Borg Warner 6258 EFR Turbo, 225-400 HP. Borg Warner 6258 EFR Turbo is the smallest turbocharger in the ultra-efficient EFR lineup. The 62mm OD compressor has a 49.6mm inducer at 44lb/min max flow - supporting up to 440hp with very large map width for outstanding power potential even at high boost. The Borg Warner 6258 EFR Turbo is the fastest spooling EFR turbo - and fits in a small package. Ideal for small engines in single turbo configuration and stock internal or modified engines. This is an excellent turbocharger for autocross, rally, drift, road racing and street driven applications. The low inertia 58mm Gamma-Ti turbine wheel is optimally matched for maximum response and fastest spool with the FMW compressor wheel. EFR 6258 uses the smallest-sized EFR compressor housing, fitting in the tightest engine bays particularly twin turbo V6 applications. Ideal for use in single turbo applications for the 260-440hp range, or as twin turbo applications 400-700+hp. Ceramic Ball Bearing only, watercooling recommended (not mandatory).
Borg Warner's latest release, the EFR (Engineered for Racing) Series turbochargers. EFR is currently the most advanced turbo of its type engineered for the performance aftermarket. Crammed full of attributes that appeal to the performance car enthusiast, EFR is at the pinnacle of what can be done with the current state of the art.
The EFR line of turbos was born out of an internal BorgWarner Turbo Systems program labeled Advanced Aftermarket Products or AAP.
The program was engineered by a cross-functional team that began with the proverbial clean-sheet of paper. No legacy products, no preconceived notions of what a turbo could or could not have; no restrictions. The aerodynamics for the product line were selected using a range of optimized combinations that would give users turbo solutions anywhere between 250 and 1000 horsepower capability per turbo. Next, a list of every notable design characteristic for an engine boosting device was tabled. Specific interest was given to new ideas that had never been formed in metal or had never been combined into an aftermarket turbo.
The result is the new EFR (Engineered for Racing) line of turbos from BorgWarner. These turbos contain a bevy of key attributes such as Gamma Ti turbine wheels, dual ceramic ball bearing cartridges and investment cast stainless steel turbine housings. Collectively, those features help give the EFR line its innovative appeal and will provide a breakthrough experience in durability, device responsiveness and installer/user satisfaction.