What enabled the base 5.7-litre V8 to produce 85 more horsepower was a complete reworking of the engine's block and vital
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| SRT engineers increased the bore of the engine cylinders by 3.5 mm to bump displacement up to 6.1 litres. (Photo: DaimlerChrysler Canada) |
components. SRT engineers increased the bore of the cylinders by 3.5 mm to bump displacement up to 6.1 litres, and raised the compression ratio to 10.3:1, up from 9.6:1. The tuned V8 also features new high-flow cylinder heads, freer-flowing intake and exhaust manifolds and a performance exhaust system, which allow the engine to breathe easier. To deal with the extra power, the block itself and many of the high-stress components such as the crankshaft, connecting rods and pistons were strengthened, while a heavy-duty oil pump keeps the vital supply of black gold constant at higher engine speeds.
To harness the massive power and torque from the big-block V8 engine, and to keep in line with Grand Cherokee's all-weather reputation, the SRT team developed its first four-wheel-drivetrain. Like its motor, the SRT8
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| To keep in line with Grand Cherokee's all-weather reputation, the SRT team developed its first four-wheel-drivetrain. (Photo: DaimlerChrysler Canada) |
builds on the Grand Cherokee's standard components, modifying parts to deal with the extra power. The high-performance Grand Cherokee utilizes a hybrid transfer case, crafted from the front half of the lightweight Jeep transfer case, and then mated to the rear half of a heavy-duty unit. The latter's rugged construction contains all the electronic components for the full-time four-wheel drive system. Along with a heavy-duty output shaft, the SRT8's unique transfer case has the capacity to handle the 410 lb-ft of torque, while weighing 27 kilos (60 pounds) less than a stock heavy-duty transfer case. SRT has also upgraded the rear differential to a Dana 44 from the European Grand Cherokee turbodiesel, fitted with a larger ring gear.
