Using power-to-weight ratio to compare vehicles

[Brian Burke]

When comparing cars in terms of power, I know HP doesn’t give us the entire picture. For example, I just read an article that compared compact sedans and one of the cars was the current Dodge Dart, which I owned. Using only the numbers, the reviewer listed the Dart’s 184hp as its “strong suit.” Having owned that car, it was a DOG and had no power whatsoever. I think a large part of that equation is how heavy the Dart was which got me thinking…is comparing vehicle power-to-weight ratios the best way to get an apples to apples comparison? I know it comes down to actually driving the car more than the numbers on paper, but short of test drives, is this the best comparison tool we have?

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[dan]

there is way more than power too weight, there is also gearing, torque, tires, suspension,

Good example was back in the day when the C-6 Z-06 made its appearance i think in 2006 they where pretty much a direct competition Rival with the Dodge Viper at the time, and power too weight was a big thing they compared, the Corvette had 505HP, and the viper had 510HP, but the vette weighed a couple hundred pounds less, so Corvette claimed better performance because they had better power to weight ratio.

well then the Viper fans then pointed the finger at the vipers better engine torque, i can’t remember the values exactly but the viper had more torque than the Corvette, exceeding 500LBFT while the Corvettes was something like 470-490LBFT i couldn’t remember… so there was the argument for the viper fans back and forth the argument went, which was faster… and in the end car and driver did a review and i have the magazine somewhere, and the Corvette had better track times and a quicker quarter mile by a narrow margin, it was very close!

what really made the Corvette faster, was not only the fact that it had a better power to weight ratio, but the engine had a higher rev… i think the engine of the LS-7 7 Liter V8 was a grand higher, at 7,000RPM, and the vipers V-10 could if i remember correctly only muster a 6,000RPM rev, so the Corvette didn’t need as tall of gears and you could really rev the engine up high between gears which made the difference.

[Brian Burke]

Great info, thanks a lot. It still sounds like p-w ratio is better than just the hp info, but like you said, it doesn’t tell the whole story. I’m sure nothing about a car’s specs say it all unless we’re talking about track times. Thanks again.

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