The new Lotus Sport Exige is the newest speed demon the Lotus sport arsenal. The 2005 Lotus Sport combines some classic styling with new features.
The Lotus Sport Exige is directly developed from the road-going Lotus Sport Exige that was unveiled at the Geneva Motor show in 2004. The heart of the Lotus Sport Exige is the bonded and extruded Aluminum Chassis, the technology for which was first introduced in the Lotus Elise in 1995. The Exige chassis, which is also used in the Lotus Elise 111R, is the latest development of this award winning structure, weighs 68kg, and has a torsional stiffness of 10500 Nm/degree. Made up of 25 separate extrusions, and bonded with an epoxy adhesive, the chassis in the Lotus Sport Exige is an exceptionally stiff, strong and lightweight structure. This Lotus technology is so world leading that it has been used on other non- Lotus products including high performance production front-engined V12 and V8 GT cars.
Double wishbone front suspension is mounted to the same suspension hard points as the road-going Lotus Sport Exige, whilst the rear suspension picks up to a revised rear sub frame. However, being a full racecar, there is adjustment for ride height, camber and castor, as well as adjustable front and rear anti-roll bars. Coil springs are mounted over Ohlins ST44 3-way adjustable dampers front and rear.
Lightweight "Z-Preg." carbon fiber bodywork was specially manufactured for Lotus by RTN, the team responsible for the Le Mans winning Bentley. These panels (front clam, "A" panel, body side and sill, roof, engine cover and rear clam) have been made using an innovative low temperature curing process. The moulds were taken directly from the Sport Exige styling "clay" and the resulting carbon fiber panels are race-ready without having to rely on the costly tooling process used in current carbon fiber technology. This is thought to be the first time that this technology has been used on such large carbon fiber panels.
An aerodynamically developed front splitter, carbon fiber rear diffuser and an adjustable carbon rear wing provide increased levels of down force. The interior of the Lotus Sport Exige is similar to the standard Exige, but the standard road car wiring harness is replaced with a full Raychem 25 system incorporating Mil-spec connectors from Beru Formula 1 Harnesses. Conventional fuses are replaced with circuit breakers, and a Stack display with integrated data recording is fitted as standard.
A racing bucket seat (driver side only) is mounted as right hand drive to optimize weight balance through right hand corners (most circuits run clockwise). A six-point seat belt, prepared for using HANS Safety System, and a removable steering wheel (with quick-connect coupling) is included in the interior package.
AP Racing provides the non-ABS braking system, which includes the pedal box (with brake balance bar and cylinders). AP Racing also provides the powerful six piston brake calipers at the front and four piston brake calipers at the rear. These calipers are mated to vented discs (344 mm diameter at the front and 330 mm diameter at the rear).
A narrow angle V6, 2,998 cc Swindon Racing Engines tuned GM racing engine is mounted longitudinally in the Lotus Sport Exige. The naturally aspirated 24-valve engine produces 400 hp (296 kW or 405 PS) at 7,750 rpm and 294 lbs. (398 Nm or 40.6 kgm) of torque at 6,500 rpm and has a maximum engine speed of 8,250 rpm. When the lightweight of the Lotus Sport Exige is taken into consideration, the power to weight ratio is a phenomenal 470 hp / tonne (0.351 kW/kg or 476 PS/tonne). The engine itself weighs 157 kg.
Breathing is via an F1-style air box and air snorkel from the roof panel of the Sport Exige directly into the six carbon fiber air trumpets.
The dry-sump engine, with a bore of 86 mm and stroke of 86 mm is water-cooled and uses an oil-water heat exchanger to efficiently cool the oil. The whole engine is controlled by a Motec M600 electronic engine management system fitted inside the cockpit.
The power is transferred from the engine to the rear wheels via a single mass stepped flywheel, AP Racing twin-disc cerametallic race clutch and Hewland NLT sequential six-speed dog type transmission (with in-line shift mechanism). The gearbox itself is cooled through an oil-water heat exchanger. A limited slip differential (separate power and brake ramp angles) completes the powertrain package.