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PageEngine installed weight has been reduced by over 80 pounds (36 kg) while power is increased 8% compared to the 1996 R/T 10. The increase results from a higher compression ratio, revised camshaft timing and intake and exhaust port refinements for increased flow. These improvements are in addition to the redesigned exhaust system with significantly lower restriction and new windage tray to reduce drag due to excess oil rotating with the crankshaft introduced on the 1996 R/T 10. The Coupe engine ratings are as follows:
| Rating Factor | 1996 Rating |
| Horsepower | 450 bhp (335 kW) |
| @ 5300 rpm | |
| Torque | 490 lb-ft (664 N-m) |
| @ 3700 rpm | |
Cylinder Heads
New lightweight cast aluminum cylinder heads save 7 pounds (3 kg) each. They have thinner water jackets that provide better cooling but reduce the quantity of coolant used by 0.5 gallon (1.9 L) per head. Better cooling in turn allows 0.5 ratio increase in compression for more power by eliminating hot spots that can produce detonation. State of the art precision cooling system design techniques determined how best to cool the heads. Precision casting cores provide coolant passages closer to typical hot spots, such as spark plugs, valve seats and the combustion chamber in general than the previous design while reducing the overall coolant volume. Coolant flow direction is reversed from previous practice because the thermostat is now located at the front of the engine. Reduced coolant volume reduces engine warm up time, which in turn reduces engine-out exhaust emissions at this critical time.
Complete redesign of the heads allowed subtle reshaping of the intake and exhaust ports. This gets more air in and reduces the work required to push the exhaust out, increasing the power potential of the engine. Cylinder head fastening arrangement is unchanged, but smaller, shorter bolts save 4.5 pounds (2 kg) over the previous mounting arrangement.
Cylinder Block
An all-new thin-wall cast aluminum block of conventional design is over 20 pounds (9 kg) lighter than its predecessor. Pressed in "dry" cast iron cylinder liners assure long life but allow the block to be cast in a commonly used alloy. They replace a "wet" sleeve arrangement that was both heavier and made assembly difficult. Assembly of the new engine is simplified as pistons no longer have to be fitted individually to their respective cylinder sleeves. Finite element analysis was used to develop a stiffer block structure using cross-bolted main bearing caps. Though stiffer and stronger, the caps are lighter, and the bolts are lighter, saving over 2 pounds (0.9 kg) per cap each. Reduced water jacket volume also saves weight. The sum of these changes is a block assembly that is over 40 lb (18 kg) lighter than before.
Chain Case Cover
A new thin-wall cast-aluminum cover for the chain case includes integral brackets for the alternator, air conditioning compressor and serpentine belt tensioner. The integral brackets simplify assembly, reduce weight and improve belt alignment.
Oil Pan
The die-cast aluminum oil pan was redesigned after extensive testing determined that oil capacity could be reduced by 2 quarts (1.9 L), saving 4 pounds (1.8 kg). The new pan has an integral oil pickup passage fed from a sump in the bottom of the pan -- the first integral pickup on a domestic US engine. This pickup system is capable of using all of the oil in the pan, whereas conventional bolt-on pickups always leave some oil in the pan. A bolt-on baffle directs flow to the sump, which has a removable screen. The combined pan and pickup saves an additional 4 pounds (1l8 kg). Synthetic oil is recommended for maximum engine protection.
Cooling System
The revamped cooling system places the thermostat housing at the front of the block, resulting in simpler, more esthetic plumbing and a weight reduction of 10 lb (4.5 kg). Bypass flow is returned to the water pump housing, which is mounted in front of the chain case cover, through a cast passage in the thermostat housing. Manifolds built into the block and heads to deliver fresh coolant from the radiator to each cylinder without passing over other cylinders on the way remain unique to Viper among US-built engines. This feature assures a more consistent coolant temperatures -- no more than 3°F (1.5 °C) difference between any two cylinders -- than any other US-built engine. Also retained is the high-capacity coolant thermostat that provides a controlled, uniform warm up conducive to low wear and low engine-out exhaust emissions.
Camshaft
Minor changes in camshaft events contribute to increased power.
Fuel Injection System
A single cable operates both throttles through a new linkage system and external cable cam that helps maintain synchronization. Throttle bodies have new contoured bores that provide a more gradual area increase just off idle than the previous arrangement to reduce throttle response sensitivity.
