Caterham Seven

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Caterham Seven
Manufacturer Caterham Cars
Production 1973 — Present
Predecessor Lotus Seven
Class Sports car
Body style open 2 seat
See also: Lotus Seven
Main article: Caterham Cars

Contents

[edit] Introduction

The Caterham Seven (Caterham 7) is the successor to the Lotus Seven. After Lotus ended production of the Seven in 1972, Caterham bought the rights to it, and today make both kits and fully assembled cars. 2007 marks the 50th year of production of the Lotus/Caterham 7.

The Caterham Seven is a small, lightweight, two-seater sports car renowned for its performance and handling. Various other manufacturers offer a similar lightweight, minimalist package in a seven-esque shape, but Caterham own various legal rights around the design, manufacturer and name of the original car and have taken legal action in the past in order to protect those rights. The modern Seven is based on the Series 3 Lotus Seven, though Caterham have developed it to the point that no part is the same as on the original Lotus.

[edit] History

Today’s Caterham cars have a blend of traditional styling and modern components. They can trace their lineage directly to an original 1950s-era Colin Chapman design. Chapman, a Royal Airforce pilot, studied structural engineering and went on to become one of the great innovators in motorsports design.

After the war Chapman became highly successful race driver and then founded Lotus Engineering Ltd. in 1952. Chapman’s vision of light, powerful cars and performance suspensions guided much of his development work with the basic design philosophy of 'adding lightness'. The Lotus 7, which is almost identical to todays cars debuted at the 1957 Earl’s Court Motor Show in London.

The first Lotus 7s were priced at £1,036 including purchase tax but it cost only £536 in kit form as no purchase tax was required. It weighed only 725 lbs. Fast and responsive, the Lotus 7 was one of Chapman’s masterworks, an advanced machine that surpassed the earlier Lotus 6 as a vehicle that could perform beautifully on the track and be driven legally on the road. The 7’s basic (and much copied) design was to stand the test of time, continuing in its popularity for the ensuing 50 years.

The 7’s evolution continued when, in 1973, Caterham Cars obtained manufacturing rights from Lotus to enable Lotus to move away from 'kit cars' and produce more up-market sports cars. Caterham renamed the car the "Super 7" – an apt name, as it was becoming clear that the car’s fundamental design was nearly impossible to improve having the right balance of strength and handling with a very light weight. Caterham's original offering was the series 4, since that was the current production car at the time of the handover from Lotus. Unfortunately Caterham suffered numerous supply problems with the Series 4 and by the middle of 1974 they had reverted to the Series 3, which was perceived to have better sales potential anyway. The modern day Roadsports and Superlights (in "narrow-bodied chassis" form) are the direct descendants of this car and therefore of the original Lotus 7.

[edit] Chassis and suspension

As with the Lotus Six before it, the original Lotus 7 utilised an extremely light space-frame chassis with stressed aluminium body panels. Although the chassis has had numerous modifications to strengthen it and accommodate the various engine and suspension setups (and to try and find more cockpit space for the occupants), this basic formula has remained essentially the same throughout the seven's life (with the exception of the dead-end Series 4, which used steel for the cockpit and engine bay and glassfibre for the bodywork). Early cars used a live rear axle, initially from various Fords, later from the Morris Marina/Ital. De Dion rear suspension was introduced in the mid-1980's and both geometries were on offer until 2002 when the live-axle option was phased out. The modern Superlight employs adjustable double-wishbone suspension with front anti-roll bar and a de-dion rear axle, located by an A-frame and Watt's linkage.

The Caterham 7 range was based exclusively on this "series 3" chassis until 2000, when the SV (Series V, or Special Vehicle) chassis was released, aimed at accommodating the increasing number of prospective buyers who could not fit comfortably in the series 3 cockpit. The SV chassis offers an extra 110mm of width across the cockpit, at a cost of 25 kg of extra weight, and both chassis sizes are available today in Roadsport and Superlight variants[1]. The SV chassis subsequently provided the basic dimensions for the Caterham CSR. The suspension was completely redesigned, bringing the front suspension inboard, using pushrods, and replacing the De-Dion rear axle with a lighter, fully independent, double-wishbone layout with new coil/damper units. Additional chassis modifications resulted in a 25% increase in torsional stiffness [2]. The CSR was released in October 2004, with a Cosworth Duratech engine and is currently available from the factory in either 200 bhp or 260 bhp form.

