History of the Lotus Omega / Carlton
In 1986 Lotus was bought by General Motors (GM).
At that time GM already owned Opel, Vauxhall and Chevrolet, amongst others.
The at the time managing directors decided that it should be celebrated with a special co-operation between Opel and Lotus, just like the product of co-operation between Chevrolet and Lotus, the Chevrolet Corvette C4 ZR1.
They wantet to rebuild an existing Vauxhall/Opel model.
They were considering two models; the Carlton/Omega and the Senator. As you know they chose the Carlton/Omega.
When the car was intruduced there was a great stir because of the cars high topspeed (176mph / 286kph). It was becomming normal to restrict the topspeed to 155mph / 250kph.
The car was first shown on the car exhibition in Geneva in 1989
Those who allready showed great interest in the Lotus Carlton/Omega was given an exhaust valve as the one in the car.
The plan was to produce 1100 Lotus Carltons and Omegas. But because of lack of interest the production was stopped after 950 cars. (No. 0001 – No. 0950).
Rebuilding of the Carlton/Omega
At Opels factory in Russelheim some Carlton GSIs and Omega 3000 24V were selected out.
They were transported to Lotus’ factory in Hethel.
Here they were disassembled for a complete rebuilt.
The engine was refitted with a forged crankshaft that increased the volume to 3.615 ccm. 3.6 liters that is.
New Graphite coated pistons from Mahle, two Garrett T25 turbochargers, a watercooled intercooler (Chargecooler),
the same ignition system as the Lotus Esprit from AC Delco and two oilcooler.
Furthermore the direction of the cooling water was changed to make it more efficient.
The cylinderhead was optimized with changed combustion chamber, for lovering compression.
The steering geometry and suspension was improved, for handling the power increase and high velocity.
Fx. with pneumatic dampers with self-nivelling of ridehight rear.
The rebuilt also implied that the floor had to be changed to contain the 6-speed ZF gearbox from Chevrolet Corvette ZR1.
The rear Differential was taken from a GM Holden Australia with 45% limited slip function.
The group C brakes with big 330mm brake discs with 4-piston calipers in front and 300mm discs with 2-piston calipers back, were provided from AP Racing.
Every engine was hand built by one person. On the primary chain tensioner, the guy building that engine had written his name or initials.
Is is rumoured that on car no. 950, every person at the Lotus factory who had been involved in building the cars, has written their names under the carpet by the drivers feet.
The whole interior was changed into Recaro seats fitted with dark grey Connelly leather.
Every car got a sign with the cars serial number mounted on the glove compartment.”Limited Edition Lotus 0001-0950″.
To complete the transition the car was equipped with a complete spoiler kit
consisting of bonnet vents, front grille, sill panels, door panels, wheel arches, rear spoiler, front and rear bumper.
In co-operation with Goodyear, special Goodyear Eagle tires were developed for the car.
The tires could be recognized by a little omega mark on the side.
The Prototype Car
The car was first revealed at the Geneva car exhibition in 1989. This car was built in just three weeks and was different from the final production car:
o The engine in the prototype was basically a C30SE, fitted with twin turbochargers and two chargecoolers from the Lotus Esprit. (Lotus presented the straight six 24V engine, before it was used in any Opel/Vauxhall.
o It had only one bonnet vent in the right side, situated above the inner arch. The final edition had a slightly different vent situated above the turbochargers and opposite to make it symmetrical.
o It had foglights in the front bumper. Lotus removed it, to get better airflow through the twin oilcoolers.
o The rear spoiler was moving up at greater speeds than 120 Km/h (75mph). Lotus considered it useless because of the possibility for the mechanism to break. Lotus designed a new rear spoiler that reduced the lift to 0 Kg on the rear axle.
o It had split rims. Lotus didn’t think it was a good idea on a car this heavy.
o The reg. plate was situated in the rear bumper. In the final edition, it was situated like in a regular Omega/Carlton, to keep the costs down.
o It had electrical adjustable seats. These were also removed to keeps the costs down.