Air Cleaner Duct
The Coupe engine obtains it air from a NACA-design intake duct at the leading edge of the hood. The underside of the duct is flanged and seals against a foam gasket attached to a matching flange on the air cleaner cover. The air cleaner and engine are protected against ingesting water by a water separator in the air cleaner cover. The water separator consists of two transverse vanes in the air cleaner cover that deflect the incoming air flow, causing the water to separate because of its inertia. The water, if present, collects in a trough at the low point of the cover and drains out onto the ground through three "duck-bill" valves. Valves of this type, which are also used to drain condensed water from the air conditioning system, open readily to release the water because of its weight, but close to prevent
Quieter operation during engine idle in neutral results from the addition of a damper to the disc hub of an all new clutch. A set of small, low-rate coil springs arranged circumferentially around the hub are tuned to make the clutch assembly act as a damper for engine torsional vibration before they reach the transmission input shaft and cause gear rattle. These springs have no effect on engagement characteristics because they are very light and compress fully at the beginning of engagement. Torque capacity of the clutch is also greater than before due to changes in disc and pressure plate. The disc is 0.4 inch (10 mm) larger in diameter and uses a higher capacity, but lighter weight, lining material that was introduced in 1996. Both increased torque capacity and greater clutch life are provided by conical machining of the face that contacts the disc. Giving the contact surface a slight taper compensates for the deflection that occurs during engagement to assure firm contact across the full face of the disc.
The Viper GTS driveline includes a more robust differential, capable of accepting up to 500 lb-ft (678 N-m) of torque and stronger drive shafts.
To enable faster recharging, a 650 CCA (cold cranking ampere) battery replaces the 770 CCA battery. The amount of acid is increased and the amount of lead in the plates reduced by a corresponding amount, which also reduces weight. Reserve power for starting remains appropriate to the task.
A higher-output generator with a 143 ampere rating is used to assure ample power to operate the Coupe's electric rear window defroster. Generator charging rate is now regulated by the JTEC PCM in common with other corporate vehicles.
A new frame developed for GTS is 60 lbs (27 kg) lighter yet possesses 25% greater torsional stiffness and 12% greater beam strength than the 1992-1995 version. Frame layout is unchanged. Improvements result from more efficient joint design and optimization of tubing diameter and section. The added stiffness reduces frame compliance for more precise cornering. Less weight also makes the car more nimble in both cornering and straight line performance. Frame refinements also include a new differential mounting scheme that increases housing stability under heavy acceleration and deceleration.
Suspension
The Viper GTS is lighter and has more power than any previous R/T 10, placing an even higher premium on precise handling. On the other hand, the broader range of GTS buyers may include persons less accustomed to driving high-performance cars than is the case with the R/T 10. The GTS weight distribution is also different, having a slightly greater rearward weight bias due to the addition of the roof and a lighter engine. To provide a car that is more comfortable and more forgiving at the limit of adhesion, GTS spring rates, stabilizer bar rates and shock absorber tuning provide somewhat more understeer.
Aluminum suspension components developed for GTS reduce weight by 60 lb (27 kg) and improve ride and handling. High-ductility A206 cast aluminum control arms and knuckles replace welded steel control arms and malleable cast iron knuckles. At the same time, the rear roll center has been lowered and the geometry revised to reduce track change during ride motion. This helps hard cornering on rough roads. In addition, the rear caster angle is increased from 6° to +1°, improving straight line tracking. Front suspension geometry is unchanged but the lower ball joint has been relocated from the knuckle to the lower control arm, reducing the bending moment in the arm under braking. This allows the control arm to be lighter than with the previous configuration. Front and rear shock absorber effective travel is increased for better control by moving the pickup points farther outboard on the lower control arms than the previous system.
Revalved shock absorbers and a higher viscosity-index hydraulic fluid minimize harshness and rate increases at low temperatures. These changes were introduced on the 1996 R/T 10 and refined to complement GTS handling characteristics.
Tires
Michelin Pilot MXX3 tires, pioneered in the U.S. market on the 1996 R/T 10, were chosen for their cool temperature traction, wet traction and low road noise -- capabilities far more necessary for the Coupe than the roadster. However, the new tires have also demonstrated substantial increases in cornering and braking traction. In standardized Chrysler-Michelin wet-traction facility tests, lap times were reduced by 6% compared to the previous tires. Peak dry road lateral acceleration on the skidpad increased by over 5%. Stopping distance from 60 mph (96 km/hr) is also reduced by over 13%, primarily due to the new tires. The carcass, tread and compound of these tires are tuned to the new suspension package to provide the driver utmost confidence in the vehicle's stability. Most notable construction change is an increase in sidewall stiffness to provide an earlier indication of traction loss than the original roadster tire, making it easier for the driver to compensate.
The fuel tank is designed to provide accommodation in the cargo area for a full-size rear tire. Compared to the 1996 R/T 10, tank capacity is reduced from 22 to 19 gallons (83 to 72 liters). The tank provides improved sealing for pump module and components.
A turbulated double-row radiator core provides increased cooling capacity under all circumstances. Turbulation increases a radiators cooling capacity without adding material or increasing the flow rate by causing turbulence in the flow that increases heat transfer. Shallow dimples in the radiator tubes cause turbulent eddies in the coolant as is passes. These eddies "scrub" smoothly flowing coolant off the inside surface of the tubes, allowing heat to flow outward more rapidly than with smooth flow.
