STI/WRX RHF55 Dual Ball Bearing Turbochargers

STI/WRX RHF55 Dual Ball Bearing Turbochargers
For the past two years Six Star Speed has been working diligently on a ball bearing conversion for the current line of RHF55 turbos available on the STI and WRX cars.  We had several goals for the project namely very high performance, high quality, much better durability relative to OEM ball bearing turbos, and a price point that would make it competitive with the high end turbochargers currently in the market.  Finally we have achieved it and are able to offer the product to the Subaru community.

Our Patent Pending ball bearing turbochargers is a retrofit to any OEM IHI RHF55 turbo on the Subaru platform. We designed it such that it is essentially a direct replacement of the journal bearing cartridge with our ultra high performance ball bearing cartridge. 

On the inside however sits our uniquely engineered high strength, high speed ball bearing cartridge.  It features dual full ceramic hybrid angular contact ball bearings in a super rigid configuration able to handle anything from stop go traffic to world class rally.  The cartridge itself is produced from very high spec materials such as hardened aircraft stainless steel and titanium alloys for low rotating weight and heat resistance.   Our RHF55 turbochargers feature Titanium Aluminide turbine wheels which are 60% lighter than the OEM inconel turbine head for reduced inertia and maximum response.  We have changed the turbine housings material from nodular iron to CFC8 Plus Stainless Steel for weight reduction, heat resistance and also putting an end to the dreaded wastegate crack.  The wastegate port has also been enlarged by nearly 50% area wise to eliminate boost creep and provide optimal wastegate capacity throughout the rev range.

The turbos are direct replacements for the OEM IHI RH55 journal bearing turbos including VF30, VF37, VF39, VF43, VF48, VF49, and VF52.  They have the basic outward appearance of an OEM turbo with some minor differences determined by the change in materials and wastegate options.

The range of turbos features five different compressor wheel sizes and three different turbine wheels.  All turbos retain OEM fitment and do not need modifications to install.  

For the racing applications this is definitely a "stealth" type upgrade as the external form factor remains stock.  The only obvious difference is the billet compressor wheel when used with a stock form housing.  The Stage 0 turbo has an OEM cast compressor wheel.

The chart below outlines the current features and options available in the series


COMPONENT FEATURE STAGE 0 STAGE 1 STAGE I.5 STAGE 2 STAGE 3 STAGE 4
60 mm OEM cast compressor wheel Standard - - - - -
60 mm 60 trim billet compressor wheel w/ETT - Standard - - - -
60 mm 64 trim billet compressor wheel w/ETT - - Standard - - -
62 mm 64 trim billet compressor wheel w/ETT - - - Standard - -
65 mm 65 trim billet compressor wheel w/ETT - - - - Standard -
68 mm 64 trim billet compressor wheel w/ETT - - - - - Standard
53 mm 81 trim TiAL turbine Standard Standard Standard Standard - -
56 mm 83 trim TiAL turbine Optional Optional Optional Optional Standard -
60 mm 84 trim TiAL turbine - - - - - Standard
OEM compressor housing 58 mm inlet Standard Standard Standard Standard Standard Standard
Turbine housing port and polish Optional Optional Optional Optional Optional Optional
TurboSmart wastegate actuator upgrade Optional Optional Optional Optional Optional Optional
AVO wastegate actuator upgrade (Twin Scroll) Optional Optional Optional Optional - -




RHF55 Dual Ball Bearing STI/WRX/LGT/FXT Turbocharger - Stage 0
Regular price: $1,999.99
Sale price: $1,799.99
RHF55 Dual Ball Bearing STI/WRX/LGT/FXT Turbocharger - Stage 1
Regular price: $2,099.99
Sale price: $1,849.99
RHF55 Dual Ball Bearing STI/WRX/LGT/FXT Turbocharger - Stage 1.5
Regular price: $2,149.99
Sale price: $1,899.99
RHF55 Dual Ball Bearing STI/WRX/LGT/FXT Turbocharger - Stage 2
Regular price: $2,299.99
Sale price: $1,949.99
RHF55 Dual Ball Bearing STI/WRX/LGT/FXT Turbocharger - Stage 3
Regular price: $2,499.99
Sale price: $2,099.99