Specialty File
When you spin the ignition key in this XKR factory special, the diagnostic display in the base of the speedometer admonishes you with the following: "INCORRECT PART FITTED," "GEARBOX FAULT," and "RESTRICTED PERFORMANCE." Let's examine those allegations one at a time.
INCORRECT PART FITTED. Just because this XKR sports an uprated engine, a rear suspension transplanted from an S-type sedan, a completely retooled interior, and a recalibrated suspension is no reason for the diagnostic computer to go into a snit.
GEARBOX FAULT. Okay, you could say that, since this XKR has a Tremec T56 six-speed manual in place of the standard Mercedes-sourced five-speed auto. Coupled to a twin-plate AP Racing clutch, a 3.69:1 limited-slip differential, and a reworked shift linkage, this manual gearbox changes the entire character of the XKR.
RESTRICTED PERFORMANCE. Not hardly. There are about 410 horsepower to be found in the 4.0-liter V-8, up from the stock 370, thanks to a six-percent-higher supercharger drive ratio, a rev limiter bumped from 6150 to 6750 rpm, and a freer-flowing air cleaner, intercooler, and exhaust system. In addition to the S-type rear axle, the suspension employs XKR Silverstone brakes, tires, and anti-roll bars, bolstered with Eibach remote-reservoir racing shocks, even stiffer springs, a solidly mounted front subframe, liberal use of spherical joints, and a straight-ratio rather than variable-ratio steering gear.
It adds up to an XKR that is far more sports car than grand tourer, and that was the goal of Mike Massey, head of Jaguar's Special Vehicle Operations and the man responsible for this machine. Variously called the XKR R-type, or the XKR Evo, the car is a test bed for various ideas that could perhaps be sold on special-edition XKRs.
After spending about an hour behind the wheel on English public roads, we would enthusiastically nominate the manual gearbox as one of those limited-production options. Although the twin-plate clutch is on the stiff side, the shifter is a sweetheart, with an action as light and precise as that of a gunsmith-honed bolt-action rifle. Moreover, the manual gearbox coupled to 410 horses delivers an immediacy of response that is guaranteed to seduce any sporting driver.
