Lotus have developed an Exige that runs on biofuel. For the moment though, this is just a research vehicle.

The Lotus Exige 265E is the most powerful road version of the Lotus Exige ever. The vehicle weighs just 930 kg unladen and runs on bio-ethanol E85 fuel (85% ethanol alcohol and 15% petrol).

The car has a slightly modified version of the 2ZZ VVTL-i supercharged and intercooled 4-cylinder engine from the standard Lotus Exige S. This now gives an estimated set of performance figures of 0-60 mph in 3.88 seconds, 0-100 mph in 9.2 seconds and a top speed of 158mph. In fact, the Lotus Exige 265E is probably the world’s quickest road-legal E85 bio-ethanol car.

Key changes have been made to the fuel system, the engine calibration and the four fuel
injectors mounted on the inlet manifold have been enlarged. Two additional 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 biomass plant crops such as cereals, sugar beet,
sugar cane and wood. As these plant crops grow, they absorb carbon dioxide from the
atmosphere, which then partly offsets the carbon dioxide (CO2) emissions produced during the
burning of the bio-ethanol fuel in the car’s engine.

Different bio-fuels were considered for this research project, bio-methanol, bio-ethanol and biobutanol. E85 bio-ethanol was finally chosen as the fuel as its characteristics allowed the
engineering project team to enhance the engine performance. The fact that this vehicle uses a
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 an optimum
timing for engine ignition and has a fast flame speed in the cylinder, so the fuel burns faster,
increasing the efficiency of the engine.

The beauty of ethanol is its ability to produce more power in the engine than with conventional
petrol fuel. Ethanol has less stored energy per unit volume than gasoline so the fuel economy is less, however as E85 ethanol is 85% sourced from renewable bio matter, there is a net reduction in carbon dioxide (CO2).

Geraint Castleton-White, Head of Powertrain for Lotus Engineering explains the rationale
behind the Lotus Exige 265E technical demonstrator: “We wanted to prove the point that green
sportscars can also be very high performing sportscars. 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. We are also pleased that this vehicle demonstrates our engineering
capabilities, our understanding of flex fuel vehicles and our knowledge of emerging fuel
technologies. It also promotes bio-ethanol as a fuel of choice for the enthusiastic driver as well
as the environmentally conscious driver.

Mike Kimberley, Chief Executive of Group Lotus explains the Lotus ‘Green Strategy’: ”Lotus
Engineering 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. 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. The
problems that are facing the automotive industry at the moment are challenging, and these
solutions fit with the Lotus culture and expertise.”

Mike Kimberley continues: “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. 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.”

The next phase for the vehicle is to upgrade the calibration to a flex fuel spec to allow use with
initially petrol, followed by the possibility of a multi fuel flex calibration to use fuels such as
bio-methanol and bio-butanol in addition to the conventional petrol and bio-ethanol.

The Lotus Exige 265E is purely a research vehicle for Lotus Engineering and Lotus does not
intend to put the car into production or sell aftermarket kits for Lotus Cars.