[edit] Engines

Early cars used the Lotus Twin Cam engine (subsequently manufactured by Vegantune), followed by Ford cross flow engines[3]. The first Cosworth BDRs appeared around 1983, in 1600 cc 140 bhp form, followed by 1700 cc 150 bhp versions three years later. By 1990 the top of the range engine had become the 2 litre Vauxhall HPC, as fitted to the Vauxhall Calibra, putting out 165—175 bhp. In 1993 Caterham created the JPE special edition (named for formula one driver Jonathan Palmer) by using a 2 litre Vauxhall Touring Car engine, putting out around 250 bhp and reducing weight to around 530kg by such measures as removing the windscreen in favour of an aeroscreen. The JPE was quoted at 0-60 mph times of around 3.5 seconds and, with Jonathan Palmer at the wheel, set a 0-100 mph-0 record of 12.6 seconds. Around 1997 the cross flow range was replaced by 8v and 16v Vauxhall units which, in various guises lived on until the end of the VX-powered Caterham Classic, in 2002.

The Rover K-series made its appearance in 1991, initially as the 1.4 litre engine from the Metro GTi. This engine became the backbone of the range for the next 15 years. The 1.6 litre k-series appeared in 1996 and the 1.8 litre a year later. 1996 also saw the addition of the 'Superlight' range, a range that successfully focussed initially on reducing weight and subsequently on bespoke tuning of the k-series to ever-higher outputs. Weight was saved by removing the spare wheel (and carrier), carpets, heater and often the windscreen (replaced with an aeroscreen), hood and doors. Lightweight "Tillet" GRP seats were usually fitted along with carbon-fibre front wings and nosecone (note however that items such as heaters and windscreens could still be specified by the Superlight customer if they so wanted). Wide-track suspension was added to the superlight, increasing the track at the front to match that at the back. The later Superlight-R offered the dry-sumped VHPD (Very High Performance Derivative) variant on the 1.8 litre k-series. Output was now up to around 180 bhp, in a car that now weighed as little as 490 kg. Three years later Caterham took the same concept to a new level and created the iconic Superlight R500, still based on the Rover 1.8 litre k-series but now tuned (by Minister Racing Engines) to around 230 bhp at 8,600 rpm in a car weighing just 460 kg. The R500 was initially available in kit-form, but quickly became a factory-build only item. Quoted performance figures still make impressive reading; 0-100 mph in 8.2 seconds (although EVO magazine quotes 8.8 seconds[4]). Perhaps unsurprisingly, such a stressed engine required frequent "refreshing" in order to keep it on the road and a series of engine revisions was undertaken throughout the R500's life in order to increase reliability. This culminated in 2004 with perhaps the most extreme production Caterham of all; the R500 EVO was bored out by Minister to 1,998 cc and delivered 250 bhp. At £42,000, the R500 EVO was hardly a sales success - it is widely believed that just three examples were sold. It did however succeed in setting a series of performance car benchmarks several of which last to this day; the 0-100 mph-0 record was set at 10.73 seconds(in second place was a Ferrari Enzo costing ten times as much) and, until the end of 2006 it remained the fastest production car timed by EVO magazine around the Bedford Autodrome West Circuit, timed at 1 minute 19.62 seconds, ahead of a Porsche Carrera GT at 1.19.70 seconds. There are two other Caterham 7's in the top 5 places, both CSR's powered by Cosworth engines. In the Jan 2007 edition of EVO magazine, the Radical SR3 1300 was timed at 1.17.10, knocking the R500 EVO into second place (with an improved 1.19.00)[5].