A rear outlet exhaust system, introduced on the 1996 R/T 10, reduces passenger compartment noise levels but has less restriction than the former system for improved performance. From the outside it produces a throatier, more pleasant sound due to the use of resonators and larger mufflers. Resonators mounted in the sills aft of the catalytic converters lead to sill-mounted pipes that turn inboard forward of the rear wheels. The pipes pass over the rear suspension and enter a shared muffler with dual outlets on the centerline of the car. There are no side mufflers. The muffler outlets have a polished ceramic coating for a long-lasting quality appearance. An insulated aluminum shield protects the trunk floor and fuel tank against heat from the exhaust system and acts as a noise barrier.
The Viper GTS retains the basic Viper character but incorporates design features that give it individuality. Unique design features begin with the twin-bubble roof line that provides ample headroom while minimizing frontal area. The roof line sweeps across the one-piece glass hatch, terminating in a pronounced spoiler. A taller windshield assures adequate headroom, but retains the same angle, width and curvature as that of the roadster. The roof and body-color windshield pillar covers, which conceal the windshield surround, contribute to the Coupe's unique appearance. The front fascia incorporates an extended lower lip that provides an esthetic balance for the rear spoiler and helps balance the car aerodynamically. Both front and rear spoiler shapes were refined during wind tunnel tests -- subtle reshaping of the front; increasing the angle and raising the rear -- to provide balanced aerodynamic down force. The lower surface of the front fascia turns downward in front of the tires directing air out from under the car to help maintain down force. The extended lower lip retains the same angle of approach as the roadster to facilitate driveway ramp crossings. The cooling air opening in the front fascia is narrower to smooth air flow into the engine compartment.
Hood
A new hood retains the same basic shape as the roadster hood, but incorporates a NACA engine air intake duct and cooling air louvers. A new seal blocking the hood-to-fascia seam assures that cooling air does not disrupt flow to the NACA duct. The NACA duct leads directly to the air cleaner housing. Cooling louvers above each front tire reduce engine compartment air pressure and enhance cooling. Full coverage front wheel house liners assure that air is drawn out of the engine compartment, not the wheel wells. A new hood inner panel relocates stiffening ribs to clear the NACA duct and louvers. It is bonded to the outer panel in the same manner as the roadster. Hood material remains SMC, a glass fiber-reinforced molded plastic.
Windshield & Windshield Surround
A new windshield surround structure accommodates the Coupe's taller windshield and includes provision for door sealing and roof attachment. A new "soft touch' flat finish paint on the windshield surround limits windshield reflections. Body-color RTM windshield pillar covers are bonded to the windshield surround.
Roof & Quarter Panels
The two-piece bonded roof assembly surrounds the hatch opening, providing a close fit for the hatch, and forms the integral rear spoiler. The roof panel is formed of RTM (Resin Transfer Mold) composite material, as are most of the body panels. RTM's preformed glass mesh reinforcement allows panels made from it to be stronger and lighter than molded parts formed by other processes. An RTM reinforcement is bonded to the inside of the panel. The roof panel assembly is bonded to the windshield surround, and to the rear "clip."
Rear Clip and Cargo Area
The rear clip, a two-piece RTM structural assembly, forms the cargo area and supports the roof and quarter panels. It provides storage for a full size rear tire with the hatch closed, in case a "flat" must be transported. The deep cargo area has a capacity of 20 cubic feet (566 L), nearly 70% more than the roadster trunk since this car is more likely to be driven on extended trips.
Rear Closure Panel
A closure panel completes the rear appearance, filling the opening created by roof, quarter panels and fascia. It supports the rear lighting units for a close fit. It also incorporates outboard pockets that conceal outlets for the passenger compartment air exhausters and the license plate pocket. It is molded of TEO (Thermo-Elastic Olefin) material, which was chosen for its dimensional stability and ability to form the taillight and backup lamp mounting flanges.
Hatch
A one-piece glass rear window forms the Coupe's cargo hatch. When closed, it is flush with the roof panel. Its outer surface is free from attachment fittings because all attachments are bonded to the under side by a unique process for which a patent is sought. Areas of the glass where attachments are located are concealed from view outside the car by an opaque black band, or frit, fused to the glass as is common practice. The attachment contact areas and associated frit are somewhat larger than is typical for mechanical fittings, but this assures a mounting system that is both esthetically pleasing and stronger than mechanical attachments. Turning the key in the hatch lock on the rear closure panel releases the latch and the hatch rises smoothly to its full-open position without manual assistance, lifted by dual gas pressure cylinders. Closing effort is moderate. Two multi-link hinges with molded plastic trim covers guide the hatch in and out of its recess in the roof panel. The rear window defroster grid has vertical, rather than horizontal lines for esthetic reasons. Spiral cords bring electrical power from wiring in the roof to the grid.
Fuel Filler Cover
The fuel filler cover is a modern interpretation of a racing fuel filler cap from the past. The polished aluminum cap and latch assembly is partially recessed in the roof panel aft of the passenger-side door. It has rounded edges to avoid snagging passing objects. Pulling the spring-loaded finger latch releases the cover and it swings open on a spring loaded hinge to reveal a conventional screw-type filler cap. An O-ring seal under the door keeps the assembly tight and quiet when closed.
