Garrett® G Series Turbochargers

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. G25-550G” 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)

G-Series Billet Compressor Wheel
Wide compressor maps indicate a larger operating range to support a variety of vehicle setups. Available in standard rotation and reverse rotation options for enthusiasts that want the perfect twin turbo installation or a single reverse rotation turbo for applications with installation restrictions. The compressor housing features a fully machined ported shroud to help reduce compressor surge. A fully machined speed sensor port provides enthusiasts the option to add the new G Series speed sensor to measure turbocharger shaft speed, a key factor in determining ideal operating conditions.
Garrett G series
Garrett G-Series Turbochargers
The new speed sensor is easy to install and does not need to be adjusted for length like previous sensors. Simply remove and plug, then insert the speed sensor and tighten the bolt. The new speed sensor is sold separately and is not compatible with GT and GTX sensors due to the new design and sizing. The addition of an o-ring between the compressor housing and backplate reduces the possibility of boost pressure leakage.
G-Series Turbo Speed Sensor

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.
G-Series Dual Ball Bearing CHRA

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.*
G-Series Water Jackets

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.
G-Series Oil Passage

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.
G-Series Rotating Assembly Exploded View

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.
G-Series Turbine Wheel

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 Turbine Housing

G-Series Reference Data

G-Series G25-550 Reference Data
G-Series G25-660 Reference Data

G-Series Dimensional Drawings

G-Series G25-550 | G25-660 Dimensional Drawing
G-Series G25-550 | G25-660 Exterior Dimensions

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