Caterham have had something of an tentative relationship with the installation of motorbike engines into their cars. In 2000 the Honda CBR1100 engine was installed into a 430 kg superlight chassis to create the Caterham Blackbird, delivering 170 bhp at 10,750 rpm (although just 92 lbft of maximum torque). The Blackbird offered near R500 performance for rather less money (Top Gear quote 0-60 of 3.7 seconds and a top speed of 143 mph at a new cost of £25,750)[6] . In 2001 a Honda Fireblade engine was offered in a live-axle chassis, via James Whiting of Ashford, Middlesex. Quoted power was 128 bhp at 10,500 rpm. Both of these models have ceased production. There has also been at least one installation of the fearsome RST-V8, created by Moto Power; a 2 litre, 40 valve 340 bhp V8 made from a pair of motorcycle engines joined at the crank. An early, pre-production review of the car/engine combination exists on the EVO website [7].

[edit] Racing

Caterham 7 on track at Spa
Caterham 7 on track at Spa

The Lotus 7 was conceived by Chapman as a car to be raced. Whilst still a prototype, in September 1957, it was raced at the Brighton Speed Trials [8] and by the end of 1958 Graham Hill was winning races with the Coventry Climax-engined 'Super Seven'[9] The car has had a strong racing history throughout its life under both Lotus and Caterham stewardship. Amongst the marques more famous races was victory in the Nelson Ledges 24-hour race in Ohio when, against a field including works teams from Honda and Mazda, a four-man team from Caterham (including both Jez Coates and Robert Nearn) won by seven laps (after 990 laps) in a modified Vauxhall HPC.

After dominating open class races for decades Caterham Super 7 Racing, a one-make championship for Caterhams, was begun in 1986. Caterham 7 races have since expanded to include club and competitive races in the United Kingdom, continental Europe, Canada, the United States and Asia. In 1995 the Caterham Academy, a novices-only format, was introduced in the UK. For £16,995 (2007 price), entrants get a modified Roadsport kit (although a factory-built option is available for extra cost) with a sealed 120bhp engine and 5-speed gearbox. Having completed the ARDS license qualification, the season then consists of four sprints followed by four circuit races. The Academy is designed as the first step in a well-established chain of Caterham race formats (Graduates, Super Grads, Roadsports, Caterham Challenge and then on to European circuit formats)[10].

The car was banned from racing in the USA in the 1960s, as being "Too fast to race" and again in the UK in the 1970s for the same reasons, which prompted Caterham Cars boss Graham Nearn to produce 'T' shirts with "Caterham Seven, the car that's "Too Fast to Race..." .Both bans were later lifted. In 2002 an R400 won its class (and came 11th overall out of 200 starters) at the Nürburgring 24-hour race by 10 laps, ahead of competition that included Porsche and BMW racecars, leading, once again, to a ban on entry in subsequent years[11].

[edit] Current range

Caterham 7 Roadsport SV
Caterham 7 Roadsport SV

The existing range provided by Caterham Cars comprises a mixture of chassis types (the traditional narrow-bodied 'Series 3' chassis, the wider SV chassis and the CSR chassis), of engines (k-series engines, which are now being phased out, Ford Duratech engines for the more powerful variants and Ford Sigma engines which are starting to be introduced for the lower-powered models) and of models (Classic, Roadsport, Superlight, CSR, in ascending order of price). All are available either factory-built or as a self-build kit. It is anticipated that the k-series engine will disappear from the lineup some time in 2007, resulting in an all Ford engine range.

[edit] Classic

The Classic represents the entry-level offering from Caterham. It is available only in the Series 3 chassis size and, as standard, comes with a 1.4 litre k-series engine (whilst available) and five-speed gearbox. There is no heater, hood or spare wheel carrier as standard (although all these can be added as options). In all other respects it is the same as a Roadsport. Quoted performance with the 1.4 litre engine is 0-60 in 6.5 seconds and a top speed of 110 mph.

