"NEAR ENOUGH IS NOT GOOD ENOUGH"

Rob Trubiani is Holden’s lead chassis engineer and he’s here to tell you why you’ll want to drive the new ZB Commodore

by SCOTT NEWMAN pics N ATHAN JACOBS

“I have a very clear idea of how a Commodore should feel,” says Trubiani

has been involved with the ZB Commodore project for around five years, but has been flat-out with real prototypes for a year or so

EET Rob Trubiani. Like many engineers he toils tirelessly in the background, often years ahead of a car’s release, but we’re thrusting him into the spotlight as he is largely responsible for the next Commodore feeling like, well, a Commodore. Trubiani is Holden’s lead vehicle dynamics engineer and as such is tasked with giving a front- or all-wheel drive European hatch a driving feel familiar to Aussies raised on decades of rear-wheel drive sedans. M

It’s a tough gig, yet one he relishes and is eminently qualified for. Trubiani followed his father’s footsteps and joined Holden as a fresh-faced engineering graduate in 1996 to work on the VT Commodore.

Since then his fingerprints have been present on every Commodore, culminating in the VF II SS-V Redline. It’s this car that has given the MOTOR crew optimism regarding the new Commodore and led to this meeting. We’re unashamed fans of the VF II Commodore and particularly the Redline; to drive it is to realise Trubiani has a clear understanding of what makes a good drivers’ car.

But making a 6.2-litre V8-powered rear-driver entertaining is one thing, achieving entertaining is one thing, achieving the same goal with a V6 and allwheel drive – or a 2.0-litre turbo front-wheel drive in the case of the base ZB Commodore – is another entirely. Nonetheless, Trubiani is adamant the new Commodore will reward keen drivers, particularly the sportier variants. “I have a very clear idea of how a Commodore should feel,” Trubiani tells MOTOR.

“We always aim to make our cars inspire confidence; they have to be good drivers’ cars. For the person who is enthusiastic and likes to drive spiritedly we like to make sure the car rewards them, but for your regular punter who’s just looking for A-to-B transport it’s about getting the car to always give them the confidence no matter what they’re doing.”

Happily, we don’t have to take Trubiani’s word for it, as we’re able to sample his work thanks to the V6 AWD prototype accompanying him today. It’s an early prototype, hand-built in Germany for chassis development, its value reinforced by Trubiani’s multiple nervous reminders during my time at the wheel that he still has a lot of work to complete in it. Despite its incomplete interior and heavily camouflaged exterior, it’s loaded with the latest (and likely final) powertrain, steering and suspension calibrations so should provide a fairly accurate preview of how the ZB Commodore will drive.

The exact model line-up is still a closely-guarded secret, however, in terms of the V6 it appears there will be at least a luxury Calais and as-yetunnamed sports model powered by a 230kW/370Nm

3.6-litre V6, the latter roughly represented by this prototype, while topping the range will be a VXR boasting 235kW/381Nm, adaptive dampers, Brembo brakes and 20-inch rims with sportier tyres, possibly Continental ContiSportContact 6s, though there will be three different tyres according to Trubiani.

Unsurprisingly, anyone used to the current thumping LS3 V8 will find the new V6’s acceleration underwhelming; equally unsurprisingly, given the similarities in engine output and kerb weight, the ZB Commodore feels very similar in acceleration to a V6 VF II.

Holden claims the ZB will be the quickest V6 Commodore ever, however, the seat of the pants impression suggests any improvement against the clock is likely the result of the extra traction of the all-wheel drive system and the nine-speed auto making better use of the available power than any extra output.

Nonetheless, it’s a willing engine, revving happily to its 6500rpm redline with a note that’s surprisingly rorty, though this prototype is far from the finished article in terms of NVH insulation. According to Trubiani, the VXR will come with a sportier exhaust. The ninespeed auto is a conventional torque converter unit; it shifts smoothly, is reasonably obedient on downshifts and won’t automatically upshift at the limit, but it does lack the crispness of the latest eight-speed ’boxes from ZF and the like. As you’d expect, the ratios are extremely closely stacked, which helps keep the V6 in its sweet spot, the tacho only shedding around 1000rpm on each upshift, bar third and fourth which seem to be virtually the same ratio.

