To make a proper purchase decision, do you really need to understand how many cams a car should have? Actually, no. Trust the opinions of the right people, or the seat of your pants on a thorough test drive, and you won't go far wrong. Still, there is interesting and often relevant information on the spec sheet. Let's take a look at a typical spec sheet and decipher some of the information encoded within.
Body Style
This is relatively self-explanatory. The vehicle's body style is something that is categorized for various regulatory reasons. It can offer a useful reference point, even if some vehicles that are clear competitors in the marketplace are considered by the government to be in different size classes. Think: sedan, multipurpose vehicle (MPV), four-wheel drives, etc. Airbags & Weight
Most spec sheets devote a line to safety equipment like airbags. In the fast-evolving field of safety engineering, the more inflatable devices you've got, the better off you are. This is by no means the entire safety story, however, since the structural design of the car is a critical (if difficult to quantify) part of vehicle safety. Another big element is vehicle weight. Though heavy vehicles are typically less maneuverable than lighter ones and may have a harder time avoiding an accident, if a crash with another vehicle is inevitable, you always want to be in the heavy vehicle. It's all simple physics.
Drivetrain
Though many manufacturers make a big deal about it, drivetrain (meaning where the engine is and which wheels are doing the driving) is only an important issue if you've got a wicked sporting streak or drive on snow or dirt regularly. Sports car people will want rear drive for the handling advantage it offers at the outer limits of traction. Snow and dirt folks will appreciate all-wheel or four-wheel drive. The rest of us can be perfectly happy with front-wheel drive year-round, even in rain, snow, and on most dirt roads.
Engine Size/ Type
When it comes to engine size/type, don't worry about the details too much-not because it doesn't matter, but because there are surprisingly few categorical assumptions you can make.
How so? Engines are measured by the volume of air it takes to fill their cylinders, which are normally expressed in liters. But it turns out size can mean very little since a very efficient small engine can hugely outperform a much bigger one. Likewise, the camshaft arrangement can be a non-issue-at least from the driver's seat. Overhead Valve (OHV) engines use the oldest technology, but the best ones can still perform extremely well. The Corvette and Viper spring immediately to mind. The engine's layout (in-line 4, V-6, V-8 or whichever) can tip you off as to the relative operating smoothness you can expect, but not always. More cylinders make for smoother engines, but there are some remarkably smooth four-cylinder engines these days.
Peak Horse Power/ Torque
Peak horsepower and peak torque are the two measures that count most in engine performance. You can tell a lot about an engine- and how much you're going to like it as these figures and the engine revolutions per minute (rpm) are associated with them. Peak horsepower represents the maximum amount of work an engine can do. "Work" in this case is sheer pulling power, which may be in the form of acceleration or load pulling. Take special note of the engine rpm that is required to generate that horsepower; if it's a high figure like 5,000 rpm or more, the engine will really need to be spinning fast to do its best work. That means a downshift or two (or even three) will have to happen before the revs are high enough to reach that peak horsepower figure. If you don't like to rev an engine up, you'll never get much of the benefit out of a high horsepower engine that needs a lot of revs.
If you tend to like immediate throttle response with a bare minimum of revs showing on the tachometer, you're a torque person. You not only want to see a big peak torque figure, but you'll want it at the lowest possible engine rpm where it's always accessible.
Transmission
Horsepower and torque figures can tell you a lot, but don't be a slave to them: this is another case where a valued expert opinion or your own thorough test drive can tell you all you really need to know. Besides, these figures are not always honest and accurate, and factors like transmission type and number of gears (more is always better), vehicle weight (lighter equals more performance) and other elements play a big role in the performance a car ultimately delivers.
Suspension
There are dozens of different suspension systems currently in production, with layouts (and names) too complicated for the average person to keep up with. The systems fall into a few basic types: Independent (the best), semi-independent (old technology) and live axle (this has been around since the Ford Model T). Independent is the preferred type, since it allows each wheel to respond to bumps without upsetting any of the other wheels. This is the best situation for ride comfort and handling. Semi-independent systems tend to be used on lower-priced cars and are fading out of production. Live-axle suspension is today found mainly on trucks and a few "old-tech" cars. Rugged and inexpensive, live axle suspension can work well, but it can't deliver the combination of ride comfort, traction and handling that independent suspension can.
Brakes
When it comes to brakes, for most drivers, the key issue is whether the vehicle has ABS (Anti-Lock Brakes). In the opinion of our expert drivers, this feature is worth whatever it costs. Skipping it on the options list can save you some money, but we believe that's a bad tradeoff. ABS allows even a novice driver to panic-brake like a pro, plus it insures you'll retain some steering control no matter how sudden the stop. Both of these factors can be lifesavers.
Rules of Thumb
Here are a few final rules of thumb: A vehicle with a longer wheelbase tends to ride more smoothly that its shorter counterparts, but it also gives up some maneuverability. There are several types of steering systems on modern vehicles, but the execution and engineering of the system is more important than its type. A tight turning circle makes U-turns easier in confined quarters. Passenger volume can be a useful measurement of interior space, but it's not the end-all, since it includes space that may not really be useable for people like the area above the instrument panel or rear parcel shelf. Last but not least, fuel economy is a great starting point for estimating how much gas your new car will burn, but it doesn't correlate perfectly with reality. Real drivers tend to burn more fuel wherever they drive. And as you've heard perhaps a million times, your mileage may vary even with the same car.
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