GrimmSpeed BB550+ Turbocharger Subaru WRX (GD) / WRX STI (GD / GR / GV / VA)

GrimmSpeed BB550+ Turbocharger - Subaru WRX (GD) / WRX STI (GD / GR / GV / VA)

The GrimmSpeed BB550+ is the bigger of GrimmSpeed's two bolt-on, factory-location ball bearing turbos for the EJ257 WRX STI and the GD WRX, built on what GrimmSpeed learned from its BB500. A larger billet 2618 aluminium compressor wheel in a 0.77 A/R housing and an Inconel 713C turbine wheel in a 10cm HiSiMo housing let it keep making power high in the rev range, while a torque bump around 4,500 rpm keeps it lively in the mid-range for a stock-location turbo.

It bolts into the factory turbo location with stock-style connections, so there is no cutting or custom fabrication. A new billet aluminium, dual-port wastegate actuator on a straight 6-gauge steel bracket holds boost steadier than a bent bracket that can flex, works with 3-port or 4-port boost control, and ships with a 15 psi base spring plus a spring pack to set base boost anywhere from 3 to 26 psi.

Note: Suits the 2.5-litre EJ257 WRX STI (GD 2.5 from 2005, GR, GV and VA) and the 2001-2007 GD WRX (EJ205 and EJ255). Not for the 2.0-litre EJ207 WRX STI (GD to 2005, and Japanese-import STIs), which use a twin-scroll turbo. A custom ECU tune is required, and supporting fuel and exhaust upgrades may be needed for your power goal. Installation by a professional is recommended.

Features

• Ceramic ball bearing centre section for quicker spool than a journal-bearing turbo
• Billet 2618 aluminium compressor wheel, 0.77 A/R A356 aluminium compressor housing
• Inconel 713C turbine wheel in a 10cm HiSiMo turbine housing
• Compressor flow of 73 lb/min (about 33.1 kg/min)
• Billet 6061 aluminium dual-port wastegate actuator, 3-port and 4-port boost control
• Adjustable base pressure from 3 to 26 psi with the included springs
• Factory-location bolt-on with no cutting or fabrication

GrimmSpeed test results

• Built-engine STI on E85 (GrimmSpeed dyno): about 530 whp and 465 lb-ft at the wheels, roughly 70 whp more than the BB500
• That run was capped at 27 psi by the 1300cc injectors; GrimmSpeed says there is another 5-6 psi left in the turbo's efficiency range

Results depend on the car, fuel, supporting parts and tune.

Pick the BB550+ for maximum top-end power on a well-supported build. For quicker response, see the GrimmSpeed BB450+ Turbocharger - Subaru WRX (GD) / WRX STI (GD / GR / GV / VA).

Pairs Well With

• GrimmSpeed 2-Bolt Up-Pipe - Subaru STI (GDB/GRF/GVF/VAB) / WRX (GDA/GGA/GE8/GH8)
• GrimmSpeed Up Pipe to Turbo Gasket - Subaru WRX/STI (GDA/GGA/GDB/GRF/GVF/VAB)
• GrimmSpeed Turbo to Downpipe Gasket - WRX (GDA/GGA/GE8/GH8) / STI (GDB/GRF/VAB)
• GrimmSpeed Turbo Heat Shield - Subaru EJ20/EJ25
• Injector Dynamics XDS Fuel Injectors - Subaru WRX / STI - 48mm Set of 4

Shop more: GrimmSpeed | Turbochargers

Need help confirming fitment? Contact our team at sales@chicaneaustralia.com.au.