ECO FUEL FOR THOUGHT
We put renewable fuel to the test to discover if it could keep grassroots motorsport alive
THE Mazda MX-5 is a brilliant car in many ways, but a recent journey proved that an accurate fuel gauge isn’t one of its strongest points.
With a 74-mile journey ahead, I set off with just a mile or two of fuel less than that figure left, according to the Mazda’s trip computer. Surely a gentle 60mph cruise and the clear roads of a 5.30am start will set that straight, I think. Empty motorway and a gentle cruise achieved, a predicted range that drops at comfortably more than a mile at a time says otherwise.
Despite the light-footed driving and an average of well in excess of 40mpg, a quick splash and dash is needed to reach my destination. In a time when EVs deliver eerily accurate trip estimations, a drive in a combustion-engined car makes a trip like this harder.
The reason we’re aiming to arrive with only fumes in the tank is because we want to sample an emerging technology that has the potential to work alongside EV tech on the road to cleaner motoring. The venue is the former site of RAF Kemble in Gloucestershire, where we’re going to find out how this MX-5 will behave with a tank full of 100 per cent sustainable fuel.
Our fuel comes from Coryton. The Essex-based firm has developed a wide range of products, including some already used in international motorsport: it worked with Prodrive to develop fuel for its Hunter T1 Dakar rally car. The fuel we’re using is a 95-octane mix, which can run in a road car without any modification to the engine or fuel system. It’s created totally from agricultural waste such as straw, plus by-products and waste from crops that aren’t fit for consumption.
Mazda UK has already proven the fuel’s capability by filling this very MX-5 with Sustain renewable fuel and touring the British Isles to lap race tracks in four countries: Anglesey in Wales, Oulton Park in England, Knockhill in Scotland, and Kirkistown in Northern Ireland. It achieved 45.6mpg on the 1,000-mile trip.
That’s all impressive, but it means that it hasn’t cut its teeth in the arena of motorsport. Auto Express is the first to find out whether that fuel stands up to an even tougher test. Instead of the gruelling Dakar rally that Prodrive entered, we’re looking at very much the grassroots end of motorsport.
We’re competing in an AutoSOLO. This is like a mini rally stage, but instead of rocks and trees, the worst you can hit is one of the cones marking out a very tight and twisty track laid out in an open area. You’re
unlikely to get out of second gear at any point, and a sharp handbrake is a bonus to tackle the more fiddly sections. Precise car control is vital.
AutoSOLO is one of 12 disciplines that Motorsport UK has grouped into its new StreetCar initiative. All 12, in categories including Autotest, Rally, and Cross Country and Trials, are competitive events that are made extremely cheap because entrants can bring their own car without the need for any modifications; just a valid MoT is required. You can compete in some series from as young as 13 or 14 years old.
Once you’ve applied for a free MSUK RS Clubman Licence, you pay a small entry fee to one of the 50 StreetCar clubs nationwide to enter. You don’t even need to wear a crash helmet or any protective gear. But with all the wheel-twirling at an AutoSOLO, we’d recommend bringing a decent pair of driving gloves.
The turnout for our event was fabulous, with a total of 53 entrants. The variety of cars on show made it a great place for even the casual petrolhead to stroll around. Mazda MX-5s are perfect for AutoSOLO; agile, quick, cheap and with a huge aftermarket for uprated parts. Predictably then, roughly half the field are Mk2 NB or Mk3 NC models. But among those sit a very varied bunch, from the new Toyota GR Yaris and Hyundai i20 N, to the gaggle of rorty K10 Nissan
Micras, and a well worn (but very fun-looking) Vauxhall Chevette. Even a 2006 Kia Picanto joins in the fun.
There are some seriously competitive regulars present, too. Two-time BTRDA AutoSOLO champ Neil Jones in his NC MX-5 is among the favourites, as is Alec Tunbridge in his Caterham Seven.
Our MX-5 is the only current Mk4 ND model on show, and I’ll take all the help that I can get: this is my very first competitive motorsport event.
