2007 Volkswagen GTI, Honda Civic Si, and Mazdaspeed 3 Dyno Tests: The Truth in Numbers

In the November 2006 issue of Automobile Magazine, we featured eight cars that point the way toward a new era of frugal fun. Three of them--the Mazdaspeed 3, the Honda Civic Si, and the Volkswagen GTI--are front-wheel drive compacts available right now on dealer lots. All three offer great value, reasonable fuel economy, versatile space efficiency, and a whole lot of power under the hood. How they produce that power couldn't be more different. They've all got sixteen-valve four-cylinder engines, but the Civic Si makes its 197 hp through spinning its i-VTEC 2.0-liter to outrageous speeds. Volkswagen's GTI also displaces 2.0 liters, but it uses a turbocharger to get to the 200-hp mark, making almost 35 percent more torque in the process. Mazda uses the same forced-induction philosophy in the Mazdaspeed 3, blowing enough air into its 2.3-liter mill to make 263 hp. Three engines that are very different--but which is the most fun? That's for you to decide. But to help you make that decision, we brought all three of them to a chassis dynamometer. A dyno, as it is commonly called, measures the amount of power that an engine puts to the ground. This number is always lower than the actual amount of power an engine makes, because some of that power is lost to turning the internals of the transmission and differential, the axles, and the hubs, as well as the brakes, wheels, and tires. Knowing the number of horses that actually get to the ground is sometimes more valuable than knowing what's happening at the engine. After all, what good is a powerful engine if the transmission sucks up half of its output? Even more important than those peak numbers is the shape of the torque curve. The shape of the curve dictates what you feel when your right foot is buried in the carpet. Some engines make close to their peak torque for a significant portion of their operating range. Others make their peak torque at only one small point--the rest of the time, the engine is delivering only a fraction of that thrust. Have a look at the individual features below, and see for yourself how differently each of these cars performed. Remember while you're looking at the charts that the peak numbers tell just a small part of the story--it's the shape of the curve that dictates how a car feels. If you have any questions, drop us a line in the Automobile Forums and we'll try to answer your tech inquiries in a way that won't make your--or our--eyes water.