Final Aussie Commodore: Magnetic attraction for special editions

Don’t spend any money, only use the parts bin for upgrades and make these the highest-performance Commodores ever. That was the brief the small crew of diehards who developed the special-edition MY17 farewell trio of locally-developed and built Holden Commodores had to work with.

The Motorsport Edition, the Director and the Magnum Ute were unveiled along with the new-look Red Bull Holden Racing Team at Holden headquarters in Melbourne today.

But motoring.com.au was part of a small media briefing in December that included a detailed rundown on the development of these cars — a process that began two years ago as the 2017 shutdown of local production came into focus.

“It really did start for want of a better word with a skunkworks program down the back of Fishermens Bend,” confirmed Holden product marketing general manager, Ben Lasry

“We are a small group of passionate engineers and marketing people and we got together and started to put these programs together without any direct approval.

“We then got pretty excited about that and took the proposal to the Board and the directors agreed there was an opportunity to take the products further and content them up further… To make them the best products we could make them to farewell the local Commodore vehicle.”

To do that with almost zero budget, around 10 to 12 engineers foraged through the parts ‘catalogue’ of the locally-developed rear-wheel drive Zeta architecture that has underpinned Commodore and Holden Special Vehicles since 2006, as well as the export Pontiac G8 GXP, the superseded fifth-generation Camaro, the Chevrolet SS and the US Chevy Caprice PPV (Police Pursuit Vehicle).

“What that gave us was these fantastic cars that really allowed us to push the boundary in terms of chassis and dynamic control,” Lasry continued.

“VFII set the bar really high. We didn’t need to touch the powertrain but we felt we could further pursue that braking and dynamic performance environment.”

Three Specials
All three special editions come with the 304kW/570Nm LS3 V8 introduced with the VFII Commodore. The SS-V Redline-based Motorsport Edition sedan and Magnum Ute get the choice of six-speed manual and automatic transmissions, while the Calais V-based Director sedan is auto-only, but adds paddle shifters.

The Motorsport Edition and the Director share the single biggest technical upgrade, the introduction of Magnetic Ride Control adaptive suspension previously restricted Holden Special Vehicles versions of the Commodore V8.

MRC uses sensors on each corner of the car to read and react to road conditions, changing the magnetic field inside the damper and therefore the patented fluid’s viscosity. The third-generation MRC used by the Commodores is controlled by a driver mode dial on the centre console that allows the choice of Tour, Sports and Performance settings. These are unique calibrations devised by Holden rather than those employed by HSV or the export Chev SS. The tune is the same for both Motorsport Edition and Director.

“By bringing the tune in-house to Holden what we have been able to do is essentially emulate our FE2 suspension from the SS and FE3 suspension from the Redline. Then by virtue of the fact the magnetic dampers have such a broad operating range, we have been able to push the performance further than we ever have with passive dampers,” lead development engineer Dan Pinnuck told motoring.com.au.

In Tour (the FE2 equivalent) the bimodal exhaust is also closed, torque vectoring is off and stability control at its most nanny-ish. In Sport, the suspension firms to FE3 levels and the exhaust turns on. In Performance mode MRC firms again, stability control is ‘loosened’, the electric-assist steering weights up and torque vectoring activates.

Double tap the driver mode and the car shifts into Track mode, which turns on launch control in manual, sharpens the throttle pedal response and further loosens the stability control for “a little more tail-happy fun” as Pinnuck puts it.

No MRC for Magnum
The Ute misses out on the trick magnetic suspension because of underbody packaging issues with the exhaust flange, which fouls the system’s stabiliser bar.

Instead, the Magnum’s passive rear suspension’s spring and dampers are softened significantly to Redline sedan FE3 tuning. To achieve that the payload was cut from 620kg to 540kg, allowing the spring rate to be 26 per cent softer and the dampers 10mm shorter. That results in a 15mm lower rear trim height. The front-end tune was unchanged.

“It was all about pulling the payload down a bit, so we didn’t have to trim it so high and have such a high rear spring rate,” Pinnuck explained.

“The ballpark figure is you put 400kg in the back; that’s pretty reasonable for this type of car. We were prepared to come down lower if we had to, but we ran it with the 400 [kg payload] in the back and the two passengers up front so it’s at GVM [Gross Vehicle Mass] and it’s still really capable.

“It’s a longer wheelbase [than the sedans], so it’s a little more stable. It’s been the surprise packet of the program for sure. On paper it looks a little short [on spec] because it doesn’t get the MRC suspension. But as soon as we got into it and everyone started driving it, everyone loved it.

“And around town, because that spring rate is so much lower in the rear it's much more comfortable.”

The Motorsport Edition alone swaps to a higher-rate rear subframe bush sourced from the US police car program [PPV] that applies a constant radial rate, rather than the different cross-car and fore-aft rates of the previous bush. Pinnuck says this provides better driver feedback on the limit laterally and under braking.

All three cars upgrade to the optional 20-incxh staggered alloy wheels size from 19s.

They also share upgrades to the front and rear Brembo rotors that are now cross-drilled. The fronts swap from a one-piece to a floating two-piece design with an aluminium hat and save 3.25kg across the front axles. Diameters stay the same front and rear.

The Director also upgrades from the Calais V’s single-piston rear caliper to the Brembo four-piston unit standard on Redline.

“The two-piece rotor delivers a more constant pedal with less pad knockback during cornering,” Pinnuck explained.

“The cross-drilling enables us to vent the gases that build up at extremely high temperatures during very heavy braking. Those gases can cause a friction drop between the brake lining and the rotor. By venting those gases it gives us more resistance to fade.”

The front rotors also have a point of distinction because they are the sole piece not leveraged from the Zeta parts-bin, instead being co-opted from the Opel Insignia program.

“The brakes were a challenge,” Pinnuck conceded.

“We put them in and they could have fallen over at any point. We had minor hiccups and minor issues with them, but we are very happy with where we ended up.”

Cooling Upgrades
The other major technical upgrade was to the engine and transmission cooling capabilities, which qualifies the special-edition trio for General Motors Level 3 track performance for powertrain cooling. That pits these cars in elite company with the likes of the Chevrolet Corvette and higher-performance Camaros and Cadillacs

To achieve that level, the engineers added an oil-to-water engine oil-cooler originally developed for Camaro, an auxiliary external transmission oil-to-air cooler for the auto and an in-tank oil-to-water cooler for the manual transmission. These two items were originally developed for the Chev SS and PPV.

Practical testing includes 24 hours of engine running at Vmax above 38 degrees Celsius and 24 hours of hot lapping of GM’s Milford test track. During those 24 hours on track in and out laps and slow laps don’t count. Also, on four occasions back-to-back fuel loads must be drained with only the one stop to refuel.

Speaking of cooling, the Director picks up the bonnet vents from Redline, but not the larger lower grille opening and facia vents introduced at VFII for V8 sports models.

“The biggest challenge to start with was the baseline we were working off,” concluded Pinnuck.

“The Redline is such a capable car and to say ‘guys go out and improve it with bits, without spending money’. That was a big challenge.

“I am glad the company let us do it because it really is a tribute to the car and the people,” Pinnuck stated.

Further MY17 Commodore reading:
Holden Director review
Holden Magnum review
Holden Motorsport Edition review
Final Aussie Commodore: Holden defends Director name
Final Aussie Commodore: Holden confirms three farewell specials