amount of fuel injected is determined by a hot film air mass metering system located in the intake manifold, and by the dual exhaust system oxygen sensors.

Electronic ignition
The Bosch ignition system is all electronic, featuring solid state ignition distribution via six individual coils, with no mechanical distributor. The system features cylinder selective anti-knock control that retards the ignition timing of individual cylinders which are about to knock. The Boxster's Motronic engine management system includes a second generation on-board diagnostics system (OBD II) for the North American market.

Spark plugs
Thanks to four valve technology, the spark plugs are centered in the combustion chambers for consistent ignition and combustion of the fuel/air mixture. Dual ignition, with two spark plugs per cylinder, as in Porsche's air-cooled boxer engines, is not required. The cylinder heads are identical and can be fitted to either the left or right cylinder bank with no modifications.

Intake system & Exhaust system
The intake manifold is made of lightweight reinforced plastic with smooth surfaces for increased air flow in the intake track. Intake air supply is controlled by a central throttle butterfly, while fuel is injected sequentially through six electronic fuel injectors. Exhaust ducts through two stainless steel exhaust manifolds and exits through two catalytic converters into the muffler and a central tailpipe reminiscent of those used on earlier Porsche roadsters.

Electronic engine management
The engine is accessible from beneath, from above and from the front through service openings. Electronic engine management is maintenance-free but can be checked by computer via the on-board diagnosis system. The camshaft timing chains as well as the poly-V belts driving the alternator, water pump, hydraulic pump and air conditioning compressor all feature automatic tensioning. Engine oil level is displayed each time the engine is started by a gauge in the instrument cluster. A service unit in the rear luggage compartment houses an oil dipstick as well as the fillers for engine oil and coolant.

Radiators
The water cooled engine influenced the Boxster's body design. Studies showed that the only way to provide heat dissipation under worst case conditions was to mount the radiator at the front end of the car. Due to the required front luggage space, the radiator could not be placed in the normal position. Porsche's engineers decided on a solution from the renowned Porsche 959. They split the radiator in half, and placed the two halves in the fenders, in front of the wheels, to generate a flow of cooling air under all conditions.

Air flow
Air flow coming out of the body upstream of the front wheels provides two advantages. Aerodynamic drag does not suffer from the fact that air flows through the radiators, and the upward flow of air coming out of the radiators counters lift forces on the front axle. The air scoop on the left side of the car supplies intake air to the engine through an air filter, while hot air from the engine compartment is forced out by a fan located inside the right side air scoop.

VarioCam^TM: Porsche's Patented System
VarioCam^TM variable valve timing system
Intake and exhaust valves are driven by four overhead camshafts and bucket tappets with hydraulic valve lash compensation. Intake camshaft opening times are controlled by Porsche's patented VarioCamTM system. With an automatic chain tensioner and hydraulic valve lash compensation, the entire valvetrain system is maintenance-free.

First used on the Porsche 968 3.0 liter four-cylinder engine, VarioCam is Porsche's patented method of altering camshaft timing for greater engine torque. VarioCam uses a timing piston, controlled by the Bosch Motronic M 5.2 engine management system, placed between the two sides of the timing chain between the intake and exhaust cams.

When actuated, the piston advances the timing of the intake cam by 15 crankshaft degrees or 7.5 camshaft degrees. Earlier valve timing creates more valve overlap and an earlier closing time than normal, resulting in additional engine torque. At high engine speeds, the piston is shifted back to its later timing position for more power. The effect of the VarioCam system is to give the Boxster engine a broader, flatter torque curve. VarioCam also lowers exhaust emissions. At low speeds and at idle, the late intake cam timing results in shorter valve overlap periods and reduced hydrocarbon emissions. At low loads and moderate engine speeds, early timing and long valve overlap times create exhaust gas recirculation, reducing NOx emissions. Cold-start emissions are also improved by VarioCam valve timing.

Four valve technology
Porsche has developed a compact solution for driving the four overhead camshafts: the first drive element is a chain leading from the crankshaft to the intermediate shaft. From here, at the front end of the engine, another chain drives the right side exhaust camshaft, with still another chain running from the clutch side to the left side exhaust camshaft.

This configuration allows the chains to use the space provided by the two offset cylinder rows of the boxer engine. Two small chains connect the exhaust and intake camshafts. The valves, closed by conical springs, are operated by hydraulic tappets with automatic lash compensation. The camshaft drive chains maintain correct tension for the life of the engine.

