GrimmSpeed BB450+ Turbocharger - Subaru STI (2004-2021) / WRX (2002-2007)

GRM.1204.1.0 - GrimmSpeed BB450+ Turbocharger - Subaru STI (2004-2021) / Subaru WRX (2002-2007)

The GrimmSpeed BB450+ is a factory-location, bolt-on turbocharger with ceramic ball bearings, a billet 2618 aluminum compressor wheel, and an Inconel 713C turbine wheel. Its 8cm turbine housing balances responsive midrange torque with sustained top-end performance. It retains stock-style connections without cutting or custom fabrication.

Specifications

• Ceramic ball bearing system
• Compressor wheel inducer/exducer: 53.4mm / 67.4mm
• Turbine wheel inducer/exducer: 49.1mm / 56mm
• Compressor flow: 61 lbs/min
• A356 aluminum compressor housing; 0.77 A/R
• HiSiMo turbine housing: 8cm
• 6061 billet aluminum dual-port wastegate actuator
• Straight, 6-gauge zinc-plated steel wastegate bracket
• 15 PSI default base pressure; 3–26 PSI adjustment with included spring combinations
• Supports compatible 3-port and 4-port boost control configurations

Vehicle Fitment

• Subaru STI (2004-2021)
• Subaru WRX (2002-2007)

Installation: Proper ECU tuning is required. Additional supporting modifications may be necessary for your setup and performance goals.

Manufacturer wastegate spring chart

Circuit Spec R is an authorized GrimmSpeed dealer. Free shipping within the contiguous US.