Caterham Seven CSR - Light Weight Loony

By Feann Torr - 16/11/2004

Caterham, a British automaker that specialises in creating track-ready sports cars as well as road registerable vehicles, has just unleashed its new 2005 model, called the Caterham Seven CSR.

The radically retro tiny two-seat roadster could be likened to another british car, the Lotus Elise, in some respects.

Though the new Seven CSR may not have the most powerful engine in the world - it is powered by a 2.3-litre 4-cylinder motor - like the Lotus Elise it relies on its minimal weight to increase performance.

Though Caterham have not yet divulged the open wheeler's kerb weight, judging by the amount of power the engine generates and the supercar-like 0-60mph (0-96km/h) acceleration times, one can deduce that it's an incredibly light car.

As an indication to the Seven CSR's weight, the entry-level Caterham Classic tips the scales at 540kg. By reducing sprung weight the net effect improves almost all aspects of a car's performance.

For instance, if you strip back a Holden Commodore VT wagon, including removing the rear and front passenger seats, all the trim and all the safety-enhancing reinforcements, it's weight will drop and the car will brake and accelerate much quicker and able to hold higher mid-corner speeds.

It probably wouldn't look very fetching, but it may take precious tenths off your quarter mile times - and that's what Caterham is all about.

By making use of a 2.3-litre Ford Duratec engine, tuned by Britain's premier racing group, Cosworth, the new Seven CSR will hit 96km/h (60mph) from standstill in just 3.1 seconds. This puts most Ferrari's to shame, not to mention another category of power-to-weight stalwarts: motorcycles.

Racing to 100km/h in about 3.2 seconds is an altogether astounding feat, and part of this is due to Cosworth's re-involvement with Caterham.

The press release proudly states: "The British built Caterham Seven CSR sees the long-awaited return of Cosworth to the road car market after a ten-year absence with two bespoke, high performance engines."

So what have Cosworth brought to the table? A deep understanding of Ford hardware.

The 2261cc Duratec 4-cylinder engine has 16-valves and in its unfettled factory condition makes 110kW of power @ 5750rpm and 209Nm of torque @ 4250rpm.

After Cosworth has finished upgrading the new DOHC engine (with items such as forged pistons, new valve springs, aggressive camshafts and new cylinder heads), it pumps out more power, to the tune of 194kW @ 7500rpm and 271Nm of torque @ 6200rpm.

The engine spins more freely thanks to Cosworth's involvement, and the end result is that wham-bam 0-96km/h time of 3.1 seconds.

The 194kW or 260bhp is tranferred to the rear wheels via a 6-speed manual transmission (with a slippery diff) and using all six of these gears, the Caterham Seven CSR will hit 155mph, or about 250km/h.

Caterham will also offer a milder 200bhp (147kW) version of the Seven CSR, and this lower-power model has EU4 emissions approval, which the company says "will provide a major boost to Caterham's already strong export market, as well as forming the cornerstone of its domestic high performance sales".

Cosworth's chief engineer for production engines, Nigel Foxhall, was beaming about the new collaboration: "I'm delighted that Cosworth has been able to work with Caterham to provide this solution, developing, building and supplying the Duratec engine for the new model.

"We worked very closely with Caterham at all stages of the development," continued Foxhall, "to ensure that not only did the engine match all performance criteria but that it could be successfully installed in the most advanced Caterham yet.

"This project is the first of many that the Production Engines department has recenty been working on. I'm extremely pleased with the result, with these two incredibly powerful brands sitting side by side on one of the most engaging high performance road cars around. The result will, I'm sure, be a perfect demonstration of what both companies stand for."

Rolling stock is comprised of fairly tame 15-inch alloy rims, but one look at the rims' width will tell you all you need to know - 6.5-inch front and 10-inch rear rims - the Seven CSR is razor sharp weapon of apex destruction. The front rims are shod with Avon CR500 tyres, 195/45 R15s up front and incredibly fat 255/40 R15s at the rear.

As well as getting a bigger engine and chunkier rubber to cope with the extra grunt, the Seven CSR also boasts what the company calls the "the most dramatic overhaul of its dashboard and trim in the model’s entire 48-year history". Oo-er.

Ergonomics have been improved with all switchgear being closer to hand, and "alloy style" instrument dials, gear-knob, handbrake and steering wheel add a little more lustre to the small cabin. There's also a bit more storage space for the new 'go-fast' Seven model.

According to Caterham, a new suspension system meant that changes to the chassis were needed, and the subsequent revisions to the Seven's tubular spaceframe have resulted in a rather nice 25 percent increase in torsional stiffness - not that the already grippy Seven really needed it.

The new suspension setup is comprised of "racetrack honed double wishbone fully independent rear suspension to increase grip and adjustability". We like that. And at the front resides an "F1-style push-rod operated inboard unit" that the British marque reckons will increase aerodynamics. The front wheel track has also been increased (by 50mm) to help with high-speed cornering.

Though the Seven's visual appeal may not be as universally effective as Lotus' light weight sports cars, the compact and highly manoeuvrable Caterham Seven CSR has such incredible performance you probably won't care about its pragmatic image when sitting in its cosy cockpit.

With a enough poke to humble just about anything on the road - two, three or four wheels - the Seven CSR is a vehicle that will never command the respect that a Ferrari F430 or Lamborghini Gallardo does, but it gets the official Web Wombat thumbs up - which is nearly as good, I'm told.

Talking about the launch of the new Seven CSR, Simon Nearn, managing director of Caterham Cars, said "Caterham has to remain at the pinnacle of its chosen niche – lightweight, high performance sports cars. We feel we've taken the next giant stride forward with the Seven CSR.

"Caterham's role as custodian of the legend is not only to ensure its continued existence but also its continued development," cotinued Nearn. "Ideas for the development of the Seven are always ongoing. Yet it was clear from the start, that many of the changes being considered throughout the company would come together and be introduced to create one truly, original all-new model for the world market."