Exhaust Tuning for Performance

My career as an automotive improvement expert began when I modified my first car. Since then, as a car enthusiast and published author, my obsession with the automobile has led me to enhance tons of vehicles both inside and out. That’s why I’m thrilled to be a part of a brand new series designed to help keep your car looking great and your engine running like new! I’m Chris Duke, and welcome to eHow’s Auto Center brought to you by Mobil1!. Hey Chris, I’ve done some basic performance mods to my car and am going to finish it off by adding a performance exhaust. How can I make sure my exhaust works well with my modifications? -John Thanks for the great question John. Many people will spend time and money doing performance modifications to the cars and forget just how integral a performance exhaust setup ‘tuned’ to their modifications is. Having an exhaust system setup to match your performance expectations is really the final piece to your puzzle. First let’s look at your manifold. Stock manifolds have irregular internal surfaces due to the rough cast iron seams and ridges. If you haven’t changed out your manifold you can tweak your exhaust with a simple port job. Attach a long-shaft flex grinding cone to a drill, and polish the inside surfaces of the exhaust manifold ports. This allows less restriction and the free flow of exhaust gases, increasing horsepower and fuel economy. Another option is to replace your headers. The application of high performance headers on a stock vehicle can dramatically increase performance, torque and fuel economy. Headers replace the stock manifold and consist of individual pipes for each exhaust port. They possess very smooth interior surfaces and gentle bends in the tube structure to allow maximum flow without creating back pressure. Be sure to check out our video on different types of headers for more tips. Many older vehicles have heat riser valves in the end of the exhaust manifold that shut off the exhaust flow for cold starting. The valve opens as the engine engine warms up. Lubricating the valve shaft and making sure it opens and closes properly ensures that there will be no back pressure. Heat riser valves stuck in the closed position can cause extreme back pressure and reduced engine performance. Now that we’ve looked at the engine for some tuning tips, let’s look at the exhaust pipes and what you can do to increase performance Replacing stock exhaust pipes with high-quality stainless steel pipes increases exhaust flow because of the smoother, polished tube interiors. They last longer than stock exhaust pipes, since their construction resists water, carbon build-up and raw fuel contamination. High performance exhaust pipes have larger interior diameters that maximize exhaust flow. Most cars will come with a single exhaust system. The single exhaust system can be split at the header pipe so it can be joined to a Y-pipe. This allows for the addition of an extra pipe, or dual exhaust setup. This simple modification can allow better free-flow and reduced exhaust system temperature. This increases horsepower, fuel economy and acceleration torque, while the addition of an extra muffler reduces noise. One more tip...or tips I should say. If you’re ultimate goal is sound and not performance exhaust tips are a quick and easy way to change the sound of your car. Install an aftermarket tip. Dual-walled, beveled and flared tips generally amplify the sound produced by the exhaust. Exhaust tips with outlets larger than the exhaust pipe inlet may amplify sound. Resonated exhaust tips are lined with fiberglass or sound dampening material and are specifically designed to reduce the sound output of the exhaust system. Well, I hope that I’ve given you a good understanding of how important a properly matched and tuned exhaust is to your performance goals! Thanks for the question John! For eHow’s Auto Center, I’m Chris Duke. Here’s to helping keep your car running like new!