‘It sounds like a spaceship’ Quentin samples a unique electric Mercedes-benz SL
Two years ago a rusty Mercedes SL entered an unorthodox restoration – it came out of the other side with electric power. Quentin Willson asks if it’s triumph of engineering or a travesty
Sounds like a spaceship’ is a description I’m fairly sure has never, ever been applied to an R107 Mercedes SL. But those are the words shouted at me by my photographer, Alex, as I drive past his lens at 70mph in a custom-converted electric Mercedes 350SL. He’s grinning and so am I – rather a lot. I may be used to electric vehicles, having owned several over the years and driven most of the current offerings, but nothing could have prepared me for the dramatic collision of sensations at the wheel of this surprising hybrid of ancient and modern. For a passionate fan of the R107 with an interest in EVS, the offer of the first test drive of the only electric classic SL on the planet was one I just couldn’t refuse. On the appointed day I headed towards the SL Shop’s Warwickshire HQ not knowing quite what to expect.
Glinting behind the showroom window was a vision of classic early 107 loveliness. Astral Silver, painted hub caps, K registration, black and silver number plates and ebony leather. Even the windows are hand winders. Apart from the lack of exhaust pipes and a Zero badge on the boot there’s no external sign that this is anything but a bone stock 350SL. The interior is standard too with just a discreet central battery charge indicator in the middle of the dash and, rare for any SL, a manual gear lever – more on that later. Sam Bailey, SL Shop’s MD, is rightly proud of his pet project, having spent two years and £110,000 transforming a terminally tired and rusty 350SL into the only electric R107 in the world. Sam’s epic endeavour began when he took an electric vehicle course at the University of London and left determined to turn the Mercedes model upon which he’s based his business into a 21st-century zero-emission classic. But he’s adamant he doesn’t want to start converting perfectly viable 107s to electric power. That he believes would be an act of sacrilege. The point of this exercise was to showcase the SL Shop’s engineering skills.
The Sportline Zero is powered by ten separate Tesla Model S battery modules – positioned across the car to give 50/50 weight distribution – a 53kw dual electric motor and, unusually for an EV, there’s a gearbox. It’s from a Mazda MX-5 of all things, and is connected to a standard open Mercedes-benz differential. The propshaft was shortened by 20mm, a Vauxhall Astra power steering pump gives assistance to the standard steering box, plus there’s a specially engineered bell housing, uprated roll bars and mounts plus yards of bright orange high-voltage electric cabling as thick as your thumb. Weighing in at 75kg more than a standard 350SL, power output is slightly more than the petrol V8 at 205hp, and charging on a 3.5kwh supply takes 7.5 hours, giving around a 150-mile range. In hindsight, Sam would have preferred to eliminate the gearbox and differential completely and just use a Tesla electric motor, but two years ago, when the build began, even used units were scarce and pricey.
Electric Classic Cars in Wales configured the electrics while Sam’s workshop restored the body and mechanicals – which burnt through a hefty £70k, including replacing corroded metal and painting the bodyshell. Just the steel wheels, hub caps and skinny tyres – all standard-spec Mercedes-benz items – came to £3000. The seats were retrimmed in leather while the door cards, dash, steering wheel and most of the interior were original.
Sam is still unsure what to do with the instrument cluster, which is standard 350SL fare, and apart from the speedo, non-functioning. Putting in faux modern gauges seemed a step too far, and what would they measure anyway? One of the more surreal experiences of driving this SL – and there are many – is not seeing the familiar Mercedes-benz oil pressure gauge needle scuttle up its arc as soon as you turn the key.
‘One of the more surreal experiences is not seeing the oil pressure needle scuttle up its arc’
On the ramp you can see where all that money went. Everything is new or reconditioned and the floor pan has been redesigned to accommodate the ten battery modules. There are five above the electric motor at the front, three in the fuel tank cavity and two in the spare wheel well, all in separate welded compartments. Sam admits that the suspension was ‘over-engineered’ with a Sportline kit which includes adjustable dampers, uprated anti-roll bars and a slew of specially designed bushes to help eliminate vibration. Compensating for the extra weight meant constantly tweaking the ride height, which on the rear still needs to come up 3mm to exactly replicate the original stance of the car. Looking at the work involved, you can’t help but be impressed by what is effectively a prototype drivetrain wrapped in a 50-year old chassis. And, as any car maker will tell you, trying to re-engineer new technology into an existing platform is the most expensive and complicated way of achieving electrification – and never the most efficient.
