The Science of Combustion: How to Improve 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 heard that having better combustion can improve performance. How exactly does that work? -John Thanks John! Improved combustion is great way to improve performance. Let’s take a look at exactly what a car’s combustion process is first. Combustion happens when fuel and air are mixed together in the cylinder through the intake valve. A spark is introduced to ignite the fuel as the piston travels up the cylinder compressing the ignited fuel. The pressure of the ignited fuel drives the piston back down. When this happens the rod connected to the piston turns the crankshaft and exhaust gases are released through the exhaust valve. This combustion cycle creates the power needed for the engine to turn the driveshaft, which in turn powers the vehicle. Now that we know how the combustion process works, let’s take a look and see what can be done to improve it to create more power. One of the most popular and easiest things to do to help your combustion process is to introduce more air and fuel to the ignition process. The air and fuel mix and the ignition are all governed by your car’s Engine Control Unit. The ECU is programmed with a standard map for ignition timing. Manufactures create timing maps with a big margin of error to cope with temperature ranges, adverse conditions, poor maintenance and minor faults. This margin means a variance of + or – 10hp. Tuning your ECU with an On Board Diagnostics Flash tool or with an after market chip preprogrammed for performance can unlock hidden potential in your engine and result in significant performance gains. If you’ve made modifications already to your engine, intake or exhaust your car’s air to fuel ratio has changed. If you don’t remap fuel tables by tuning your ECU some of the performance you would have gained may be lost. ECU tuning may void your vehicle’s warranty so be sure to check your owner’s manual or ask your local mechanic before tuning. Some vehicles can benefit from higher octane gasoline. Higher octane fuels slow down the combustion process giving you a slower more controlled burn. Even if you haven’t tuned the ECU your vehicle may benefit from higher octane gasoline. Moving to a higher octane fuel allows for a higher compression ratio and will increase power. Now, not all vehicles can benefit from this and in some cases you can even cause internal damage by using additives or gasoline’s such as racing fuel with a very high octane rating so be careful in your selections, due your homework, and ask your local mechanic. Better to ask if it’s safe than to ask if he can fix it! If you are building a car for high performance you will most likely have to replace your fuel injectors. Performance injectors provide more efficient combustion. They will help to assure you’re not ‘running lean’ which is when you have too much air compared to fuel. The flip side to that is that you could end up ‘running rich’ which is when you are using too much fuel compared to your air intake. Situations like this are more suited for high performance engine mods and not when you are just looking to add a few horses under the hood. Performance spark plugs, wires and ignition coils can also help with combustion by providing a more powerful, cleaner spark to ignite all of the fuel being provided. Don’t forget, your local mechanic is always a great source of information if you need more detailed help. Well, I hope that I’ve given you a little more insight into what exactly goes on inside your engine! Learning the ins and outs of just how internal combustion works can go a long way to creating performance safely without breaking the bank! Thanks for the question John! For eHow’s Auto Center, I’m Chris Duke. Here’s to helping keep your car running like new!