How to Make More Horsepower - Part V

Over the last few months we have talked about many bolt-on items to make more horsepower. The last item in the series will be on the internals of the engine. There are several items you can do inside the engine to make more horsepower. These items range from easy and fairly inexpensive to difficult and expensive. We will look at a few of these this month.

The easiest way to get the most horsepower from an engine is to replace it with a bigger engine. More cubic inches are always better. Of course you can make a better built smaller engine run better than a poorly designed big block.

The valve train of an engine can be improved by replacing components with better components. Replacing the stock rocker arms with roller-tip rocker arms will create less friction which will provide more power. Installing a more aggressive cam will open and close the valves better. You can even replace the cam with a roller cam. This will also produce less friction and provide more power. When considering replacing the valve train, work with a cam manufacturer to make sure you have all the right components. You may need to valve springs. Also, remember bigger is not always better when choosing a cam. Going too big can give you a rough idle and low vacuum.

The engine heads can be improved too. A fairly cheap item is to have the stock heads ported and polished. This will make them flow better by cleaning up the runners. Replacing the stock heads with a set of performance aftermarket heads will make a big difference but can be costly. You can also have bigger valves installed in the head to increase intake and exhaust flow. Many aftermarket performance heads will already have bigger valves.

Those first two items can be done without a complete engine rebuild. But if you plan on rebuilding your engine, here is another item to consider, piston size. This includes both the diameter and top. To fit a bigger diameter piston in, you will need to have the cylinders bored. A bigger bore will allow the engine to fill up with more air and fuel. Increasing the height of the piston will increase the compression ratio. A higher compression ratio will give you more power, but be careful not to go to high. The higher you go the higher octane gas you will need to burn. Also, you will want a lower compression ratio if you plan to run a supercharger, turbocharger, or nitrous.

These past articles should help you get some ideas of how to make more horsepower. There is no substitute for planning. Sit down and determine what you want to do with your vehicle and the horsepower level you want. If you just want more power for your daily driver, consider some of the previous options (exhaust, intake, etc.) These will help with gas mileage too. If you want an all out race vehicle, you will need to determine what type of racing you want. There are a lot of choices to make. Check with some of the aftermarket performance manufacturers, some offer complete performance packages. Don’t forget to check with people at shows, on message boards, and friends as there advise can be invaluable.

CYA next month!
Vincent Wright
sales@kmwperformance.com
http://www.kmwperformance.com