Fascias
Front and rear fascias feature new lines that integrate them with the overall body design as described in Exterior Design, above, but construction remains the same as the roadster.
Ornamentation
The Coupe is identified by low-profile body-color "Viper GTS" badges on the sides of the hood and right side of the rear fascia. The rear cloisonné medallion of the roadster is replaced by the Viper logo-design CHMSL on the Coupe. The front cloisonné medallion continues as on the roadster.
Door Structure
Coupe door construction follows that of the roadster -- stamped steel front and rear faces bonded and riveted to RTM inner and outer panels with a steel beam connecting them for side impact protection and structural strength. Inner panels are all new, however, to accommodate the window system. Outer panels are modified slightly, also to accommodate the window system. Door stanchions, which anchored the seat belt turning loops on the roadster, now support the electronic entry system push buttons and emergency inside release handles.
Door front faces use heavier gauge material than on the roadster and the toe box structure that supports them are strengthened to support the added weight of power windows. Door hinges, which were redesigned for the 1996 roadster, have two more blades and are 1 inch (25 mm) taller than the original design for increased strength and mounting stability. Cast aluminum construction of the new hinges makes them lighter than their forebears.
Power Latches and Locks
Power door latches and locks are standard on the Coupe. The latches are driven by electric motors. From outside, the latch is released by pressing a button on the door stanchion that operates a switch to power the latch motor. A one-finger door assist handle that is partially recessed in the stanchion encircles the button. From inside, the latch is released by pulling inward on a conventional handle, the same one used on the roadster, recessed in the door trim panel. Like the outside handle, it operates a switch to power the latch motor. Both button and inside handle have travel and firm resistance, which is provided by springs, that give the feel of mechanical systems. Motor-operated latches provide room in the shallow doors for full-drop windows.
Locking is electrical, not mechanical as on conventional systems. Locking occurs when power to the switches that operate the latch is cut. The doors may be locked using a one-way toggle switch in the bezel just above each inside door release lever or with the RKE (Remote Keyless Entry) transmitter. Locking, unlocking and RKE logic are provided by the Electronic Entry Module (EEM). An amber indicator lamp in the face of the switch indicates an unlocked condition. If the doors are left unlocked when exiting the car, the EEM turns the indicator off after 35 seconds. Doors also lock automatically when vehicle speed exceeds 8 mph (13 km/h) for maximum safety and security. Pulling the inside handle unlocks and releases the latch simultaneously if the car is stationary. The doors will not unlock and cannot be opened with the inside release handle if the car is moving above the automatic locking speed. If the passenger exits the car at a stop, the door re-locks when the car again reaches the automatic locking s peed. (See also Electronic Entry Module in the Body Electrical and Electronics section.)
If a power latch is inoperable, the door can be unlocked and opened with a manual release lever on the inner face of the door stanchion. After unlocking the hatch with the key, the release lever can be reached through the hatch opening. Each manual release lever is recessed flush with the stanchion trim and labeled. It uses a cable to release the latch.
Power Windows
Power windows are standard on the Coupe. Operating switches are located in the center console for easy access by driver or passenger. Power windows are used because the shallow doors and compact passenger compartment afforded no room for a manual crank. Windows drop completely into the door, driven by an electric motor through a compact cable and drum mechanism. For stability and to keep the windows sealed, particularly at high speed, the rear edge of the glass is guided to its full height by a track extending to the top of the stanchion. At the front, the nose of the glass also rides in a track and a small exposed clip provides added stabilization at the top front corner.
Door Sealing
The door sealing system was designed specifically for the Coupe. It combines extruded tubular sections with molded details at the belt line to form a single unit for each door. Below the belt line and aft of the stanchion, the weatherstrip is integral with a steel-reinforced retainer that is pressed over flanges on the body panels. From the top of the stanchion to the base of the windshield, the weatherstrip snaps into a stamped steel retainer fastened to the roof and windshield surround. The upper tubular section includes a lip under which the glass nestles when closed. A clip extending from the weatherstrip retainer at the top front corner of the window helps hold the glass snugly against the weatherstrip at high speeds.
Remote Keyless Entry System
Remote Keyless Entry (RKE) is standard and provides the only means to lock and unlock the doors from outside the car under normal circumstances; the doors have no key cylinders. The system uses a battery-operated transmitter -- two are provided with the car -- carried by the driver in conjunction with an Electronic Entry Module (EEM) in the car. LOCK and UNLOCK buttons on the transmitters are clearly labeled. To verify system operation, pressing the LOCK button on the transmitter causes a single chirp from the horn; pressing UNLOCK produces two horn chirps. To reduce the possibility of locking keys in the car, the RKE system prevents door lock motor operation using the door switches if the keys are in the ignition and the driver's door is open. (See also Electronic Entry Module in the Body Electrical and Electronics section.)
