1. Engine supercharger oil feed / return pipe: Feed / Return oil lubrication for turbocharger. It requires to withstand higher operating temperature and maintain higher cleanness level.2. Engine supercharger coolant feed / return pipe: Feed / Return coolant circulation for turbocharger. It requires to run at a higher working temperature.3. Engine EGR pipe: Exhaust-gas recirculation pipe which leads the engine exhaust gas from exhaust manifold into the inlet manifold through EGR valve and re-combustion. It is used to reduce the NOx of the exhaust gas. In general speaking. EGR pipe is made from stainless steel, requires precise dimensions and operating at high temperature.4. Engine AKF pipe: Fuel vapour pipe. Fule vapour is recycled to the inlet manifold to avoid it directly into the air. This pipe is normally made from stainless steel and requires high cleanness level.