Garrett G-Series II G25-700 54mm Turbocharger

Garrett G-Series II G25-700 54mm Turbocharger — Select Turbine Housing

Part Number: 934075-5002S

The Garrett G-Series II G25-700 is a compact, standard-rotation, dual-ceramic-ball-bearing turbocharger designed for high-output street, competition, and specialty-performance applications where packaging, response, and substantial airflow must be combined in a small frame. Garrett rates the G25-700 for 350–700 horsepower and references engine displacements from 1.4 to 3.0 liters. Garrett horsepower ratings represent potential flywheel horsepower based on compressor-map choke flow and are not a guaranteed wheel-horsepower figure.

The G25-700 uses a 54mm inducer and 67mm exducer compressor wheel with a 65-trim profile and 0.70 compressor-housing A/R. The turbine stage uses a 54mm inducer and 49mm exducer Mar-M alloy wheel with an 84-trim profile. Garrett identifies a maximum allowable turbocharger speed of 160,000 rpm.

As part of Garrett’s G-Series II range, the G25-700 incorporates revised compressor aerodynamics that provide up to 10 percent greater compressor flow than the corresponding first-generation G-Series unit at peak pressure ratio and peak turbocharger speed. Garrett also identifies increased efficiency at high flow rates. The G-Series II supercore retains compatibility with Garrett’s first-generation G25 compressor and turbine housings, allowing an existing standard-rotation G25 installation to be upgraded without redesigning the complete turbo system when the existing housing part numbers are confirmed compatible.

This listing is structured as a selectable-housing product. The Garrett 934075-5002S supercore may be combined with either of two externally wastegated V-band turbine housings, or ordered as one of three Garrett factory-assembled and calibrated internally wastegated turbochargers. A supercore-only option is also available. All five verified standard-rotation turbine configurations use an open, non-divided volute and a V-band turbine outlet.

RAD recommends the Garrett 934076-5005S complete turbocharger with the 0.72 A/R V-band inlet, V-band outlet, and internal wastegate as the general catalog default. It combines Garrett factory assembly and actuator calibration with a balanced turbine A/R that is appropriate for a broad range of responsive 1.8–3.0-liter street and track applications. Applications operating near the upper end of the G25-700 airflow range, or installations requiring greater wastegate authority, may be better served by the 0.92 A/R housing or one of the external-wastegate configurations.

Key Features

• Garrett G-Series II G25-700 standard-rotation turbocharger platform
• Garrett horsepower reference range: 350–700 hp
• Garrett displacement reference range: 1.4–3.0 liters
• 54mm compressor inducer and 67mm compressor exducer
• 54mm turbine inducer and 49mm turbine exducer
• Dual ceramic ball-bearing cartridge with steel bearing cages
• G-Series II compressor aerodynamics with up to 10 percent more flow than the corresponding first-generation G-Series compressor at peak pressure ratio and peak turbo speed
• Increased compressor efficiency at high flow rates compared with the first-generation configuration
• Maximum allowable turbocharger speed: 160,000 rpm
• One-piece center-housing and backplate architecture
• Twin piston-ring sealing on both sides of the shaft assembly
• Mar-M alloy turbine wheel rated for exhaust-gas temperatures up to 1,050°C
• Stainless-steel turbine housings rated by Garrett for temperatures up to 1,050°C
• Oil restrictor and water fittings included
• Machined compressor-housing port for an optional Garrett turbo-speed sensor
• Two externally wastegated and three internally wastegated standard-rotation turbine configurations
• Garrett factory-assembled internal-wastegate turbochargers include a calibrated 0.5-bar actuator
• Compatible with the verified standard-rotation Garrett G25 housing family listed below

Kit Includes

• Garrett G-Series II G25-700 supercore, part number 934075-5002S, when an external-wastegate or supercore-only configuration is selected
• Compressor housing, compressor wheel, center housing rotating assembly, and turbine wheel
• Garrett oil-restrictor fitting
• Garrett water fittings and plugs
• Selected Garrett standard-rotation G25 turbine-housing kit when an external-wastegate housing variant is ordered
• Garrett factory-assembled and calibrated turbocharger with selected internally wastegated housing and 0.5-bar actuator when an internal-wastegate variant is ordered
• Supercore-only variant excludes the turbine housing and wastegate actuator

Technical Specifications

Compressor

• Compressor inducer: 54mm
• Compressor exducer: 67mm
• Compressor trim: 65
• Compressor-housing A/R: 0.70
• Compressor inlet: approximately 3.00-inch hose connection
• Compressor outlet: approximately 2.00-inch hose connection
• Maximum allowable turbocharger speed: 160,000 rpm
• Optional Garrett turbo-speed sensor kit is sold separately