The RKE transmitter uses radio waves to operate the system, making it omni-directional -- it doesn't have to be aimed at the receiver. It has a range of up to 23 feet (7 m) from the car. A single owner-replaceable generic battery with an expected life of five years powers the transmitter. The transmitter case is designed as a key fob and includes unique Viper graphics.
Fog Lamps
New front fog lamps provide a wider, shallower light pattern than their predecessors, making them more effective in fog. New lens optics help distribute the light. A new mounting system allows easy aiming of the light pattern. A manually operated screw on the inboard side of each lamp adjusts the beam vertically. The adjusting screw is reached through an opening in the radiator closure panel covered by a snap-in rubber cap. The bulb can also be replaced through this opening. The bulb socket is housed in a rubber plug that snaps into the lamp housing. A simple wire clip retains the bulb in its socket. Clear covers in the fascia, which are removable to clean the lamp lenses, remain the same as on the roadster.
CHMSL
The Coupe's CHMSL serves the added function as an identification badge. Thirty LEDs, each with its own reflector to project the light rearward, are clustered together in the shape of a Viper emblem. The rim of the emblem and viper "head" on the CHMSL lens are raised and painted silver to contrast with the body. The viper head is silhouetted by the CHMSL illumination. The high-output LEDs mount on a printed circuit board and draw only 0.5 amperes compared to the 2 amperes for the two-bulb unit used on the roadster.
Seats and tracks are all new, providing a weight reduction of 20 pounds (9 kg) compared to the R/T 10 seats. Lighter weight results from optimization of seat structural components consistent with strength requirements. These seats also have the following new features:
Steering Wheel & Steering Column
A new three-spoke magnesium steering wheel supports the driver air bag. It has the same compact 14-inch (358 mm) diameter and leather-wrapped rim applied over molded foam as its predecessor. A new tilt steering column provides support, guidance and crash-energy management for the driver air bag. It has the same range of adjustment as the former column. A two-piece, telescoping steering shaft connects the steering wheel to the steering gear.
Adjustable Pedals
Fore and aft position of all three pedals is adjustable in unison over a range of 4 inches (102 mm), allowing the driver to custom tailor control locations. Maximum leg room with pedals in the full forward position is the same as on the roadster; all adjustment is rearward of that point. A soft-touch, cogged knob recessed in the steering column lower cover to the left of the column moves the pedals smoothly and easily over the full range of adjustment. Blade-type clutch and brake pedal arms are suspended forward of the roadster location but have a dog-legged shape that provides the same leg room as the roadster in their full-forward position. Brake and clutch pedal blade edges apply force to their respective operating linkage through eccentric cams. A finger follower on the side of each pedal blade rides in a groove in the side of each cam that parallels the face of the cam to keep the blade in contact with the face at all times. Turning the knob rotates the cams under the pedals through a system of gears and torsion cables. Friction is low and rotation is easy, but the cams cannot rotate out of adjustment under load because they are driven by worm gears, which will not turn as a result of torque applied to the mating gears that turn the cams. The accelerator pedal, which transmits far less force than the brake or clutch pedals, is suspended on a pivot that slides in a track. A cable and gear arrangement similar to that for brake and clutch moves the slider in unison with the other two pedals. Through extensive use of aluminum, this feature adds only 2 pounds (1 kg) to the weight of the car. A patent is pending on the design of the adjustment mechanism.
Steering Wheel & Steering Column-Mounted Controls
The horns are operated by a membrane switch mounted beneath the flexible driver's air bag cover in the steering wheel. Switch effort is low and this switch provides a large and easily accessible target for horn operation. The ignition switch key cylinder is illuminated by a halo ring from a single bulb in the column. A unique ignition key has a Viper logo molded into the key head. In addition, the blade of the key has a black anodized finish.
A robust multi-function switch lever on the left of the column operates the turn signals, high beam headlights, optical horn and windshield wipers. Pulling back part way on the lever when the headlights are off, flashes the high beams. A detent in the switch indicates this point. Pulling back past the detent latches the high beam function when the headlights are on. Rotating the knurled outer ring of the knob operates the wipers. Variable delay low-speed intermittent, continuous low-speed, and high-speed modes are available. Windshield washers are operated by a push button in the end of the lever. Pushing the button when the wipers are off, turns the wipers on for as long as the button is held plus one cycle. The hazard warning lamp switch, which is electrically integrated with the multi-function switch, is operated by a latching push button that extends above the top of the steering column. When the lamps are flashing, the button extends higher than when they are off.
Instrument Panel & Console-Mounted Controls
A pair of rocker type power window switches is mounted in the center console forward of the shifter in the location for easy access by driver and passenger This location was formerly occupied by front and rear fog lamp switches. The rockers are labeled with white ISO power window symbols.
Adjacent to the power window switches is the Coupe's rear window defroster switch. The momentary-contact push button returns to its released position after each depression. The switch is identified by a white ISO defroster symbol. An LED indicator in the button shows when the defroster is on. The defroster is operated by a relay mounted in the rear fuse block. The relay includes a timer that turns the defroster off after approximately five minutes. (See also Wiring System in the Body Electrical and Electronics section.)
