2006 and 2007Jeep Grand Cherokee SRT-8
A Jeep that does 0-60 in under five seconds...
Powered by a 6.1-liter Hemi V8 producing 415 horsepower and 410 lb.-ft. of torque, the first-generation Jeep Grand Cherokee SRT8’s performance numbers included 0-60 mph in under 5 seconds, 0-100-0 mph in the low 19-second range, and 60-0 mph braking distance of approximately 125 feet.
Dan Knott, Director of SRT, claimed that the 2006 Grand Cherokee SRT8 “... has the raw power to outperform the Porsche Cayenne Turbo, while providing exceptional ride and handling, world-class braking, race-inspired interior appointments and functional, performance-oriented exterior enhancements.”
SRT engineers had to create a drivetrain that was robust and reliable enough to handle 410 lb-ft of torque. One part of the equation was to create a new transfer case, combining housing components from two existing units with needed upgrades. They used the front half of a NVG transfer case chosen for its capability and light weight, and mated it to the rear half of a heavier-duty case, chosen for its ruggedness and ability to house electronic full-time four-wheel drive system components. The output shaft was upgraded to handle the torque. The result was a transfer case that could handle the power, but weighed 60 lb less than a Jeep heavy-duty case.
Under normal driving conditions, from 5% to 10% of torque was directed to the front wheels, but as much of the V8’s torque as needed could be directed forward when additional traction or stability was required. Remaining torque was sent via a heavy-duty driveshaft (designed for the European Jeep Grand Cherokee diesel) to a Dana 44 rear differential upgraded with a larger ring gear within a new axle housing.
Jeep Grand Cherokee SRT8 Powertrain
The specially tuned 6.1-liter SRT engine retained the classic Hemi orange-painted block. The Jeep had a specially designed intake manifold and fresh-air induction system to retain water-fording capability of up to 19 inches, with exhaust headers having individual tubes encased in a stainless steel shell. The intake manifold was designed with larger-diameter and shorter runners for higher-speed tuning. Exhaust was routed through a large-diameter (2.75-inch vs. 2.5-inch) exhaust system with 4-inch chrome tips. The transmission was an upgraded Mercedes WA580.
Jeep Grand Cherokee SRT-8 Ride and Handling
SRT retuned the dampers, sway bars, spring rates, stability control, and bushings, using new front suspension knuckles with a different camber angle. The ride height of the 2006 Jeep Grand Cherokee SRT8 was one inch lower, to cut aerodynamic drag and lower the center of gravity. Forged 20-inch five-spoke aluminum wheels were shod with high-performance Goodyear W-rated four-season tires with run-flat capability. Tire dimensions were 255/45/20 in the front, and a massive 285/40/20 in the rear. With an optional hitch package available from Mopar, the 2006 Jeep Grand Cherokee SRT8 was capable of towing up to 3,500 pounds.
All four wheels had four-piston performance brake calipers developed by Brembo, finished in gloss black. Under braking, these calipers clamped down on 360 x 32mm vented rotors up front, with 350 x 28mm vented rotors in the rear.
A new front fascia reduced lift and drag, and increased airflow to the engine, while other changes funneled air to the brakes; in the rear, the fascia was changed to accommodate dual 4-inch exhaust tips. Sill extensions increased downforce. Three exterior colors were available: Bright Silver, Brilliant Black and Inferno Red. The interior was medium slate.
Power-adjustable performance seats in the front held occupants during aggressive maneuvering. Interior accents included a “carbon-fiber” technical finish on the leather-wrapped steering wheel, instrument-panel brow and shift knob, complemented by a “refined aluminum” finishing on the center stack, shifter and door-switch bezels.
Instrumentation included a 180-mph (300 kph) speedometer, tachometer, fuel level, and temperature gauges, trimmed with a blue accent in a carbon fiber-trimmed binnacle. Oil pressure and temperature could be monitored.