Mustang Hoonicorn RTR

There has always been a fine line between brilliance and insanity. Van Gogh, for instance, lopped his ear off and then painted The Starry Night. Prince went from rock symbol to, well, just a symbol. Nikola Tesla invented everything from FM radio to spark plugs, then invented a death ray and attempted to have conversations with pigeons.

What you see on these pages is a bit different. In the case of Ken Block’s most audacious set of wheels ever, there’s brilliance in its insanity, behind and around it. Without the insanity, the brilliance behind this car, dubbed the Hoonicorn, could never exist.

The Hoonicorn itself rests comfortably in the grey area between genius and sheer lunacy, sitting with more presence than a military display and packing an arsenal to match. Every part of the erstwhile 1965 Mustang has undergone the Spinal Tap treatment to the point where it’s difficult to know what to salivate over first. We’re kids in a candy store and diabetes is on the horizon.

Because numbers speak louder than words, we’ll head to the engine bay first. Ford Racing supplied the Hoonigan team with a Roush Yates-prepared V8, packing a series of absurd figures; a 630kW and 976Nm barrage firing from 6.7 litres’ worth of American steel. Naturally aspirated as the big V8 may be, it’s still breathing easy, thanks to eight velocity stacks feeding directly into eight individual throttle bodies.

This sort of tech isn’t what you’d expect to find bolted to simple Yank muscle; individual throttle bodies grace precision instruments like the E90-series M3 and Yamaha R6, ensuring micron-accurate fuel/air mixtures into each cylinder. Yet here they sit, plumbed into the long velocity stacks that draw from a custom-made air box, which sits as proudly and menacingly as the air scoops on Top Fuel dragsters.

Fans of Top Fuellers would be most able to describe the sound that comes from this thing. It’s other-worldly, a shrieking, violent series of staccato blasts from the twin side mounted exhausts. If the air that flows through the intake has precious little in the way of restriction, the gas that surges out has even less. There are no impediments at any point high flow headers handle one bank of cylinders each, drumming exhaust and excess fuel into straight pipes, undeterred by such pedestrian obstructions as catalytic converters and silencers. The excess fuel is no mistake, either; the MoTeC engine management system is tweaked to ensure big petrol dumps on throttle-off moments, guaranteeing bursts of fire and noise on every over-run and gear change.

This sort of tech isn't what you'd expect to find bolted to simple Yank muscle

The furious, flame-spitting V8 has the privilege of powering the most unique Mustang of all time. There are Mustangs, there are powerful Mustangs, and then there’s the Hoonicorn. There’s a very good reason the manic motor sits so far back in the engine bay; a bullet-proof diff and set of half-shafts sit in front of the engine, powering and overpowering the front wheels, thanks to a four-wheel drive system usually reserved for Dakar racers. Bar a couple of stillborn ’60s concepts, Hoonicorn is the first-ever all-wheel drive Mustang, tipping it firmly into the space reserved for window lickers. French outfit Sadev, makers of all wheel drive systems for WRC and FIA Cross Country Cup racers, supplied their biggest and strongest unit, which immediately failed in the face of the sheer brawn of the 6.7-litre V8. The Sadev SC90-24 drivetrain that propels Dakar Rally drivers to glory is capable of handling an immense 750Nm of torque. This is quite a bit. However, 976Nm is quite a bit more. Cue a series of awesome, if unfortunate, engineering setbacks.

One of the drive shafts was reduced to sheared metal, the transmission had a heart attack and the main prop shaft was wrung around itself like a raspberry twister. With no stronger systems available, the Hoonigan engineers beefed up what they could, where they could, and concocted a mechanical fuse of sorts. The 18.4cm, triple-plate clutch probably good enough for a Mack truck was engineered as a sacrificial ‘weak point’ in the drivetrain, saving the gearbox and drivetrain from the fury of the Roush Yates bruiser. ASD Motorsports, in charge of body fabrication and chassis set-up, constructed a two-piece bell housing so that the clutch, when turned to ashes, could be replaced in as little as 90 minutes, anticipating quite accurately that it’d need replacing often.

The main propshaft was wrung around itself like a raspberry twister

ASD, a North Carolina warehouse of speed, had worked on the Mustang in secret over the course of two years. Ken Block expressly asked for secrecy, referring to the Mustang only as the ‘Unicorn’ for the course of the build. It’s easy to see where Hoonicorn fits in the mix, then.

Block presented ASD with a concept and a weary 1965 Mustang in 2012, back when the world was captivated by his airborne antics through the streets of San Francisco in Gymkhana Five. In the months before blueprints were on ASD’s table, Block and the Hoonigan team sat down with RTR, the tuning house and brainchild of renowned drifter Vaughn Gittin Jr, to come up with a car that would turn public preconceptions of his Gymkhana series upside down, inside out and back to front.