A new rotary headlight switch also operates the fog lamps. Rotating the knob to the park or on positions and pulling out turns on the fog lamps. Rotating the knob to the off position also turns the fog lamps off. The fog lamps turn off automatically when the high beam headlights are on. Translucent white ISO switch nomenclature and the knob pointer are backlit by an amber bulb for nighttime visibility. A thumbwheel-operated control to the right of the instrument cluster and below the message center adjusts gauge lighting intensity. It provides a pulse-width modulated power output to the lamps --rapidly repeated pulses of varying width. Wide pulses produce bright light, narrow ones dim light.
Structure
Revised panel structure places the speedometer and tachometer side-by-side for easy viewing through the top of the steering wheel. The relative positions of these gauges are reversed from the roadster and the message center is repositioned to the right and below the new speedometer location. These three units now reside beneath a common eyebrow. The HVAC control panel and the radio receiver locations are switched relative to those in the roadster (the radio is now on top) to provide room for the Airbag Electronic Control Module (AECM) in the restricted instrument panel environment. The new passenger air bag resides in the previous glove compartment location.
Gauges
The speedometer is calibrated to register a maximum of 200 mph (320 km/hr) with the same sweep as the previous 180 mph (300 km/hr) unit. The speedometer is driven electronically by the JTEC PCM, which conditions the digital signal from the distance sensor in the transmission. Graphic design and lighting remain unchanged from the roadster.
Message Center & Indicator Lamps
The relocated message center retains the black matte finish appearance from the roadster but incorporates the following new functions:
The following message center indicators are retained from the 1996 roadster:
Turn signal indicators are mounted together in a oval window between the speedometer and tachometer.
Receiver and CD Player
An AM/FM stereo receiver with integral CD player is standard on the Coupe. Viper Coupe is the first and only Chrysler vehicle to use this unit. Its compact, European-size chassis fits readily into the instrument panel center stack.
The receiver incorporates vehicle speed-sensitive automatic volume control circuitry (AVC). When activated, AVC automatically adjusts the volume of the sound to compensate for changes of interior noise level due to variations in vehicle speed. It is no longer necessary to turn the volume up to hear at high speeds or down to a more comfortable listening level when stopped at a traffic light. The AVC button on the face of the receiver toggles the circuit among three settings: off, 1 and 2. Setting 1 is for operation with the windows closed; setting 2 is used with the windows open. When the system is on, AVC 1 or AVC 2 is illuminated in the display.
Power Amplifier
The cargo area-mounted power amplifier has a peak power rating of 200 watts, 80 more than the roadster system. Amplifier output characteristics are equalized to the car interior acoustic characteristics.
Speakers
The Coupe has six speakers. Rear woofers are rated at 100 watts. They are mounted at the base of the hatch and angled upward slightly to project sound to the passengers. Door tweeters are rated at 90 watts and 6.5-inch (165 mm) mid-range door speakers are rated at 50 watts.
General Information
Air conditioning is standard on the Coupe. The system provides a substantial improvement in air flow rate and cooling performance compared to the previous roadster system. An enhanced performance air conditioning mode provides even more cooling consistent with the needs of a closed vehicle by mixing recirculated air with ambient air.
HVAC Manual Control Panel
The new enhanced air conditioning mode is identified on the control panel by a car silhouette with arrows to show both recirculated and outside air flow. It is counterclockwise from the "normal" air conditioning "snowflake." Other modes and functions remain the same as on the roadster control panel.
Air Distribution System
To provide recirculated air for use in the enhanced air conditioning mode, a recirculation air duct connects an opening on the passenger's side of the toe box to the air intake plenum, returning partially cooled inside air for additional cooling. A vacuum-operated door between the recirculation duct and the plenum controls flow. In enhanced air conditioning mode, cooling air flow is comprised of approximately 60% recirculated air and 40% ambient air. Total air flow through the instrument panel outlets is increased by 50% over the roadster system. In the "normal" air conditioning mode, the system provides 20% more air flow than the roadster unit as a result of increased blower capacity and redesign of the ducts to eliminate restrictions. The system includes three central outlets and two lap coolers, as on the roadster, but a port has been added to the bottom of the driver's side lap cooler duct to direct cooling air flow to the footwell. Recirculation flow in the enhance air conditioning mode has a similar eff ect on the passenger's side. Air exhausters in the "saddlebag" area aft of the rear wheels enhance air flow through the passenger compartment for increased comfort.
Door Trim Panels
New door trim panels are formed in one piece, but retain the same appearance as the roadster. New stanchion trim panels provided an opening for the emergency latch release lever.
Headliner and Sun Visors
Cloth headliner material is bonded to a molded R-RIM composite support that closely conforms to the roof panel for maximum head room. Two mesh storage pouches nestle between the courtesy/reading lamps at the front of the headliner. New sun visors are padded for head protection in frontal collisions.
