A turbo flange is a piece of metal that has been machined to connect a turbocharger to an intake or exhaust system. Commonly made of mild steel or stainless steel, a turbo flange can also be manufactured from aluminum. Depending on the particular application, there are several different types and styles of turbo flange designs that work on a vast array of turbocharger sizes and ports. Most flanges are produced on a computer numerical controlled (CNC) machine or on a flame cutter, while some high-performance, specialty pieces are created from a solid chunk of billet material on a milling machine.
Unlike a camshaft or a cylinder head, a turbocharger is not connected directly to an engine. A turbo charger is fitted into an exhaust and intake system via the aid of a turbo flange. The flange connects to the turbocharger in one of several ways, as well as to the exhaust and intake pipes through the use of flanges. Each flange, regardless of its function or application, also commonly uses a flange gasket. The gasket is sandwiched between the flange and the turbocharger housing.
The mounting surface of a turbo flange must be extremely flat and finished to a proper tooth so that it might bite into the gasket material properly. This is critical due to the tremendous amounts of boost pressure that can be generated by the spinning turbocharger. The smallest imperfection in the flange or its adjoining, mating surface could result in a loss of pressure. This will be felt in the engine as a loss of power and could possibly destroy other critical engine components, such as pistons, cylinder walls and valves. Other types of damage that could potentially result from a damaged or blown turbo flange are oil leaks, lack of oil pressure to the turbocharger bearings and heat damage to the turbo from misdirected exhaust gasses.
Typical attachment methods for the turbo flange to the turbocharger are through the use of bolts or through being welded onto the turbocharger. Due to the unavoidable tendency for variation in the casting and machining of the turbocharger bodies, welding typically provides the best method of placing the flange properly onto the housing opening. Through slight manipulation and adjustment, the welder is able to properly line the edges of the flange opening with the edges of the housing opening. This creates a smooth flow and transition of the gases as they flow from the turbocharger into the engine's intake system, resulting in better power and performance.