4Focus – Rob Marshall takes a look at new car technical innovations in the Bugatti Chiron, Volkswagen ID.4, McLaren Artura and Ford Focus ST Edition.
While virtually every modern motorcar possesses ‘air con’, often in collaboration with climate control, conventional systems are not required to work perfectly at speeds exceeding 260mph – or over 300mph in the case of the latest Bugatti Chrion Super Sport. Like lesser vehicles, the Chiron draws-in cabin ventilation air from outlets positioned beneath the windscreen. However, at over 155mph, the resultant air pressure reverses, causing air to be sucked from the cabin, instead. A simple ram air flap helps to overcome the problem.
While the Bugatti’s basic shape must facilitate efficient aerodynamics, the steeply raked windscreen and the glass roof option conspire to make the cabin uncomfortably hot in bright sunshine. The air conditioning hardware, therefore, has to be substantial. It possesses two condensers, 9.5 metres of aluminium piping and an engine-driven 10kW (13 horsepower) rated compressor. The manufacturer claims that the system is sufficiently powerful to chill a living space, measuring 80 metres squared.
Amazingly, Bugatti’s engineers have crammed these components alongside ten other heat exchangers, not including the aforementioned condensers. These include three radiators for the engine coolant, a further trio for the incoming air charge, and one each for the engine, transmission, differential and hydraulic system oils – all within a bodyshell that also hosts an 8.0-litre W16 engine.
It is interesting how some technicians and car owners turn their noses up at certain technologies. For decades, the disc brake has been seen as consistently technically superior and desirable, due possibly to its historical association with motorsport. Since most economy cars have been fitted with front disc brakes since the 1970s, only the most basic models persevered with drum brakes on their rear axles.
Yet, while the exposed nature of disc brakes is ideal for heat desperation, this quality is not the priority under light load conditions. As the back brakes tend not to perform much of the braking effort, drum brakes are adequate for most everyday conditions. Furthermore, disc brakes are prone to moisture ingress and, should sufficient heat not be generated to evaporate it away, corrosion and subsequent binding can set in.
As the electric Volkswagen ID.4 is rear-driven, its strong regenerative braking works on the rear hubs. Therefore, the back brakes are virtually superfluous. While the decision to use drum brakes instead of discs has raised eyebrows in certain quarters, it makes perfect technical sense. Apart from being less prone to corrosion, Volkswagen claims an efficiency advantage. As pads drag slightly on discs, disc brakes can increase rolling resistance – especially when surface corrosion is present on the exposed metal surface, which is common if the car has not been used for several days.
The VM states that the ID.4’s drum brake linings should last throughout the car’s lifetime. Yet, when queried, it could not provide an actual time frame. Volkswagen also could not explain to us whether the shoes could even be replaced, or not. This, in itself, could be a rather worrying development for the repair market…
Should your business conduct MOTs, you will be aware that faulty tyre pressure monitoring systems will attract a test fail, on vehicles made from 2012. Similarly, should your garage replace tyres, then you know that certain TPMS valves are vulnerable to corrosion and require dismounting, plus a service kit fitting, every time you break the bead.
An exciting development comes from Pirelli, which embeds the TPMS sensor within the tyre structure, negating both corrosion problems and maintenance needs. Fitted first to the McLaren Artura hybrid supercar, the Cyber Tyre system results in greater information accuracy, because the sensors contact the tyre, not the rim. While such precision may be overkill for everyday road cars, race track requirements are very different.
Being embedded within the tyre structure allows the Cyber Tyre software to include details about the tread compound, load index and speed rating. It also alerts pressures and temperatures deviations to the driver faster and more accurately. Under track conditions, the system instructs the driver when the safe maximum tyre speeds are reached and advises on the most appropriate tyre pressures for optimum track performance. It also provides instructions about post-race tyre cooling techniques.
Pirelli sees the Cyber Tyre as an ideal technology for future everyday cars, including those fitted with 5G network communications. In November 2019, Pirelli showed this was possible, when it demonstrated TPMS sensors imparting road surface information at the world-first 5G enhanced ADAS event in Turin.
When comparing the current generation Focus against the original 1998 Escort replacement, it becomes clear that Ford is content to follow, rather than innovate in this sector. The company’s decision to concentrate on more profitable SUVs and pick-up trucks explains why its current Focus appears to have fallen into relative mediocrity compared to its forebears. Yet, behind the wheel, not all of the magic has been lost. Decent dynamics remain and some renegades within Ford have exploited this quality with the surprising introduction of the Focus ST Edition.
Despite boasting electronic trickery that other manufacturers have employed, such as an electronically adjustable limited- slip differential, the heart of Ford’s adjustable chassis is a coil-over suspension system. To develop these stainless-steel encased two-way adjustable dampers, Ford relied on the expertise of aftermarket specialist, KW Automotive of Rochester, Kent. Yet, committed owners are required to get their hands dirty.
Damper adjustments are performed manually under the wheel arches, using a mini tool kit that resides in the boot. This allows the driver to select any one of twelve jounce settings, which control the degree of upward damper movement (i.e., stiffness) and sixteen rebound settings, which controls the rate at which each damper returns to its established position. While the ride height is 10mm lower overall, compared to the stock ST model, the dampers also facilitate an extra 20mm adjustment, if desired. To help owners, Ford provides detailed instructions about which damper adjustments work best under certain driving conditions, including a specific setting for the Nürburgring race circuit.
The springs are powder-coated in Ford Performance Blue and possess a 50% higher spring rate than the standard ST fitments. In addition, each bespoke alloy wheel rim complements the springs and dampers, possessing a structure that enhances contact between the tread and road surface. They are lighter, too. Each rim also reduces unsprung weight by 10%.
The Focus ST Edition also features a 280PS 2.3-litre turbocharged engine, with a six-speed manual transmission. 0-60mph is dispatched in under 5.7 seconds; the top speed equates to 155mph. Judging by previous performance Fords, this Focus ST Edition could be the firm’s performance hatchback swansong, assuring its future classic status. Prices start from £35,785.