Increased engine performance often means increased engine speed and load. Original factory crankshafts may not withstand the added stress resulting in catastrophic engine failure. Additionally, factory Subaru crankshaft rod journals are lubricated from only one main oil feed. Cosworth billet crankshafts feature full-flow oiling whereby each rod journal is lubricated from two main sources. This provides superior lubrication during sustained high rpm use preventing rod bearing failure. Cosworth Subaru crankshafts are manufactured entirely in house from EN40B steel in a light weight-high strength design with a unique Isotropic Superfinish.