The AC 3000ME is a mid-engined sports car originally sold by AC Cars. The two-door coupé debuted at the 1973 London Motor Show. Sales did not begin until 1979 and lasted until 1984. Rights to the 3000ME and tooling were transferred to a second company who managed to produce a small number of additional cars before going into receivership themselves in mid-1985. A third company acquired the rights to the car with plans to begin selling a revised version under a different name, but only a single prototype was ever produced.
The AC 3000ME was based on a prototype called the Diablo built by the Bohanna Stables company and shown at the London Racing Car Show in 1972.
Peter Bohanna was an automotive body structures engineer. His experience included working with fibreglass structures as a boat engineer and a stint with Ford's Advanced Vehicle Operations in the UK doing bodywork for the Ford GT40. In late 1967 Bohanna was at Lola cars working on the T70, where he met Robin Stables, who prior to his arrival at Lola had been a racing mechanic and Lotus dealer.
In 1968 Bohanna and Stables won a design contract for a new sports car tendered by a young aristocrat named Piers Weld-Forester. The partners designed a two-seat mid-engined car to be powered by the 2.2 L inline six version of BMC's newly announced SOHC E-series engine, code-named ARO25. Production problems would delay release of this engine until 1972. In late 1968 Weld-Forester partnered with Ernie Unger to form a new company named UWF (for Unger Weld-Forester), and bought the Unipower GT production line from Universal Power Drives. Bohanna and Stables' subsequent work for UWF was to design a car to replace the existing Unipower GT, but this design would not reach production. Instead the partners started the Bohanna Stables company and resumed development of the earlier mid-engined design, which would become the Diablo.
The 1972 Diablo prototype was built with the 1.5 L inline four version of the E-series engine and 5-speed manual transaxle that was used in the Austin Maxi.
Bohanna Stables had sought interest from both AC and TVR before the Diablo was shown at the Racing Car Show, but neither company committed to the project. After the car's debut AC's Keith Judd drove the Diablo to the company's Thames Ditton headquarters and convinced AC owner Derek Hurlock to take the project on.
AC acquired the rights to the Bohanna Stables Diablo design and assigned two of their engineers, Alan Turner and Bill Wilson, to develop it into a production car. AC also hired Bohanna and Stables to consult on the redesign. The Diablo's steel tubing spaceframe was completely re-engineered. A new engine had to be found for the car, as British Leland expected to need all of the E-series engines produced at their Cofton Hackett factory for their own models. The substitute chosen was a Ford V6.
AC first showed their version of the car at the 1973 London Motor Show. This prototype was called the AC 3 Litre, or the AC 3000. Later pre-production prototypes were called the AC ME 3000. Press releases of the time indicated that the company hoped to be able to build and sell the car at the rate of 10 to 20 cars per week. AC suggested that pricing would to be somewhere between ₤3000 and ₤4000.
Even though the car debuted in 1973, development was still ongoing, with the car's styling not finalised until 1974. A prototype failed the 30 mph (48 km/h) crash portion of the new Type Approval tests that had been instituted in 1976, necessitating a chassis redesign. The revised chassis passed on the next attempt.
Several pre-production prototypes were built, with their number variously reported as eight, nine or eleven cars.
The car officially went on sale when it appeared at the 1978 NEC Motor Show. The name was now the "AC 3000ME". The list price for the car had risen to ₤11,300. The first customer cars were not delivered until 1979, by which time they had to compete with newer designs like the Lotus Esprit. The delays meant that the 3000ME was out of date by the time it reached production. Prices also continued to rise; a road test by Autocar magazine in March 1980 reported that the car cost ₤13,238. The same test expressed some reservations with the car's handling when pushed. Several other contemporary reviews expressed similar misgivings.
As early as August 1975 AC was planning to offer a turbocharged version. The forced induction system was originally expected to be supplied by Broadspeed.
By 1980 turbocharged conversions were available, but from a company run by engineer and photographer Robin Rews rather than Broadspeed. Rews' conversion for semi-competition applications used a Garrett AiResearch turbocharger blowing through a 1½" Reece Fish carburettor mounted to a custom intake manifold. Boost was limited to 7.0 psi, and the compression ratio was reduced to 8:1 by the use of low-compression cylinder heads. A Bosch fuel pump supplied the system. Rews used Rotomaster turbochargers for regular road car conversions. The conversion raised power to 200 bhp (149.1 kW). Rews also modified the rear suspension geometry to add toe-in to improve the car's handling. 19 cars received turbocharger upgrades from Rews' Rooster Turbos company. Attempts to convince AC to offer the turbo conversion as a factory option were unsuccessful.
A road test of another turbo conversion in December 1983 shows that the Rooster Turbo conversion had evolved. The turbocharger was now an IHI unit, and while the "standard" turbo compression ratio was still 8:1, special pistons sourced from Cosworth would lower it even further to 7.2:1 to permit the use of higher boost. The carburettor for this later conversion was also the standard 3000ME unit, although like the earlier conversion it was a blow-through system. A waste-gate and a dump-valve handled boost control. The conversion cost ₤1180 until 1984, when prices rose to ₤2000.
Rew and Rooster Turbos also did at least one twin-turbo conversion. This engine used the Cosworth pistons, Weber carburretion and water injection to cool the intake charge. Output was estimated to have been 300 bhp (223.7 kW).
By the early 1980s Derek Hurlock's health had been poor for some time. The world economy was in difficulty, and sales of the 3000ME had never reached the volumes hoped for. After building fewer than 80 cars, Hurlock called a halt to production. In 1984, production stopped at Thames Ditton and the car and the AC name were licensed to a company registered as AC (Scotland) plc. This company was run by David McDonald, and operated out of a new factory in Hillington, Glasgow. Production goals were set at 40 cars per week. A total of 30 additional cars were built to the original 3000ME specification. The Scottish cars are distinguished from the Thames Ditton cars by their body-coloured air-intakes and grilles.
3000ME chassis #129, registration VPC 634X, which had previously served as both a factory demonstrator at AC and Managing Director Andrew Hurlock's personal ride, was used by AC (Scotland) as a development mule for an updated car. Aubrey Woods, a former BRM production engineer, was tasked with the related development. The original Ford engine was replaced by an Alfa Romeo 2.5-litre Busso V6 engine. While the original gearbox was retained, other parts of the running gear were swapped for Alfa parts. AC (Scotland) also began work on a Mark 2 prototype of the car, which was nearly complete at the time of the company's closing. Changes were also made to the suspension to eliminate the earlier car's unpredictable handling at the limit AC (Scotland) went into receivership in June 1985. The license agreement with AC Cars ended in November 1985.
The chassis of the 3000ME was a perimeter frame whose central tub was made of folded sheet steel with an integrated roll-over bar. Some reviews of the car call the central tub a monocoque. Subframes were fitted at the front and rear. Bodywork was of glass-reinforced plastic (GRP). Weight distribution was 40/60 front/rear.
The car's suspension comprised upper and lower A-arms with coil springs and telescopic shock-absorbers both front and rear. The configuration incorporated anti-dive/anti-squat geometry. The suspension arms and uprights were fabricated by AC. No anti-roll bars were fitted to production 3000MEs. The braking system used dual hydraulic circuits to activate a Girling caliper operating on an AC-made rotor at each wheel. Early tyres were 195/60VR-14 Pirellis, which later grew to 205/60VR-14 size mounted on 7 in (178 mm) wide alloy wheels from Wolfrace.
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