Jeep Grand Cherokee Trackhawk: Driven

Is 707hp in an SUV as ridiculous as it sounds? We go Stateside to find out

The Jeep Grand Cherokee features Isofix mounting points. I mention this because, if you're buying an SUV, it's quite likely you've got a family, and want to transport them safely and securely.

And, should you be driving around with your family in a Jeep Grand Cherokee Trackhawk and decide, for whatever reason, to engage the launch control mode, you'll want to ensure your loved ones are fastened in as tightly as possible. Trust me, they'll thank you for it when you hit 60mph in 3.5 seconds, thanks to a supercharge-assisted, 707hp whack of V8 muscle. And they'll probably thank you again, 11.6 seconds later, when you'll have travelled a quarter-mile. Which is around the point when the entire family will come together in the communal realization that the Trackhawk is no ordinary SUV.

Instead, the Trackhawk is the answer to a question not that many people have thought of asking: what happens when you stick a supercharged V8 engine from a muscle car into a practical, runaround mid-size SUV?

The random-sounding fusion is the result of SRT, Chrysler's performance arm, being given the task of producing the world's fastest SUV. A traditional approach to doing this would probably be to try and strip down its weight, lower it a bit and rework the dynamic handling. Instead, SRT took a look at the Mopar Hellcat 6.2-litre engine - as used in the Dodge Challenger Demon - and decided to shove it in the front of a Grand Cherokee.

This required a fairly wholesale reworking of the car's internals, both to ensure enough air could get to the supercharged V8 to keep it cool when it was producing 645lb ft of torque at 4,800rpm, and also to fit a strengthened drivetrain, with upgraded transmission, rear driveshaft, CV joints and differential, in the existing Grand Cherokee architecture. Notably the Hellcat engine has never been used to power all four wheels of a car before. It does quite a nice job of doing so in the Trackhawk: the car's top speed of 180mph is determined by the aerodynamic limitations of its boxy SUV shape, rather than any lack of power.

Despite all the work to the mechanicals, the exterior of the Trackhawk isn't that different from a regular Grand Cherokee. A few small Trackhawk nameplates, Supercharged symbols and yellow Brembo brake calipers offer the only clues that this SUV can cope with a run down Santa Pod as well as the school run. Those brake calipers, incidentally, are the largest ever fitted to a Jeep model, which is quite useful given the extra heft of the Hellcat engine pushes the Trackhawk's weight up to a not inconsiderable 2,433kg.

Amazingly though, you don't feel the car's weight as much as you'd expect when you take it on track - as we were given an all-too brief chance to at the Spring Mountain Circuit in Nevada. Clearly, it's not exactly a nimble sports car in the corners, and you suspect those brakes would quickly wear down from the sheer work they're doing, but SRT's work to fit the Trackhawk with independent front suspension, Bilstein dampers and various other bits, results in handling that is far more poised than you'd expect.

The engine isn't as brutal as you'd think, either. It sounds great, but unless you're absolutely determined to put your foot to the floor with reckless abandon it delivers power in a far more usable form than you'd expect from a muscle car-derived motor.

It would take far longer with the Trackhawk than we had to really work out its potential, and limitations, especially since our circuit-only session meant we never got the car out of Track mode - which sends 70 per cent of the power to the rear wheels. Still, the first impression is of a package that makes a lot more sense in the metal than it does on paper. Which is a supremely rare feat.

The other overriding sensation, though, is that launch control mode. Stop the car, straighten the wheel, and put your left foot hard on the brake, then apply your right-foot hard to the accelerator. Wait a second or so, while the Trackhawk does some magic to pre-position the supercharger bypass valve, pre-loading it to build up torque, and then let it go. All that's left to do, as you hurtle forward at astonishing speed, is question whether you really did buckle up your little one tightly enough...

Inspired? Buy a Jeep Grand Cherokee here

James Attwood

JEEP GRAND CHEROKEE TRACKHAWK
Engine: 6,166cc supercharged V8
Transmission: eight-speed automatic, all-wheel drive
Power (hp): 707@6,000rpm
Torque (lb ft): 645@4,800rpm
0-62mph: 3.7sec
Top speed: 180mph
Weight: 2,433kg (kerb)
MPG: 20.4 (claimed)
CO2: TBC
Price: $85,900