First drive: Commodore Evo V

HOLDEN says VY Commodore is its biggest model development program since the VT launched this generation of the company's big car back in 1997.

But the engineering development story for the fifth take on the most successful Commodore bodystyle ever is perhaps best described as evolutionary rather than revolutionary.

Holden says it has focussed on precision and refinement with VY. The engineering program began four years ago and apparently included 875,000 staff hours and more than 1.5 million durability and test kilometres.

First, the new bodyshell design is slipperier than before, Holden claiming a 4.2 per cent reduction in aerodynamic drag - to a 0.319Cd - thanks to the sharper corners and lines of the rear bootlid and front fascia.

It is claimed this has resulted in a three per cent reduction in fuel consumption at highway speeds, although official claimed fuel figures remain unchanged.

Bodyshell stiffness is also said to be marginally improved thanks to the different rear sheetmetal, but no figure has been put on this either.

Holden says lift has also been reduced by a big 47 per cent to 11.7kg at 100km/h, resulting in a reduction in the yawing moment coefficient of seven per cent and therefore slightly better stability in crosswinds.

From the driver's seat, however, the most apparent engineering change is the revised steering.

Featuring a stiffer torsion bar and revised valving - but not the Monaro's slower overall steering ratio - the new set-up features an increased response curve in relation to driver input. The steering wheel's frame is now weight-saving magnesium.

Commodore's regular (non-FE2) front suspension now incorporates the low speed tuning technology first seen on VXII rear shock absorbers, with a progressive disc stack for the compression stroke aimed at delivering a more compliant low speed ride up front.

Acclaim models benefit from larger 15x7-inch alloy wheels, while the SS sedan is now fitted with 18x8-inch alloys with Monaro's 235/40 R18 Bridgestone tyres.

In terms of the powertrain, the Gen III V8's peak power output has been increased 10kW to 235kW (still at 5200rpm) for SV8 and SS sedan and ute. Holden's optional V8 remains at 225kW.

Achieved via a different, full-length twin exhaust system (which has the pleasant byproduct of a throatier exhaust note) and the same induction changes necessitated on Monaro due to its projector headlights, the uprated V8 also features 5Nm more peak torque than the Gen III fitted to VXII, with 465Nm produced at the same 4400rpm.

Curiously, the optional 225kW V8 has dropped in torque, back from 460Nm to 450Nm. Holden says this is due to its move to the ECE (formerly DIN) method of engine performance measurement, although this doesn't account for the fact peak torque is now produced at a lower 4000rpm, making the base V8 more tractable.

The V8 automatic transmission's clutch pack has also been uprated from a six-plate to a seven-plate design for increased durability, while both V6 and V8 autos feature increased capacity hydraulic force motors to reduce shift shock.

Also US-sourced, the V6 features increased beaming stiffness (11 per cent vertically and five per cent horizontally) courtesy of redesigned engine-to-transmission bracing.

The result is a marginally smoother V6, but no changes have been made to peak outputs because of the engine's relatively imminent replacement by the all-alloy OHC HFV6 in 2004.

Likewise, the supercharged V6's outputs remain the same, but the SV6 does get a "Dampolator" - a combined accessory drive isolator and crankshaft damper aimed at enhancing smoothness above 4000rpm.

V6 service intervals have been increased from 10,000 to 15,000km following a change in camshaft bearing material from copper-lead to aluminium-lead, and by increasing oil capacity - via a larger cast alloy oil pan - from 5.2 to 6.1 litres.

Rear wheel arch noise has been reduced significantly by the fitment of full rear wheelhouse liners, while further engine noise isolation is the aim of an engine-side dash absorber and new absorption material for the passenger side dash mat, centre console and under-instruments hush panels.

Other detail engineering changes include a plenum wind deflector in front of the windscreen and wind tunnel designed exterior mirrors that reduce wind noise by 2.5 and 3dBA respectively.

Finally, on the safety front, a strengthened front floor area aims to reduce floor intrusion, while an energy absorbing tray has been fitted below the instrument panel to reduce lower limb injuries.

Load limiting seatbelts are now fitted to both front occupants, with front airbag characteristics to suit. A front passenger airbag is now standard on all sedans and wagons.

DRIVE IMPRESSIONS:

AFTER driving the VY there's no doubting where Holden has placed its emphasis for this car - on changing the looks.

