A car’s power-to-weight ratio is more important than its engine output.
A car’s power-to-weight ratio is more important than its engine output.
A group of enthusiasts talking about their favourite sports cars is akin to a game of Top Trumps. But in this case, actual playing cards aren’t involved, and the only figures that will probably be compared are horsepower numbers and century sprint times. I have imagined German engineers sitting around a table discussing the same issue, perhaps with ginormous beer steins in hand. “Our halo model must have more horsepower than all its rivals, ja?” Horsepower figures make it easy for drivers to compare performance cars – on paper, at least. Larger power figures will always excite marketers, too, because they can make cars “easier” to sell.
But an engine’s output is only one of the factors that determine the performance. When it comes to sports cars, the power-to-weight ratio has greater significance, for it more accurately indicates a car’s performance potential. Let’s imagine two rival models with similar prices. Car A has 300bhp and weighs 1.5 tonnes, while its rival, Car B, only has 250bhp but weighs one tonne. To an average driver, Car A seems like the better choice because it is more powerful than Car B. An above-average driving enthusiast, however, would argue the opposite, because although Car A has 50bhp more, its power-toweight ratio of 200bhp per tonne is lower than Car B’s power-to-weight ratio of 250bhp per tonne.
Let’s imagine two rival models with similar prices. Car A has 300bhp and weighs 1.5 tonnes, while its rival, Car B, only has 250bhp but weighs one tonne. To an average driver, Car A seems like the better choice because it is more powerful than Car B. An above-average driving enthusiast, however, would argue the opposite, because although Car A has 50bhp more, its power-toweight ratio of 200bhp per tonne is lower than Car B’s power-to-weight ratio of 250bhp per tonne.
A higher power-to-weight ratio improves a car’s driveability. The car will seem lighter and more nimble, especially when cornering, since there are more ponies per kilo of sheet metal. Using the aforementioned example, Car B might be more fuel-effi cient as well, since the motor has less weight to move. But how does one decide between two competing and similarly priced sports cars with the same power-to-weight ratios? Well, that’s when other factors, such as how a car makes you feel, come into play.
Jeremy thinks comparing horsepower figures is childish, but he’s always ready for a good game of top trumps.
