HSV W427 2008 Review

HSV W427

Overall rating: 3.5/5.0
Engine/Drivetrain/Chassis: 3.5/5.0
Price, Packaging and Practicality: 2.0/5.0
Safety: 3.0/5.0
Behind the wheel: 4.0/5.0
X-factor: 4.5/5.0

About our ratings

OVERVIEW
With petrol prices at record levels, interest rates on the up, talk of 'social responsibility' and the need to downsize everywhere you turn -- and public opinion suggesting local car builders have lost relevance -- could you pick a worse time to launch a $150K-plus Aussie-built 7.0-litre (427ci!) "supercar"?

Probably not -- which makes HSV's feat of selling out its 2008 build allocation of Australia's most expensive, most powerful and largest capacity production road car yet, even more amazing...

HSV's $155,500 7.0-litre 375kW limited-edition W427 was launched earlier this week to the rampant ringing of the cash registers across the go-fast Holden arm's 57-strong dealer network. Built to celebrate HSV's 20th Anniversary year and assembled at HSV's Clayton factory, 90 W427s will be built between now and the end of 2008.

As this article was written, every one of those cars has a confirmed retail customer's name on it. HSV has guaranteed it will build no more than 427 W427s. It has reserved build numbers #1-5 and #427 for its own cars, but the others are up for grabs.

What it will not do is build cars without a confirmed customer order. HSV is adamant no W427s will be built for stock.

With Aussie musclecars now a collectable commodity, initial interest in the instant classic has been stronger than even HSV insiders imagined. HSV's top dealer, City HSV in Perth, is currently holding 15 confirmed W427 orders, the deliveries of which will stretch well into 2009.

Only a handful of those 15 are included in the initial 'sold out' batch of 90 cars.

Though the car gets body tweaks, most of the money has been poured into the underpinnings -- engine, gearbox, brakes, etc (see MECHANICAL below). That's not to say the W427 is poorly equipped, it's just not up to the standard you'd expect from other $155K cars. You're paying a premium to be part of HSV history, the enthusiasts would argue.

You're also buying into an ownership experience which begins when HSV's own customer care group contact you once your W427 order is confirmed. You'll be invited to observe the assembly process at Clayton and receive special W427 mementos. On delivery you'll get a special certificate and a personalised letter from Tom Walkinshaw, HSV Chairman and the man behind the 'W'.

That said, included in the W427's standard specification is just about every goodie HSV can throw at the car -- within the bounds of its Holden origins, anyway. Climate control air, rear park sensors, priority key system (which stores user settings for audio, climate etc), top-spec audio, full power pack, trip computer, Bluetooth and the top-line Datadot (micro and nano) antitheft ID technology are among the equipment list.

Like all HSV V8s, the W427 gets the normal HSV steering wheel, instruments, and ancillary gauges. Check out our latest E Series review here for this nuts and bolts stuff.

By way of unique-to-W427 items, the list includes logoed, all-leather, eight-way electric front seats (re-trimmed versions of the GTS's sports seats), W427 sill plates and badging and special 'Technical Cubic' carbon-effect dash and door spears.

We'd like to have seen some more 'bling' in the W427's cabin -- perhaps by way of stitched leather dashpads and door tops, alcantara headlining, unique seats and the like. Think AMG Black Series...

Or at the very least a choice of interior colour! Though there are five exterior colours offered (red, white, black, silver and graphite), all W427s feature an essentially monotone red interior. Just as well it looks better than it sounds...

Currently there are only three options offered on the W427: satnav; sunroof and rear DVD entertainment system. These are offered at HSV's normal rates.

HSV's offshoot, Walkinshaw Performance, will also repaint your W427 Panorama Silver -- the colour of the original Walkinshaw Group A this car in part commemorates. We expect this option to be pricey!

Despite being a limited edition, the car will be covered by a full HSV warranty and exotic engine internals or not, will only require normal service intervals. There are no special running-in or operating requirements and the car runs standard unleaded -- though HSV recommends 98RON and quotes its power, torque and fuel consumption figures (375kW, 640Nm and 17.2L/100km combined) based on the top line fuel.

