Lotus Engineering, the engineering consultancy division of Group Lotus Plc has developed a bio-ethanol E85 version of the Lotus Exige . The research vehicle is a true Lotus (it weighs just 930 kg unladen) and is called the Lotus Exige 265E. 265 indicates the approximate horsepower and is consistent with the naming strategy of other one-off and limited run Lotus variants such as the Lotus Sport Exige 240R; the E indicates the environmentally favourable bio-ethanol E85 fuel (85% ethanol alcohol and 15% petrol / gasoline) that powers this extremely high performing sportscar.
Key to this performance is a slightly modified version of the 2ZZ VVTL-i supercharged and intercooled high revving 4-cylinder engine from the standard Lotus Exige S. This now gives an estimated set of performance figures that would thrash the majority of “Super-Unleaded” performance cars: 0-60 mph in 3.88 seconds, 0-100 mph in 9.2 seconds and a top speed of 158 mph! In fact, the Lotus Exige 265E is probably the world’s quickest road-legal E85 bio-ethanol car.
The heart of the Exige 265E is a Roots-type supercharger (with a sealed-for-life internal mechanism meaning that it does not require the use of the engine’s oil) and air to air intercooler attached to the tried and tested 4-cylinder, 1.8 litre 2ZZ-GE VVTL-i engine. Using a development of the supercharger and intercooler package from the Exige S, the Exige 265R has peak power of 264 hp (197 kW, 268 PS) at 8000 rpm, 184 lbft (249 Nm) of torque (at 5500 rpm) up by 46 hp (34 kW, 47 PS) or 21% and 25 lbft (34 Nm) or 16% over the standard gasoline Exige S. Maximum engine speed is 8000 rpm (8500 rpm transient for up to 2 seconds).
Ethanol produces more power in the engine than with conventional petrol / gasoline fuel. This is due, in part, to the additional oxygen atom attached to the ethanol alcohol molecule so helping the combustion process in the cylinder to burn more effectively, efficiently and with more power. The roof scoop ensures that the air-to-air intercooler works as efficiently and effectively as possible in all climates and environments. All charge air ducting has been kept as short as possible with large diameter pipes making sure that the bends in these ducts are not too tight, to the benefit of throttle response and efficiency. The Roots-type Eaton M62 supercharger is run from the crankshaft, and has an integral bypass valve for part load operation. A “Stage One” sports exhaust exits from the centre of the undertray.
The 2ZZ VVTL-i engine has two cam profiles – a high speed cam and a low speed cam. The seamless switch point between these two cams is completely variable depending upon driving conditions and engine load, and the driver will not know which cam is being used at any point. This gives the Lotus Exige 265E a smooth and linear surge of power from idle speeds all the way to the maximum 8500 rpm.
An electronic drive-by-wire throttle ensures the quickest engine response possible whilst keeping the emissions as clean and as low as possible, to meet relevant legislative demands. Four enlarged fuel injectors have been fitted to increase fuel flow into the engine under normal operating conditions. Two additional fuel injectors have been fitted at the supercharger inlet to increase the amount of fuel being injected into the engine under higher engine speeds and loads. This has also enabled the engineering project team to take advantage of ethanol’s higher cooling effect to further coolthe charge air prior to combustion, which in turn reduces the amount of power required to operate the supercharger. A true Lotus solution where the ethanol does more than just provide energy for combustion!
Extra Functions for the Lotus T4e Engine Management System. The Lotus T4e Engine Management system is used in the Lotus Exige 265E. This engine management system has been programmed to optimise the ethanol in the supercharged and intercooled engine.
The lightweight C64 six-speed gearbox is fitted with the closest ratios and gearset afforded by the transmission. The gearbox offers a fast, precise and light gearshift, ensuring drivers have total control and flexibility to apply the power exactly as and when required.
Aerodynamics is the key
The Lotus Exige 265E uses the same aerodynamic package as the production Exige. Like all Lotus cars, the Lotus Exige 265E isn’t all about straight-line performance. The Lotus Exige 265E is probably the world’s quickest road-legal E85 bio-ethanol car. Not only is the engine important to the performance but also so is the aerodynamic package, which creates 41.2 kg (90.64 lbs) of downforce - 19.3 kg (42.46 lbs) at the front and 21.9 kg (48.18 lbs) at the rear - at 160 km/h (100 mph). This downforce ratio between front (47%) and rear (53%) is balanced and remains constant at the speeds of which the Exige 265E is capable.
The Legendary Chassis and Body
The Lotus Exige 265E is built around the revolutionary and award winning extruded and bonded aluminium tub, with a light weight steel rear subframe, as used in the Exige. The chassis tub itself weighs just 68 kg (150 lbs) and has a torsional stiffness of 10,500 Nm per degree. The body of the Lotus Exige 265E remains unchanged from the Exige as it is already a winning formula that is both effective and stunning to look at. To further differentiate the Lotus Exige 265E from its production cousins, two bold stripes (in yellow to symbolise the bio-ethanol fuel and green to demonstrate the environmental considerations of the vehicle).
Lightweight Lotus Sport five spoke forged alloy wheels have a slightly wider section, when compared to the standard Exige wheel, to accommodate the optional extra track use only specification slick tyres. These wheels, with Lotus Sport etched on one spoke of each wheel, are painted in “High Power Silver” colour.
The Brakes and the Suspension
The brake system has been upgraded to 4-piston AP Racing calipers with sport brake pads and increased diameter 310 mm drilled and vented discs at the front. Brembo single-piston sliding rear calipers with 282 mm diameter discs are fitted at the rear. High grade silicon brake fluid, metal braided brake hoses are all linked to the proven Lotus track tuned servo-assisted fourchannel ABS system that enhances braking performance and minimising stopping distance without taking over from the skill of the driver.
To suit different driving styles and road conditions, the Lotus Exige 265E has been fitted with Ohlins two-way adjustable dampers and ride height adjustment to reduce the ride height from 130 mm to 120 mm and an adjustable front anti-roll bar.
An oil “Accusump” is included as an oil reservoir backup for extreme track use. Cornering speeds and the lateral forces generated within the car when driven on the track are far higher than what can be experienced safely on the road and the “Accusump” ensures that, under these extreme conditions, the engine oil pressure remains constant.
A “Stage One” sports exhaust is fitted with the bifurcated exhaust pipes exiting from the centre of the anodised-finish 3-piece rear diffuser. Front driving lamps, twin oil coolers, central door locking, alarm (with immobiliser) and air conditioning (weighing in at a minimal 15 kg, 33 lbs) completes the equipment package.
The unique interior trim takes the black, green and the yellow theme of the exterior paint colours by using predominantly black trim with green and yellow highlights on certain components including the padded leather door inserts and the seats.