Fuel Economy Vs. Performance

Fuel Economy Vs. Performance

Gas Mileage - EPA gas mileage results are listed on the window stickers of all new vehicles. The current high-mileage champs are the Honda Insight and Toyota Prius, both averaging around 70 miles per gallon. At the other extreme of the scale lies the Ford Excursion, with around 12 mpg.

Compare the statistics. With gasoline at $1.50 per gallon, and the average driver traveling around 15,000 miles in a year, the Insight's gasoline bill would be $321.00 for the entire year, while the Excursion pays a whopping $1,875.00. Therein lies the second major problem faced by the onslaught of SUV's: not only are they 6 times as likely to kill, they consume 6 times more petroleum than the most fuel efficient vehicle.

I'm not suggesting that you shop on gas mileage alone, but be aware of more fuel-efficient alternatives. For example, a Subaru Outback Limited wagon has roughly the same interior dimensions as a Jeep Grand Cherokee Limited. They both have full-time all-wheel-drive and they have the same luxury equipment. The Jeep costs about $8000 more than the Legacy (most of it profit for Daimler-Chrysler).

However, that's not the only difference between them. The Legacy averages 28 miles per gallon on the highway, while the V-8 powered Jeep gets 60 % of that (17 mpg). Using highway mileage, their 15,000 mile fuel expenses come out to $803 for the Subaru and $1323.00 for the Jeep. (That $520 difference in gasoline savings is just the beginning: insurance rates for SUVs run significantly higher than for cars, because they cause more damage in accidents and cost more to fix.)

Performance - Performance has become an important safety feature for modern drivers. A responsive gas pedal allows you another option (brake or accelerate) when an accident unfolds before you. Good performance allows you to pass slow-moving vehicles on country roads, and to merge into fast-moving feeder lanes on expressways. Fast thinking and a responsive throttle can help you to avoid an accident that a slower vehicle couldn't.

When evaluating a vehicle, take a close look at the engine size (expressed in liters), the number of cylinders (4, 6, or 8), and the engine's power output (expressed in horsepower). By comparing the horsepower of two different vehicles with the same drive train and overall weight, you can determine which vehicle is faster, or has the better performance. A lighter car will be faster than a heavier one if the horsepower is the same. An engine's strength (expressed as torque) is determined by two factors, the number of cylinders and its horsepower. A six-cylinder engine with 140 horsepower will have more torque than a four-cylinder engine with the same horsepower rating.

Double overhead cam (DOHC)-equipped engines offer many advantages over single overhead cam (SOHC) engines. Because DOHC engines have twice as many intake and exhaust valves as a SOHC motor, they run cooler and more smoothly, quietly, and efficiently. To ensure against costly DOHC engine repairs, make sure you change your engine's timing belt every 60,000 miles.

Performance-minded shoppers may be looking for turbocharged or supercharged vehicles. These have performance-enhancing devices that re-utilize the engine's exhaust flow (turbocharger) or excess torque (supercharger) to increase the horsepower.

If you're looking for a powerful engine, make sure that it's balanced with good brakes, a sports suspension and performance tires. Be aware that they can also increase your insurance premiums, especially if you're a younger driver.

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wheres the statistics?

Horsepower = Torque * RPM * Const,
where Const depends only on measurement units selected.
The number of cylinders has nothing to do with it.

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