POWER TO WEIGHT CONUNDRUM
THE power-to-weight ratio is a calculation commonly applied to cars to enable the comparison of one to the other. It is the power output (in horsepower) divided by the weight of the vehicle, to give a measure that is independent of the vehicle’s size. Power-to-weight ratio is often quoted by manufacturers at the peak value, but does it actually mean anything to the car buyer?
After all, there are plenty of sports utility vehicles (SUVs) that deliver excellent power to weight ratios, sometimes bettering “pure” sports cars. Together with the advent of driver aids, this means these SUVs may be able to challenge these sports cars even on the track. Note that these “pure” sports cars usually have rear-wheel drive and few driver aids. The question is; does this make a Porsche Macan Turbo as good as, say, a BMW E30 M3, to drive? Or for that matter, is the Tesla Model S more fun to drive than a race-prepped Mitsubishi Cyborg?
“Selling” the power to weight ratio is a crucial part of marketing modern performance cars. This is because the remarkable increases in engine power over the past twenty years have outpaced the gains in curb weight among most performance cars. Most modern performance cars are much heavier than their older counterparts (check the current BMW M3 against the older ones) but produce greater horsepower. Does it mean abetter ratio power to weight ratio equals a better car?
The problem with the ratio is that it is essentially just a statistic. It implies that the additional power can balance the addition of weight. Two cars with similar power to weight ratios should be the same to drive, shouldn’t it? Unfortunately, it is not so cut and dried. A spirited lap around Sepang Circuit in a Porsche Macan Turbo does not feel the same as a race-prepped Mitsubishi Cyborg although they have similar power to weight ratios (an assumption, of course). A race-prepped Proton Saga would be more fun around Sepang than a Lotus Elise for the simple reason it takes more effort to produce a competitive laptime than the more powerful Elise.
In essence, the weight factor is more fun than the power side. Light cars will always be more engaging and more fun than a heavier and more powerful car. Some mediocre cars become interesting and fun once you gut the interior, put a roll cage on and boost the power somewhat (yes, that Proton Saga). It only makes sense. Lighter cars can use lighter wheels and tyres to make them even more responsive. Lighter cars don’t eat up consumables like brake components and tyres the way heavier cars do.
The main problem about such vehicles is that it is difficult to meet expected levels of safety, comfort, and noise suppression without increasing its weight. Every new car model nowadays are heavier, taller, and more ponderous than their predecessors. They just have a better power to weight ratio.
Here is a list of cars with the best power to weight ratios. Where does your car stand? Hand me the keys to that Proton Saga any day (although a spin in one of these would not be refused).