In this article I'm going to discuss some simple and cheap ways to enhance your cars performance to boost your horsepower. Doing so will also (usually) increase gas mileage and increase rear end torque.
I did a lot of modifications to my 96 Firebird. Some of them were very hard and very expensive, but there are a lot of simple modifications you can do to your domestic or import car that are cheap and simple to install that allow you to improve performance. Depending on how much you want to spend and how much work you want to put into it, you can spend a lot of money on a car and sometimes not get a lot out of it. When deciding on whether or not to start modifying a car, you have to take into account what kind of engine it has, what is the stock HP, and whether or not any companies make prefabricated parts for it to allow you to modify it. So, for example, if you have a Ford Escort and you want to get it up to the same horsepower as a V8 Trans Am or something, you're going to have to spend a lot more money than you would if you probably just searched around and found an older model used car that's already got a large engine in it, or a different car that is easier to modify and give you more bang for your buck.
But, as for the modifications, most can be installed yourself or installed cheaply by a local muffler shop or some place similar. First, we'll look at the intake system.
Cold Air Induction
Cold air induction is a very simple modification most people can make to their cars, and many aftermarket car parts manufactures make prefabricated cold air induction systems for most models. By default, your car has an air filter that connects into the throttle body that's within the engine compartment. When the default system is in place, hot air is sucked into the throttle body within the engine area and you have a reduced flow because of the smaller sized tubing and connectors that go between it and the air filter. Installing a cold air induction system removes the parts from the throttle body to the air filter, and tries to move the air filter to a place away from the heat of the engine, so it's sucking in colder air. Colder air cools your engine off slightly, and gives you more air into the throttle body to allow for more combustion. Cold air kits also come with higher flow air filters (normally K&N) that are reusable, so they last forever - you just have to clean them every now and then. As I mentioned, many companies make cold air kits for your car already, so you just have to check and see if one is made and if it's within your price range. If you're lucky, you might have more than one company who makes a system for your car and then you can pick and choose. They're fairly simple to install, and normally come with instructions that you could use to install it yourself in your garage. If you can't find a premade cold air kit for your car, sometimes you can make your own out of metal pipes or hoses that you can purchase at automotive stores or fashion yourself out of other parts. Do a search around on some forums or newsgroups about your car and more than likely someone has written up some instructions as to how to make your own if no one makes one for you.
If you don't want to spend the money or can't find a cold air kit for your car, you can install a K&N High Flow Air Filter. It just allows for more air to flow in than standard air filters which also increases horsepower, but to a lesser degree (although they claim anywhere from 10-20hp, but that's really pushing it for just a filter).
Read more about Air Intake Systems on AutoAnything.
Cat Back/Muffler Kits
A cat-back is a exhaust kit for a car that replaces all the exhaust pipes from the catalytic converter back (hence the name). This includes a new muffler and often times new exhaust tips. There are many, many cat-back systems out there to choose from for most cars and you can pick them based on how loud you want it to sound, or if you don't want it too loud you can find a quieter system. Cat-backs normally cost around $300 or so and can normally add around 10-20hp to your ride, so it makes for a good pretty cheap investment. With the additional exhaust tips, it can also add to the look of your car so you can pick what your preference is.
If you don't want to install an entire cat-back, you can install just an aftermarket muffler. Again, many choices here and having a higher flow muffler will add some horsepower too. You'll have to check and see who makes what for your car and decide on how you want it to sound.
With a cat-backs and mufflers, you will most likely have to have it installed somewhere, unless you have your own car lift and know how to weld. Most places, like Midas, don't charge a lot to install a cat-back and don't take too long. Just make sure that they're qualified and know what they hell they're doing so your new exhaust system doesn't fall off on the ground as soon as you drive off. If there are specialty automotive shops in your area, they can usually install it for you too, but will probably charge more.
Read more about Exhaust Systems on AutoAnything.
