Flashback Fridays: 2006 Jeep Grand Cherokee SRT8

Story by John LeBlanc Originally published, August, 2006 - WILLOW SPRINGS, California - While lined up alongside other Chrysler Street and Racing Technology vehicles waiting in the pit lane of Willow Springs race track for our turns to get in more hot laps before the course is closed, one of the Chrysler SRT engineers pokes his head into my rolled-down driver’s window to get some feedback. “Awesome turn-in, with tons of grip exiting through the apex. This thing is dead flat through the tightest corners here and super stable through that long, high-speed right-hander that goes on like Woodstock at the end of the track,” I enthuse through my helmet. “The engine is ‘right there’ all the time. And the brakes are like hitting a brick wall. A real point-and-shoot type of vehicle.” I also mention that, of all the SRT vehicles available, this might be the most fun to drive. A knowing smile curls across the Chrysler guy’s face. I could have been talking about the ground-pounding Dodge Viper SRT10 Coupe or the rumbling Charger SRT8 modern muscle car or the tossable Crossfire SRT6 roadster also on hand for a full day of track thrashing. But, no. I was referring to the surprising — and substantial — 2006 Jeep Grand Cherokee SRT8, Chrysler’s latest experiment gone right from the white coats in the SRT labs. Just how did the SRT boffins make a huge, sport-freakin’-utility vehicle behave like an elephant dancing on the head of a pin? And, more specifically, how did they enable it to post performance numbers such as zero to 96 kilometres an hour in less than five seconds — faster than either a Porsche Cayenne Turbo or a BMW X5 4.8is? With the somewhat ubiquitous Chrysler 5.7-litre Hemi V8 as a starting point, SRT powertrain engineers created a 6.1L edition, similar to the engines found in SRT versions of the 300C, Magnum and Charger but producing 420 horsepower and 420 pound-feet of torque once installed into this brute-ute. Power from the big mill is sent through a special torque converter to an SRT-upgraded five-speed version of the Mercedes-Benz automatic transmission that is also used in various other new Chrysler products. Needless to say, the new Grand Cherokee SRT8 is the most powerful Jeep ever. Although more “track” than “trail rated,” this is still a Jeep, so all-wheel drive is de rigueur. To deal with the extra grunt, a new all-wheel-drive system combining housing components from two existing units was developed for the hot rod Jeep. Employing the front half of a lightweight transfer case to the rear half of a heavy- duty case, anywhere from 5% to 10% of torque is directed to the front wheels. As much of the big Hemi’s torque as needed can be directed forward when additional traction or stability is required. “We wanted the acceleration that only four-wheel drive can provide,” says Dan Knott, SRT’s director. “Our goal for the Grand Cherokee SRT8 was to have a well-balanced vehicle with a high fun-to-drive quotient.” But more fun to drive than a Viper or Charger? Let me explain. SRT-tuned dampers, sway bars, spring rates, suspension bushings and new front suspension knuckles featuring a revised camber angle make up the chassis changes. Ride height is lowered 25 millimetres. Twenty-inch wheels wearing 255/45R20 rubber in the front and squirrel-squishing 285/40R20s in the rear not only provide much-needed grip, they also give the impression your ride has definitely been pimped. The Viper and Charger have big-time grip and balanced rear-wheel-drive characteristics. But one’s driving skills need to match their admittedly high limits. Granted, they are faster around a race track such as Willow Springs than the bigger Grand Cherokee SRT8. But, in the Viper, going over that limit can mean a backward trip into the track wall (as a fellow journalist learned during the event). And the Charger’s mass is almost as challenging to gather once you have the back end coming around. The Grand Cherokee SRT8′s higher centre of gravity, however, combined with its all-wheel drive, means you can left-brake this beast into luscious four-wheel drifts all day long. Push too far and you can let the front wheels bail you out of most potentially expensive misjudgments. Like I said, it’s wa-a-ay too much fun, especially with the thought of giving this type of thrill ride with four others aboard. Gravol, anyone? Referring to the speedy SUV, 2005 Targa Newfoundland veteran Knott ventured, “If we do Targa next year, I want to try this. I think it would be a blast.” If a track-ready SUV is prodding you to ask why, perhaps the SRT credo of “best performance at the best price” is your answer. At $53,925, the Jeep is 54% the cost of the BMW X5 4.8is and 42% of the Cayenne Turbo. With only 1,500 examples slated for North American showrooms, Jeep will most likely find enough buyers who won’t find the Grand Cherokee SRT8 questionable whatsoever.

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