FP no longer recommend using oil supply from the cylinder head for the FP GREEN&trade for the Mitsubishi Evolution 9 or FP RED&trade for the Mitsubishi
Evolution 9 in applications that run elevated boost pressures.
Oil pressure measurements made on various engines indicate that in some cases the amount of available oil pressure at the cylinder head feed location is
less than desirable. This head feed location prioritizes the turbo oil supply after all other oil supply duties within the engine. We want the turbocharger
to be supplied with a minimum of 45psi of oil pressure under full engine load,
and sourcing oil supply from the cylinder head simply does not ensure this under all circumstances or possible combinations of engine configuration, oil
viscosity, temperatures, balance shafts, main and rod bearing clearances etc.
Relocating the oil supply to the oil filter housing allows the turbocharger to be fed by a more stable and consistent source. This source is much higher
pressure than required by the turbocharger (can be over 150psi), so our line kit includes a inline filter that also features the appropriate size restrictor
to limit the pressure at the turbo to a maximum of 70psi hot oil pressure.
While many may insist that 20 or 30psi of oil pressure is sufficient to supply a typical floating journal bearing turbo, it is our specific experience that
this is not always true in the case of an automotive racing turbocharger used in a performance application where excessive EGT, high shaft speed and
maximum thrust load are the norm, not the exception.
Currently, damage resulting from insufficient oil pressure can still be repaired under the standard product warranty in cases where the turbocharger was
purchased and installed prior to the introduction of this new solution to oil starvation. Of course it would be preferable to update the oil feed to the
turbo prior to having a problem, and existing customers will be helped in every way possible in their efforts to update their oil feed lines in existing