Here come the '99s10-5-98

October 5, 1998 Design News

ANNUAL AUTO ISSUE Technology Highlights

Here come the '99s

Just ahead of the new millenium, car makers are gearing up with new styling, engines, transmission technologies, body designs, safety features, and electronic goodies that will make next year a pleasure in the vehicle of your choice

David J. Bak, International Editor; Mark Allan Gottschalk, Western Technical Editor; John Lewis, Northeast Technical Editor; and Charles J. Murray, Senior Regional Technical Editor

STYLE AND SUBSTANCE

OLDSMOBILE IMPORT BUSTER. Oldsmobile's Alero joins the Intrigue and Aurora in an import-busting lineup with its distinctly non-domestic appearance. Gone are the ribbed cladding and power bulges--the "in-your-face" look--of the Pontiac Grand Am, its sister car. Instead, Alero designers employed smooth, clean lines, a refined face, and a subtle blister on the hood that provides the "less-is-more" look import buyers crave.

FORD DEBUTS POWER ADJUSTABLE PEDALS. Ford claims to be the world's first automaker to introduce power-adjustable pedals in a sport utility vehicle. Standard on the 1999 Lincoln Navigator and optional on Ford Expedition, the system offers up to 3 inches of linear travel adjustment, while maintaining constant spacing between pedals and a constant distance between the pedals and the vehicle's floor. An illuminated instrument-panel-mounted switch operates a small 12V dc motor on the brake and accelerator pedals to move them up or down. Height-challenged drivers can now sit farther from the steering wheel while maintaining good contact with the pedals. Ford's adjustable-pedal system accommodates 95% of the American male and female population. The power adjustable pedals benefit all drivers with increased seating distance from the steering wheel, increased knee bolster legroom, more comfortable arm positions, better access to console features, and more headroom.

ODYSSEY GETS POWER DOORS. Honda's Odyssey EX has dual power-sliding rear doors that drivers can actuate in three ways: the outside handle, a master switch on the instrument panel, or a remote-control key fob. Safety features cause the door to reverse if it meets resistance. The left door won't open if the fuel-filler door is ajar, and neither door will open when the vehicle is in motion.

HONDA'S HIDDEN SPARE. To maximize cargo space and allow the rear seat to fold flat, Honda engineers moved the Odyssey's spare tire to a compartment under the floor, just behind the front seats in previously unused space. A compact double-wishbone rear suspension fits under the flat floor, completing the package.

A MIATA WITH MORE. More what, you say? More everything. For '99, engineers at Mazda redesigned the company's most recognizable model, the Miata, to have a more muscular body, more horsepower, more trunk space, and a stiffer structure. Smooth curves, slight wheel flares, and slim oval headlights maintain the appearance of its predecessor while cutting the coefficient of drag a few ticks to 0.36 (with the top up). The 1.8(liter) DOHC four-cylinder engine now produces 140 hp thanks to cylinder head changes, a higher 9.5:1 compression ratio, and a variable-intake control system. By some act of magic, engineers increased trunk space 42%, even though the overall car is essentially the same size. And extensive finite element analysis improved the chassis' bending and torsional rigidity without adding appreciable weight.

ENGINES THAT CAN AND WILL

GM'S SHORTSTAR. Spun off from Cadillac's line of Northstar engines, GM's 3.5(liter) twin-cam V6 debuts in the 1999 Intrigue. For drivers of GM's V6 engines, many of which still employ the push rod 3800, this engine is a major change. It employs a 24-valve design with a chain-driven camshaft and a "limp-home" mode that allows it to continue running in the event of sudden coolant loss. A wide power band develops 230 lb-ft of torque at 4,400 rpm and 215 hp at 5,500 rpm.

NEW ENGINE FOR GRAND AM. The re-designed Pontiac Grand Am now uses GM's 3400 V6. The 3400 cranks out 170 hp at 5,200 rpm and 195 lb-ft of torque at 4,000 rpm. Its high torque at low engine speed provides a more powerful launch, which the 3400 accomplishes with the same fuel economy as the 3.1l engine it replaces.

MORE HORSES FOR SIERRA. The re-designed GMC Sierra offers three new higher power, more efficient, cleaner Vortec engines. The engines build on Vortec's cam-in-block design by incorporating a new deep-skirt, cast-iron engine block. They also feature deep-thread bolts, larger crankshafts and camshafts, and re-designed valve trains and cylinder heads. The engines include Vortec 4800, 5300, and 6000 models. The 6000, the most powerful of the three, kicks out 300 hp and 355 lb-ft of torque.