With 20 litres of fuel in the tank, it’s time for some advice from the friendly drivers and brilliant volunteer marshals. I learn that the cones are numbered, and have arrows pointing to which side to aim for.
“As long as you can count, you’ll be fine,” is the common advice. I’m not showing off to say that I’m confident of counting up to the final cone (43) in the comfort of my own home, but while I’m hanging on to an MX-5 for dear life, it’ll probably be a different matter.
Overnight rain means the track is wet. This leaves me weighing up whether it’s better that reduced grip levels give me more time to learn the direction of the course, or if the greater risk of skidding into a cone at an embarrassingly low speed cancels that out.
There’s no time to dwell on it, because I’m in the first group of the day. The competitors all queue up, setting off roughly 20 seconds apart from the next. The line gradually shrinks until I reach the front.
Waving
Wait for the wave from the marshal that signals the all clear to go. Set 2,500rpm, drop the clutch and... wheelspin. Lots of it. Not the cleanest start, but the tight first slalom section only needs first gear in these conditions. It’s going well for 10 cones, but then I miss one. I complete the course, knowing that my time will be invalidated. Not the best start. Did I notice the fuel? No; the car behaved exactly as it did on pump fuel.
Still, you get three runs on each route, so there’s time to redeem myself. At the front of the queue once again, I set slightly less than 2,500rpm for my second attempt and am less aggressive when releasing the clutch, which results in a better launch. I go to the correct side of cone 10 this time, which gives me the perfect chance to make an error somewhere else instead. Which I duly do barely five seconds later.
Heading into cone 17, there’s a rough transition from smooth-ish tarmac to rough, broken concrete at a right-angled bend. Here, I’m slightly too trusting of the balance between traction and the 2.0-litre engine, and my keenness on the throttle results in armfuls of opposite lock to correct the oversteer. It’s great fun, but certainly not the fastest way around.
Further difficulty arrives at cones 24 and 25, which is a tight hairpin on the loosest surface of the course. It’s made even looser by 52 other drivers chewing it up since my last trip. As I touch the brakes at a similar point to before, I scoot straight ahead into another cone. I lose valuable time turning around, and chalk up a five-second penalty. Never mind winning, getting a clean run on the board would be nice.
Things improve with a clean run – and my best time regardless of penalties – at the third attempt. The combined results of my first three runs sees
“I complete the course, knowing that my time will be invalidated. Not the best start. Did I notice the fuel? No; the car behaved exactly as it did on pump fuel”
me 28th out of 53, and I know there’s a huge amount of potential for improvement.
The second course is similar to the first, but some of the cone arrows have switched. I record three clean runs and feel like I’m getting the hang of it now.
Sets three and four take place on a new layout. With the easy slalom section straightened out, it gives the Mazda a chance to stretch its legs more.
The track is drier now, too. After the initial launch, I can leave the car in second gear and drive it like a go kart: left foot covering the brake; right foot on the throttle; ignore the clutch until the finish.
The runs in round three feel great and pass without incident, but my times really start to tumble for the fourth round, where the layout remains the same. I start to gel with the car, using that 181bhp to gently slip the rear tyres, the weight transfer to change direction more quickly, while keeping things smoother and more precise in the tightest areas. That’s something the top-three drivers did all day. Jones is the overall winner, with a cumulative time 7.3 seconds clear of Tunbridge. Jamie Yapp is a further 3.6 seconds back in third in his RenaultSport Clio 182.
What gave me the greatest encouragement was that in round four, I was 12th quickest; a huge improvement from the start of the day. With all of my rounds combined, I take home a debut finish of 19th.
There was even enough sustainable fuel in the tank to cover the drive home, averaging an economy figure in the high-forties. As such an expensive pastime, motorsport needs more basic entry routes such as this. And while sustainable fuels will have more widespread implications for the environment should emissions regulations tighten further, at the very least, they could help to keep grassroots motorsports like this going for decades.