The filter housing source is much higher pressure than what is available at the cylinder head. Relocating the oil supply to the oil filter housing allows the turbocharger to be fed a sufficient supply of oil pressure and volume.
Some people 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 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 could still be repaired under our Complimentary Repair Policy at our discretion.
The graph attached shows how oil pressure varies at different locations within the EVO 4G63 engine. You can see how much lower the pressure at the cylinder head is than the oil pump very clearly in this graph.
Our new oil line, pictured above, will supply you with a block off bolt for the stock head feed location and all the supplies needed to feed your larger journal bearing turbo directly from the Evo's oil filter housing. Included in the kit are the following pieces:
You can find detailed installation instructions at the following link:http://www.forcedperformance.net/merchant2/merchant.mvc?Screen=Evo_Oil_Install
Turbo oiling specifications from Mitsubishi can be found here:http://store.forcedperformance.net/merchant2/graphics/subaru_oil/MHI_Oil_Specs.pdf