While Porsche has made it abundantly clear that they have no concerns about trying to meet new corporate average fuel economy standards in the U.S. in the coming decade, that doesn't mean that aren't doing anything to improve the fuel consumption of their cars. Relative to their performance, Porsche cars have always comparatively efficient anyway, with the current 2008 Carrera 2 coupe be being rated at 18mpg city/26mpg hwy. That's a lot better than most SUVs. That's actually better than a V6 Saturn Vue at 16/23mpg.

Nonetheless, in the quest for ever-increasing performance, Porsche has evolved the 911 once again for 2009. This year the fuel is injected directly into the combustion chambers instead of into the intake ports. As with other similar arrangements at other manufacturers, the benefit is both increased output while using less fuel to do it. Output of the 3.6 and 3.8L engines is now up 20 and 30 percent horsepower respectively. In combination with the the new 7 speed dual clutch gearbox, the fuel consumption of these updated drivetrains is reduced by 13 percent. Interestingly, Porsche first developed the dual clutch gearbox in the 1980s for the 962 race car but has never used it in a production model while numerous other manufacturers are now using that setup. Now if Porsche had instead cut the displacement and maintained the current power levels, the efficiency improvement likely would have topped 20 percent. After all, does cutting a couple of tenths of a second off the 0-60 time when you're already in the mid-4 second range really make any difference in the real world where most people driving these cars are posers anyway?

[Source: Porsche]

Volvo is now offering a Getrag Powershift dual clutch transmission in its smaller cars - the C30, S40 and V50. The new gearbox is paired up with a 2.0L four cylinder turbodiesel. Volvo is using a six-speed wet clutch unit with a torque capacity of 332lb-ft. The diesel engine is rated at 136hp and 236lb-ft of torque and yields combined mileage ratings of 39.2mpg (U.S.) in the C30 and 39.9mpg in the sedan and wagon models. Those are improvements of about 8 percent in comparison to a conventional automatic transmission. The dual clutch transmission has an advantage over conventional automatics because it eliminates the losses inherent in a torque converter and provides greater flexibility in gear ratio selection. Compared to a conventional manual transmission, the faster shifts and electronic control provide efficiency increases as well. Unfortunately for American drivers, we can't get the diesel here (yet) but we will be getting the Powershift gearboxes in the not too distant future, perhaps in conjunction with the launch of the Fiesta.

[Source: Volvo]

We knew already that the 2009 Dodge Journey would be receiving a dual-clutch transmission for overseas markets, but Chrysler has just announced that the '09 Dodge Avenger and 2009 Chrysler Sebring will also offer the tranny. Mated to a 2.0 liter diesel engine, both fuel economy and CO₂ emissions will improve by about six-percent. Chrysler's dual-clutch transmission is jointly produced by Getrag. One clutch engages the even ratios while the other operates on the odd. Efficiency is increased due to increased mechanical efficiency.

We are hopeful that the American market will get some dual-clutch love from Chrysler after their new transmission plant in Indiana is ready in 2009, though we're not expecting it to be mated to the diesel-four if it does show up on our shores ... we're not that lucky.