![]() Naturally, the DCT has 33% quicker shifts than Honda's 5-speed automatic, but even when compared to the modern ZF 9-speed automatic used for the V6 TLX, the DCT retains an advantage in upshift speed, Kipfer said. “It was getting the feeling just right and making sure they are quick shifts without shocks,” he explained. The engineering team’s biggest task in developing the DCT was to optimize the transmission’s ability to change gears quickly, without hammering the car’s occupants with hard upshifts, said Kipfer. The DCT’s first seven ratios are all lower than those in the old automatic, while the eighth gear’s 2.212:1 ratio is higher than the 2.512:1 of the old one, for better highway fuel efficiency. This wider ratio spread contributes, along with changes to the engine, to the TLX’s four-cylinder scoring 2 mpg higher on the EPA’s city driving cycle and 4 mpg higher on the highway test. Where the old 5-speed’s lowest gear was an 11.768:1 ratio, the TLX’s DCT launches with a 14.084:1 ratio. The 8-speed’s additional ratios permit a much wider ratio spread than the old 5-speed automatic, contributing to the speedier acceleration and improved fuel efficiency. ![]() But DCT clutches demand use of a more costly dual-mass flywheel, so the torque converter solution is no more expensive overall, according to Kipfer. The torque converter, supplied by Cardington Yutaka Technologies, Inc., is more expensive than a clutch for the same application. ![]() In fact, the TLX 2.4-L car accelerates to 60 mph 1.5 s faster than the TSX did, thanks in large part to the use of a torque converter, he noted. Incorporating a torque converter into the unit not only provides internal NVH benefits that help deliver the low-speed refinement most drivers seek, but its inherent torque multiplication boosts off-the-line acceleration. “The main issue is the low-speed launch.” Honda's product planners and engineers interviewed drivers of cars equipped with DCTs, and “the main thing they talked about was how unrefined and unsporty they are,” said Kipfer. This gives the DCT-equipped TLX the smooth low-speed driving dynamics of a traditional automatic transmission with a gearbox that is more efficient, according to Chris Kipfer, the Assistant Large Project Manager responsible for drivetrain. Honda claims it's the first production DCT so equipped. The base car pairs its 2.4-L I4 with a Honda-developed 8-speed DCT, which features the novel twist of a torque converter in place of a clutch. The 2015 Acura TLX replaces the TSX and the TL, and offers a ZF-sourced 9-speed automatic transmission (the 9HP) with the optional 3.5-L V6. In the case of the Acura TSX, that meant only five speeds at a time when six is standard and 9-speed automatics are available. Honda has traditionally built its own automatic transmissions (uniquely without planetary gearsets), a strategy that has led to its transmissions sometimes falling behind industry fashion in the number of gear ratios. The cars can lurch when trying to move at parking-lot speeds, and a DCT can make inch-perfect parallel parking frustrating. Hopefully it's as good as Acura claims because the 8-speed is now the standard gearbox for all ILX models the automaker's release makes no mention of the return of the six-speed manual transmission option.Dual-clutch transmissions-essentially two parallel gearboxes that hand off power from one to the other, and do it more efficiently and quicker than either planetary automatics or conventional manual transmissions-seem like a dream technology for engineers seeking both performance and fuel economy.īut computer management of their clutches is tricky, and drivers accustomed to the silky launch provided by a torque converter-equipped planetary automatic are frequently disappointed by the driving dynamics of DCTs. Acura claims that this first of its kind automatic transmission combines the smooth launching of a traditional torque converter automatic with the lightning quick shifts of a dual clutch gearbox. The ILX also inherits the TLX's gearbox, an 8-speed dual clutch transmission with a torque converter putting power to the front wheels. That's a few ticks below the TLX 2.4's tune by both measures, but should be a modest performance boost over the current model. Stated power remains at 201 horsepower, but torque grows from 170 to 180 pound-feet. The 2.4-liter direct-injected mill is upgraded with the same improvements that we've seen under the hood of the larger Acura TLX sedan. The current ILX is available with a choice of either a 2.0-liter or 2.4-liter i-VTEC engine, but the new 2016 model will make the 2.4 standard across the board, dropping the smaller engine from the options list.
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