MECHANICAL
Close to two years of development work has gone into the W427. Former GM Holden boss Denny Mooney opened up the doors in Detroit for HSV to source the race-style dry-sumped fuel-injected 7.0-litre V8 from Corvette's highest performance naturally-aspirated model, but this is far from just an engine swap.

HSV developed the W427's oiling system and worked through multiple iterations to solve the various packaging, cooling and performance issues related to the new engine's configuration. The oiling system, including the large front-mounted Setrab oil cooler, is a work of art.

The core engine is identical to that featured in the Corvette Z06. Displacing 7008cc, the alloy-blocked two-valve-per-cylinder V8 is oversquare (just) with a 104.9 x 101.6mm bore and stroke. It is redlined at 7000rpm -- 400rpm higher than HSV's LS3 V8 and 800rpm up on the Holden V8s -- and features titanium conrods. In W427 trim it's rated at a stonking 375kW at 6500rpm and 640Nm at 5000rpm.

Key factors in delivering these outputs are the W427's bespoke cold air intake and exhaust systems. The former features a central air intake due to the location of the dry-sump system's oil tank. This in turn required the radiator to be canted rearwards.

HSV's engineers say the airbox's efficiency compares well with the Corvette's intake system, despite the packaging challenges the sedan-based W427 presented.

The exhaust system pulls out all stops. Ceramic-coated equal length headers feed into four-into-one stepped collectors and the spent gases flow then through relocated 3-inch catalytic convertors. The rear half of the exhaust is 2.75-inch and electronically-controlled vacuum actuated bi-modal mufflers tune back pressure and allow the W427 to satisfy Australia's tough drive-by noise regs (Ford recently adopted the same strategy for its XR8 Falcon.)

The gearbox is unique in the HSV family, but Ford fans will be familiar with its designation. A six-speed manual (no auto is offered), the Tremec TR6060 box is also Corvette-sourced, but in the case of the W427 uses an M10 ratio set. Differing from the Corvette's MM6 Tremec in first and third gear ratios (and featuring wider gears and different synchros, HSV techs say) the box is 'fed' by a single-plate GM Performance LS7 clutch pack. Both pedal and actuator are new to decrease clutch effort and allow higher clamp loads.

Even the limited-slip differential is new. Though it shares its design and 3.7:1 final drive ratio with the rest of the HSV range, its internals are double shot-peened and lapped for durability and strength.

The W427 rides on springs that are 30 per cent stiffer than those of the GTS and its ride height has been lowered 20mm. In addition, HSV has adopted firmer rear suspension bushing for the multi-link IRS system and has eschewed Holden's running change (more here). HSV has completely overhauled the calibration of its Magnetic Ride Control (MRC) dampers for the W427 (see more in ON THE ROAD).

HSV has developed a unique braking package for the W427 to cope with the performance potential of the car. Unlike the rotors fitted to the GTS and other HSV models, the massive ventilated discs of the W427 are two-piece floating type -- employing a V8 Supercars-style strap-drive system to keep the rotor separate from the hub.

The 380 x 35mm floating front rotors are grooved but not cross-drilled. By way of comparison, the GTS uses 365 x 32 one-piece discs.

New AP Racing six-piston calipers increase pad area by 50 per cent over the GTS. However, such is the size of the calliper itself that HSV has had to commission a special 20-inch wheel design. The fronts are 20 x 8s, with the rears 20 x 9.5.

Bridgestone Potenza RE050 low-profile rubber -- specially developed for the HSV E Series -- is standard.

The W427 is fully Euro III emission-compliant, but it may surprise many it will require little tweaking to pass the next round of emission upgrades (Euro IV), say HSV's calibration engineers. This is important as HSV will likely build the W427 well into 2010-11, unless the 427-unit build limit is reached before then.

As noted above, the car has been subject to all of HSV/Holden's normal durability testing, including hot and cold climate and altitude checks. Normal service intervals apply.

