It’s faster than a speeding Porsche Cayenne Turbo. It laughs at the face of a BMW X5 and sprints to 60 mph faster than a new Mustang GT. The new super car, Jeep’s rowdy Grand Cherokee SRT8 is equipped with a powerful 6.1 liter Hemi V8, delivering a potent 420 horsepower and 420 pound-feet of torque. This SUV family hauler is definitely not your average SUV and you will know soon enough once you hear its throaty roar as it reach a quarter mile in a matter of 13.5 seconds which by the way is only a muscle car territory.
Despite the power delivered by Jeep’s Grand Cherokee SRT8 it still doesn’t match the performance of the Dodge Viper SRT10 Coupe and for this same reason why the Hennessey Performance created the new SRT600 package. The Hennessey Performance was the same people responsible for tuning up the Viper and since it wants to always create something more powerful than its previous masterpiece it has developed the performance package that will enable the Grand Cherokee SRT8 to finally defeat the ferocious Dodge V10 Viper in a 0 to 60 and quarter mile sprint.
Actually this was already accomplished with the new Hennessey SRT600 fortified Jeep, the Viper was outpaced to 60 mph by half a second and cross the quarter mile finish line two-tenths sooner than a much lower and lighter Viper.
Ever wondered where the Jeep’s added Saturn V-like thrust comes from? Instead of a solid rocket booster, a big Garrett turbocharger has provided the boost to a modified 6.1 liter V8. How did the Hennessey Performance accomplish this? First they started by removing the stock SRT8 V8 and tear it down to the cast-iron cylinder block. Afterwards heavy-duty bearings were added before the installation of aftermarket forged steel connecting rods, forged-aluminum 9.5:1piston, and high performance piston rings.
Hennessey has also reworked the cylinder heads creating a full porting on the intake and exhaust runners along with polished combustion chambers. And on airflow test bench conducted by Hennessey the ported heads flow 360 cfm on each intake port which is about 60 cfm more than stock.
To further increase airflow to the cylinders a single Garrett T4 turbocharger that delivers seven psi of thrust was added. The custom-made stainless-steel headers deliver exhaust to the turbo, then boost is fed through the 3.5 inch polished stainless steel tubing, a big front mount air-to-air aluminum intercooler and custom inlet tubing replete with twin billet-aluminum blow-off valves. To keep the turbo’s boost in check is a single 44 mm wastegate while the 180 degree thermostat helps the Hemi to remain cool.
Hennessey has also added a high-volume fuel pump that delivers a continuous flow of petrol likewise the oversized fuel injectors and a special fuel-pressure regulator are being monitored by a custom-programmed engine computer. The result of all these process is a 6.1 liter V8 that delivers 600 horsepower at 5200 rpm backed by 650 lb-ft of torque at 4000 revs. Such powerful torque requires a lot of engine airflow that lead the Hennessey to fit a dual three inch diameter stainless steel exhaust system, high flow mufflers, and a polished four inch diameter exhaust tips. At rest, the SRT600 is like a meek lamb but try to flat-foot the throttle and it awakens into a monstrous beast. A word of caution: The Hennessey SRT600 Jeep SRT8 is not for the faint-hearted.
The modifications done on the Jeep SRT8 was maintained at a minimum level which means that aside from the engine, the basic components of the SRT8 like for instance its Jeep fuel filter , the factory SRT spec Brembo disc brakes and many more were not altered. The exterior was however enhanced by adding a few SRT600 badges and optional 20×10.5 inches forged aluminum wheels wrapped in a Michelin Pilot Sport 2 295/30ZR20 tires.