Transmission
The new Porsche model comes with new transmissions tailored to the power and performance characteristics of the 2.5 liter boxer engine, the speed range of the Boxster, and its mid-engine design.

Five-speed manual
The Boxster comes standard with a five-speed manual gearbox featuring gear ratios designed for optimum performance. The short transmission ratios allow acceleration performance of 0-60 mph in 6.7 seconds (0-100 kph in 6.9 seconds) and flexibility, with 50-75 mph (80-120 kph) acceleration in fifth gear in 11.4 seconds.

Five-speed Tiptronic S
Porsche also offers the Boxster with an optional Tiptronic S five-speed automatic transmission. As with the existing four-speed Tiptronic S on the 911, an electronic system shifts gears and controls the mechanical lock-up clutch in the torque converter. The transmission control unit features five different adaptive shift programs, applied according to the needs of the driver, with a range extending from economy to performance.

The Boxster's Tiptronic S electronic transmission makes logical decisions in choosing the right gear. Whenever the driver suddenly takes his or her foot off the accelerator, the system will sense the car is no longer under power and will prevent the transmission from shifting up, keeping the current gear engaged. Operation of the brakes will make the transmission shift down at the appropriate road speed. Grade detection prevents the transmission from upshifting too soon on uphill and downhill grades. Whenever the wheels spin on slippery roads, the automatic transmission will upshift earlier for torque management and driving stability.

Tiptronic S enables the driver to participate in the shifting process, choosing the five gears as appropriate. Transmission control on the Boxster has become even easier. The choice of manual or automatic mode depends on the position of the selector lever. Once selection of the manual mode is made, shifting is done exclusively through the upshift and downshift buttons on the steering wheel hub, as on Formula One racing cars.

Traction Control (TC) and Automatic Brake Differential (ABD)
A further option available on the Boxster provides traction when accelerating on slippery surfaces. TC traction control operates throughout the entire speed range, combining Porsche's ABD automatic brake differential and intervention in the engine management system to reduce power as soon as the driving wheels start to spin.

With the ABD system, the wheel spinning fastest is slowed down by the wheel brake. If both drive wheels spin despite ABD, the wheels are slowed down so that they are able to maintain traction. Brake intervention is combined with the Motronic M 5.2 engine management system, which cuts fuel injection when necessary, then retards the ignition timing in order to reduce engine torque. TC traction control can be deactivated by a console switch, while the ABD automatic brake differential remains active. In that case, under acceleration the car will react like a vehicle with a conventional limited slip differential.

Suspension
Placing the engine in the middle of the car is a time-honored and successful Porsche philosophy. As early as 1934, the Auto Union Grand Prix cars designed by Porsche featured an advanced mid-engine design with their 16-cylinder power units between the driver and the rear axle. That philosophy continues today with the latest Porsche 911 GT1 race car.

Mid-engine design concentrates the weight of the car in the middle, which serves to reduce the inertia moment around the car's vertical axis. What this means in practice is very agile response to steering inputs with smooth and nimble behavior in curves. With the Porsche Boxster's equal axle load distribution, its low center of gravity and its relatively long wheelbase, the car offers excellent driving characteristics.

Steering
The rack and pinion steering of the Porsche Boxster features hydraulic power assist. Bumps or adverse forces coming up from the road are absorbed by the hydraulic steering mechanism, and power assist substantially reduces the steering forces required when maneuvering and parking. The telescopic steering wheel adapts to the driver's needs and provides the precision required by demanding drivers.

Front and rear suspensions
Both the front and rear suspensions are refined versions of the MacPherson strut, with transverse control arms and spring struts. Experience gained with vacuum pressure cast aluminum components on the chassis of the latest Porsche 911 prompted the use of light alloy on the Boxster suspension. On the front axle, the sub-frame, transverse control arms, longitudinal arms, and the wheel supports enclosing the shock absorbers are all made of cast aluminum. At the rear, the transverse control arms, longitudinal arms, wheel supports and shock absorbers are all connected to an aluminum structure that reinforces the rear body structure.

Elasto- kinematics
Porsche 911 Carrera suspension performance was replicated for the Boxster to ensure directional stability, lateral acceleration and controllability under all conditions, with smooth and forgiving behavior at the limit. A design offering increased safety under such driving conditions was developed by Porsche's engineers in designing the Weissach axle, first featured in the Porsche 928, a modification of axle geometry under lateral forces in bends called elastokinematics. On the 928, this effect generated toe-in on the rear axle alone through kinematic forces, thus countering oversteer. The Boxster takes this design a step further.

