2006 Holden VZ Commodore: Stronger, Faster

By Feann Torr - 18/Jan/2006

It was only a matter of time before Holden took the fight back to Ford wit its 8-cylinder hero car range, and with the advent of the new 6.0-litre engine, codenamed L76, the SS vs XR8 battle is about to hit fever pitch.

Never before have these rival cars been so close in specification, though the Holden's lighter weight will surely give it a slight performance edge:

Holden SS: 260kW, 510Nm
Ford XR8: 260kW, 500Nm

Interestingly, GM Holden's V8 range of Commodores are the first vehicles in the world to be outfitted with the new 8-cylinder, 6.0-litre L76 engine, which says a lot about the importance of the Australian brand within the global structure at GM.

Holden is quick to point out that its new 2006 model 8-cylinder VZ Commodore is the "most powerful standard engine ever offered by Holden" and will certainly put the V8-powered Commodores and Statesmans back in the minds of performance sedan buyers who simply want the latest and greatest.

Though the new Mexican-built 6.0-litre V8 engine is the biggest change to the new '06 VZ Commodore, other changes to Australia's most popular car (for 10 years running, I might add) include minor upgrades to the SS models, such as new 18-inch alloy wheels, silver grey accent stitching on steering wheel, gear knob and handbrake handle for all interior combinations, plus a new exhaust system for V8 models, an upgraded performance brake package, while a new colour has been added to the ute range - devil yellow.

The performance brake package will improve deceleration, and is standard on the Commodore SS sedan and SS Ute, and the SS Crewman gets performance front brakes only.

Up front, the new vented discs measure 320mm x 32mm (the LS1 models got 296mm x 28mm), while the rear vented discs measure 286mm x 18mm (replacing 286mm x 16mm solid discs).

GM Holden's big chief, American-born Denny Mooney, reckons the company listened to what its customers wanted from their V8 sedans, and the major criterions were: a) affordable performance, b) low end torque and responsiveness, and c) economy. "The extra power is mainly noticeable where it's most usable down low in the rev cycle," Mr Mooney said.

While the first two categories have been easily achieved with the new 6.0-litre mill, economy is still an issue. Based on the ADR 081/01 (roughly the litres of fuel used per 100km on the city/highway cycle combined) the SS, SV8 and SS Ute models average 14.0 litres in the automatic model and 14.6 litres in the 6-speed manual. This is quite impressive for an engine that displaces 366 cubic inches in the old money, but will still cost you a few extra bob at the bowser.

"We've heard what our customers have been saying about usable torque and the new L76 engine delivers that well. The cars deliver excellent power-to-weight ratio and we've also managed to retain the impressive fuel economy which the Holden V8s can deliver."

Technically speaking, the new alloy V8 engine benefits from a range of changes when compared to the Gen III 5.7-litre LS1 engine that has powered the performance Commodore range since the VT Series II in 1998.

These changes include an all-new aluminium cylinder block casting, new flat-top piston designs, increased compression ratio (up from 10.1:1 to 10.4:1), increased capacity, revised high-flow cylinder heads, new inlet and exhaust valves, plus larger, 90mm single-blade throttle bodies, external knock sensors and a more powerful engine control unit (ECU).

The result of the new Gen IV 8-cylinder engine's upgrades culminate in 260kW of power @ 5600rpm and 510Nm of torque @ 4400rpm - and this is across all V8 variants in the Holden range. And which models get the new 510Nm engine? All of them:

Berlina sedan
Berlina wagon
Calais
SV8
SS
Ute SS
Crewman SS
Crewman Cross 8
Statesman
Caprice

GM Holden assures us that torque delivery has improved significantly low in the rev range with the advent of the larger engine, which makes sense, giving the Commodore models "improved acceleration, low speed engine response and improved ease of towing than the previous 5.7-litre engine," according to Holden literature.

Holden has also fabricated a new exhaust system for the V8 Commodore range to ensure the vehicle's adhere to the new ADR79/01 emission regulations, while at the same time allowing the new L76 engine to breath easily at all engine speeds.

As you can see from the table, Holden's 5967cc engine is a good 600cc larger than Ford's Boss260 engine, and understandably makes more torque, albeit at higher revs. Peak power for both engines is 260 kilowatts of power, which is about 349 ponies in the old money; and that's not to be baulked at, whichever measure you're used to.

Though both engines are fairly close in power and torque outputs, the Holden Commodore is expected to be the performance leader thanks to its lighter overall weight (the Ford's rear suspension system is the killer there, being quite sophisticated and hence rather heavy), and will interesting to see how they fare, mano-e-mano, when Holden launches the new 2006 range of VZ Commodores in February.

Another powertrain upgrade for the '06 V8 Commodore is the inclusion of two slightly fettled transmissions: the 4L65-E 4-speed auto has been altered and a new shaft speed sensor has been included (which Holden says improves shift quality and consistency), while the 6-speed manual gearbox, the Tremec T56, benefits from a new clutch and pressure plate to cope with the boosted torque levels.

GM Holden was keen as mustard to implement a cylinder deactivation system in its new V8 engine, similar to Chrysler's Multi-Displacement System (MDS) seen in its Hemi V8 engines (which helps improve fuel economy by between 10 and 20%), but says that "significant testing and calibration development requirements mean Holden has not initiated cylinder deactivation technology." Bummer. Perhaps we'll see this system later in 2006 when the stubby-looking VE Commodore arrives? It's doubtful, but a man can dream.

So there it is - Holden's new 2006 Commodore, resplendent with its power-packed 6.0-litre air/fuel pump and ready to go toe-to-toe with Ford's previously more grunty 5.4-litre V8. Who will win? Probably Holden - but so long as the Ford vs Holden battle remains tight, we'll be happy Wombats.

The MY06 Commodore variants will begin production in February at GM Holden's Elizabeth plant in South Australia, and we can't wait to drive the new model, so stay tuned for the road test.

Pricing:

SS Sedan: $51,790
SS Ute: $41,490
SS Crewman: $47,690

(Models not listed remain at 2005 prices)