Cosworth Vega

Chevrolet Cosworth Vega
1975 Chevrolet Cosworth Vega
Overview
Manufacturer	Chevrolet (General Motors)
Also called	Cosworth Twin-Cam
Production	1975–1976
Model years	1975–1976
Assembly	Lordstown Assembly- Lordstown, Ohio, United States
Designer	GM & Chevrolet Design staffs Chief Stylist, Bill Mitchell Engine Designer, Calvin Wade
Body and chassis
Class	Subcompact
Body style	3-door hatchback coupe
Layout	FR layout
Platform	GM H platform (RWD)
Powertrain
Engine	122 cu in (2.0 L) DOHC EFI I4
Transmission	4-speed manual 5-speed manual w/overdrive (1976)
Dimensions
Wheelbase	97.0 in (2,464 mm)
Length	176.4 in (4,481 mm)
Width	65.4 in (1,661 mm)
Height	50.0 in (1,270 mm)
Curb weight	2,760 lb (1,250 kg)

The Chevrolet Cosworth Vega is a subcompact four-passenger automobile produced by Chevrolet for the 1975 and 1976 model years. It is a limited-production version of the Chevrolet Vega, with higher performance.

Chevrolet developed the car's all-aluminum inline-four 122 cu in (1,999 cc) engine, and British company Cosworth Engineering designed the DOHC cylinder head. 5,000 engines were built.

3,508 cars were made. They were priced $900 below the 1975 Chevrolet Corvette.

Known at Cosworth Engineering as Project EA, a Cosworth racing engine based on the Vega aluminum block produced a reported 260 hp (190 kW) and powered Chevron and Lola race cars to wins in the 2-liter class in their first outings. The ZO9 Cosworth Vega engine is a de-tuned version. Bore, stroke and valve sizes are identical but it lacks the EA engine’s dry sump lubricating system (unnecessary in a street use car), has a lower compression ratio and different valve timing, and uses Bendix electronic fuel injection instead of Lucas mechanical injection to cope with a wider range of operating conditions as well as emission controls.

In March, 1970 John DeLorean, GM’s general manager and vice-president, sent engine designer Calvin Wade to England in search of cylinder head technology to improve the Vega's performance. Fuel injection would be needed to control emissions without power loss; also stronger internal parts to work with the existing block and the Cosworth head. That summer, DeLorean authorized Wade to build a prototype Cosworth Vega engine. A meager budget, and resistance from managers between Wade and DeLorean, meant low priority for the project, but once approved by DeLorean it could not be killed.

In June, 1971 the prototype gave 170 hp (130 kW) on dual Holley-Weber two-barrel carburetors. At Easter, 1972 GM President Edward Cole drove three Vegas for comparison: a base model, an all-aluminum small-block V8-powered prototype, and the Cosworth. He pledged approval from the Engineering Policy Group for DeLorean's request to initiate Cosworth production. Approval of development aimed at U.S. Environmental Protection Agency (EPA) certification soon followed, and Wade began a 12-car development program to accumulate test mileage in a range of environments including high altitude, heat and cold, to test the engine’s eligibility. At the GM desert proving ground, the car reached 122 mph (196 km/h).