HSV's New Coupe: The All Wheel Deal

By Feann Torr

The car's only just been launched and already the comparisons are being bandied about: "Watch out Porsche," and "The Aussie Euro-trasher" are but a few.

While Holden Special Vehicle's new $89,950 car, called the Coupé 4, is built for speed -- able to hit 100km/h from rest in just 6.1 seconds -- it's not likely to put an AWD Porsche to shame around Germany's famed Nürburgring.

But in its defence, this latest breed of Australian muscle car has many merits, the most obvious of which is its AWD transmission and the extra grip it affords.

Comparisons with more expensive brands will always please HSV, but as it stands the word on the street is that this is the best driving HSV yet - which is quite a lot to swallow for those who worship Australian rear wheel drive performance cars.

But more than just arbitrary comparisons, the engineering that went on behind the scenes makes for a far more compelling story. So, without further ado, let's get to it...

Making use of the naturally aspirated Chev-sourced LS1 V8, it makes 279kW (374bhp) @ 5700rpm, and a massive 475Nm of torque @ 4000rpm ensures a quarter mile run of 14.3 seconds.

Apart from the big-time power on offer from the fettled 5.7-litre V8 engine, the AWD transmission will ensure the Coupé 4 has more grip than most.

The mammoth task of actually developing Australia's first low ride height AWD coupé has proven to be an engineering triumph for the relatively small, close-knit HSV development team.

"Lowering the ride height (from Avalanche wagon) changed the entire geometry of the front suspension – the roll centre, camber, toe settings, etc", says HSV AWD Engineering Program Manager, Joel Stoddart.

"Correcting that meant designing a totally new lower control arm and steering knuckle assembly.

"At the rear it was a matter of fitting a current Coupé semi trailing arm and switching to 19 X 9-inch rear wheels (front are 19 X 8-inch) with a unique offset to maintain the correct wheel track," commented Stoddart.

The wider track, along with the flared wheel arches, give the Coupé 4 a much more aggressive look than its forebears, and the chrome grille, front fog lights and 19-inch alloy wheels ensure its range-topping status is clearly visible.

HSV's Head of Design, Julian Quincey, said that the team set out to create an "upmarket" yet "understated" look for the Coupé 4, "one that expressed the unflustered composed way that the vehicle puts its power down."

"The wheel arches flow into the sills, front facia and rear skirts using subtle blending between the surfaces," Quincey said, clearly pleased with his work.

As a pointer to the unprecedented level of co-operation that exists between HSV and GM Holden, these major modifications are carried out during the vehicle's build process at Holden's Elizabeth plant.

There it's attached to a ‘rotisserie’ system – developed by the HSV team – which allows the body to rotate to make the specialised work easier.

The body actually starts as a left hand drive US spec Pontiac GTO, since that model's fuel tank location behind the rear seat leaves space for the Coupé 4's stylised dual exhaust treatment.

In a 20 minute computer controlled operation the plasma cutter removes the necessary sheet metal from the guards and cut precise holes so that an extra cross member can be fitted to support the transfer case.

"From the Elizabeth plant it's transported to HSV' Clayton plant where the remaining HSV enhancements are completed. Coupé 4 is the first ‘unique to HSV’ vehicle to be built at the Holden plant and we couldn't have done it without the close support of Holden's engineering and production staff," said Stoddart.

The ability of the AWD chassis to accept significantly more rear roll stiffness, in contrast to its rear wheel drive siblings, unlocked some very impressive characteristics.

By doing this, HSV reckons that understeer tendencies are "virtually eliminated" and initial response to changes of direction is ultra crisp and precise.

This is assisted by the 27mm front roll bar incorporating a ‘race car inspired’ double ball joint drop link arrangement which suffers none of the delay in motion seen in conventional bushes. The rear roll bar is 16mm in diameter and tyres are 245/35 front and 255/35 rear with 19-inch rims all round.

In it's standard mode, or when cruising, the AWD system apportions torque 38:62 front:rear, and is constantly changing depending on the level of grip for each wheel.

The HSV constant AWD system includes a 4 wheel traction control system that makes use of ABD (Automatic Brake Differential). Other safety features of the Coupé 4 include driver and passenger airbags, side impact airbags and active head restraints.

The stoppers comprise big 349 x 32mm ventilated and cross-drilled front discs, while 315 x 18mm ventilated and cross-drilled discs adorn the rear axle, which together with the vehicle's tightly tuned suspension will make for rapid deceleration.

While it will be interesting to see how HSV's new all-paw performance coupe goes against tough competition, such as the 5.1 second 911 Carrera 4S, it's (expected) heavy kerb weight and low-tech 4-speed automatic transmission won't do it any favours. And it wouldn't be the fairest of comparos anyway, seeing as the Porky costs more than double the price (about $233,300 in automatic guise).

But on a local level, HSV's continuing use of ever-wider tyres has ensured it's RWD cars have kept up with the competition (namely FPV), and now with an AWD model on offer it can claim an even sharper apex shaving tool, and it be will interesting to see if Ford responds with a 4WD sports sedan using the Territory's underpinnings in the next few years.

HSV's new Coupé 4 retails for $89,950 plus on road costs.