[King T]

A good article from GM Inisde News about the VF Commodore

VF Commodore Technical Details

So it's finally here. After much anticipation and speculation, we can finally say what the new VF Commodore is, what's in it and why. A new Commodore is always a big, once a decade event that carries much expectation. Especially when, like the VE, the new car is a major export program where 20% or more will go to markets on five continents including the much-anticipated return to the USA under a new brand/model.

(Very early VF aero prototype - it has fibreglass front panels. Used to test both Coefficient of Drag and cooling opening to sustain engine temperatures, hence the duct tape over the grille. Note the filler filets on the lower fascia examining various aspects of minimising drag. This is close to the final shape.)

(Not just for looks - if you wonder why the rear lights are the shape they are, aero work is part of the reason.)

So, before we descend into a lot of verbiage about what is or isn't new, let's just run some raw figures.
-60% of the chassis/shell is not interchangable with VE - including nearly 100% of the front suspension/steering other than nuts, bolts and bearings/bushings
-282 complete prototypes were created including 48 crash test mules destroyed in 70 separate tests (some did a minor and major test). The crash test prototypes, complete in every particular, cost $350,000 apiece - but passed NCAP and NHTSA testing with flying colours
-3.2 million kilometres were covered and vehicles/components tested across Australia and in Arizona, Detroit, Sweden, Canada, two locations in Spain, Germany
-Totally new Global A electronic architecture enabling accident avoidance, parallel or a perpendicular park feature not in any GM or competitor car
-First competition mode for ESC, steering on a Holden (not HSV)
-First launch control on a Holden (not HSV)
-First staggered wheel/tyre combination on a Holden (not HSV)
-New manufacturing processes including hot-stamping of chassis components, mult-coating of suspension springs and aluminium instrument panel crossbrace
-Totally new interior with two minor carryover parts
-Comprehensive infotainment package including Bluetooth streaming and HUD integrated with Satnav and G-meter for Competition mode in relevant models
-EPS enabling new features but crucially reductions in fuel consumption and emissions along with improved precision and feel/feedback in every model
-CD down from 3.3 to 3.09.

Does that sound like a mid-cycle enhancement to you...........?

Holden had two aims in mind with VF. Prove that the notion that Holden=Commodore and Commodore = Holden is wrong. Prove that Commodore is a quality, refined and sophisticated product with real user benefits and a great value-for-money propostion. With products like Cruze, Colorado and other portfolios being delivered Holden is already repositioning itself as a multi-facet company you don't have to be shamed into supporting, but also can consider without stigma.

As well as focussing on efficiency, every part of VF was evaluated to make it better and serve a purpose. For example, the propshaft to the diff and the crown wheel assembly are now matched and marked on the flanges so the balance points align. Despite coming from two different sources, inventories are computer-matched so they are married in the same car. Sorta like Perfect Match! This reduces vibration with enhances smoothness while reducing wear and friction.

New acoustic wheelhousings reduce wet- and dirt- road noise by absorbing impacts more quietly. A new acoustic blanket material is more effective at reducing ambient noise beween compartments, as is a new aircon plenum. The shifter on auto models is now better-isolated to reduce transmitted NVH from the motor. The interior was tuned to suppress NVH on cruise or normal driving, while still allowing a satifying growl on hard acceleration or overrev on sports models.

(New aluminium hood - about 20lb. I went to lift the leading edge up, and nearly flipped it off the bench after trying the old steel one!)

Suspension

As well as the requirement to fit the EPS causing the front suspension member to be reprofiled, Monroe Shocks installed new equipment to double-coat coil springs allowing a thinner wire for reduced weight. Previously two different cast-iron steering knuckles were used for Commodores and the PPV. A new aluminium suspension upright is not only validated for both and actually stronger, but is lighter. Similarly, new linear-control arms which were steel castings welded to tube are now replaced by light alloy. Not only do these measures remove weight at the polar end of the car; they also remove unsprung weight.

The front body module horns incorporating crossmember mounts have gone down in gauge but are now ultra-high-strength steel instead of just high strength; weight down, strength up. Similarly, the A-pillars are slimmer but stronger due to being UHSS, as is the perimeter crossbrace across the front of the roof. This involved a new process in which glowing red-hot blanks are stamped out.

(You can see the new alloy suspension knuckles with the brake callipers bolted to them, plus the new aluminium linear control suspension swinging arms.)


(Rear suspension has detail changes (some debuted on MY12 VE) - Evoke has a unique lighter differential. Rear upper control arms are alloy in lieu of cast iron. Rear sway bar links are crossbolted with extra fasteners in V8 models.)

The Mando EPS uses a hollowed-out central shaft. The components include the new casing and assembly. The EPS components are heavier than the hydraulic unit, but the overall assembly is lighter. The EPS provides a combined mileage improvement of about 0.2 l/100 km which doesn't sound like much but it is proportionally larger on the urban side because power steering is mostly utilised at slower speeds.

It also allows idle to be set at 550rpm and this is unaffected by loading the power-steering by attempting to turn the steered wheels when stationary. It also brings NVH improvements because the EPS is smoother and more immediate in response, being a dry, belt-driven worm-drive setup. It's also enclosed and maintenance-free. No more red stains on the driveway from power-steering pump or ram leaks.

The change from hydraulic to electric power steering is very comprensive. To put in, Holden had to change the crossmember (including uprights, suspension), steering rack, body control modules which required teh totally new loom plus major and minor BCMs - and then perform careful tuning per steering 'feel' (sport, luxury, competitve). The VE had 13-26 CPUs. VF has 23-30-something depending on options.