Block and Gittin’s teams filtered through a stream of wholly inappropriate cars as possible bases for the project, from trucks to Ford Mavericks (the American sedan/coupe that is, not the rebadged Nissan Patrol foisted on us in the 1990s). Finally, to honour its 50th birthday, they decided on the iconic 1960s Ford Mustang. One could argue that as Ford supplies both men and both teams, choosing a Ford was political expediency, but cynicism gets you nowhere.

The stock Mustang coupe was studied, considered, and then almost entirely scrapped in favour of space frames and tech from the playbooks of Formula 1 and the World Rally Championship. Underneath the carbonfibre, homage-to Mustang bodywork, behind the Hoonicorn’s 6.7-litre tower of power and around the Dakar-spec driveline sits the most advanced suspension ever fitted to a Mustang. With a standard ’Stang of that era running leaf springs and a live rear axle, it wasn’t hard to go one better. However RTR, Hoonigan and ASD Motorsports went above and beyond with pushrod suspension front and rear.

Billet aluminium control arms and pushrods are the only wheel-facing suspension components; at the front, the inboard springs, dampers and anti-roll bars sit in front of the engine, lined up next to the front drive shafts. The same inboard set-up dominates the rear, with a fuel cell wedged as low as possible in the space frame; it’s almost comically small compared to the engine it’s feeding.

Thanks to its supremely focused chassis, the Hoonicorn has an almost preternatural agility, sliding through turns, finding slip angles and generally behaving in a way that squares up against logic and knocks it out in the first round.

There’s a huge amount of pliancy in the set-up, which is integral to the Gymkhana videos and Gymkhana Seven in particular. Block’s tyre-shredding theatrics extend across a range of unforgiving surfaces, from the grooved concrete of LA’s freeways to the cobbled pavers of Chinatown, taking in jumps, kerb hops and surface transitions with a smoothness that belies how hard the suspension has to work to keep everything in line.

Block asked for one more miracle a chassis setup mimicking his WRC Fiesta

On top of the tortuous Gymkhana track, the chassis also has to deal with huge shunts of grunt delivered in a binary fashion. It’s either on, with 630 killer watts trying to spit the Hoonicorn into oblivion, or it’s off, leaving the beleaguered chassis to deal with a pair of locked and sliding rear wheels and seemingly infinite front-end grip, thanks to ultra-sticky Pirellis.

In an engineering oddity, the handbrake hydraulically locks the rear wheels and simultaneously disengages drive from the front end rendering the Hoonicorn a two-wheel drive, 1360kg hunk of pirouetting metal leaving only the chassis, tyres and Ken Block’s pair of brass bells to keep everything together.

With control already tenuous, Block asked for one more miracle a softer, more flexible chassis set-up, allowing him to transfer weight around the car to load and unload tyres, playing with the limits of adhesion and mimicking the feel of his WRC Ford Fiesta RS sashaying effortlessly over a gravel rally stage.

To achieve the seemingly impossible, ASD Motorsports’ engineers softened the Hoonicorn’s suspension to its conceivable limit and Pirelli in turn committed sheer heresy, changing the compound of its top-tier ‘P Zero Trofeo R’ tyres to one that offered cumulonimbus-sized plumes of smoke… and less grip.

The rationale behind the smoke is fairly obvious, but reducing grip seems more than slightly mad, considering the Revelations-worthy force of the 6.7-litre powerplant. But Block needed to balance the grip required for acceleration and braking with the slip needed to slide through, around and under various different obstacles.

Notions of balanced grip and a compliant chassis seem violently at odds with how this car sits still, let alone how it moves. At any speed and any angle, it exudes unrestrained aggression, tearing through the thin line between brilliance and insanity with all four wheels spinning, a testament to overlooking the ‘why’ and choosing the ‘why not’.

Gymkhana Seven is wrapped around the Hoonicorn; it’s as much an homage to the car, its soul and character as it is a display of Ken Block’s driving prowess in new surrounds. Somehow, the Hoonicorn doesn’t need to endure the long jumps and heavy landings of Gymkhana Five; it doesn’t need to blow its tyres off the rim, break fluorescent tubes or knock apes from Segways. Gymkhana Seven is the same as the six that preceded it and yet completely different.

If repeating the same thing and expecting a different result is the definition of insanity, Gymkhana Seven proves that it’s possible for insanity to lead to brilliance. The Hoonicorn, on the other hand, proves that it’s possible for brilliance and insanity to be one and the same.