The Lotus Carlton (also called Vauxhall Lotus Carlton, Lotus Omega and Opel Lotus Omega) is a Vauxhall Carlton/Opel Omega A saloon upgraded by Lotus in order to be able to reach speeds up to 285 km/h (177 mph) with acceleration to equal contemporary sports cars. Like all Lotus vehicles, it was given a type designation—Type 104 in this case. The exterior changes were minimal with the addition of a rear spoiler, cooling vents on the bonnet, Lotus badges on the front wings and bootlid, a bodykit and considerably wider wheel arches distinguishing it from a standard Carlton. The car was only sold in one colour, a shade of green called Imperial Green (similar to British Racing Green). Engine and drivetrain Performance modifications started with an upgraded engine, which was enhanced by Lotus from the standard Opel 24v straight six unit (used in the GSi). The engine was enlarged to a capacity of . Lotus then added two Garrett T25 turbochargers, which provide up to of boost from about 1,500 rpm. The original distributor ignition system of the engine was replaced with a three-coil wasted spark system. The distributor drive was re-purposed as a water pump drive for the water-air intercooler circuit. The intercooler itself is manufactured by Behr and is capable of reducing the temperature of the compressed charge from to . In addition to the aforementioned engine modifications, Lotus directed a number of engineering changes to the engine so that it would perform reliably with the higher power output. To cope with the higher cylinder pressures (about ), the external webbing on the engine block was reinforced. The crankshaft was replaced as well; early development crankshafts were machined from billet steel in Italy, but the production units were forged by Opel and sent to Maschinenfabrik Alfing Kessler for machining. The cylinder head was left mostly the same as the 4 valves per cylinder from the donor car, although the combustion chamber was milled to reduce the static compression ratio to 8.2:1 (from 10.0:1). The engine was fitted with forged slipper pistons produced by Mahle. Piston connecting rods were replaced with new units made to an original Lotus design. The same ZF 6-speed manual transmission as fitted to a contemporary Chevrolet Corvette ZR-1 was used to transfer power output to the rear wheels via a rear limited-slip differential shared with the V8 Holden Commodore. Chassis, brakes, and steering The multi-link