FG Falcon: Ford goes to finishing school
BY BYRON MATHIOUDAKIS | 17th Feb 2008
Key to achieving this have been advances in computer-aided engineering (CAE), enabling Ford Australia to find and eliminate or heavily reduce noise, vibration and harshness (NVH) sources and/or pathways.
A dedicated Vehicle Refinement Team – led by ex-Volkswagen Group specialist Michael Stellamanns – correlated real-world test data with the latest CAE processes and technologies to “maximise vehicle harmony across key NVH areas.”
Better powertrain and mechanical harmonics
The venerable 4.0-litre in-line six-cylinder engine benefited from such measures, beginning with a new dual-plenum composite intake manifold that features ‘optimised’ architecture for maximum sound quality. Ford says it is a “powerful yet refined” note.Using special ribbing in the structure of the manifold cuts undesirable higher-frequency noises while emphasising the ‘good’ lower-frequency sounds.
“The split-plenum geometry and manifold volume also emphasise the firing order and primary harmonics at the throttle, which contributes to the more powerful sound character of the latest generation I6 engine,” is how Ford puts it.
The implementation of four Air Intake System resonators also cleans up unwanted noises, as does a flow resistance optimised acoustic venturi in the air-cleaner box.
The promise is the elimination of that age-old Falcon bugbear, intake system resonance that occurs at the throttle orifice, for a cleaner, sportier engine note.
This has been tricky, as the I6’s increased power and torque outputs result in a higher volume of airflow generated by the airbox and air ducts, which then equals more noise within the air-intake system.
So Ford has also added rigidity-enhancing ribbing on the airbox and intake duct to quell airflow noise through surfaces and walls, while the quartet of resonators have been specifically tuned to do the same.
Meanwhile, the I6 Turbo engine has seen its turbocharger intake manifold revised to lower back-pressure and produce a sportier sound, backed up by a specially tuned exhaust system with specific exhaust mufflers.
Another FG refinement fix is a quieter and more consistent power steering system, featuring a new, quieter aluminium pump, redesigned hoses, different internal tuners designed to eliminate the flow fluctuations and pressure ripples that cause steering-related noises.
Behind the dash a new cross-car instrument panel beam has been fitted, while a completely redesigned steering column is said to cut steering wheel vibration at idle compared to the outgoing BFII.
Furthermore, new hydraulic engine mounts bring on big steps in refinement qualities through more effective engine mass damping at low frequencies, says Ford, which then manifests itself as a smoother ride and reduced cabin noise levels.
New cooling pack isolators cut vertical and cabin-directed vibrations, resulting in less vibration felt through the steering wheel and seat at idle and on rough-road surfaces, while a better ignition coil pack cover absorbs high-frequency noise generated from the engine.
For all V8 buyers, who now enjoy the added muscle of the Boss 290 5.4-litre double overhead cam powerplant that was previously the exclusive provenance of the BA-BF FPV GT models, there is a new Semi Active Muffler (SAM) as part of its exhaust system.
A first for an Australian car, and similar to that found on the Aston Martin V8 Vantage and Jaguar XK8, the SAM promises best-in-class sound quality, with a 3dB noise drop.
It is made up of a cylindrical valve that is mounted on the muffler end-plate protruding inside the intermediate muffler, which opens and closes to change the exhaust sound. At low revs it remains closed, forcing the exhaust gasses to pass through a series of baffles in the intermediate muffler.
However, once the V8 burbles beyond 2800rpm, this spring-loaded valve opens, providing an alternate pathway for the exhaust gasses to pass through the muffler. This results in a subdued sound at low engine speeds for a 10 per cent increase in speech intelligibility and a fuller V8 roar at higher revs.
Structural refinements
The FG features significant wind noise and body sealing advances as a result of a Ford Australia-first SFBS single-piece body-side panel, which the firm says improves body tolerances, leading to better door fit and margins.In particular, going to a SFBS – as Holden has with the VE Commodore – cuts down the part-to-part tolerances in the body stamping and assembly processes that is normally associated with multiple body-side components.
Improved margin tolerances in the door seal gaps significantly cut wind noise levels and reduce sensitivity to cross-winds and gusts, while delivering better door closing efforts.
Ford says the FG’s SFBS incorporates a new, industry-best practice door design, with doors that are fully ‘inset’ into the body for “reduced wind noise and better noise attenuation performance under cross-wind conditions.”Further to this end, there is the Australian-first practice of incorporating three door seals – two door bulb seals plus margin filler seals - “... which reduces wind noise levels for the customer appreciably”, according to Mr Stellamanns.
The seals are hidden from the oncoming airstream for better seal contact under all driving conditions. They are CAE designed for good load compression rate and consistent performance around the door perimeter.
New door hinges featuring a new locating pin for better door fit tolerances and more consistent door closing efforts have been introduced, while redesigned glass run weather strips on the doors deliver a palpable reduction in air leakage paths around the glass.
Other wind noise related cuts have occurred as a result of the new Falcon’s completely redesigned sheetmetal, especially around the aerodynamically optimised A-pillars, and the introduction of a new, larger mirror head, which deals with the inevitable trail wake of airflow that results as it swirls around by directing it downwards and outboard away from the door window.
The FG’s windscreen wipers live in an “aerodynamic bubble” below the high velocity airflow stream over the vehicle for less drag and turbulence and reduced wind noise over the wipers.
It doesn’t end there either.
Improvements have been wrought in body sealing and sound packaging, which directly impact engine, wind and road noises.
Ford says that the dash, floor and boot sound-deadening material has been both optimised and increased on all models to cut cabin noise levels – particularly high-frequency ones.
The dash panel pass-through sealing especially cuts engine noise intrusion, with close attention focussed on quelling pathways via the heater and air-conditioning pipes, cables, wiring and the pedal box. This also helps with structural robustness in that area.
There is also a thicker inner-dash insulator a larger coverage of the piece of front floor sound deadening insulator for reductions in engine, transmission, exhaust and road noise improved parcel-shelf airflow and noise management and the implementation of a specially lined duct featuring noise-absorption material, that swirls its way around from the newly designed extraction vents to the rear of the car.
Finally, the FG Falcon’s new wheel and tyre package was specially tuned to be road-noise reductive.
Aiding this are stiffer and lighter new CAE-designed wheels (the steel rims rise by five per cent and the alloys between five and eight per cent in stiffness) and new tyre and tread patterns created specifically for reduced NVH properties.
New suspension members, featuring improved suspension path and body-panel interaction, have also been incorporated, while the suspension linkage and bush isolation properties have also been optimised.
According to Mr Stellamanns, Ford Australia subjected the FG Falcon up to a 175km/h limit, and from hot-mix to corrugated gravel, to help improve its quietness.
“Comforting the driver” while enhancing the “fun-to-drive sounds” were the overall refinement goals, he said.
Read more:
FG Falcon: No FG wagon - yetFG Falcon: Inline Aussie six's final swansong
FG Falcon: A better packaged interior
FG Falcon: Engineered to lead