Borg Warner EFR 6258 Alu Supercore Borg Warner EFR is a compact series of turbochargers for motorsport and tuned engines where both wastegate, relief valve and boost valve are integrated. The EFR series is the choice if you want the best turbochargers. Frame size: B1 CHRA: Alu Compressor side Compressor housing inlet: 2,5" (63,5mm) Compressor housing outlet: 2" (50,8mm) Compressor wheel inducer: 49mm Compressor wheel exducer: 62mm Speed sensor port Turbine side Turbine wheel inducer: 58mm Turbine wheel exducer: 51mm This is a Supercore (Compressor housing and center part) Turbine housing and wastegate are purchased separately.