Weight-to-Power Ratio in Exotic Cars

If you're a fan of exotic cars, you've probably read about the weight-to-power ratio in reviews. But what exactly does it measure? The weight-to-power ratio tells you how many pounds of a vehicle each individual horsepower has to haul. Alternately, the power-to-weight ratio tells you how many horsepowers are allocated for each pound of car.

Why does this matter? Because the harder an engine has to work to get the vehicle moving, the less efficient it is. That translates into poor fuel economy and mechanical wear and tear. And when you're spending big bucks on rare vehicles like these, every penny counts... even if you've got a lot of pennies to spend.

Best: Pagani Zonda

Pagani Zonda S 7.3 Roadster
Pagani Zonda S 7.3 Roadster. Pagani

The Pagani Zonda debuted in 1999 at the Geneva Motor Show. It was the brainchild of former Lamborghini designer Horacio Pagani, who was responsible for much of the bodywork on the Countach and Diablo. The car carried a 12-cylinder Mercedes-Benz AMG with 394 hp, but it also carried a design influenced heavily by Mercedes' "silver arrows" on the track.

  • Weight: 2,667 lbs.
  • Horsepower: 678 hp​
  • W/P Ratio: 3.93 lbs/hp

Best: Pagani Huayra

Pagani Huayra
Pagani Huayra. Pagani

Another of Horacio Pagani's creations, the Huayra succeeded the Zonda as the flagship model. Its run of 100 vehicles, which went on sale in 2012, was sold out in three years. The Huayra was the "Top Gear" track record holder from 2011 until 2016, with a speed of 1:13.8.

  • Weight: 2,976 lbs.
  • Horsepower: 700 hp​
  • W/P Ratio: 4.25 lbs/hp

Best: Bugatti Veyron

Bugatti Veyron Grand Sport Sang Bleu
Bugatti Veyron Grand Sport Sang Bleu. Bugatti Automobiles

Although Bugatti's heritage lies in Italy, this vehicle is pure German engineering. The Veyron was designed and built by Volkswagen, Bugatti's parent company, and it was in production from 2005 until 2015. With a top speed of almost 268 mph, it holds the record as the fastest street-legal vehicle in the world.

  • Weight: 4,162 lbs.
  • Horsepower: 1,001 hp​
  • W/P Ratio: 4.16

Best: Aston Martin One-77

Aston Martin One-77
Aston Martin One-77. Aston Martin

The One-77 made its debut at the 2009 Geneva Motor Show and won the Best Design award in 2009 from Auto Express magazine in the U.K. Power comes from a 7.3-liter V12 mounted in a low, front-mid-engine configuration. The transmission is a six-speed with paddle shifters.

  • Weight: 3,306 lbs.
  • Horsepower: 700 hp​
  • W/P Ratio: 4.72 lbs/hp

Best: Lamborghini Aventador

The Lamborghini Aventador LP 700-4 debuted at the 2011 Geneva Motor Show as a replacement for the Murcielago, which had served as an iconic supercar for a decade. But it's no rehash of the Murcielago. It has an entirely new 12-cylinder engine positioned in the rear, in front of the axle. The high horsepower is coupled with 509 lb-ft of torque and the new Independent Shifting Rods 7-speed transmission. 

  • Weight: 3,472 lbs.
  • Horsepower: 700​
  • W/P Ratio: 4.96 lbs/hp

Worst: Lotus Elise

Lotus Elise
Lotus Elise. Lotus Cars

This fiberglass-body roadster has been in production since 1996. The weight-to-power ratio may seem surprisingly poor given the car's relatively light weight. But its four-cylinder engine's output is worse than that of some economy cars.

  • Weight: 1,931 lbs.
  • Horsepower: 134 hp​
  • W/P Ratio: 14.41 lbs/hp

Worst: Porsche Panamera

2010 Porsche Panamera. Porsche

Porsche entered the passenger-sedan market with the Panamera at the Shanghai Auto Show in 2009, although the company had been planning a similar vehicle since the late 1980s. The Panamera is available with gas, diesel, hybrid, and plug-in options, but its gas V-8 engine is a weakling.

  • Weight: 3,880 lbs.
  • Horsepower: 300 hp​
  • W/P Ratio: 12.93 lbs/hp

Worst: Rolls-Royce Phantom

The Phantom has been Rolls-Royce's flagship model since 1925, and by modern standards, these vehicles remain stuck firmly in the past. Weighing more than 5,500 pounds, the Phantom needs every one of its engine's 12 cylinders. It does 0 to 60 mph in less than 6 seconds, but it's incredibly inefficient.

  • Weight: 5,622 lbs.
  • Horsepower: 453 hp​
  • W/P Ratio: 12.41 lbs/hp

Worst: Maybach 62

Maybach 62S at the 2010 L.A. Auto Show
Maybach 62S at the 2010 L.A. Auto Show. Kristen Hall-Geisler for About.com

Maybach, a German luxury brand until World War II, was revived in 1997 by parent company Daimler AG. The Maybach 62 cost $500,000, and the V-12 powered vehicle was nearly as inefficient as its British cousin, the Rolls Royce.

  • Weight: 6,330 lbs.
  • Horsepower: 543 hp
  • W/P Ratio: 11.66 lbs/hp

Worst: Bentley Mulsanne

Bentley Mulsanne at Pebble Beach
Bentley Mulsanne at Pebble Beach. Bentley Motors

Unlike other big European sedans, the Bentley gets its power not from a V-12 but from a twin-turbo V-8 engine. That gives the Mulsanne plenty of pickup, going from 0 to 60 mph in just 4.8 seconds. But that performance comes at the price of a terrible weight-to-power ratio.

  • Weight: 5,700 lbs.
  • Horsepower: 505 hp​
  • W/P Ratio: 11.29