Bulkhead and Quarter Trim Panels
A new bulkhead trim panel includes a storage compartment with a one-piece, latching door below a storage pocket with mesh front, both between the seats. New quarter trim panels provide closure from door opening to bulkhead and cargo area upper trim panels.
Cargo Area Trim
The cargo area is fully trimmed for a neat appearance. Carpeting covers the floor and sides below the belt line. The spare tire has a separate carpeted cover. Above the belt line, molded trip panels provide the covering. The rear edge of the hatch opening is covered by a separate molded panel that also includes a cover for the latch.
Dual roof-mounted courtesy/reading lamps are recessed in the headliner. They illuminate together when the doors are opened and individually using adjacent push-button switches. Each lamp swivels to direct light to the desired location.
Cargo area illumination comes from a lamp integrated with the latch for the hatch. Unlocking the hatch also turns on the lamp.
The wiring system has been simplified and its serviceability improved by providing an engine compartment power distribution center (PDC), a passenger compartment fuse block under the instrument panel on the driver's side and a cargo area fuse block. The PDC is the primary electrical power distribution point in the car. It is mounted on the driver's side of the engine compartment with the JTEC PCM mounted just below it. It contains high-current maxi-fuses that replaced fusible links in the primary electrical power circuits, providing enhanced circuit protection and easier replacement. It also houses mini-fuses and relays for underhood electrical equipment, minimizing power loss in the wiring and making the fuses and relays easy to locate for service.
Relays for the fuel pump and rear window defroster as well as fuses for them and for the cargo area-mounted audio system power amplifier are mounted on the new rear fuse block in the cargo area. Proximity of this fuse block to the cargo area-mounted battery reduces power losses and simplifies the wiring for these rear mounted electrical systems.
An electronic entry module controls operation of the Remote Keyless Entry and Vehicle Theft Alarm systems. It includes the RKE receiver and also operates the automatic door locking feature. The module attaches to the driver's side of the frame backbone in the footwell area and is concealed by the console.
Driver & Passenger Air Bags
Air bag passive restraint systems work in combination with the active seat belt system, which must always be worn, to provide occupants with the maximum available crash protection. When deployed, the driver air bag extends outward to the side window while the passenger air bag reaches from the side window to the driver air bag. The air bags are only the major element in a passive restraint system that also includes the steering wheel, steering column, knee blockers, toe box structure and frame. These elements combine to manage impact energy for the occupants' protection.
The driver air bag module is the smallest full-body unit available in the U.S. to fit properly on the 14-inch (358-mm) steering wheel. The bag has both a unique shape and an internal tether to help protect the driver against severe frontal impacts. The inflator uses conventional pyrotechnic inflation material and ignition system.
Like the driver air bag, the passenger air bag uses a pyrotechnic inflator chosen for its light weight and compact size. The inflator is supported by steel brackets welded to the toe board structure. The passenger air bag resides where the glove compartment was on the roadster, and its "door" replaces the glove compartment door. At deployment the air bag tears open the seam at the bottom of the door and it swings up on a living hinge.
Air Bag Construction
Both air bags are constructed of porous nylon mesh that allows rapid dispersion of inflating gas while containing combustion products. Inflating gasses disperse through the fabric during post-deployment deflation.
Steering Wheel & Column
When the driver contacts the air bag during an impact, the steering wheel helps to absorb and distribute the load. It transfers some of it to the steering column and some to the toe box structure, which is designed for use with an air bag. Steering shaft upper and lower sections collapse during impact to reduce transmission of impact forces from the frame to the driver. A nylon coupling between the two sections breaks, allowing the shaft to collapse.
Structural Refinement
Modifications to the front structure direct and control crush in frontal impacts consistent with air bag restraint system requirements. New brackets on the toe box structure support the steering column and stamped steel knee blockers concealed by the lower instrument panel covers. Impact loads are transmitted from the occupant to the vehicle structure through these brackets. The passenger side knee blocker brackets are combined with the air bag inflator brackets for simplicity.
Airbag Electronic Control Module
A centrally located AECM (Airbag Electronic Control Module) controls and monitors the driver and passenger air bags. Both bags deploy simultaneously during a sever frontal impact. The AECM includes operating electronics, a collision detection sensor and system diagnostics. It is mounted on the frame backbone just forward of the HVAC controls. A single piezo-capacitive accelerometer in the AECM discriminates between impacts severe enough to warrant air bag deployment and minor bumps or normal operating conditions.
Air Exhausters
Large air exhausters in the "saddlebag" area of the cargo compartment limit air pressure buildup in the Coupe's compact passenger compartment during air bag deployment. They also enhance air flow through the car for occupant comfort. Furthermore, they reduce door closing effort by preventing the buildup of air pressure when the doors contact the weatherstrips. Mesh inserts in the cargo carpet assure unimpeded air flow to the exhausters.