After a quick explanation that the gearbox can be used conventionally – with five forward gears and one reverse – as a semiautomatic or simply left in third, I turn the ignition key and wait. No thrum, no burble, no beat. Counter-intuitively, the standard alternator charging warning light in the instrument binnacle glows red to tell you you’ve got power and you’re ready to go. The clutch pedal acts as a switch so needs to be quickly depressed and released with no bite point. I ease the accelerator down and without a sound the Sportline Zero moves off. The first, and most reassuring sensation is that the feeling of weight is still there. The steering feels the same – big Mercedes wheel, nose-heavy, slow and lumpen – but still Stuttgart authentic. Dab the brakes and they too deliver the same cushioned pedal resistance you’d find in the standard car. But press the accelerator harder and any familiarity with the 107 ends. The electric motor whines, the car surges forward and the faster you go the more you’re struck by a chorus of strange and futuristic noises. A whine from the differential adds to the space-age soundtrack and you’re instantly reminded of the sounds of science fiction movies. This is the same celluloid noise of lunar rovers, spaceships and flying cars imagined by all of those Hollywood sound engineers. But this time, it’s for real.
The weirdness of the tactile sensations of a normal Mercedes 350SL coupled to the noises of something out of Blade Runner makes me laugh out loud. Whooshing, whining and whirring, I’m reminded of a line from Aldous Huxley’s Brave New World, ‘Speed, it seems to me, provides the one genuinely modern pleasure’. Well Mr Huxley, I’ve got news for you – there’s now another new sensation – silent speed. Well, almost silent. As the whines from the gearbox and diff grow louder, mixing with the climbing whirr from the motor, I’m now making a noise like the Batmobile. This electric SL can really shift and I begin to wonder if the traditional burble from the original alloy V8 might be a preferable aural
‘Two hours in, the SL Zero is still performing like a Duracell bunny’
companion. Probably, but the sheer ingenuity of engineering this old Merc to drive so well on battery power makes you forget any nostalgia for its traditional powerplant. This is a one-off, something uniquely special, a test-bed for the future. And engine noise, let’s not forget, is just the sound of wasted energy.
Anxiety is never far away in photoshoots with old cars. Constant switching on and off, nine-point turns and sprints past the photographer’s lens often means overheating, fuel vaporisation and other mechanical misbehaviour. But two hours into this shoot the Sportline Zero is still performing like a Duracell bunny. And that’s another new sensation – liberation. You don’t have to keep a wary eye on temperature and oil pressure or worry about a lumpy idle that ends in an engine stall and five minutes of repeated churning to restart. The more you think about all of that friction-based, fossil-fuel faffing – all those spinning belts, pulleys, sprockets, cams, cogs and crankshafts – you wonder why it’s taken us 100 years to develop a simple, silent, fume-free alternative to the internal combustion engine that does what we want. And one that requires minimal maintenance and attention. The only instrument I have to watch is the battery charge indicator, which over three hours of continuous driving falls by just 15%.
As I hand the keys back to Sam I feel conflicted. The R107 is a car I love and I’ve owned lots in my time – a handsome, soft and pillowy boulevard icon made more charming by lazy, wuffling V8s. But take away the bewitching heart of the 107 and is a large helping of that allure gone? The Sportline Zero retains the looks and familiar sensory responses of the original but without that well-mannered eight-cylinder beat. What replaces it though, is a sense of wonderment. That it drives so well is a marvel. Even at this early prototype stage, still with a few noise and vibration issues, I’m repeatedly struck at how captivating it feels. And that poses a much broader question – if the cost of electric conversions fall enough, how viable, and desirable will battery-powered classics become? Electric Classic Cars in Newtown, Wales has had some notable successes – a Ferrari 308, Porsche 911, Lancia Fulvia, Fiat 500, Land Rover Defender, Range Rover, VW Karman Ghia, and even a