The long-neglected 3.8 V-6, used only in top-of-the-line minivans, faced challenges from stronger GM and Ford engines. It was given another 14 hp and 13 lb-ft of torque, lower emissions, and better gas mileage, from better airflow (including ducting), a revised intake manifold, and a 24% larger throttle bore. The heads and combustion chambers were redesigned to raise the compression ratio from 8.9 to 9.6:1.
On the 2.4 four, a smoother cylinder bore finish and new piston design allowed quicker engine break-in.
With regard to the V-10: in the Viper, tubular stainless steel exhaust manifolds replaced cast iron components, saving 24 lbs. A new reduced overlap camshaft resulted in a smoother engine idle and allowed an increased spark advance at idle without compromising emissions. The Ram V10 had calibration revisions, including outside temperature data input, increasing power from 295 bhp to 300 bhp and torque from 425 lb-ft to 440 lb-ft.
The 360’s new camshaft added up to 15 bhp and the torque curve was widened to provide more responsive performance in the normal driving range. Meanwhile, the 318 in the Grand Cherokee got 15 degrees more spark advance (which requires premium fuel), while a 25% reduction in backpressure added 25 bhp. The cooling fan motor was now electric, eliminating a power drain of up to 20 bhp.
As for emissions:
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