The only hiccup in terms of abnormal servicing requirements is the air filter. Situated in front of the radiator, servicing the hi-flow element requires the front bumper of the car to be removed and replaced.

PACKAGING
The W427 gets unique front and rear bodywork. Since the unveiling of the original show car at the Melbourne International Motor Show, however, the final look of the production W427 has been tweaked.

The centre grille section retains the HSV's latest 'mouth' (complete with uvula!) but extends Audi-esque below the bumper line. The former matt black section is now a gloss black and some of the additional black detailing of the show car (around the front-quarter panel vents, for example) is body colour for the production models.

The front underbumper section is 60mm wider than the E Series and there are V8 Supercar 'winglet' inspired profiles at the front corners of the car.

Incongruously, the wildest current HSV has perhaps the most understated rear spoiler. The vestigial three-piece carbon-fibre unit is more 'flap' than wing. An attention to detail many will miss is that its underside is gloss-painted to match the underbumper 'diffuser' style detailing.

The W427's alloy quad exhaust tips are profiled to match the castellated theme of the 20-inch alloys. The wheels are the work of up-and-coming HSV designer Adam Dean Smith. Remember the name; he's destined for big things -- not just big wheels!

As all HSV sedan models share the same basic Commodore configuration, there's not much left to say, save for the fact that this might be a supercar, but it'll cope just as well with five big blokes and their luggage as a yellow cab would. There's perhaps only one other sedan in the world that can say the same -- the E63 AMG... Even the M5 is pushing it with three plumbers across the backseat.

SAFETY
The W427 carries over the full complement of Holden and HSV's active and passive safety equipment and driver aids -- stability control, antilock brakes (with EBD and EBA) and traction control.

As noted below, the W427 gets its own calibration for all of the above. It also benefits from MRC's contribution to active safety -- a car this potent needs top notch suspension.

The W427's brakes appear well up to the task of trackwork and the car rolls on to the road with the benefit of Commodore's solid body shell. Though still rated at only four-stars, the latest Commodore delivers a good safety story according to ANCAP's Crash Lab boffins.

The W427 gets six airbags, but in a safety overview we'd be remiss in not commenting on those A-pillars again. Please fix them Holden. Soon!

COMPETITORS
HSV says this car is pitched against the BMW M5, Mercedes-Benz E63 AMG, Audi S6 V10 and Maserati's Quattroporte -- cars ranging from $205-270K. And they said it with a straight face!

As we noted above, buying a W427 is buying into the HSV legend.

As good as the car is dynamically, we simply can't see many monied individuals shifting from the rarefied air of the Ms and AMGs to the brand from Clayton. All of which is a relatively moot point, if the demand stays strong for the 427.

For the record, HSV says around 30 per cent of the W427s already accounted for have been sold to HSV first timers. Equally there's a fair proportion of cars that will be purchased, parked and added to existing HSV-focussed garages.

This tester was expecting the opposite from the W427 -- fire and brimstone, an engine that idled at cruise revs and needed 2000rpm to get off the line. Pedal efforts that required a week's acclimatisation in the gym were a given. Or so I thought.

In truth there are no cammy histrionics and even the clutch effort is closer to shopping trolley than supercar. Throttle response is sharp, even when cold, and the engine note assertive but not obtrusive.

Steering is firmed up over a normal Commodore, but is hardly a chore. Without doubt, the W427 is a car you could drive to work everyday without making any allowances other than lifting the limit of your fuel card. It is really very, well... normal, in this regard.

Our drive program was a quick road loop on Melbourne's north-western outskirts and a few 'part' laps of a damp Calder Park. In deference to the condition of the track, we were unable to use the main straight. That meant the W427 was unable to stretch its legs. All this transpired to deliver the opportunity for a 'taste' of the car, not a 'test'.

But there's strong indications that in many ways the limited edition 7.0-litre car is true to its role as a calling card of 'all things HSV' and a worthy celebrant of the Holden offshoot's 20th Anniversary. Forgetting the pricetag for a moment, the W427 is also an indicator of the levels of sophistication and expertise HSV's engineer division attained.

