Le Mans winner Andy Wallace talks to PH about the rise of electric steering – and why it's a good thing
By Dan Prosser / Sunday, August 29, 2021 / Loading comments
Remember all that hand-wringing a decade ago when the 991-era Porsche 911 was new? Down on its front axle was a rack that used not hydraulic fluid and a pump to help pivot the wheels left and right, but a motor. Yup, the 911 had gone electric – or at least its power steering had.
This, we all howled, would mean the end of steering feel in the 911. And we were partly right, because those early cars did have a mushiness about their steering that we’d never come across in Porsche’s rear-engined sports car before. Very quickly, though, the electric power-steering system improved and a good deal of that squishy, vague sensation was engineered away.
The 911 wasn’t the first high-performance car to ditch hydraulic for electric power steering, but it did transition quite early – only now is Ferrari making the switch itself. We are firmly in the age of electric steering assistance, so much so that McLaren’s decision to stick with the old technology for arguably its most technologically advanced road-going model yet – the plug-in hybrid Artura – raised more than a few eyebrows.
“One feature that is unashamedly not new on the Artura,” read the press release, “is McLaren’s trademark hydraulically assisted steering.” But why the pride – they’re not a bunch of Luddites down in Woking, are they? “Proven on generations of McLaren supercars,” the statement continues, “it remains the ultimate system for providing feedback.” Later on, McLaren tells us: “Steering feel is the most immediate and pure connection between car and driver, and the most tactile way to maximise driver engagement. McLaren has always favoured electro-hydraulic assistance over a fully electric steering setup and has maintained this with the Artura, to best deliver the immediacy, on-centre feel and detailed feedback for the driver.”
Though they may have improved over the last decade or so, it remains the case that electric power-steering setups still don’t offer quite the same tactility as the old pump-and-fluid kind. This was illustrated very vividly to me earlier this year when I drove a 997-era 911 GT3 back-to-back with a current 911 Carrera S for a PH video. The older car has hydraulic steering and the new one electric, and as you drive along a road and guide the cars through corners, the 997 will give you a clear sense of the grip you have to lean on as its wheel chatters and chirrups in your fingertips, while the new car will leave you guessing, relatively speaking.
So why the great rush to adopt electric power steering (McLaren’s technophobes the obvious exception) when the technology hasn’t yet evolved to be as good as hydraulic steering? Well, most car makers will tell you that, chattery steering feel aside, electric power steering is actually better and has been for years.
For one thing, there’s a fuel efficiency advantage. Hydraulic systems keep their pumps running all the time when on the move, even when driving in an arrow-straight line, to keep pressure in the hydraulic system. Because they’re powered by the engine, these setups literally burn fuel and increase carbon emissions. Now more than ever, and as manufacturers strive to make their cars cleaner and more efficient, that’s a very good reason to switch to electric.
But that alone doesn’t exactly add up to ‘better’. One man who is well placed to explain the other advantages of electric power steering is Andy Wallace. The Englishman won Le Mans at the first time of asking in 1988 (at the wheel of a Group C Jaguar), has a hat-trick of 24 Hours of Daytona wins to his name, helped develop road cars like the Jaguar XJ220, McLaren F1 LM and numerous recent Bugattis, and he’s also been on something of a journey of his own with electric power steering setups.
“I was right in the middle of my racing career when electric power steering came in,” he tells me. “I didn’t know where I was with it to begin with. You lost all the self-aligning torque feeling. It was horrible. I felt like I had to learn how to drive the car again. All those early systems did was make it so you could actually turn the wheel, because with wide slick tyres and lots of aero, that was very difficult to do.
“We were running about three degrees of castor angle at the time. What we realised was that once you had electric steering, you could go to 14 degrees or more with all the benefits of very high castor. Without electric assistance it would be impossible for the driver to even turn the wheel with all that castor.”
A sceptic at first, Wallace gradually began to recognise the advantages of electric power steering. His moment of epiphany, though, would come much later while working with Bugatti’s road car engineers as a development driver for the Chiron, which has electric steering assistance. “People say they don’t like electric power steering because the early systems were appalling, almost completely devoid of feel,” he says. “They’re so much better now. Once you decide to have electric power steering, you just open the floodgates. You can do so many things. The scope for tuning is absolutely enormous.
“There’s a small team of people at Bugatti working on steering. I find working with them fascinating – it’s a lot of algorithms, but also seat-of-your-pants stuff as well. If you make a small change to the algorithms, you make a huge change to the feel of the steering.
“As an example, when I did the 300mph run in the Chiron, the steering engineers were playing a lot with the calibration. The faster you go, the less you need assistance. In fact, over 250mph you almost don’t want any at all. Below 125mph you want quite a lot, but at very high speeds, you want the car to track dead straight if you let go of the wheel. You can easily achieve that with electric power steering: the car will go completely straight. That’s almost impossible to do with hydraulic steering.”
A car as potent as the 1,500hp Chiron benefits from electric steering another way. “When you have 1,600Nm of torque, the car is trying to twist its own chassis under hard acceleration. It’s like torque steer in a front-wheel-drive car. With four-wheel drive and so much torque, the car tries to steer itself, changing its own direction of travel. With an electric system, though, we can clamp down on that entirely.’
Using an electric setup, engineers can toy with variable ratios and levels of assistance, too, all of which explains why Wallace is a total convert to electric power steering. He wouldn’t choose to go back. And yet, I’ve never come across such a system that matches a very good hydraulic setup for steering feel (never mind an unassisted rack…). I suppose the question is whether or not that one benefit of hydraulic steering is enough to outweigh all the myriad advantages of an electric one. McLaren seems to think so, although on that particular hill it stands very much alone these days.
- Bugatti Chiron goes 304mph
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