The desire to build the fastest road-legal car and to win the attendant bragging rights has motivated car makers since the dawn of motoring.
Koenigsegg is the current holder, after an Agera RS managed a two-way average of 278mph on a closed stretch of dual carriageway in Nevada last year. That pipped the 270mph that Hennessey had previously achieved with the Lotus-based Venom GT at the Kennedy Space Center in 2014, although that run was one-way only and too brief to qualify for a Guinness World Record.
Now the Texan company is planning to mount a serious assault on 300mph with its first custom-built car, the Venom F5, which was shown as a styling buck at the Geneva motor show. So why is company founder John Hennessey planning to take it record breaking?
“For our clients, being the fastest really matters. They want it to be the best,” he says. “The last car went 270mph and was still pulling, but it had a massive amount of downforce and drag; it had a drag coefficient of 0.44.”
The F5 will have a carbonfibre structure with metal subframes front and rear, its shape heavily influenced by aerodynamic modelling based on its projected top speed – officially quoted at 301mph – and it will havea full-length undertray as well as a deployable rear wing. Hennessey says that the drag coefficient will be a considerably more slippery 0.33, and that number may be improved before the first production car arrives.
Having less drag means that the F5 won’t have a dramatic power increase over the Venom GT, the last versions of which were producing a claimed 1430bhp from a twin- turbocharged GM V8 mounted in a heavily modified Lotus Exige chassis. The new car switches to a custom-built 8.0-litre twin-turbo V8 that Hennessey claims will have a billet-milled block and cylinder heads and will produce 1600hp (1578bhp).
“That was the number we decided we needed,” he says. “By our calculations, we can hit 300mph with less than 1600hp, but I always like to feel I’ve got more power in case it’s hot or we’re running at higher altitude.”