Unibelt three-point active restraint systems are provided for both occupants. Vehicle sensitive retractors, which lock only in a collision or during hard deceleration, allow upper body movement under normal operating conditions. However, the retractors maintain light tension on the shoulder belt section to assure proper positioning when needed. They mount on the bulkhead between the seats, concealed by the bulkhead trim panel. To help make the belts easy to put on, the webbing is threaded through a guide loop on the inboard side of each seat back. When the buckle is unlatched, the latch plate retracts with the belt until it reaches the guide loop. If there is slack in the webbing when the latch plate reaches the guide loop, the webbing slides freely through the latch plate until fully retracted. While the webbing will slide through the latch plate during retraction, it can be cinched snugly over the occupants lap when buckled for a secure feeling and proper positioning when needed. This feature also allows th e use of an approved forward-facing child safety seat (Rearward-facing infant seats may not be used at any time. The body structure also includes a child seat tether anchor. New outboard buckles stand above the cushion for easy access. They are supported by flexible plastic strips so they can be moved out of the way when entering the car. Soft molded plastic scabbards conceal the webbing and plastic support. A refined end-release buckle design has a raised, concave button that is easy to release and also helps guide the latch plate into place when buckling up.
Side Impact Protection
Viper Coupe doors meet 1997 dynamic side impact protection criteria. In addition to the side guard door beam and sill interlock features, which carry over from the roadster, Coupe doors include 2-inch (50-mm) blocks of high density, impact resistant foam between the inner panel and the trim. These enhance impact load distribution in order to meet the more stringent dynamic impact criteria. Latch striker brackets, the door hinge pillar-to- sill structure and door-to-sill interlock are also stronger. In addition, reinforcements added to the tops of the doors to support the windows also contribute to side impact resistance.
Vehicle Theft Alarm
The Coupe's Vehicle Theft Alarm (VTA) is integrated with the RKE system. It is armed by locking the doors, either with the RKE transmitter or a door lock switch. It is disarmed by unlocking the doors with the RKE transmitter. To maximize the security potential of the system, the RKE transmitter output signal that arms and disarms the alarm includes a rolling code. Rolling code change each time a transmitter button is pressed to protect the system against unauthorized disarming through use of scanners or random signal generators. The receiver is synchronized with the rolling code from the transmitter. As with the roadster, VTA monitors the ignition switch, hood switch and door ajar switches in the latches. The Coupe system also monitors a hatch ajar switch in the latch, and a switch in one of the hatch gas struts which closes when the strut extends, as would occur if the glass hatch is broken to gain entry. As in the roadster's alarm-only system, opening any of the monitored areas or attempting to start the ca r without disarming the system triggers pulsed horn signals for up to 2-1/2 minutes and flashing of the parking lamps, taillights and an LED warning indicator on the top of the instrument panel for up to 18 minutes. Simultaneously, the fuel injection system is disabled to prevent the car from being driven. If the alarm was triggered but the horn and lamp warning has ceased, the horn will sound three times when unlocking the doors and disarming the alarm to alert the driver to check for tampering.
Locking the doors with the RKE transmitter initiates a 15-second countdown to VTA arming. During the countdown, the LED warning indicator is on steadily. As the system arms, the horn chirps once and the warning indicator begins flashing continuously at a low rate to indicate the system is armed. This also serves as a visual deterrent to would-be thieves. (See also Remote Keyless Entry under Door Systems in the Body Exterior and Systems section.)
Theft Resistant Steering Column Lock
The steering column incorporates a stronger ignition switch and lock assembly for increased vehicle theft resistance. The lock housing in the column more positively retains the lock than in the past to resist extraction of the key cylinder. The key cylinder now fails under heavy load in a way that still prevents starting the car. Attempted removal of the lock cylinder with a slide hammer, which is the commonly used technique, causes the key cylinder to break internally, leaving behind in the column a portion of the switch-to-key cylinder interface that continues to prevent the ignition switch from rotating or the column from unlocking. This redesign is accompanied by a reduction in key cylinder turning effort of up to 20% compared to the previous design.
Final Drive Unit
A more robust final drive unit, introduced on the 1996 roadster, provides an added benefit of long-term quiet operation that is especially beneficial to the Coupe. Operation remains quiet because noise-inducing wear is minimized in this unit.
Clutch
Quieter operation during engine idle in neutral results from the addition a damper to the disc hub of an all new clutch as described in the Powertrain & Chassis section under Clutch.
Exhaust System
The rear-outlet exhaust system introduced on the 1996 roadster has a throatier sound than the previous side-outlet system. Its combination of sill-mounted resonators and rear muffler unit effectively controls interior noise. The muffler heat shield and conventionally padded carpeting in the cargo area also help bring the exhaust noise perceived by the passengers to an acceptable level without adding unnecessary weight.
Major focus of body noise reduction was on avoiding wind noise due to weatherstrip leakage. This has been effectively accomplished, even at speeds well above the legal limit, as described in the Body Section under Door Systems. A fully carpeted cargo area also helps reduce interior noise.
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