Turbine

• Turbine inducer: 54mm
• Turbine exducer: 49mm
• Turbine trim: 84
• Turbine-wheel material: Mar-M high-temperature alloy
• Garrett turbine-flow comparison: 15–20 percent more flow than the referenced GTX turbine architecture
• Garrett peak turbine-efficiency reference: 74 percent
• Turbine-housing material: stainless steel
• Turbine-wheel and turbine-housing temperature rating: up to 1,050°C
• Turbine outlet: V-band on every listed standard-rotation configuration
• Scroll type: open / non-divided on every listed configuration

Center Housing, Bearings, Lubrication, and Coolant Connections

• Bearing system: dual ceramic ball bearing with steel cages
• Center-housing construction: one-piece center housing and backplate
• Shaft sealing: twin piston rings on both compressor and turbine sides
• Cooling: water cooled
• Coolant hardware: two -6AN water fittings and two plugs
• Oil-feed hardware: -4AN oil-restrictor fitting with approximately 1mm orifice
• Oil-drain flange, drain hose, and engine-side drain provision are not included
• Oil pressure, feed-line arrangement, drain sizing, and drain routing must follow Garrett’s installation requirements for the specific engine and oiling system

Available Turbine Configurations

• 0.72 A/R V-Band / V-Band, External Wastegate — Garrett housing 740902-0069: open-scroll V-band turbine inlet, V-band turbine outlet, external wastegate required. Supplied as the 934075-5002S supercore plus the selected Garrett turbine-housing kit.
• 0.92 A/R V-Band / V-Band, External Wastegate — Garrett housing 740902-0068: open-scroll V-band turbine inlet, V-band turbine outlet, external wastegate required. Supplied as the 934075-5002S supercore plus the selected Garrett turbine-housing kit.
• 0.49 A/R T25 / V-Band, Internal Wastegate — Garrett complete turbo 934076-5004S; housing 740902-0080: open-scroll T25 turbine inlet, V-band turbine outlet, internal wastegate, and Garrett-calibrated 0.5-bar actuator.
• 0.72 A/R V-Band / V-Band, Internal Wastegate — Garrett complete turbo 934076-5005S; housing 740902-0076: open-scroll V-band turbine inlet, V-band turbine outlet, internal wastegate, and Garrett-calibrated 0.5-bar actuator. RAD recommended general catalog default.
• 0.92 A/R V-Band / V-Band, Internal Wastegate — Garrett complete turbo 934076-5006S; housing 740902-0077: open-scroll V-band turbine inlet, V-band turbine outlet, internal wastegate, and Garrett-calibrated 0.5-bar actuator.
• Supercore Only — Garrett 934075-5002S: compressor housing and complete center rotating assembly supplied without a turbine housing or wastegate actuator.

Application Notes

• This is a universal performance turbocharger and is not a vehicle-specific bolt-on assembly.
• Garrett’s 350–700 horsepower range is a compressor-based flywheel-horsepower reference. Actual output depends on engine airflow, fuel, charge-air temperature, exhaust-manifold design, turbine housing, boost pressure, backpressure, and tune.
• The 0.49 A/R T25 internal-wastegate configuration prioritizes compact packaging and early response. It may create greater turbine-side restriction as airflow and power approach the upper end of the G25-700 range.
• The 0.72 A/R configurations provide the broadest general balance between boost response and turbine-flow capacity for responsive street and track applications.
• The 0.92 A/R configurations provide additional exhaust-flow capacity and may reduce turbine inlet pressure at high engine speed, with some reduction in low-speed boost response.
• The externally wastegated housings provide greater flexibility in wastegate size, placement, spring selection, and bypass-flow capacity. The external wastegate and all related plumbing are sold separately.
• The internally wastegated variants are complete Garrett assemblies with a calibrated 0.5-bar actuator. Final boost pressure depends on actuator preload, boost-control strategy, exhaust backpressure, manifold pressure, and wastegate-flow capacity.
• Garrett identifies the internal-wastegate housings as having a large bypass port intended to improve boost control, but boost creep remains application dependent.
• Every verified standard-rotation G25 housing in this listing is open scroll. Garrett does not list a divided standard-rotation G25 housing for this turbocharger.
• The G25-700 supercore is compatible only with the verified standard-rotation G25 housings listed in this description. Reverse-rotation housings are not interchangeable.
• G-Series II uses the corresponding first-generation G25 compressor and turbine housing interfaces, but every existing installation should be confirmed by part number before components are reused.
• Turbine-inlet flange or clamp, turbine-outlet weld flange and clamp, external wastegate where applicable, oil-feed line, oil-drain line, coolant hoses, intake plumbing, charge piping, exhaust manifold, downpipe, boost-control hardware, and application-specific fasteners are not included unless separately stated.
• Garrett turbo-speed sensor kits, compressor-speed display hardware, and electronic boost-control components are sold separately.
• Final turbocharger and turbine-housing selection should be based on an engine-airflow model and the intended operating range rather than displacement or peak-power target alone.

Emissions and Competition-Use Notice

This universal performance turbocharger is intended for racing and competition applications. Vehicle modifications must comply with all applicable emissions, registration, noise, and road-use requirements. It is the purchaser’s responsibility to determine whether the product is legal for the intended vehicle and use.