Mitsubishi EVO 4G63
Adjustable Oil Pressure Regulator
Oil Pressure Pump Inlet
4 - Stage System
Oil Pressure Pump Outlet
Optional Extra Scavenge Inlet
Low Profile Billet Oil Pan
Engine Oil Feed
Mitsubishi 4G63 Dry Sump System
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.
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.
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.
Selecting the proper system for your application
The baseline pump for the 4G63 engine is a 3-stage (one pressure and two scavenge), with the two 1.700" scavenge sections mounting directly to the dry sump oil pan. An additional scavenge section can be added to make the pump a 4-stage. This added section can be used to scavenge a low mounted turbo (where a gravity drain will not be adequate), scavenge oil from the head, or scavenge the valve cover for added vacuum.
If more scavenge sections are needed please contact us so we can configure a pump to meet your needs.
For high powered road racing applications where oil quality degrades over time due to aeration, an air/oil separator pump option is available to defoam the oil before returning to the oil tank. Keeping pure oil in the oil tank is critical for preventing oil pump cavitation and crank bearing issues. Exhaust modifications and slight clearancing on the OEM engine block may be needed depending on the pump configuration.
Pressure Gear Size
There are two different pressure gear size options available for the 4G systems: 1.250" and 1.450". All systems come standard with the 1.250" gear to match the OEM oil flow rate. An upgraded 1.450" pressure gear with a 20% increased flow rate is available for engines that have added valve train oilers, higher flowing turbo, or use a billet aluminum block.
All pumps come with a Standard spring in the oil pressure regulator with a High and Low spring sent with the kit.
Please see our Technical page for more info on oil pressure.