The powertrain is not Trubiani’s department, however, what is his department is the all-wheel drive system that gets the power to the ground. The ZB Commodore features a ‘Twinster’ system, a term that rose to prominence with the release of the Ford Focus RS, though its production debut was in the Range Rover Evoque. Instead of a traditional Haldex (Golf R) or three-diff (WRX STI) allwheel drive setup, Twinster saves weight by using a front power transfer unit to send torque to the rear wheels, a maximum of 50 per cent in the case of the Commodore.

A pair of electronically-controlled clutches at the rear axle is then able to apportion up to 100 per cent of that torque to either rear wheel and deliver true torque vectoring to help rotate the car.

Trubiani is a big fan: “Has [all-wheel drive] detracted from being a Commodore? No, not at all. For me this adds a new dimension.

It’s fairly new technology…for us it was important to know how it interacted with the rest of the car, its effect for instance on steering feel as it’s shuffling torque fore-aft or side-to-side, so it was a matter of learning all of those things. It’s had a lot of testing in Europe on ice, so it’s been heavily tuned to cope with low-friction surfaces and it does that very well, then we had to make sure it worked well on gravel and also on a wet asphalt road.”

Key to the Twinster system’s effectiveness is its ability to be pre-emptive. It’s a slightly misleading term as any system can only react to input, however, it effectively means the Twinster’s brain is faster than the other systems in the car. In the milliseconds it takes for the car to recognise a throttle and/or steering input, the all-wheel drive system has already calculated how it’s going to shuffle power in response.

Unlike the Focus RS, the ZB Commodore doesn’t ‘overspeed’ the rear axle to induce oversteer, so you can forget any thoughts of powerslide heroics, but the Twinster does have a tangible, if subtle, effect on cornering attitude. Whereas a Haldex system in particular can still feel largely front-led, the ZB Commodore’s throttle can be pinned at the apex with confidence, secure in the knowledge that the outside rear wheel will help drive the car towards corner exit. Despite the slippery conditions today traction is never a problem, though the overly conservative ESP still nibbles away on corner exit as the pace is upped slightly; the final cars will have a Sports mode that will loosen the reins and ESP can also be completely deactivated, an important feature to Trubiani.

“I think Holden does stability control incredibly well and I think having the safety system there is great,” he says. “[But] I do basically all my development work with the system off to make sure the car has fundamental stability, and then the safety systems are really just there in case something goes wrong.”

Aside from the odd flash under hard acceleration the ESP lays dormant, as the Commodore’s 245/45 ZR18 Continental ContiSportContact 5s work well in the wet and judging grip levels is made easier by the highlight of this initial Commodore encounter: its steering.

The weighting is spot-on, as is its gearing at about 2.6 turns lock-to-lock. Even more impressive is the lack of any on-centre dead spot – a traditional bugbear with electrically-assisted systems – and the

“For me, AWD adds a new dimension”

This prototype – “one of the sporty variants” – wore 18-inch wheels and 245/45 Continentals; VXR will wear 20s with better rubber

Mechanically, the ZB Commodore feels very polished

3.6-litre atmo V6 will apparently be offered in two tunes – 230kW/370Nm for regular models and 235kW/381Nm for VXR Holden-designed camouflage hid ZB’s real shape for months, though is redundant now we know the final design

Trubiani v The ’Ring Wheel man

ONE good reason Rob Trubiani knows how to make a good performance car is he knows how to drive them. Trubiani is one of a very limited number of people in the General Motors world to have Nurburgring accreditation, which allows him to drive during the industry test days.

In order to earn this accreditation, required during development for the fifth-generation Chevrolet Camaro, Trubiani had to pass GM’s rigorous internal high performance driving course as well as a three-day course at the Nurburgring.

“The GM licensing before they allow you to get to the Nurburgring is really, really strict,” explains Trubiani.

