‘In terms of driving dynamics, we always start from a clean sheet,’ explained Jos van As. But how, given the interrelation of components? By starting from the start, not working backwards.
Van As talks through the methodology, showing the 5 is more than a scaled down 7 (or, indeed, a 1/6th-price Rolls-Royce Ghost…). His work begins before a CAD pixel is created, through a logical build-up process:
• DNA – ‘Here, we define proportions, weight distribution, drive concept, aero effects such as lift coefficient front and rear, and so on’
• Suspension – Spring and damper rates are decided upon (‘ride quality was the focus with F10’)
• Tyres – Design of car, weight of car under different load conditions (‘for example, we can decide what size wheels we can fit, and what pressures we need’)
• Steering – Ratio, speed of response (‘the 5 Series has EPAS, like the 7 Series, but the ratio is faster’)
‘This standard car is the base; we add on dynamic features to this platform, all controlled by ICM.’
As yet, then, there are no specific ‘sport’ suspensions for the 5 Series, but more dynamic variations of the standard car, created through technological add-ons. That’s what you can achieve with electronic dampers and adaptive anti-roll, ‘all controlled by ICM’.
Sounds like a cop-out? Not at all, such is the advanced level of ICM. ‘It’s all interconnected, all systems are parameticised. The chassis alone has 45,000 parameters – so it is quite hard work to get it right!’
While those high-end cars could indeed have a fair few suspension settings, ‘the customer does not need 45,000 (!), so they get 4. ‘
‘These characterise the car in 4 different ways – making 4 cars in 1 from a dynamic point of view.’
Shrunken 7 Series, then? No – it’s a fair bit more than that…
BMW Z4 has 3 Series Convertible to thank