Earlier this year, Jaguar introduced its all-new XK coupe and convertible. With a completely new chassis, including a lighter, stiffer, all-aluminum body, beautifully designed inside and out, with a uniquely British style, the new XK is a revelation among grand touring coupes
While the new XK, thanks to its lighter weight, is already about as fast as the former XKR, it’s been no secret all along that an even higher-performance, supercharged XKR version was on the way.
It’s almost here. Set to arrive in dealerships beginning in October, the new XKR gets 120 more horsepower (40 percent more) than the XK, yet the ‘R’ tips the scales only slightly heavier than the XK and about 200 pounds lighter than the last-generation XKR. With 420 horsepower on tap for well under 3700 pounds for the coupe, the XKR has an impressive power-to-weight ratio that’s actually 36 percent better than the standard XK. The Mercedes-Benz SL55 and M6, though they have more power, are also considerably heavier and it’s not that big of a difference.
Power comes from Jaguar’s familiar aluminum DOHC V-8 with four valves per cylinder, but it’s been specially tuned for the XKR - and of course, given the ‘R’, fitted with a supercharger. Intake valve timing is variable for the first time on the XKR.
Love it or hate it, that familiar supercharger whine underhood is an expected sideshow. But one of the first things you may notice after firing up the engine with the red, console-mounted start/stop button is that it’s remarkably absent of blower sound. The same supercharged engine is also offered in the S-Type R and the XJR, but it sounds quite different in the XKR, more like a naturally aspirated engine. Jaguar engineers intentionally tuned out much of the whine; you only notice the ‘blown’ induction sound and supercharger whine at full throttle, or near it. In all, engineers say that peak supercharger noise has been reduced by five decibels versus the previous XKR. While intake noise is muted, the exhaust instead has been tuned beautifully, with a raucous, throaty V-8 sound at full rip. At idle it has the smooth character of a German V-8, but when being driven hard it has more the character of an Italian exotic crossed with an American muscle car. That great compromise between quiet cruising and raucous power delivery when driving fast was achieved through an Active Exhaust system, which alters the flow through the primary silencer depending on throttle position and rev.