Lotus Sport Exige

Hethel Weapon


March 2005

It's the coolest car to roll out of Hethel for years and, if we all wish very hard, this unique 400bhp Sport Exige could become Lotus GT racer.

There's an old adage amongst employees at Lotus Sport, motorsport department of the famous Norfolk sports car manufacturer, that they can supply customers with anything from a sports exhaust to a one-off GT racing car. While countless customers take them up on the offer of the former, one extremely bold, extremely wealthy and extremely private individual recently took them up on the latter. If I ever meet him, I'll shake him firmly by the hand, for the result of his unflinching financial commitment is this: the spectacular Lotus Sport Exige.

Designed and built in total secrecy at Lotus's Hethel base, the project took less than six months from blank computer screen to menacing finished article, and called on the expertise of the Lotus Design team, Lotus Sport's engineers and a number of specialist motorsport companies, including RTN, the team responsible for the Le Mans-winning Bentley.

The project was overseen by Lotus Sport's general manager, Chris Arnold. Normally a race project would be designed to comply with a particular set of regulations, but as the countless domestic and international race series make GT racing a regulatory maze, and the customer wanted a car he could use to compete in anything from short-distance sprint races to long-distance GT events in his native South East Asia, the team had to build a car that would, or could, be made to comply with a number of different sets of rules and regulations.

Arnold is quick to remind us that the car is a one-off, tailored to the customer's demands, but it's obvious that should there be sufficient interest from teams wishing to use the Exige, the car could be developed and adapted to suit most requirements. Looking at the car, it's hard to imagine Lotus won't have teams knocking at its door, for the Lotus Sport Exige is a mouthwatering prospect, both visually and technically.

Remove the bodywork, and it reveals its inner beauty.  Mounted longitudinally in a bespoke rear subframe, the 3-litre, narrow angle, naturally aspirated V6 is a race-bred unit originally designed by GM for use in SR2 Sports Prototype racing, which means it packs a mighty punch and has the durability to match. Built by Swindon Racing Engines, and breathing through a roof scoop that feeds into an Fl-style airbox, the V6 develops 400bhp at 7750rpm and 2941b ft of torque at 6500rpm, enough to endow the 850kg Exige with a power-to-weight ratio of 478bhp per ton.

Mounted to the end of the engine via a new bell-housing is a Hewland NTL six-speed sequential transmission and limited-slip differential. Look more closely at the car and the detailing is fantastic, with everything tailored for lightness, reliability and rapid serviceability.  A three-point AP Racing air-jack system has been installed to facilitate quick tyre changes, and the standard wiring harness has been replaced with a full Raychem 25 system complete with quick release aerospace-quality Mil-spec connectors as used in today's F1 cars. Conventional fuses have been replaced with circuit breakers, again to aid quick fixes mid-race, while a Stack display with integrated data recording nestles behind the quick-release steering wheel.

Lotus Sport Exige rear

Before any of the styling work could start, the design team had to work closely with Arnold and the engineers to define the dimensions of the car. 'The body shape was really driven by the engine,' explains Arnold. 'We wanted to have a longitudinal installation because it gave us more scope with the transmission, but to do that meant we had to lengthen the wheelbase by 200mm, which in turn meant widening the track by 100mm, to bring the proportions back.

"Traditionally, I'd be coming at the design from an aesthetics standpoint,' says Hatt, 'but obviously with this car it was crucial to combine good functional aerodynamics and aesthetics.  There was an aero wish-list that we wanted to get on the car, and we also had to look carefully at how the panels would break down, to make them both easier to mould and also quick to remove in a race situation.

"Initially we worked with some Photoshop images of the standard Exige to get an idea of what the car might look like with a longer wheelbase and wider track. The main design, working the surfaces, if you like, only took a few weeks, but there was a good month or so of hacking up clamshells before we could get to that stage!"

The overall result is remarkably s the essential shape of the original road car, thanks to distinctive elements such as the headlights being retained. However, the closer you get to the car so the passing resemblance is overwhelmed by the deliciously exaggerated front and rear track that combine to create an epic Coke-bottle shape when viewed from above.

As chief of design, not only is Russell Carr Hart's boss, but he is also the man who penned the original S2 Exige shape.  So what does he think of his understudy's efforts?

"I think if you look at the race-car it has the proportions we would have liked to give the road car - a little bit wider and a bit longer, and a bit closer to the ground. It looks like a natural competition evolution of the roadgoing Exige."

The bodywork is something of a manufacturing masterpiece as well, thanks to the expertise of RTN, who managed to take moulds from the Lotus Sport Exige 'clay' model, rather than relying on expensive tooling. With the exception of the doors, which are standard road Exige items, the rest of the body panels are made from Z-preg carbon composite, which uses a new, low temperature curing process. It's believed that this is the first time such large carbon fibre panels have been made in this way, The rewards are lower production costs and a total bodyweight (minus doors) of just 44kg.

With both front and rear clamshells removed it's impressive to note that the central structure of the car is identical to that of the Elise and Exige road cars.

Lotus Sport Exige interior

"The chassis tub is a standard road car item. We literally took it off the factory assembly line, says Arnold. All we had to do was drill some holes to accommodate the roll cage, as he regs state that an eight-point cage is required, so we've bolted the extra pair of pickups to the front suspension turrets to further brace and stiffen the structure. The front suspension pickup points are the same as the road car, too there was no alternative from a regulatory and costs perspective but the road car is pretty much spot-on anyway so it was no problem."

Ohilins ST44 three-way adjustable dampers are fitted front and rear, while massive AP Racing 344mm front and 330mm rear discs are clamped by brick-sized six-pot front and four-pot rear callipers. They are attached to bespoke centre-lock hubs and squeeze inside ultra-lightweight OZ racing single-piece cast magnesium wheels (I 7in at the front, 18in at the rear), which in turn, are shod with Yokohama racing tyres.

With such a tight build schedule, the car has only been run momentarily in the workshop, and as such hasn't turned a wheel. However, by the time you read this, it will have undergone a low speed systems check and then been given a high speed shakedown test at Hethel by former Lotus F I driver Martin Donnelly. Once he's established a baseline set-up, the car will be crated-up and flown to its owner, who must be on the verge of bursting with anticipation at the thought of developing and racing this unique and spectacular piece of modern Lotus competition history.

With the real resurgence of interest in GT racing, and with Ferrari, Aston Martin, Maserati, and Porsche already heavily committed to racing recognizable version of their road cars, if this one-off project attracts sufficient interest from privateer teams, we'd have eh tantalizing prospect of Lotus racing alongside them.   Here's hoping.