Increasing concern for the perceived global warming issues and the depletion of fossil fuel reserves led Lotus engineers to look at a number of different concepts aimed at delivering a more environmentally friendly package without sacrificing performance.

The Lotus Exige 265E runs on environmentally friendly bio fuel and has been developed by Lotus Engineering, the engineering consultancy division of Group Lotus, to offer an alternative to the traditional sports machine.

The research vehicle is a true Lotus weighing in at just 930 kg and boasting a massive 197 kW. The car is a prototype developed to explore more environmentally friendly ways to power Lotus sports cars. At this stage there is no firm plan to put the car into full production.

The Exige 265E has been designed to run on bio-ethanol E85 fuel containing 85 percent renewable ethanol alcohol and 15 percent petrol.

Key to the 265E’s performance is its modified 2ZZ VVTL-i supercharged and intercooled, high revving 4-cylinder engine, as used in the standard Lotus Exige S.

Although it is significantly kinder on the environment the experimental Exige 265E delivers performance figures that would thrash the majority of ‘Super-Unleaded’ performance cars, accelerating from 0 to 100 km/h in just 3.88 seconds and from 0 to 160 km/h in 9.2 seconds.

Lotus believes the Exige 265E is arguably the world’s quickest road-legal bio-ethanol car with a top speed of 252km/h.

Lotus engineers have made key changes to engine calibration and the fuel system as well as enlarging the four fuel injectors mounted on the inlet manifold to enable the use of bio ethanol rich fuel.

Additionally, two fuel injectors have been fitted at the supercharger inlet to increase the amount of fuel being injected in to the engine under higher engine loads and to further cool the charge air prior to combustion.

The bio-ethanol can be made from bio-mass plant crops such as cereals, sugar beet, sugar cane and wood. These plant crops absorb carbon dioxide (CO2) from the atmosphere as they grow partly offsetting the (CO2) emissions produced in the car's engine.

Lotus considered different bio-fuels for the research project including bio-methanol, bio-ethanol and bio-butanol.

E85 bio-ethanol was finally chosen because its characteristics allowed the engineering project team to significantly enhance the engine performance while retaining its environmentally friendly credentials.

The Exige 265E’s pressure-charged engine provided even more opportunity to exploit the performance characteristics of a high-octane fuel. Ethanol has a high octane rating, which allows optimum timing for engine ignition as well as having a fast flame speed in the cylinder, allowing the fuel to burn faster, increasing the efficiency of the engine.

Ethanol was also attractive because of its ability to produce more power than conventional fossil fuel.

The Lotus Exige 265E produces maximum power of 197 kW at 8,000 rpm and 249 Nm of torque at 5,500 rpm.

This equates to a 21 percent increase in power and a 16 percent increase in torque, compared with the standard petrol engine Exige S.

The Exige 265E has a power to weight ratio of 211 kW/tonne.

According to Geraint Castleton-White, head of Powertrain for Lotus Engineering, the rationale behind the Lotus Exige 265E is to prove the point that environmentally friendly sports cars can also still be very high performance sports cars.

“The fact that we have produced a research version of the Exige that is more powerful than the standard road car is a testament to the benefits of going green,” said Mr Castleton-White.

“This vehicle demonstrates our engineering capabilities and enhances our understanding of flex fuel vehicles and our knowledge of emerging fuel technologies,” he added.

“It also promotes bio-ethanol as a fuel of choice for the enthusiastic driver as well as the environmentally conscious driver.”

Chief Executive of Group Lotus, Mike Kimberley, says the Lotus 'Green Strategy' is actively pursuing technologies that will improve the efficiency and environmentally friendliness of engines in the future.

“Carbon dioxide reduction is a priority, as is anything that can reduce our reliance on fossil fuels,” said Mr Kimberley.

“We are one of the world leaders in powertrain engineering especially in the internal combustion sector and we are researching into all areas of alternative and conventional fuels to get greater efficiencies, power, performance and reduce net emissions and Bio Ethanol research is one area where we are expert,” he said.

“The problems that face the automotive industry at the moment are challenging and these solutions fit with the Lotus culture and expertise" he added.

"We have decided to develop a thorough understanding of the techniques and technologies of what alternative fuels can achieve, to produce vehicles that are both fun to drive and environmentally friendly,” he continued.

“We are also working, globally, on hybrid and electric vehicles together with governments and universities and as an engineering organisation we have a duty and a desire to promote these ideas to a worldwide customer base" he concluded.