Apart from refinements to the steering you'll need to be a ride/handling or performance testing expert to detect any further differences wrought by the number of detail changes for VY Commodore.

As a result, it's really the interior itself that is the most noticeable change from behind the new-look steering wheel.

Though not as comprehensive as BA Falcon's all-new interior (outboard air vents are carried over from VT and the steering column stalks introduced for VXII remain unchanged, for instance), it's a refreshing change for Commodore drivers who have lived with the stylish but oh-so-familiar interior for five years now.

The new interior is a classy, Euro-look affair with large, tactile rotary air-conditioning controls and an array of push-buttons for the Blaupunkt audio system, which contrasts with the multi-function approach of Falcon's piano keys.

As with Falcon, there's a modern information display revealing everything from trip computer to audio functions - but mounted within the instrument cluster not on the centre console.

A stylish new woven headlining material lifts overall cabin ambience considerably even in base Executive models, making Commodore's driving environment unquestionably more upmarket.

Narrower spokes make the new Volkswagen-look steering wheel more functional, and we liked the steering wheel's new, braille-equipped audio controls too.

To go with the new-look steering wheel is that dramatically improved steering, with better on-centre feel that requires less driver input to achieve similar results as before.

It still lacks the feedback of AU Falcon (we've yet to drive BA) and yet requires constant correction to maintain a straight line, but the steering - long a Commodore shortcoming - is now at least more responsive and precise than before.

Thanks to full rear wheel arch linings, there's also considerably less noise from road debris contacting metal out back.

Following are our first drive impressions of Commodore's three engines in low, high and sports series models.

Executive V6:
MECHANICALLY the least changed of all VY Commodores, the entry level Executive (which is no longer available with the optional V8 with the advent of SV8) feels slightly less coarse and slightly smoother shifting.

There's less shift-shock, but the V6 remains loud and gruff - despite efforts to isolate its noise, vibration and harshness - and will face stiff competition in unchanged 152kW form from Falcon's new twin-cam 182kW base six.

But the change of camshaft bearing material to extend service intervals by 5000km to 15,000km is welcome.

We could not discern any difference in the front suspension's bump-stroke progression, which is not necessarily a bad thing as the VT/VX Commodore family has always offered an excellent long-legged ride, a trait the VY Executive continues.

As praiseworthy as any mechanical change to the base model is the addition of a passenger airbag although air-conditioning is still missing, along with traction control.

Calais supercharged V6:
THE unchanged 171kW supercharged V6 remains the standard Calais engine (the naturally aspirated V6 and V8 are still optionally available) and as such the most luxurious Commodore benefits from the V6's small NVH gains.

However, because the new "Dampolator" that aims to both dampen crankshaft vibes and isolate auxiliary drive NVH isn't designed to kick in until over 4000rpm, the raucous nature of the SV6 below that point remains at odds with Calais''more refined pretensions.

That said, the luxurious new Calais interior is a vast improvement and new features like the in-dash six-CD system extra cupholders, chrome-rimmed instrument dials and rear parking assist fit the prestige bill nicely.

SV8 235kW Gen III V8:
SITTING neatly between S and SS Commodores, the Executive-based SV8 seems the ideal street sleeper, with only subtle "V8" badging, new five-spoke 17-inch wheels and a rear wing giving clues to what lurks beneath its bonnet.

Exactly $9000 cheaper than the SS, SV8 may be the least expensive V8 Commodore, but it shares the uprated 235kW engine and FE2 sports suspension with the more aggressively styled SS sedan and ute but missing out on creature comforts like sportier seats, side airbags and a higher specification level including six-CD audio and three colour-coded instrument backgrounds instead of SV8's red.

As such, it drives just like an SS (apart from slightly crisper turn-in thanks to the latter's larger wheels), in which the extra 10kW and 5Nm of torque are difficult to feel.

There is, however, a noticeable improvement in both exhaust and induction note.

Better steering and a skerrick more peak power and torque make the SV8 a slightly more rewarding drive than the previous SS, but you'll have to go looking for the improvement.

Don't miss out on the VY Commodore styling story coming on Friday, September 13, along with a detailed breakdown of new equipment for each model. If you want the pricing story, go to "New Models" and read our story "New Commodore: New look, old price".