The Jeep Grand Cherokee Trackhawk is the definition
of a high-performance SUV. The Jeep’s so fast that it makes other
performance-oriented machines look slow. But, Hennessey Performance isn’t
content with the SUV’s output and is now offering a new performance package for
any owners that want some extra oomph.
The SUV has the fabled 6.2-liter supercharged Hellcat V8 engine that produces
707 horsepower and 645 pound-feet of torque. But Hennessey’s HPE850 Upgrade, as its name
implies adds an additional 145 hp to the machine. Hennessey claims the upgrade brings
total output to 852 hp and 845 lb-ft of torque. To get that kind of power from
the V8 engine, the tuning company upgraded the SUV’s software, attached a
high-flow air induction system, and increased boost to 14 psi via a lower
pulley upgrade.
Hennessey has put out a dyno run of the
SUV to back up its claims. Interestingly, the tuning company decided to test
the Jeep in its rear-wheel-drive setting. We’re not sure if doing the run with
all-wheel drive enabled would’ve resulted in different numbers, but we have
seen a difference before.
On the dyno, the herculean SUV put down 722 hp and
655 lb-ft of torque to the wheels. The tuner factors in a drivetrain loss of
roughly 20 percent, which comes out to a total of 866 hp and 786 lb-ft of
torque at the crank. If you go off of the dyno’s figures that’s an increase of
159 hp and 140 lb-ft of torque over a stock example.
