Porsche Hastech Engineering Porsche 911 Crankcase Ventilation Oil Blow by Separator H911 106 KIT 928 341 028 37R C4 (1999 2005) and 911 Turbo 993 631 901 00 C4 (1999 2005) and 911 Turbo (2001 2005) models Porsche Vent hose for 911 (1970 1973) models Features and Benefits:Reduces the oil blow by from the crank ventilationKeeps the oil in the engine while still allowing good crank ventilationVery simple mounting sandwiches between the crankcase and ventilation the lid breather coverUsed on all Hastech race & street enginesRecommended for all aircooled Porsche 911 engines to help reduce oil consumption caused by ingestion of oil laden air into the intake caused by excess crankcase windage and blow by Fits all aircooled Porsche 911 models from 1965 through 1998