With 335 horsepower (340 metric horsepower) on tap, the 3.0-liter supercharged V-6 is about 50 horsepower short of the 5.0-liter V-8 it replaces, but it will significantly improve gas mileage, raising the base U.S. XJ to 25 U.S. mpg combined (in European tests) from the current XJ's EPA-rated 19 mpg combined, a gain of nearly 33 percent. Maximum torque is generated between 3,500 rpm and 5,000 rpm, the plateau sitting at 332 pound-feet. All models of the XJ are also upgraded from a six-speed automatic to a new eight-speed automatic from ZF.
Jaguar says the new supercharged V-6 can get the XJ (both normal and long-wheelbase) to 60 mph in just 5.7 seconds and on to an electronically limited top speed of 155 mph. Again, that's a tick off the current 5.0-liter model's 5.4-second time, but likely to be considered a fair trade for better mpgs by mileage-conscious buyers.
2013 Jaguar XJ
While these changes have been announced by Jaguar's official global outlet, U.S.-market-specific changes haven't yet been released, so any of the above may be subject to change. The supercharged versions of the 5.0-liter V-8, however, remain unchanged for the 2013 model year even at the global level, so we expect them to stick around here as well.
For the full details, including a lot of diesel-flavored forbidden fruit, read on to page two for the official release.