Lotus Omega

BACKGROUND

When General Motors (GM) bought Lotus Cars Limited in February 1986,
the Managing Director of Lotus, Mike Kimberly, and the president of GM Europe, Bob Eaton agreed-on "making something together".
This "something" should be an Opel/Vauxhall with-the performance and handling of a Lotus.
The plan was to make an extremely modifiedstandard car by Lotus with all
the company`s skill and compatance as consultants and car-manufacturers.

In October 1990 the first cars were sent from Russelsheim in Germany to the Lotus factoryin Hethel,England .
The Opel engineers had reinforced the standard engine block with
additional cast ribs and reinforced the engine mountings.
The Lotus engineers-first action was to dismantle the engine, gearbox and interior before themodification could start.

In order to get enough space for the new 6-speed ZF gearbox from GM`s Chevrolet Corvette ZR 1, the Lotus engineers had to enlarge and modify
the floor end thetransmission-tunnel.
A sporty but discreet body-kit consisting of wider wheel-archess,front spoiler, rear wing and side skirts was mounted.
The cd-figure was thus reduced from0.031/0.032 to 0.008/0.000.
The interior was redesigned: Conolly-leather on the Recaro seats front and rear, suede on the door trim panels and Alcantara on the steering wheel.
Hardwood on the fascia and Wilton floor-mats.

Each engine was built by the engineer in Aston Martin-style at the Lotus factory. The Opel engine block was further reinforced and bored and together with
the extendedstroke by 8.7mm, it now had 3.6 litres instead
of the original 3.0 litres.
The 24-valve cylinder head was modified to get a larger combustion-chamber volyme.
Graphite coated pistons from Mahle were fitted and lowered the
compression-from 10:1 to 8,6:1.
Reinforced connecting rods, forged crankshaft, special hardened-camshafts
and a modified lubrication system with oil spray on the piston fromunderneath completed the engine modifications.
The inlet manifolds were nickel-coated in order to make them withstand temperatures up to 750 C.
The electronic multipoint injection-system was taken from the Lotus Esperit (Delco`s GMP 4-system) and three special ignition-coils produced power to the three pairs of sparkplugs.
The injectors fitted were Rochester`s largest 4.75 g/s.
The two water-cooled Garret T25 turbochargers with 0.7 bar overpressure charged the engine and Lotusòwn system-of intercoolers.
Liquid and circulation-pump decreased the inlet air-temperature-to less than 60C.
The cluch was taken from sachs with special spring pre-tenionersthat took the main strain and the flywheel was of split type.
The sturdy rear differentialgear was taken from the Australian Holden and
held a limited-slip function.

The front and rear suspensions got changed geometry, new coil-springs, shock absorbers and lower mountings.
The shocks were self-adjusting to prevent camber-deviationsduring hard cornering.
The camber-angels were increased and the electronic systemfor the shocks
were re-programmed in order to cope with the higher strain that
followed the higher speed.

On the 17-inch rims, new special developed ZR-tyres from Good Year were developed for the Lotus Omega/Carlton 235/45 ZR 17 on the front and 265/40 ZR 17 on the rear.
The front brakes were changed to the much larger 330-mm front and the rear to300mm.
Both with ventilated discs and racing callipers.

The actual car production started in October 1990 and ended the
same month in 1992.
A total of 1100 cars were ordered but only about 950 were actually made accordingto reliable sources.

When the Opel Company`s man in charge for engine development,
Fritz indra, designed the engine, the idea was that it should also
be for racing purposes.
It was tried on the track but without any real success.