HOLDEN Special Vehicles (HSV) has finally launched its long-awaited long-wheelbase version of its successful E Series.

The WM Grange has been a while coming. It was unveiled at the Australian International Motor Show in Sydney last October, before prices were revealed at the Melbourne International Motor Show in March.

Priced from $82,900, the latest WM Grange range represents a $7000 drop compared to the $89,950 WL Grange that was discontinued in July last year.

On sale this week, HSV is expecting the Grange to continue the trend of its smaller brethren by breaking HSV sales records.

Year-to-date in 2007, 1685 HSV vehicles have found homes, double that of the same period last year, and 30 per cent up on 2005’s January to April result.

April represented the eighth consecutive month of unprecedented growth for HSV, with 475 units shifted. The company claims it already has a “firm” order bank for its new luxury sedan.

Moving the Grange is a Chevrolet-sourced 6.0-litre Gen IV LS2 V8, delivering 307kW of power at 6000rpm and 550Nm of torque at 4400rpm.

With a compression ratio of 10.9:1, these figures were ascertained running on 98 RON premium-unleaded fuel.

The WM Grange’s LS2 V8 features tubular four-into-two-into-one extractors and an exclusive-to-HSV limited slip final drive ratio of 3.7 for the six-speed manual gearbox model, and 3.27 for the automatic.

The latter is GM’s 6L80E six-speed automatic transmission with a Tiptronic-style sequential-shift facility first seen on a Holden-based product in the VE V8 models in August.

In contrast, last year’s Grange vintage used a 297kW/530Nm version of the 6.0-litre Gen IV V8, mated to a four-speed automatic gearbox.

Bringing everything to a stop (in 36 metres from 100km/h) in the WM Grange is a new AP Racing brake package, which consists of 365mm front and 350mm rear grooved and ventilated rotors with four-piston front callipers.

HSV’s widely reported $4.5 million Magnetic Ride Control (MRC) variable suspension damping system – a first for an Australian-produced vehicle – is one of the Grange’s main drawcards.

Introduced in the short-wheelbase VE Commodore-based E Series cars last year, MRC is described as a semi-active electronic suspension system and consists of an electronic control unit that sensors change in road conditions and driver style to update the dampers pistons every 100th of a second.

With constantly variable dampers, sensors feed in the information to help maximise tyre-to-road contact for improved handling, roadholding and grip over a wide range of conditions.

HSV claims that MRC also reduces the vehicle’s bodyroll, pitching and bumps, for a smoother ride.

It all forms part of the HSV’s WM Caprice-derived suspension, which includes MacPherson struts with a direct-acting anti-roll bar up front and a multi-link independent set-up with an anti-roll bar out back. Both ends include progressive-rate coil springs.

Steering is a hydraulically powered variable-ratio rack and pinion device, enabling a turning circle of 11.4 metres.

The Grange’s front track is 1592mm while the rear registers 1590mm.

Electronic stability control (calibrated specifically by HSV for the WM Grange), traction control, and ABS brakes with electronic brake-force distribution and brake assist are also part of the Grange’s chassis control systems.

Much of the specific calibrating and retuning of these GM parts has been the work of HSV’s chief engineer John Clark.

Visually, the WM Grange stands out from its more mundane Caprice cousin with a uniquely designed front bumper and rear “bib” featuring a chromed grille and lower-intake surround up front. Chrome also surrounds the windows.

Other bespoke Grange items include 10-spoke 19-inch alloy wheels (eight inches wide up front, 9.5 inches wide at the rear) with specially designed Bridgestone tyres (245/40R19 up front, 275/35/R19 at the rear), a lower rear diffuser, four exhaust outlets, a flush-mounted rear spoiler, LED tail-lights and Grange badging.

The job of changing the Caprice into a Grange fell to HSV’s chief designer Julian Quincey.

Inside, there is a “chunky design” steering wheel, special HSV instruments and the choice of either dark “Onyx” trim (the standard fitting) or “Light Urban” trim.

Also included are rain-sensing windscreen wipers, self-levelling bi-Xenon headlights, heated wing mirrors with puddle lamps and position memory, 10-way power-adjustable front seats with memory, tri-zone climate-control, front and rear parking assist radar, a tyre-pressure monitoring system, cruise control, a trip computer, and a dual-screen rear-seat DVD player.

The first HSV to wear the Grange name was the 195i and 215i versions of the VSII Statesman Caprice-based cars in October 1996.

Both used revised versions of Holden’s famous Australian-built V8 – with the former employing the 185kW/400Nm 5.0-litre OHV engine while the latter made do with a bored-out 215kW/475Nm 5.7-litre unit.

These gave way to the WH (VT Commodore-derived) Grange that heralded the 250kW/473Nm 5.7-litre LS1 GEN III OHV V8s shipping in from Chevrolet in North America.

Less known outside enthusiast circles is HSV’s WH Grange 180i, powered by a supercharged version of the old Buick V6 Ecotec engine. This produced just 180kW and 380Nm, and only lasted a little over a year from July 1999.

According to HSV’s new managing director Scott Grant, the Grange represents his performance division’s “singularly most popular repeat purchase vehicle in the HSV line-up”.