“So getting through the GM system was quite a challenge.

You’ve got to be within a percentage lap time of one of the top guys [and] in my day a guy called John Heinricy used to be the director of the high performance group and he was an 11-time Sports Car Club of America champion.”

Trubiani used this ability to good effect when he set an 8min19.47sec lap at the ’Ring in a Holden VF Redline ute in 2013. Initial practice suggested 8min30sec would be possible, but with just one timed lap Trubiani put it on the line, in the process establishing a record for a utility vehicle.

The question is, with the 304kW LS3 V8 and additional upgrades, how much quicker would a VF II be? – SN natural, progressive feel as lock is applied. It’s a verdict that brings a smile to Trubiani’s face, as he admits he has spent “hundreds of hours on it”, constantly refining the ones and zeros in order to provide the best feedback possible. It doesn’t have the same textural feel as, say, a Toyota 86, but as passenger cars go it’s excellent, with a great wheel that feels slightly smaller than that in the VF II.

Initial impressions of the ride are that it’s surprisingly firm; there’s quite a lot of road information transmitted through the seat.

For a Calais or base model it’s probably too biased towards control over comfort, however Trubiani explains “this is one of the sporty variants, but not VXR”. The VXR will run its own tune thanks to its adaptive dampers and 20-inch rims; hopefully its Sports damping mode will offer a similar level of control to this prototype – the way it recovers from bumps on a typical Australian country road is impressive – while offering a softer ‘Comfort’ mode for scarred city streets and the like.

Striking the right balance is tricky according to Trubiani: “If you’re too aggressive the car can be uncomfortable or choppy; on the luxury models we let the car use more of its suspension travel but we never want the car to oscillate or feel like it’s struggling to stay in control. There’s many millions of damper combinations so you’ve got to add the control in where you need it without impacting other things.”

Mechanically, the new ZB Commodore feels like a very polished product. It has great steering, tidy handling, a well-controlled ride and enough pace from the V6 to entertain, but a nagging question remains in the back of my head: is it a performance car? I put the question to Trubiani, with the criterion being that a performance car will make you want to search out a great road for the hell of it, while a good sporty car will entertain on a great road without making you want to go to that extra effort.

Trubiani answers without hesitation: “Based on that criterion I would say yes, it’s a very good drivers’ car.” Based on this initial exposure – admittedly a fairly short drive in a valuable prototype with non-switchable ESP – I’m not totally convinced.

Holden’s product communications manager Mark Flintoft reveals they recently had a number of current customers, including Redline-owning motorsport fans, behind the wheel and apparently all came away impressed, but swapping into a Redline sedan at day’s end illustrates the VXR is going to have to be quite special to match its predecessor’s level of pure driving appeal. It’s not just about that awesome V8, but also the way the Redline can be driven right at the ragged edge with confidence and accuracy. Hopefully the VXR’s brake, suspension and all-wheel drive upgrades can bridge that gap.

However, for the roughly 80 per cent of Commodore buyers who choose a V6 the new ZB is a more tantalising proposition. It’s just as quick, more technologically advanced, safer, more economical and more capable across a wider array of conditions thanks to its all-wheel drive system. From Holden’s point of view, they just want you to try it. Flintoft: “We know there’s scepticism regarding the vehicle and the decision to keep the Commodore nameplate, but it’s probably best for people to hold any judgement until they’ve actually driven the car. If customers are currently driving a V6 or are open to driving a car that feels great without focusing on cylinder count, I’m sure they’ll enjoy the new Commodore.”

There are still many questions to be answered regarding the ZB Commodore, including exact variants, equipment levels and, most important, price. However, on driving dynamics alone we’d agree with Flintoft’s assessment: if you’re currently driving an Evoke, SV6 or Calais, the ZB Commodore will be familiar yet an important step forward in key areas, in no small part thanks to the effort of Trubiani and the rest of Holden’s local engineering team. For the V8 die-hards? Well, there’s always the new HSV-converted Camaro. M