Supercharged Caterham guns for king of the lightweights

There’s not much on four wheels of a reasonable price tag that’ll stick with a sorted Caterham Seven on twisty back lanes or flat-out track. And now things just got really gnarly. A new, 310bhp supercharged Seven is now on sale, and with all that horsepower pulling not-all-that weight, it’s no surprise that the Caterham Seven 620R will hit 60mph in 2.8s seconds or less; depending on grip levels. At a touch under £50k that’s a pretty nuclear bang for your buck!

One smallest of niggles with even the quickest of Caterham cars – like the windscreen-less, screaming R500 that lapped the Top Gear test track like a meteor on rails – was perhaps a little lack of truly bottom-end, instant get up and go-go-go. Running 2-litre, Ford 4-cylinder engines means a lovely, crisp throttle response in the R500, and, don’t get me wrong, as much shove as most mere mortals will ever really need. But, just think if it had a chunk of forced induction punch to back up the rest of its distinctly well-rounded performance package. An early-boosting supercharger would do it. Oh, hello 620R, is that a supercharger hanging off the side of your 2-litre Ford Duratec engine?

As a huge fan of the Caterham R500 – I drove it right after the Stig had finished with it; enjoying his personal set-up for the fully adjustable suspension – and can honestly say that it’s a dream drive of grip and agility. However, from time to time, even in the wonderful R500, if you’re not quite in the right gear, something exotic with a huge dollop of instant, big-engine torque, might give an R500 driver a “see ya later!” surprise. And no-one likes those.

A supercharger forces more air – and therefore more fuel – into the engine at pretty much whatever pressure you like over and above the natural atmospheric pressure at sea level; around 14psi. Double that air-intake pressure to say 28psi and you can add in more fuel to burn in that extra air. More burn simply means more power. And where a turbo needs exhaust gases from a powering engine to run it, a supercharger is powered by a belt from the crank, so as soon as that engine is turning, so is the ‘charger.

That means extra torque right from the bottom of the rev-range, and in a car that’s a light as a biscuit-less biscuit tin, the forward-shove starts to get very serious. On the rear axle are a pair of Avon ZZR ‘cut slick’ tyres with a ‘soft’ and grippy compound to chew this full-bloodied 310bhp into the tarmac. Around 2.8 seconds is probably about the best we can expect from a rear-wheel-drive-only Caterham, but just imagine what its in-gear acceleration will be like too. Big-boost-blistering, basically – all the way to 155mph!

The most hardcore Caterham yet built for the road gets plenty of top-end tidbits to tempt buyers out of their circa-£50k, including a unique gunmetal chassis, an air-flow optimised nose cone and a race-developed cooling package for oil, air and water. The old-school, but still clearly good enough, De Dion rear suspension set-up remains, while the front track is wider and there are high-performance dampers all round. Its wheels are small and light at 13-inches tall.

Carbon fibre makes plenty of appearances inside and out, including the carbon dash and race seats that we’re now happily used to in the hotter Sevens. The revised dashboard looks plenty more premium however, and there’s a quick-release Momo steering wheel to keep sticky-fingered speed freaks at bay.

The hardest-charging, supercharged Caterham Seven 620R is ready to order now, with first deliveries expected later this year. But, hang on, is it as quick as this rabidly-rapid Radical SR8 RX?!

By Dan Anslow