McLaren F1, 1993
The McLaren F1 is a sports car designed and manufactured by Gordon Murray and McLaren Automotive. On March 31, 1998, it set the record for the fastest production car in the world, 240 mph (391 km/h). As of April 2009, the McLaren F1 is succeeded by three faster cars in sheer top speed, but is still the fastest naturally aspirated production car.
The car features numerous proprietary designs and technologies. It is lighter and has a more streamlined structure than even most of its modern rivals and competitors despite having one seat more than most similar sports cars, with the driver's seat located in the middle. It features a powerful engine and is somewhat track oriented, but not to the degree that it compromises everyday usability and comfort. It was conceived as an exercise in creating what its designers hoped would be considered the ultimate road car. Despite not having been designed as a track machine, a modified race car edition of the vehicle won several races, including the 24 Hours of Le Mans in 1995, where it faced purpose-built prototype race cars. Production began in 1992 and ended in 1998. In all, 106 cars were manufactured, with some variations in the design.
Chief engineer Gordon Murray's design concept was a common one among designers of high-performance cars: low weight and high power. This was achieved through use of high-tech and expensive materials like carbon fibre, titanium, gold, magnesium and kevlar. The McLaren F1 was the first production car to use a carbon-fibre monocoque chassis.
The idea was first conceived when Murray was waiting for a flight home from the fateful Italian Grand Prix in 1988; Murray drew a sketch of a three seater sports car and proposed it to Ron Dennis, pitched as the idea of creating the ultimate road car, a concept that would be heavily influenced by the Formula One experience and technology of the company and thus reflect that skill and knowledge through the McLaren F1.
Engine
Gordon Murray insisted that the engine for this car be naturally aspirated to increase reliability and driver control. Turbochargers and superchargers increase power but they increase complexity and can decrease reliability as well as introducing an additional aspect of latency and loss of feedback, the ability of the driver to maintain maximum control of the engine is thus decreased. Murray initially approached Honda for an NA powerplant with 550 bhp (410 kW; 560 PS), 600 mm (23.6 in) block length and a total weight of 250 kg (551 lb), it should be derived from the Formula One powerplant in the then-dominating McLaren/Honda cars.
When Honda refused, Isuzu, then planning an entry into Formula One, had a 3.5 V12 engine being tested in a Lotus chassis. The company was very interested in having the engine fitted into the McLaren F1. However, the designers wanted an engine with a proven design and a racing pedigree.
The final result is a custom-built 6.1 L (6064 cc) 60-degree V12 with an aluminium alloy block and head, 86 mm (3.4 in) x 87 mm (3.4 in) bore/stroke, quad overhead camshafts for maximum flexibility of control over the four valves per cylinder and a chain drive for the camshafts for maximum reliability, the engine is dry sump. At 266 kg (586 lb), the resulting engine was slightly heavier than Murray's original maximum specification weight of 250 kg (551 lb) but was also considerably more powerful than he had specified. The bespoke engineered engine for the McLaren F1 is called the BMW S70/2.
The carbon fibre body panels and monocoque required significant heat insulation in the engine compartment, so Murray's solution was to line the engine bay with a highly efficient heat-reflector: gold foil. Approximately 25 g (0.8 ounce) of gold was used in each car.
The road version used a compression ratio of 11:1 to produce 627 hp (468 kW; 636 PS) at 7400 rpm—considerably more than Murray's specification of 550 horsepower (404 kW). Torque output of 480 ft·lb (651 N·m) at 5600 rpm. The engine has a redline rev limiter set at 7500 rpm.
In contrast to raw engine power, a car's power-to-weight ratio is a better method of quantifying acceleration performance than the peak output of the vehicle's powerplant. The standard McLaren F1 achieves 550 hp/ton (403 kW/tonne), or just 3.6 lb/hp. Compare with the Ferrari Enzo at 434 hp/ton (314 kW/tonne) (4.6 lb/hp), the Bugatti Veyron at 530.2 hp/ton (395 kW/tonne) (4.1 lb/hp), and the SSC Ultimate Aero TT with an alleged 1003 hp/ton (747.9 kW/tonne) (2 lb/hp).
The cam carriers, covers, oil sump, dry sump, and housings for the camshaft control are made of magnesium castings. The intake control features twelve individual butterfly valves and the exhaust system has four Inconel catalysts with individual Lambda-Sond controls. The camshafts are continuously variable for increased performance, using a system very closely based on BMW's VANOS variable timing system for the BMW M3; it is a hydraulically-actuated phasing mechanism which retards the inlet cam relative to the exhaust cam at low revs, which reduces the valve overlap and provides for increased idle stability and increased low-speed torque. At higher RPM the valve overlap is increased by computer control to 42 degrees (compare 25 degrees on the M3) for increased airflow into the cylinders and thus increased performance.
To allow the fuel to atomise fully the engine uses two Lucas injectors per cylinder, with the first injector located close to the inlet valve - operating at low engine RPM - while the second is located higher up the inlet tract - operating at higher RPM. The dynamic transition between the two devices is controlled by the engine computer.
Each cylinder has its own miniature ignition coil. The closed-loop fuel injection is sequential. The engine has no knock sensor as the predicted combustion conditions would not cause this to be a problem. The pistons are forged in aluminium.
Every cylinder bore has a nikasil coating giving it a high degree of wear resistance.
From 1998 to 2000, the Le Mans-winning BMW V12 LMR sports car used a similar S70/2 engine.