With bespoke stability control, ABS and MRC calibrations, the W427 is a step beyond the current E-Series range cars. The MRC settings (more here) are a case in point. As HSV chassis engineer David Slater explained, the ability to accurately and continuously fine tune and time damping response via MRC moves the art beyond the norms of damper tuning.

Since the launch of the E Series HSVs in August 2006 (more here), the engineers themselves have learned more about the system and the 'tools' it offers.

These 'learnings' have been applied in the W427. The end result is a car that controls roll better without the need to resort to tree trunk like antiroll bars. The end result is a car that, though it rides on significantly firmer springs and 20-inch wheels, still manages to deliver a reasonable, but still overtly sporty, ride. Yes, you'll feel big bumps, but you won't wince nearly as often as in previous generations of 'dumped' hotties.

On the road the W427 has an engaged, light and wieldy feel but doesn't go as far as becoming flighty -- a good result for a near-2000kg car with racecar performance potential.

Turn-in is sharp for a big car and feedback through the front-end probably a step up on the rest of the E Series range. There's a touch more kickback than we remember, but this is more a function of the 'conversation' between tyre patch and driver than a real fault.

The MRC's 'Track' setting corrupts the ride on less than perfect bitumen and allows a higher degree of road input. We'd rarely use it on the road -- stick to the default setting, it's a good compromise.

Ironically, on the track it's arguably not firm enough -- though three abbreviated laps of a circuit like Calder isn't enough for us to pass judgement. Given the W427's overall ability, it begs the question of whether HSV should widen the calibrations further and add another setting -- delivering Comfort, Sport and Race calibrations for example.

The stability control calibration is also unique to the 427. It uses a different strategy from existing Holden and HSV products and relies more on the traction control system to tame the car. This might sound counterintuitive, but as the traction control is allowed to intervene earlier, it makes the end result more subtle.

Coping with 375kW or more pointedly 640Nm of torque -- with plenty of that total on tap at middling revs -- it was in action for much of each Calder lap and occasionally on the road loop when the LS7's taps were opened. HSV's engineers claim the W427's settings 'loosen up' the car but trust us when we say it still retains a very tight rein on proceedings. This is a car that desperately needs a dynamic stability control mode like the best Europeans.

It's the heart of the W427 and HSV's integration into the Holden architecture that will deliver plaudits.

The 7.0-litre engine is smooth and revs like a powerplant half its displacement. There's a b-i-g deep timbre to its voice when used in anger and a real linearity to its power delivery.

The way the engine builds revs is quite unlike 'normal' V8s. While it's not necessary to rev the engine hard, it rewards you with a torrent of torque as it revs beyond 4000rpm.

When the cooking model HSV and Holden V8s are preparing to sign off at 4500rpm, the LS7 is begging for more. At 5500rpm it's at its mountainous torque peak and the whole car feels alive. It's this aspect of the W427 that HRT legend and HSV stalwart, Mark Skaife, says is his favourite aspect of the package. We're not about to argue with Skaifey.

There's a hard rev-limiter at 7000rpm and you don't need to be cack-handed to hit it -- especially in the lower gears. Yep, this engine revs fast. That said, we don't want to give the impression it’s all about top end. Thanks to substantial local calibration work, the engine is deliciously flexible and will pull from virtually standstill to god knows how fast in fourth gear without a touch of clutch.

The AP sourced brakes were strong at the track even on the second day of testing for the cars. There's a more sophisticated feel to the pedal than previous HSV installations. Like an AMG or M car, there's good initial bite but an adequate amount of pedal travel with which to modulate your braking effort.

We'll look forward to a proper drive of the W427 on a proper racetrack some time in the future -- or better still a drive on some of our favourite roads. In the meantime, the thing that really impressed the writer about the 427 is its overall polish. Whether that's what purchasers of the hottest ever HSV really want remains to be seen.

To comment on this article click