A diesel engine combusts fuel in a much different way than an internal combustion engine. Whereas an internal combustion engine uses a spark to ignite the fuel, a diesel compresses air to create heat and then uses the heat to ignite the fuel. A factory diesel may not fully combust the fuel in the engine, but with the right performance parts, you can increase not only your fuel economy, but also your power.
The molecules in hot air are further apart than the molecules in cold air. This means that when you try to compress hot air, it will not compress as much as cold air. Because compressing air creates heat, the more you are able to compress air, the hotter it gets and the better able it will be ignite the fuel in your combustion chamber. Put simply, cold air compresses better than hot air. To make sure that your engine is getting an ample supply of the coldest air available, you need to install a cold-air intake.
Heat is only one of the elements required to combust a fuel; you also need air. The standard diesel draws air into the combustion chamber with the suction created when the piston withdraws. This means that you may not get enough air to fully combust the fuel in the chamber. A turbocharger pumps more air into the combustion chamber so that you can burn more of the fuel your engine pumps into the chamber, which means you get more power and fuel economy.
When you increase the amount of air that goes into your combustion chamber, you also increase the amount of exhaust gases that need to escape the chamber. If your stock exhaust is not large enough to handle the higher volume of gases, then you can have a bottleneck, which will leave exhaust gases in the chamber, limiting the amount of fuel and air that can flow into the chamber. In order to improve the flow of exhaust out of the chamber, you may need to install a performance exhaust.
One of the best ways to increase the performance of an older diesel engine is to increase the flow of air into the engine and exhaust gases out of the engine. If you are having a hard time deciding which parts would work best for your engine, you should talk to a diesel supply store or visit websites like http://unitedoil.net.