[edit] Roadsport

The Roadsport is available in both S3 and SV chassis sizes and is more or less a Classic with a more powerful engine and a few more extras as standard; heater, hood and spare wheel/carrier are all standard as are carpets. At the moment the engine options encompass both Rover k-series and Ford Sigma options, although the k-series is expected to disappear from the options list once supplies are exhausted. Suspension is the same as for the classic; double-wishbone and anti-roll bar at the front and de dion axle located by an A-frame at the rear.

[edit] Superlight

The Superlight is available in both S3 and SV chassis sizes. The list of standard equipment reflects the Superlight's bias to track work; Wide-track front suspension, 6 speed gearbox, Carbon fibre dashboard and front wings, GRP aeroscreen and seats, racing harness, removable steering wheel. Quoted weight for the Superlight is about 50 kg less than the Roadsport, due in part to the lack of a spare wheel and carrier. Engine options again are something of a temporary mix of incoming Ford Sigma and outgoing Rover k-series with an additional option of a 2 litre, 210 bhp Ford Cosworth Duratec engine in the Superlight R400.

[edit] CSR

The CSR represents the top of the range and in some respects can be considered a separate model. It has its own chassis, suspension and interior and is available with either 2 litre (200 bhp) or 2.3 litre (260 bhp) Ford Cosworth Duratec engines. Quoted performance for the CSR260 is 0-60 in 3.1 seconds and a top speed of 155 mph.

[edit] CSR Superlight

In 2006, Caterham introduced its new flagship model, the CSR Superlight. Based on the CSR260, this model adds a ‘Superlight’ lightweight specification to the CSR, further extending the CSR260’s already epic performance envelope. Aimed at the enthusiast, the 2.3 litre Cosworth-powered road legal Caterham CSR260 Superlight brings all the performance credentials associated with its stablemate, like a supercar-humbling 0-60mph time of 3.1 seconds and a licence-losing top speed of 155mph, yet swaps the windscreen, carpet, heater and weather gear for a limited slip differential and a quicker steering rack. Twenty five kilos lighter than the standard CSR260, this model variant also adds distinctive Superlight styling to the exterior, including a wind deflector, a carbon fibre dashboard and wings, a black powder coated cockpit, quick release MOMO steering wheel and ‘black pack’ that disguises otherwise aluminium detailing. Of particular note are ‘Dynamic Suspensions’ Damper units developed by specialist Multimatic for the car. The damper units lend the already capable CSR a further edge in terms of handling and cornering performance. It features the same 2.3 litre (260 bhp) engine as the CSR260, but weighs only 550 kg and has a Power-to-weight of 472bhp-per-tonne.

Caterham have celebrated the 50th year of production with a couple of special edition "50th Anniversary" paint options. The Caterham website also suggests that 2007 will be marked with a "New Ultra-Performance model (TBC)" [12] although no details have yet been released.

[edit] Notes

In the anime éX-Driver, one of the three lead characters, Souichi Sugano, drives a yellow Caterham Super Seven JPE.

[edit] References

  1. ^ See http://www.caterham.co.uk/showroom/index.htm
  2. ^ "Caterham Sevens, from conception to CSR", by Chris Rees
  3. ^ This paragraph largely draws from Chris Rees' book "Caterham Sevens from conception to CSR", published by MRP, ISBN 1-899870-61-X,
  4. ^ EVO Magazine, Issue 100, January 2007. Published by Dennis Publishing Limited
  5. ^ EVO Magazine, Issue 100, January 2007. Published by Dennis Publishing Limited
  6. ^ See http://www.topgear.com/drives/G1/A0/roadtests/10/01.html
  7. ^ See http://www.evo.co.uk/carreviews/evocarreviews/49734/caterham_rst_v8.html
  8. ^ Caterham Sevens, from conception to CSR by Chris Rees
  9. ^ The Lotus Book, by William Taylor, Published by Coterie Press. ISBN 1-902351-13-4
  10. ^ See http://www.caterhamracing.com
  11. ^ Caterham Cars, press release 16/April/2003, also see http://adac.24h-rennen.de/portals/24h/extern/ResultDB/live.asp
  12. ^ http://www.caterham.co.uk/assets/html/about/heritage.html

[edit] External links

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