When Cosworth designed its XD engine, it was with 500 miles at Indianapolis in mind. Similarly, when Judd produced its DB, 24 hours at Le Mans was the target. And yet now these units have shown themselves to be the very best at pushing cars up a hill of just a mile or so in length for little more than 30 seconds.
These are not the only engines used in the British Hillclimb Championship (BHC), though, and you’re as likely to hear a screaming, supercharged motorbike unit as a ripping V8 at Prescott, Shelsley Walsh, Loton Park or any of the other hills that are visited by the BHC.
This is no surprise because, as we discovered last month (RE V33N7) British speed hillclimbing is a category with a great degree of diversity due to a relatively open set of regulations. This has resulted in very high levels of aerodynamic and suspension technology in the fastest cars that go head-to-head in the Top 12 Runoff, the climax to an exciting day of uphill racing.
Power or weight?
Those aero developments are very much driven by the engine the car is packing. As we were told last month, drag is not such an issue if you have close to 700bhp on tap. On the other hand, weight might be, and this is where the most intriguing question about engine choice arises: is it better to have a lightweight car with a less powerful engine, or a relatively heavy car with more power?
The word ‘relatively’ is used here because even the heavier top-line cars are just over the 400kg mark, which, for reference, is half the weight of a current Formula 1 car, with its 798kg limit. The lightest ’bike engine cars can weigh as little as 280kg, with the most highly developed tending to be around 300kg.
The ’bike engine of choice is, predictably, Suzuki’s fabled Hayabusa, though others are used. On the car engine front, for Class L (the over 2.0-litre unlimited class, which