MY 2012 introduced cast alloy rear suspension upper control arms which are continued. Evoke now uses larger anti-roll bars, and on Sports V8 models these are much larger, including an 18mm rear bar. Newly-developed tyres from Bridgestone with different sidewall characteristics maintain comfortable ride and great grip with precise steering and stability despite firmer overall settings.

From the ATS comes a new, lightweight, rigid but less-tranmissive steering column shaft which reduces weight and transmitted NVH from the engine cradle. In every case, and there are more, not only was a weight loss targetted, but the resulting component also had to meet strength and durability requirements as well as being improved in it's primary function and aid in NVH suppression.

Aside from the weight reduction, other measures included airflow enhancement stem-stern. Getting the bootlid spoiler right in aluminium, bending and maintaining that lip during the series of hits the part takes took a lot of work, but it's vital as that provides a laminar effect which breaks the air over the tail of the car and prevents drag. Holden is unapologetic about the shape of the cars: form was secondary to function and the design shape was modified; the shape of the entire front and side was governed by aerodynamics. Even the ridge where the body runs around the tailights serves an aero purpose. On the Evoke model, the grille opening is the smallest size possible to support cooling. If the heavy-duty tow pack is installed, they will break off some handprint-sized tabs pre-scored on the lower inside of the grille which provides more cooling area. The underbody panels continue in VF and the rear splitter is functional in smoothing flow under the car and reducing lift and drag. Many hours were spent at Monash University's windtunnel validating extensive computer modelling and trying fillets and different opening configs.

(New electric power steering - sensor on steering column detects deflection and depending on steering module mapping for speed and effort provides precise assistance- reduces drag on motor.)


(New instrument panel bracket - about half the weight and very cleverly crush-stamped from a square extrusion. Reversed, the one die and weld fixture makes them LHD or RHD)



(The observant might note the badge on this car, and the side being pranged.....)

Other new features affecting all cars include the front seats, which are from GM's Human Factors laboratory. Huge cost reduction for Holden not having to engineer them, including the power versions plus seatbelt tethers and the sensors for airbag and warning light deployment. They are standardised frames used across GM product lines, locally-made with local-designed seat cushions. They allow the Volt's thorax/pelvic side airbag to be used. This channels side-impact and pole-test loads through the much stronger pelvis rather than the ribs resulting in best test results - and importantly, probably also real world outcomes. They are also lighter than previous seats.

Engines are again tweaked for economy and emissions - the 3.0 in the Evoke models is now below the magic 200gm/km Co2 rating. The reason the Australian SIDI 3.6 LFX is limited to 210 Kw is so the car can be driven by probationary licence holders in Queensland. The torque band has been improved on this motor. On the 3.0, peak torque is now impressively low at 2600 rpm. This shows up as a willingness to both pull taller gears and change down less, and to spin very willingly. The system is now a single resonator/muffler design, with a large volume pressed, rather than rolled, muffler which produces a nice note and a fuller torque curve. I'd love to get this motor in a smaller car.

The other feature is the now somewhat-familiar MyLink which provides streaming apps like Stitcher and Pandora, steams your Smartphone Nav into the car audio, and in the upper-spec cars GPS. GPS is optional on all, but has to be ordered with the car to provide for the wiring and extra BCM.

ISOFIX child restraint brackets are now standard across the range, combined with the usual straps. Holden hopes ISOFIX will be legalised within weeks - it is a formality. We were shown a video of side by side tests with ISOFIX and conventional tethers, and ISOFIX provides superior click-connector, easy-fitting solid restraint mounts, without the conventional strap's side movement and resulting flailing limbs ; which could cause injury to adjacent siblings.

New smaller steering wheels, combined with careful EPS calibration provide agility at slow speeds with improved boosting, but also feel at higher speeds. There are three separate 'maps' of effort and ramp-up response versus speed; comfort/luxury for Evoke, Calais and Caprice models, sport for sports models and switchable for Redline models which also enables Launch Control and a Competition ESC that allows more enthusiastic and sideways driving before stepping in to halt the fun.

Standardised controls familiar to Cruze, Volt, Opel models. The shifter and surrounds are similar to recent Opel, GM units elsewhere. Electric parking brakes are standard throughout the range. No more pinched pinkies from the infamous VE handbrake.

Aluminium bonnet and bootlids (hood and trunklids) not only reduce weigh, enabling the use of one strut for the bonnet, but the bonnet is also designed to be pedestrian friendly and collapse while stopping the pedestrian headbutting the engine block.

Sports Models
Sharing a comparative trim level with the Evoke the SS (6.0 Gen IV) and SV6 (3.6 LFX or LPGi) models gain pleather/cloth seats and dash/doortrim wraps, stiffer FE2 springing and damping, revised steering patterns to favour sporty driving and 18 in. wheels with 245/45 tyres. Stepping up to the SS-V gets real leather instead of pleather/fabric including a leather/suede-wrapped dash. It also gets keyless entry/start plus remote start on autos, native satnav with life traffic updates and a colour central instrument display with enhanced functions. Proximity and blind zone alerts included. SS, SS-V and Redline all get uneven-stiffness IRS halfshafts premiered on cars like Corvette and CTS-V to combat wheelhop - successfully by the sounds.

Finally - and yes America, this is the basis of the Chevrolet SS - is the SS-V Redline. It has stickier 245/40 and 275/35 f/r wheels on 8.5 and 9.0" rims, FE3 suspension which has stiffer antiroll bars and springing, plus a competition setting for the steering and ESC which allows more 'getting squirelly'. It also gains launch control on manuals and a HUD with integrated speed limit display and G-meter amongst it's other functions. It has Brembo front brakes and forged alloy ten spoke wheels, polished on darker colours, charcoal/black on lighter and brighter colours like white, silver, Fantale. It has the full suite of lane departure, collision detect, proximity and blind zone alerts.