Low Temperature Thermostat + Redline Water Wetter
Installing a lower temperature thermostat triggers your radiator to cool off the engine when it reaches a certain temperature. Most cars with a standard thermostat have it set by default for around 200 degrees. However, you can buy a lower temperature one for 160, so it will start cooling the engine when it reaches 160 degrees instead of 200. This will let your engine run cooler and give you some extra HP. The next thing you can add is Water Wetter by Redline Oils. Water Wetter is a pour in product that you add to your radiator fluid. Adding one bottle will reduce engine temperatures by about 7 degrees or so. If you were to use a half and half mixture of just Water Wetter and water, it would cool it even more. But, it doesn't have freeze protection like anti-freeze, so it's not a very viable option for every day drivers. However, one bottle is about $7 and helps cool off your engine somewhat, so it's worth the investment. It also lubricates the water pump and helps keeps your radiator free of rust and corrosion. You can read their full technical writeup about it. (PDF). You can normally pick up a thermostat and Water Wetter at a local auto supply store for less than $20.
A very cheap modification you can do to any car is to change out all the fluids from the standard dinosaur oils to more efficient synthetic types. For just about any type of fluid that goes into your car (with the exception of gasoline) there is a synthetic fluid or oil that you can use to help improve performance. I always use Royal Purple motor oil in my car. It is the best oil in the world and can actually help increase your cars horsepower, as well as a multitude of other things, including helping to reduce engine wear and improved gas mileage. You can change out pretty much any type of fluid in your car with either products from Royal Purple or Red Line, and now many other manufacturers, such the popular Mobile One are entering the market with transmission fluids, brake fluids, gear oil, and even grease. A good fuel system treatment, like Red Line's Complete Fuel System Cleaner can help keep fuel injectors spraying at their fullest and keep the entire fuel system free of corrosion and improve gas mileage as well. Although these may cost a little more, they are one of the easiest changes you can make and can help significantly. Remember, don't use a higher octane gas than your car's manual recommends unless you've made a specific modification (such as a computer chip modification) that requires it. Using a higher octane fuel, even on occasion, is not necessary as it does not provide more power to your car or any more cleaners than is in regular fuel. Also, don't waste your money on "oil additives" like Slick 50 or other gimmicks. These have been proven time and time again to be primarily bunk and don't help your cars performance or gas mileage. Adding to your car can sometimes even void the warranty.
Read more on How to Save on Gas at AutoAnything.
High Performance Spark Plugs and Wires
There are many brands of spark plugs and spark plug wires than can improve performance by creating a faster spark, along with lower heat resistance and a longer life span than standard plugs and wires. I use Bosch Platinum +4 plugs. There are many different brands of wires to choose from based on your model car that can help improve performance too. It's also a good idea to place some heat shielding around them, depending on where they are positioned in the engine. I've had several spark plug wires melt because of how close they are to the exhaust headers.
Computer Chips and Programmers
On most new cars since the mid 90s have had computers and computer chips in them to regulate the functions of the car, such as the timing, the gear ratios, the amount of fuel that goes into the engine, the speed of the transmission shifting, and so forth. There are many aftermarket computer chips and "power programmers" that you can purchase to reprogram or reset your cars computer chip to increase performance by modifying these variables. Often times these are in the high price range (usually around $400) but can make a significant difference to your cars horsepower and torque, especially when combined with many of the modifications mentioned above. These are usually one of the easiest modifications to apply, because all you have to do is either plug them into your cars computer socket or crimp it into some wiring. Most of them offer options to switch them on and off so if you have to take it in to get it inspected or take it to the dealership, you can turn them off and make sure your car is in default settings.
Read more about Performance Chips on AutoAnything.
If you do all these modifications you can probably expect to add about a good 20 rear wheel hp (meaning true & solid horsepower). Once you've added all these performance enhancements you'll probably want to pick up a radar detector, lest you end up paying even more to the police department.
In my next article I'll talk about some simple modifications to improve your car's suspension and handling.