The elastokinematic design of the Boxster's suspension provides a negative toe position on the outer front wheel under the influence of lateral forces. The outer rear wheel, in turn, develops a positive toe position. With increasing lateral acceleration, this system increases the car's understeer, allowing the driver to apply the brakes in a corner while maintaining control of the vehicle. The normal consequences of the weight transfer which occurs under such conditions are minimized by this suspension feature.

Wheels and tires
Extra large wheels and tires contribute to the Boxster's dynamic performance on the road, with 6J by 16 alloy wheels in front and 7J by 16 alloy wheels at the rear. Tire dimensions are 205/55 ZR-16 at the front and 225/50 ZR-16 on the rear wheels. Available as an option are larger wheels, measuring 7J by 17 at the front and 8.5J by 17 at the rear with 205/50 ZR-17 front and 255/40 ZR-17 rear tires.

Braking System

Monoblock design
The Boxster's all disc power brakes feature alloy four-piston brake calipers in a single-piece, or monoblock, design. The single piece brake caliper design comes straight from the Porsche 911 GT1, and is of the same type used in Formula One. Brake discs are internally ventilated front and rear, and the anti-lock braking system (ABS 5) is fitted as standard.

Brake cooling
Brake calipers come with four pistons which vary in diameter to avoid uneven brake lining wear. In addition to the heat dissipation reserves of the Boxster's brakes, Porsche's engineers directed the cooling air flowing to the front discs, not just through two ducts, but also through two guide spoilers connected to the longitudinal control arms, ensuring that the cooling air is always plentiful. The advantage of the alloy monoblock brake design is the minimization of brake fade even under extreme conditions.

Body Systems

The new Boxster is designed to be quick, fast, and agile, as well as to be a long distance touring roadster with ample cockpit space for two persons and two trunks with a total capacity of 9.1 cubic feet (260 liters) for luggage. For the body, Porsche designers could have chosen lightweight body materials like aluminum or fiberglass. Instead, the entire body shell of the Boxster is made of two sided hot galvanized steel, because steel offers better deformation performance and ease of repair.

Strength
The front end structure, patented by Porsche, improves body integrity without extra weight by using high-strength body panels, reinforced where appropriate. The side impact panels in the doors, as well as the reinforcements on the bulkhead crossmember, are made of an extra strong steel/boron alloy formed at high temperatures. Where strength or design features can only be achieved by stamped parts, Porsche has used tailored blanks, laser-welded metal blanks of varying thicknesses, to provide extra strength.

Porsche engineers have also saved weight by leaving out material wherever possible on stampings, which are corrugated to provide overlap of welded body panels. The rollover bars behind the cockpit are made of stainless steel. Additional high-strength steel reinforcements are built into the windshield frame for added protection in the event of a rollover. As a result, the Boxster's rollover protection meets U.S. safety standards for coupes.

In addition to the complete engine and the transmission housings, suspension components, transverse arms, wheel rims and brake calipers are all made of aluminum. In all, nearly 20 percent of the parts and components of the Boxster are made of aluminum, resulting in an overall vehicle weight of just 2822 pounds (1280 kg).

Safety features
The mid-engine design offers safety in an accident, enhanced by a series of deformation structures between the outer contour of the car and the passenger cell that absorb energy. Impact forces are reduced, and the crumple behavior of the steel body minimizes collision forces acting on the driver and passenger. Safety is further enhanced by two full size airbags fitted as standard equipment in all world markets.

The aero headlamp units in the Boxster's nose offer unusual design and a high level of function and optical quality. The surface covers are made of a high-strength plastic resistant to most types of damage usually encountered on the road, and are lighter than conventional glass headlamp covers.

To provide high quality illumination for night driving, the low beam and high beam are projected by separate headlamp systems. Both have free form reflectors using the entire cross section of the headlamp for greater illumination intensity. The beams intersect as they leave the reflectors to produce high light yield from a compact design. The foglamps use small reflectors.

Aerodynamics

Coefficient of drag
The Porsche Boxster follows the spirit of the 356 and the 550 Spyder, but meets much higher levels of aerodynamic performance in terms of frontal area, total drag and total lift. Wind tunnel testing also focused on air flow management as part of safety, driving characteristics, heating, cooling and ventilation. With a drag coefficient of 0.31 and lift forces on the front and rear axles reduced to a minimum, it sets new standards in its class. The Boxster's smooth undertray reduces the car's drag coefficient by a full six percent, and the smooth floor pan reduces lift forces on the front axle by 36 percent. When activated, the speed dependent rear spoiler minimizes lift forces. It deploys at speeds exceeding 75 mph (120 kph), and returns to its rest position when speed drops below 50 mph (80 kph). Porsche aerodynamicists measured a lift factor of only 0.13 on the front axle and 0.10 at the rear.

