The Mitsubishi 4G63 engine has been around for almost 40 years and is a very popular platform for auto racing due to its simple, robust design and ability for high power output. This engine does have limitations though. As g-load, boost pressures, and RPM increase, two critical problems start to emerge: oil pump cavitation and excessive blow by pressure in the crankcase.

Oil pump cavitation: This engine uses a spur gear style oil pump that is incorporated in the front engine cover and driven by the timing belt. This design works for OEM applications operating within its designed parameters, but this internal pump starts to cavitate due to pump inlet restrictions once RPM and oil flow demands increase. Another cause of cavitation with the 4G63 is oil pump starvation. The high g-loads generated during racing from acceleration, cornering, and deceleration force the oil to move away from the oil pump pickup in the oil pan, exposing the pickup to air and limiting its ability to maintain oil pressure. 

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Excessive blowby: There are two factors that drastically increase the power output for the 4G63 - increased boost and increasing the alcohol in the fuel. Both of these also drastically increase the blow by entering the crankcase generating unwanted positive pressure. This pressure will keep oil trapped in the head, resist piston movement, and even blow out oil seals, so large vents are added in most wet sump applications to allow the gasses to escape and reduce pressure. The problem is that this also allows large amounts of oil to be carried out of the vents by the blow by gasses and fill the catch can or make a mess in the engine bay.

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 The solution to these problems is to eliminate the internal oil pump completely and replace it with a true dry sump oiling system that uses a spur gear style oil pressure pump and roots style scavenge pumps. The pressure section of all Dailey Engineering oil pumps is made of a 9 tooth spur gear with specially designed pump housings that allow the "SP Series" pumps to run over 10000 RPM pump speed without cavitation. The roots style scavenge sections will effectively evacuate the crankcase of all the oil and blow by gasses that cause resistance to the pistons and rotating assembly. The vacuum generated by removing the blowby gasses will increase engine performance. All of the blowby gasses and oil will be pumped to an external oil tank where the gasses can be vented properly. 

Switching over to a dry sump oiling system on your 4G engine has many other advantages as well. Please see our Technical page to explore the advantages of a dry sump system.