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Sigma
The New Ford Sigma Engine Range |
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Development
Replacing the K
Replacing the venerable Rover K-Series engine was never going to be an easy task for Caterham’s engineering team. The K-Series was the perfect match for the Seven when it was launched in 1991; a modern, lightweight, free-revving engine from a UK manufacturer.
Over a 15 year period a huge range of variants were installed in thousands of Sevens, from humble 1.4 105bhp units to the fire-breathing 2.0 250bhp powerplant used in the record breaking Superlight R500 Evolution in 2003.
However, following the development of the 2.3 litre Ford Duratec powered CSR in 2004, it became clear that Caterham needed a smaller, lighter, EU4 emissions compliant engine to replace the K-Series. With rapid growth in demand from export markets for an EU4 engine, and the halt in production of the K-Series in 2005 following Rover’s collapse, Caterham began a 2-year engineering programme to find a worthy successor.
Full-circle
The Caterham engineering team studied 80 engines from 19 different manufacturers to find the new heart for the Seven. Everything was considered, from hi-revving Japanese bike engines through to rotary, turbo and supercharged units. Ultimately the team concluded that the new engine had to fit the lightweight character of the car, be affordable, reliable and easily meet current and forthcoming emissions regulations so it could be sold globally.
The decision was reached early in 2005 to use Ford’s 1600 Sigma engine, which not only matched all these criteria but would also provide a healthy gain in power, torque and economy over the K-series, ultimately boosting the Seven’s real-world performance. The worldwide support for the engine from Ford ensures that the engine will be compliant with the upcoming EU5 legislation and beyond.
After the Sigma had been selected the team realised that Colin Chapman’s original Lotus 7, launched in 1957, was powered by a Ford engine. With Sigma scheduled for a 2007 launch, the Seven has neatly come full circle back to Ford power for its 50th Anniversary year.
Sigma Development
Caterham chose Power Torque Engineering, a specialist in Ford Power Products with a 40 year history, to supply the Ford Sigma engine. In combination with Caterham’s long-term tuning partner Minister Power, the standard 1.6 100bhp Ford unit was developed first to 125bhp and then to 150bhp, providing the two basic variants for the UK market.
Crucially, an EU4 compliant version has also been developed in parallel for export markets around the world, which constitute more than half of Caterham 7 sales. Overseas owners will be offered a 1.6 115 Bhp EU4 emissions approved engine in the Roadsport or Roadsport SV at launch. This engine has been tuned exclusively for Caterham’s Export market and utilises Ford’s latest technology in the form of its Ti-VCT variable cam timing.
Caterham’s management team took the decision to make a substantial investment in testing and final development of the Sigma car. The development process has included a massive 10,000 mile road test schedule and 1200 miles of circuit testing, as well as many visits to the dyno. With the engineering team testing the engine’s limits in conditions as diverse as the Highlands of Scotland and Estoril circuit in Portugal, Caterham has ensured that the Sigma has proven reliability and is worthy to power a legendary performance car for years to come.
Technical Specification:
Ford Sigma 1.6-litre
Overview Technical features:
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High level of running refinement and low emission levels |
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Aluminium alloy cylinder block and head |
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Cross flow cylinder head |
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Structural aluminium oil-pan for increased engine stiffness |
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Twin overhead camshafts each with five bearings |
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Sequential multi-port fuel injection system |
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Long life, glass fibre reinforced camshaft drive belt with automatic tensioner |
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State-of-the-art Twin Independent Variable Camshaft Timing (on Ti-VCT variant) |
| Ford Sigma 1.6 (125 bhp) |
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| Capacity (cc) |
1595 |
| Number of Cylinders |
4 |
| Compression ratio: |
11:1 |
| Bore/Stroke (mm) |
79,0/81,4 |
| Max Power (bhp/rpm) |
125 @ 6100 |
| Max Torque (lbs ft/rpm) |
120 @ 5350 |
| Ford Sigma 1.6 (150 bhp) |
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| Capacity (cc) |
1595 |
| Number of Cylinders |
4 |
| Compression ratio: |
11:1 |
| Bore/Stroke (mm) |
79,0/81,4 |
| Max Power (bhp/rpm) |
150 @ 6900 |
| Max Torque (lbs ft/rpm) |
120 @ 5600 (tbc) |
| Caterham Sigma 1.6 Ti-VCT EU4 |
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| Capacity (cc) |
1595 |
| Number of Cylinders |
4 |
| Compression ratio: |
11:1 |
| Bore/Stroke (mm) |
79,0/81,4 |
| Max Power (ps/rpm) |
115 @ 6000 |
| Max Torque (Lbs ft/rpm) |
115 @ 4150 |
LEARN MORE ABOUT THE NEW FORD SIGMA RANGE:
Chassis Construction
Request more information or a test drive
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