Piecing together a homemade turbo setup can save you substantial amounts of money compared with buying a complete aftermarket turbo kit. Full aftermarket turbo kits come pre-tuned to efficiently maximize the engine's horsepower, while simplifying the installation procedure. However, if you're willing to research the parts needed for your own particular engine and horsepower goals, you can set up a homemade turbo kit that works equally as well as the more expensive kits. Building your own turbo kit also gives you the option of purchasing used turbo components, which can save you even more.
Find a turbocharger to use with your homemade setup. This is the most important part of the turbo system, as the size of the turbocharger you choose is what decides the ultimate horsepower potential of your setup. Also, different turbochargers may require different supporting modifications. For example, some turbos are oil-cooled, which requires tapping of the stock oil pressurization system. This is generally more complicated than setting up an air-cooled or water-cooled turbo. Choose a turbocharger that will meet your horsepower goals, while allowing for the easiest setup procedure.
Find a turbo exhaust manifold that fits your engine and turbocharger. These can either be purchased aftermarket, or custom made by a fabrication shop. Since the turbocharger mounts to a flange on the exhaust manifold, choose a manifold that will fit your turbo if you purchase aftermarket. Find an aftermarket down pipe, or have your fabrication shop make a custom down pipe for your setup. This is the exhaust portion that connects the exhaust manifold to the rest of the exhaust system.
Piece together an intercooler kit. This is the radiator and piping system that cools the turbocharged air before it enters the engine. Numerous manufacturers make custom intercooler kits for virtually every make and model. Alternatively, universal intercooler units can be purchased and mounted to any vehicle. This will require custom fabricated intercooler piping, but is still often cheaper than purchasing a complete aftermarket kit.
Gather the rest of the supporting turbo parts. You need various rubber and/or steel braided lines for the turbocharger lubrication system. These can be custom built from universal automotive lines, available from most auto parts retailers. A cone-shaped air filter is needed for mounting to the turbocharger inlet to filter the intake air. A blowoff valve is also needed. These are spring-actuated valves that less excess pressurized air out of the intercooler system. Most blowoff valves are universal and will mount directly to a flange included on your intercooler piping.
Have an engine management system professionally installed and tuned. These either modify or replace the stock engine control unit (ECU), allowing for custom tuning of the engine parameters. Since turbo systems substantially increase the airflow into your engine, extensive modification of the stock fuel curves is needed to make horsepower from your turbo setup while keeping the engine reliable. A professional dyno tuner can custom tune your engine so that it runs smoothly and makes maximum power out of your homemade turbo kit.
