Everything You Need to Know about Engine Performance

March 19, 2012

Learning what goes into engine performance can help you diagnose performance issues or how to shop for a more robust car.

High Performance

Engine performance is usually a big factor when considering the purchase of a new or used car. Many people don't know anything about how an engine works; they just know that it makes the car go. That doesn't mean that you can't be performance conscious about any vehicle you buy; from a sleek Corvette to a simple minivan. The nice thing is that all gasoline cars operate on the same basic principals, so it's easy to gain a general knowledge about what engine performance is all about. Here are a few factors to consider when researching the performance of a new car.

Intake

Engine performance all starts here. As the air flows into the engine it is mixed with fuel and burned to make power. Intakes with fewer restrictions will allow an engine to make more power. This is because restrictions in the intake path slow the air down before it reaches the engine, and reduce the amount of air that the engine can pull in at any given point in time.

Timing

Many modern engines have advanced modifications that increase performance by tuning the way the engine works in different conditions. Systems like Honda's popular i-VTEC system (intelligent Variable Timing Electronic Control) change the timing of the valves--the mechanism that controls the intake of air and the release of exhaust in your engine. By using different valve timing at different RPM (Rotations Per Minute, or speed your engine is working at) this allows your cars engine to work better in a variety of different conditions. This equals out to more power.

Compression

The compression ratio of your engine refers to how much the pistons compress the air that comes into the cylinders. High performance cars tend to have higher compression ratios. This allows the car to produce more power, but the downside of this is that cars with higher compression ratios usually require premium fuel which is more expensive.

Turbochargers and Superchargers

Turbochargers and superchargers are basically compressors that pressurize the air coming into the engine. This allows the engine to mix more air with fuel which can result in a drastic increase in overall power output. More and more cars are hitting the market equipped with turbocharged and supercharged motors. However converting a conventional engine to a forced induction setup is a very involved and costly process.

Exhaust

The last step in the process. Like the intake, reducing restriction in the exhaust almost always results in more power. Cars with performance exhaust system optimize the exhaust flow to have as little backpressure as possible. This allows the engine to expel the waste fumes as quickly as possible so it can burn more fuel faster. Performance exhaust systems usually use high-flow mufflers which tend to be louder than stock equipment.

    There are a few advantages to knowing these basic principals that govern the performance of your car's engine. Not only can you be a smarter consumer, but you can also have a better appreciation of what is going on under the hood when you press on the gas pedal.

    Related Questions and Answers

    Where can I Buy Performance Engine Rebuilding Kits?

    Performance engine rebuild kits can be purchased wherever you see a specific marque advertised heavily. For example, if you drive by a store that advertises performance enhancements for Acura Integras ('94-'97 or so), then it's a good bet that turning into their driveway will bring you to a whole new subculture of performance that you didn't know existed. On a more general level, you'll find that AutoWeek or Car and Driver will also advertise hotter cams and manifolds for Sentras or Altimas or other Nissans. JCWhitney, which has been around for nearly a century offering aftermarket performance pieces, is another good place to try. You might even be able to, at least, start the process at your local AutoZone, Pep Boys or NAPA Auto Parts.

    What are the Most Popular Street Performance Engines?

    The most popular street performance engines today are the Chevy small block series, starting with the 350. The rest of the line includes the 383, 402, 427, 396, 454 and 505. You'll find these engines in vehicles like the Chevy Camaro, the Corvette ZR1 and 06. Interestingly, you'll also find a whole bunch of race tuners working with the rolling stock coming out of Acura and Honda, as these engines can be worked on with new performance chips. There's a wide variety of performance parts available for them. Including new low restriction manifold systems, intake systems and intercooler systems that not only help keep the air/fuel charge cool, but also help to remove heat from the engine, so that these vehicles can perform up to their potential.

    Will Higher Octane Gasoline Increase Engine Performance?

    Increase in engine performance won't happen to your car unless it is made to run on premium gasoline. Instead, what you will be doing is throwing money down the gas tank pipe, unless your car is knocking badly and really needs a tune-up. A higher-octane gasoline will halt the knocking. If your car is meant to run on 87 RON (road octane) gasoline, then that's what you should be using in it. Actually, if you run a higher octane gasoline, you could be risking burning a major part of one of your piston crowns if the engine and octane don't agree. That could be a rather costly mistake. We're not saying that it will happen, but it could happen, so the best solution is to run your car on the octane recommended by the manufacturer.

    Are there Any Fuel Additives that Improve Engine Performance?

    Companies do not improve engine performance. Improvement isn't usually seen if you use one of the many "performance enhancers" you may find advertised on the Internet, in the back pages of a weekly magazine like AutoWeek, or a monthly like Car and Driver. Simply put, unless you're driving a diesel with fouled injectors, you won't see any major performance increases. Even though people tell you that you are coating the inside of your engine with Teflon or molybdenum or some other exotic metal. The reason, frankly, is that you have oil constantly circulating in your engine, and it won't circulate any better or worse if you use one of the "performance enhancers".

    Do Auto Performance Chips Really Increase Engine Horsepower?

    Auto performance chip's reprogramming is one of the first things that race tuners and others do to increase the performance of their vehicles. The way this is done is that the memory is carefully de-soldered from your car's ECU (Electronic Control Unit) or microcomputer, and then is carefully reprogrammed with new instructions that can result in hotter performance. How much hotter can you get out of a chip reprogram? It has been reported that some vehicles have seen their gross horsepower output numbers increase in the vicinity of 30% or more, and some performance enthusiasts have seen their 0-to-60 times drop from the 12-second range to the high-10s. That's a phenomenal improvement.

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