Mitsubishi 4G15 engine is very popular in Malaysia due to the Proton Saga megavalve and Proton Wira 1.3 and 1.5, the original material for this type of cylinder head gasket is normally Asbestos type and after that is Graphite after the asbestos material is ban.
Due to there are a lot of people modified the engine with Turbo spec install into it, the normal material of cylinder head gasket can not stand for this kind of high temperature and pressure.
After that, there are people trying to use metal type of gasket which they try copper and aluminium as well, but this 2 type of metal can't meet the requirement.
Finally they need to use the material which the metal type is use for the 4G6series and 4G9series of engine.