The Most Powerful Small Frame Turbocharger On The Market
All-New compressor and turbine aero combined with high temperature resistant materials allowed engineers to push the limits of performance.The G-Series G25-550 and the G25-660 turbochargers are compatible with 1.4L – 3.0L engine displacements and capable of producing up to 550 and 660 flywheel horsepower. Ideal for single and twin turbo installations – G Series 25 turbochargers are smaller and outflow all comparable products on the market.Understanding the Name: A new name designates a new generation of industry leading technology and innovation. G25-550 “G” designates 81 years of Garrett® heritage. “25″ classifies the size of the frame. The remaining 3 digits identify the “max horsepower” rating of the turbocharger. (ie 550)
Compressor Aero
Forged fully-machined compressor wheel and new aerodynamics increase maximum horsepower output and boost response. The CFD (computational fluid dynamics) engineered compressor wheel increases air flow up to 15% for 60mm and 30% for 67mm with 79-80% efficiency. (Compared to GTX GenII)



Center Housing
A new one-piece center housing and backplate increase durability and product safety by reducing the number of failure points associated with the turbocharger. The center housing to turbine housing v-band connection allows for 360 degree orientation when installing with Garrett® non-wastegated turbine housings.
Water Jackets
Four large water jacket ports increase cooling capacity and allow enthusiasts to customize water line routing to help improve the installation process. The turbocharger comes with two -6AN water fittings and two plugs. *Recommended to install waterlines on opposite sides of the housing.*
Oil Passage
A single stage oil passage directs pressurized oil to the new oil cavity ensuring proper bearing lubrication at both sides of the cartridge. Each turbocharger includes (1) -4AN Oil Restrictor Fitting with a 1mm Orifice to provide the turbo with the recommended 40psi of oil pressure.
Rotating Assembly – Twin Piston Rings
A shorter bearing cartridge allows us to incorporate twin piston rings on both sides of the shaft wheel assembly. This will reduce the likeliness of oil leakage at the seals from the center housing to the compressor and or turbine stage.
Turbine Wheel Aero
The all new G-series turbine wheel flows 15-20% more than GTX and has peak efficiency of 74%.The turbine wheel features all new aerodynamics to improve flow and boost response. The new turbine wheel is made of Mar-M super alloy and is capable of handling exhaust gas temperatures up to 1050 degrees C / 1922F.
Turbine Housings
All G Series Turbine housings are made from Investment Cast stainless steel to provide ultimate durability and temperature resistance up 1050 degrees C / 1922F. Internally wastegated housings are compact, efficient, and designed with maximum bypass port size to reduce boost creep and provide better boost control. Turbine housings are available in a variety of wastegated and non-wastegated, open volute, T25 and Vband configurations and reverse or standard rotation – so be sure to order the correct part for your application.
G-Series Reference Data


G-Series Dimensional Drawings


