1998 Dodge, Chrysler, Plymouth, and Jeep Changes

Engines

3.8 V-6

The 3.8 V-6, long-neglected and used only in top-of-the-line minivans, faced challenges from stronger GM and Ford engines. It now provides another 14 hp and 13 lb-ft of torque, and has lower emissions and better gas mileage. The boost came from better airflow, including ducting, a revised intake manifold, and a 24% larger throttle bore. (Airflow was generally poor among Iaccoca-era powerplants). The heads and combustion chambers were redesigned to raise the compression ratio from 8.9 to 9.6:1.

2.4 Four

A smoother cylinder bore finish and new piston design allow quicker engine break-in.

V-10 (Viper)

Tubular stainless steel exhaust manifolds replace cast iron components, saving 24 lbs. A new reduced overlap camshaft results in a smoother engine idle and allows an increased spark advance at idle without compromising emissions.

V-10 (Ram)

Calibration revisions, including outside temperature data input, increase power from 295 bhp to 300 bhp and torque from 425 lb-ft to 440 lb-ft.

5.9 V-8 (360)

A new camshaft adds up to 15 bhp and the torque curve is widened to provide more responsive performance in the normal driving range.

5.2 V-8 (318)

In the Grand Cherokee, 15 degrees more spark advance (which requires premium fuel) and a 25 percent reduction in backpressure add 25 bhp over the current 5.2L engine. The cooling fan motor is now electric, eliminating a power drain of up to 20 bhp.

Less pollution across the board

They used to say that reducing pollution meant cutting power. Not true, as we show:

• The Viper has new, lighter exhaust manifolds that heat up faster, allowing for quicker light-off of the catalyst. This allows the engine to burn cleaner earlier in the cycle.
• New combustion chambers, smoother cylinder bores, and new piston designs cut emissions by 17% in the 3.8 and by 33% in the 3.3 V-6. (The engines are closely related).
• The 2.4 engine's hydrocarbon emissions are reduced by 20% by a new cylinder head gasket and smoother cylinder bore finish.

Car and truck changes

Most car and truck changes for 1998 were designed to reduce noise, vibration, and harshness:

• The passenger compartment in the Dodge Ram pickup is quieter due to a completely new interior package that absorbs more sound. Better chassis tuning results in reduced body vibration.
• A new anti-lock braking system allows smoother and quieter operation for Chrysler Cirrus and Sebring Convertible, Plymouth Breeze and Neon and Dodge Stratus and Neon.
• Improved aerodynamics on sunroof option for Cirrus, Breeze and Stratus reduces wind noise.
• A structural transmission collar made of lightweight aluminum is new for all vehicles with 2.0L and 2.4L engines, to reduce noise and vibration at high engine speeds.
• A new intake manifold for the 2.4L engine on Plymouth Voyager and Dodge Caravan minimizes "rumble," improving the sound quality of the engine.
• Added foam in the dashboard, dampers that reduce steering wheel vibration at idle and a refined cowl screen between the hood and windshield reduce wind and road noise in the Stratus and Breeze.
• Softer rubber on the exhaust hangers for Neon transmits less exhaust noise and reduces vibration.

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