CHRYSLER LUXURY LINE DEBUTS REDESIGNED 3.5l V6. Among the design changes in the 3.5l engines that will be introduced in the 1999 LHS and 300M: a 26% increase in crankshaft stiffness from optimizing the distance between the main bearings and rod bearings, the size of the main bearings and rod bearings, and the diameter of the cylinder bores. Additionally, engineers achieved a 28% increase in engine-block stiffness by incorporating a structural, die-cast oil pan, increasing the number of fasteners holding the main bearing caps in place from two to six, and incorporating a structural beam that ties all the main bearing caps together. They also increased the transmission-case stiffness by 14% and powertrain stiffness by 41%. Premium seals and gaskets prevent fluid leakage, and cast-iron cylinder liners improve durability. Oil-drain passages cast right into the engine block speed oil return, even under high-speed conditions. Heat-treating the aluminum block makes it stronger than gray iron, and using forged steel instead of nodular iron increases crankshaft strength.

JEEP GRAND CHEROKEE GETS THREE NEW ENGINES. One of two newly designed engines debuting in the 1999 Jeep Grand Cherokee is the 4.7l V8 engine. Key design objectives included improved performance, efficiency, smoothness, durability, and lower emissions. The engine puts out 230 hp and 295 lb-ft of torque--5% more power at roughly 10% less displacement than the 5.2l V8 it replaces. Moreover, the engine delivers 7% better fuel economy and gives off 30% fewer emissions. The engine has a cast-iron block, two cast-aluminum cylinder heads, a single overhead camshaft per bank, and two valves per cylinder. A tuned-length runner intake manifold, free-flowing intake and exhaust ports, and fast-burn combustion chambers optimize "breathing" and combustion efficiency. Displacing 4,701 cm³ (287 cu. inches), the engine sports a relatively small 3.66-inch (93 mm) bore and a 3.4-inch stroke (86.5 mm) to help it fit into the Grand Cherokee's compact engine bay. Aluminum cylinder heads, a hollow camshaft with sintered-steel lobes, magnesium valve covers, and a molded composite intake manifold contribute to an overall weight reduction of 54 lbs (24 kg) compared to the previous 5.2l engine.

A new five-cylinder 3.1(liter) turbo-diesel engine is available in Cherokees assembled in Graz, Austria, for sale in markets outside the U.S. Built by VM Motori in Cento, Italy, the engine provides approximately 20% more power and torque than the 2.5l diesel engine it replaces. This additional power gives the Jeep up to 12.5% faster acceleration, a higher top speed, and more load-carrying and towing capacity. The 3,125-cm³ (191-cu.-inch) in-line turbo-diesel with intercooler has a 3.62-inch (92-mm) bore and a 3.7-inch (94-mm) stroke. It has a cast-iron block and individual cast-iron cylinder heads with two valves per cylinder. Electronically controlled diesel injection provides smooth operation and low emissions. An electronic accelerator, also known as "drive by wire," guarantees fast and precise response to driver input.

The third engine choice for the Grand Cherokee is the re-engineered 4.0l 6-cylinder in-line engine, which is reportedly quieter, more powerful, and cleaner than the previous design while delivering comparable torque at 225 lb-ft. Power output is 195 bhp when meeting Tier 1 U.S. emission standards--which apply in most U.S. states--or the European stage II emission standards. That compares with ratings of 185 bhp for the previous-generation engine. The engine has a cast-iron block and head with two valves per cylinder. The 3.88-inch (98.4-mm) bore and 3.41-inch (86.7-mm) stroke give a total displacement of 3,958 cm³ (242 cu. inches). A new slitter-vane water pump is 50% more efficient than its predecessor, contributing 2 hp to the power gain. An elastomer-coated steel intake manifold gasket, two-piece silicon-molybendum alloy cast-iron exhaust manifold, and multi-layer steel exhaust gasket have double the expected life of the previous components. Separation of the exhaust manifold into two pieces reduces internal stress, contributing to the extended life. An automated belt tensioner and coil-on-plug ignition improve the durability and serviceability of the engine. The new intake and exhaust manifolds enhance the sound quality of the engine and produce the lower, "throaty" sound preferred by customers.

MERCEDES-BENZ SUPERCHARGES ENGINE. For 1999, Mercedes-Benz offers the only supercharged engine in the sports-car category: a 185-hp, 2.3l DOHC in-line V4. Powering the SLK 230 Kompressor, the engine produces 200 lb-ft of maximum torque--equivalent to many larger six-cylinder engines but with less weight. Peak torque, moreover, is actually a plateau available from 2,500 to 4,800 rpm.

The SLK's crankshaft-driven supercharger features twin three-lobed rotors that turn at up to 12,000 rpm, compressing incoming air. An intercooler cools the pressurized air to create a denser intake charge, boosting power further. To increase component durability and conserve fuel, the belt-