Interior

Dashboard
The Boxster cockpit offers a new rendition of classic Porsche style. The ignition lock is still located to the left of the steering wheel. Instruments are grouped in an arc with three large gauges slightly overlapping each other. As is normal for a Porsche, the most prominent feature is the central tachometer, with the analog speedometer to the left. For the first time, the numbers on the analog scales use the same typography as the model designation at the rear of the car.

Analog and digital displays
Beneath the analog displays for road speed, engine speed, coolant temperature and fuel level, the dashboard of the Boxster features three additional digital displays: the odometer, the trip odometer and a digital speedometer beneath the tachometer, displaying in either English or metric units. Beneath the analog gauge on the right is the oil level display, which allows the driver to check the engine oil level each time the ignition is turned on. As an option, the Boxster offers an on board computer displaying average speed, average fuel consumption, fuel tank range and outside temperature, with an acoustic warning which sounds whenever the car exceeds a preset speed limit.

Seats
Boxster's twin bucket seats meet Porsche standards for side support and comfort. Fore-and-aft adjustment is controlled by a spring and backrest adjustment is electric. The driver's seat comes with manual height adjustment.

Interior trim
The large interior trim pieces in the Boxster are made of thermoplastic polyolefin (TPO) film, a special polypropylene material. This new material, making its debut in the Boxster, does not cause a chemical odor inside the car nor produce a layer of mist on the windows. With the same type of plastic being used for the base components, trim and controls, future recycling of Boxster interior components will be easy and convenient.

Heating system
The heating system controls in the Porsche Boxster are integrated into the instrument panel module, and the heating system operates consistently regardless of engine load and temperature. With the heater controlled as a function of air flow, heat is available quickly from the heat exchanger, with its constant supply of hot coolant. The heating system comes with an air recirculation switch to keep out dust or unpleasant odors.

Wind deflector
The Boxster offers fresh air motoring at its best. To reduce air buffeting inside the car, and to allow for quiet conversations, Porsche offers a multi-piece wind deflector consisting of two perforated panels, clipped in position on the two rollover hoops behind the seats, with a plastic window in between to provide clear vision through the interior rearview mirror.

Convertible Top

Electric soft top
The power convertible top of the Boxster provides maximum comfort and convenience for the occupants, with excellent weather sealing and efficient noise control for driving at high speeds. Extensive work in the Porsche wind tunnel reduced wind noise to a minimum.

Cast magnesium
The top spars are made of cast magnesium, elegant and light at the same time. An entirely new type of kinematic structure folds the top like the letter "Z" before it disappears beneath the top cover, with the top facing out. The spars move smoothly and easily, and the top structure opens and closes via a compact electric motor. Once the driver releases a central latch on the windshield frame, opening or closing the top takes only 12 seconds.

Design award
Even before the Boxster started production, its innovative top concept was awarded a design prize by the International Magnesium Agency in Ube, Japan, an acknowledgment of the work done by Porsche's engineers with magnesium materials.

Optional hard top
A removable aluminum hardtop is available as an option to further reduce the noise level inside the car and to maintain a consistent interior climate. The hardtop, with its heated glass window, weighs just 55 pounds (25 kg).

Warranty

New vehicle warranty
Every new Porsche sports car is covered by a two-year bumper-to-bumper limited warranty with unlimited mileage, including Porsche's roadside assistance program. The galvanized body and 26-step paint and anti-corrosion process enable Porsche to warrant each car against rust perforation for 10 years and unlimited mileage. In addition, the paint has a three-year limited warranty.

Leasing and Financing

Porsche Credit Corporation
Porsche Credit Corporation offers attractive leasing, financing and balloon payment plans for Porsche sports cars. Conventional fixed rate financing is available with standard terms up to 84 months. The Porsche Preferred Lease program is available with lease terms as long as 60 months. Porsche Options, an innovative retail balloon loan, combines the economies of leasing with the benefits of ownership. Porsche Credit Corporation also offers conventional and Porsche Options financing to U.S. customers participating in Porsche Cars North America's tourist delivery program.

All Porsche Credit Corporation programs are subject to credit approval and available only through authorized Porsche dealers in the United States. Certain programs may not be available in all 50 states. Similar programs are available to authorized Porsche dealers in Canada through a Canadian financial organization.

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