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Chrysler Going Mainstream with 8-Speed; 9-Speed Automatic Coming

New gearboxes cut “a chunk” out of fuel consumption.

by on Sep.01, 2011

V-6 versions of the 2012 Dodge Charger will get the new 8-speed gearbox, as will the V-6 Chrysler 300.

Chrysler will become the first automaker to go mainstream with a fuel-saving 8-speed automatic gearbox, but has learned the Detroit maker is also developing an even more efficient 9-speed transmission.

Automakers are searching frantically for ways to improve mileage as they struggle to meet the 35.5 mpg fuel economy target for 2016 – and the 54.5 mpg standard recently enacted for 2025.  While all sorts of advanced – and expensive – options are under study, makers like Chrysler have realized they can achieve significant efficiencies simply improving the transmissions already found in every car on the road.

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The new Chrysler 8-speed will debut on the V-6 versions of the Dodge Charger and Chrysler 300.  They will deliver a full 4 mile per gallon increase in highway mileage, boosting the Dodge sedan to 31 mpg on the highway.

“That’s a chunk,” said Chrysler spokesman Vince Muniga, who also confirmed that “We’re working on a 9-speed” automatic gearbox that is expected to be even more efficient.

Transmissions serve as the mechanical link between the engine and the wheels.  They’re designed to keep an engine running as close as possible to its optimum speed, which means better performance, improved mileage and enhanced passenger comfort.

More gears – if engineered properly – enhance a transmission’s function, so a 9-speed would result in “lower operating speeds, say lowering the engine RPMs from 1800 to 1500” while cruising, explained Muniga, “and that would get you still lower emissions and better mileage.”

The challenge is to engineer the gearbox properly – especially the computer control system used to operate a modern transmission.  One of the challenges is to prevent what is known as “hunt-and-seek,” where a gearbox constantly changes gears when driving over hilly terrain.

Chrysler is the latest maker to up the gear count, matching the offerings of high-line makers like Lexus, BMW and Mercedes-Benz – but the first to offer an 8-speed in a mainstream line-up.  The new transmission is expected to start rolling out into other models over the next few years.

Motorists will notice an immediate payoff, the 2012 version of the Charger delivering 19 mpg in the city, 31 on the highway and 23 in combined driving.  The 2011 Charger with a 5-speed got just 18/27/21.

As for the 9-speed, it is still under development and sources say the timing for its roll-out – and the choice of vehicles it will be used in – has not been locked down, though spokesman Muniga confirms it will be used in one or more future front-wheel-drive products.

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