2006 Jeep Grand Cherokee SRT8

Driving a sport/utility vehicle on the track was once about as much fun as playing beach volleyball in loafers. No more. After taking the new Jeep Grand Cherokee SRT8 around California's Willow Springs Raceway, we can visualize a showroom-stock race series built on this remarkable new SUV.

Not only was Jeep's ueber-ute an absolute hoot ripping off laps at Willow, it also scorched most of the competition in the sprints, muscling its way in between Mercedes-Benz's mighty ML55 AMG and Porsche's Cayenne Turbo as one of the quickest sport/utilities we've ever tested. The Grandest of Cherokees recorded a 0-to-60-mph time of 4.8 seconds compared with the Porsche's 5.1, and the Jeep didn't let up, beating the turbo Cayenne to 100 and in the quarter mile, 13.5 seconds at 101.6 mph versus 13.6 at 101.8. It also beat the Cayenne in the slalom and recorded higher lateral gs on the skidpad. Admittedly, the 4800-pound Jeep has a slight weight advantage on the 5000-pound Porsche, but if it works for Lotus, why not for a family car?

The Jeep SRT8 is the 11th of the hyperkinetic kids fostered for the Chrysler Group since the Street and Race Technology development center was created in 2002. It's also the first sport/ute and the first Jeep to benefit from SRT's extreme-performance makeover, which begins with massive engine power, here a larger-bore version of the Grand Cherokee's 5.7-liter Hemi (which delivers only 330 horsepower). The 6.1-liter then was extensively tweaked to produce its 420 horsepower and 420 pound-feet of torque, delivered to all four wheels through a special torque converter to an SRT-upgraded five-speed automatic gearbox and then on to the front and rear differentials through a specially designed transfer case. The result is smooth, linear, and thrilling doses of power, accompanied by a soundtrack that only a large-displacement V-8 engine in full tune can compose.

SRT methodology insists on track-capable suspension and commanding brakes. As well as its usual tuning to shocks, springs, anti-roll bars, and bushings, SRT lowered the ride height an inch, recalibrated the Electronic Stability Program, and fit high-performance 20-inch Goodyear radials on lightweight forged alloys, staggered in size to exploit the rear-biased powertrain. Four-piston Brembo brakes with big, vented rotors provide excellent clamping force at each corner.