Garrett G-Series II G38-1000 62mm Turbocharger

Garrett G-Series II G38-1000 62mm Turbocharger — Select Turbine Housing

Part Number: 938272-5003S

The Garrett G-Series II G38-1000 is a standard-rotation, dual-ceramic-ball-bearing turbocharger platform developed for high-output street, competition, and specialty-performance applications requiring more turbine-flow capacity than the G35 frame without moving to the larger G40 turbine. Garrett rates the G38-1000 for 500–1,000 horsepower and references engine displacements from 2.0 to 5.5 liters. Garrett horsepower ratings represent potential flywheel horsepower based on compressor-map choke flow and are not a guaranteed wheel-horsepower figure.

The G38-1000 uses a 62mm inducer and 88mm exducer compressor wheel paired with a 74mm inducer and 66mm exducer Inconel turbine wheel. Garrett identifies the turbo as a 6266 reference configuration and sets the maximum allowable turbocharger speed at 125,000 rpm. The new G38 frame occupies the space between Garrett’s G35 and G40 families, combining the familiar 62mm compressor class with a 66mm turbine exducer and a dedicated G38 turbine-housing family.

The G-Series II compressor aerodynamics provide increased pressure-ratio capability for higher boost operation and improved efficiency at high flow rates. Garrett also uses a lightweight aluminum backplate and a fully machined turbo-speed-sensor port. Compatible Garrett speed-monitoring systems are sold separately.

This listing is structured as a selectable-housing product. The Garrett 938272-5003S supercore may be combined with one of six verified standard-rotation G38 turbine housings. Three open-scroll housings use V-band turbine inlets, while three divided housings use T4 turbine inlets. Every available housing uses a V-band turbine outlet and requires an external wastegate. Garrett does not currently list an internally wastegated G38-1000 assembly.

RAD recommends the 0.95 A/R open-scroll V-band inlet and V-band outlet housing, Garrett part number 757707-0038, as the general catalog default. It occupies the middle of the available A/R range, avoids the manifold and wastegate-layout requirements of a divided T4 system, and provides a practical balance of response and turbine-flow capacity for typical 4.0–5.5-liter single-turbo applications. Final housing selection should still be based on engine displacement, airflow, power target, exhaust-manifold design, turbine inlet pressure, and intended operating range.

Key Features

• Garrett G-Series II G38-1000 standard-rotation turbocharger platform
• Garrett horsepower reference range: 500–1,000 hp
• Garrett displacement reference range: 2.0–5.5 liters
• Garrett turbo reference: 6266
• 62mm compressor inducer and 88mm compressor exducer
• 74mm turbine inducer and 66mm turbine exducer
• Dual ceramic ball-bearing center section
• G-Series II compressor aerodynamics with increased pressure-ratio capability
• High-flow compressor efficiency intended to support cooler, denser charge air
• Maximum allowable turbocharger speed: 125,000 rpm
• Lightweight aluminum backplate
• Fully machined compressor-housing port for an optional Garrett turbo-speed sensor
• Inconel turbine wheel for high-temperature durability
• Stainless-steel turbine housings
• Three open-scroll V-band inlet configurations
• Three divided T4 inlet configurations
• V-band turbine outlet on every verified housing
• External-wastegate configuration on every verified housing
• Dedicated standard-rotation G38 turbine-housing family shared with compatible Garrett GXR38 supercores

Kit Includes

• Garrett G-Series II G38-1000 supercore, part number 938272-5003S
• Compressor housing
• Forged and fully machined compressor wheel
• Center housing rotating assembly
• Inconel turbine wheel
• Selected Garrett G38 turbine-housing kit when a complete housing variant is ordered
• Supercore-only variant excludes the turbine housing
• Oil-feed, oil-drain, and coolant fittings are not identified by Garrett as included with the current G38-1000 supercore and should be ordered separately

Technical Specifications

Compressor

• Compressor inducer: 62mm
• Compressor exducer: 88mm
• Compressor outlet: hose-style connection
• Compressor-housing A/R: not published in Garrett’s current G38 product page or product flyer
• Compressor trim: not published in Garrett’s current G38 product page or product flyer
• Maximum allowable turbocharger speed: 125,000 rpm
• Optional Garrett turbo-speed monitoring hardware is sold separately

Turbine

• Turbine inducer: 74mm
• Turbine exducer: 66mm
• Turbine trim: 84 as identified on Garrett’s current turbine-flow chart
• Turbine-wheel material: Inconel
• Turbine-housing material: stainless steel
• Available turbine-housing A/R values: 0.85, 0.95, and 1.06
• Available turbine inlets: open-scroll V-band or divided T4
• Turbine outlet: V-band on every listed housing
• Wastegate arrangement: external wastegate required for every listed housing

Center Housing, Bearings, Lubrication, and Coolant Connections

• Bearing system: dual ceramic ball bearing
• Cooling and lubrication: engine-oil supply and coolant circulation required
• Coolant-port fittings and hoses must be selected for the application
• Oil-feed flange, restrictor, line, and engine-side adapter must be selected for the application
• Oil-drain flange, gasket, hose, fittings, and engine-side drain provision are not included
• Oil pressure, feed restriction, drain sizing, and drain routing must follow Garrett’s installation requirements for the specific engine and oiling system

Available Turbine Configurations

• 0.85 A/R V-Band / V-Band — Garrett 757707-0037: open-scroll V-band turbine inlet, V-band turbine outlet, external wastegate required.
• 0.95 A/R V-Band / V-Band — Garrett 757707-0038: open-scroll V-band turbine inlet, V-band turbine outlet, external wastegate required. RAD recommended general catalog default.
• 1.06 A/R V-Band / V-Band — Garrett 757707-0039: open-scroll V-band turbine inlet, V-band turbine outlet, external wastegate required.
• 0.85 A/R Divided T4 / V-Band — Garrett 757707-0042: divided T4 turbine inlet, V-band turbine outlet, external wastegate required.
• 0.95 A/R Divided T4 / V-Band — Garrett 757707-0043: divided T4 turbine inlet, V-band turbine outlet, external wastegate required.
• 1.06 A/R Divided T4 / V-Band — Garrett 757707-0044: divided T4 turbine inlet, V-band turbine outlet, external wastegate required.
• Supercore Only — Garrett 938272-5003S: compressor housing and complete center rotating assembly supplied without a turbine housing.

Application Notes

• This is a universal performance turbocharger and is not a vehicle-specific bolt-on assembly.
• Garrett’s 500–1,000 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 G38-1000 is a new Garrett frame size rather than a direct G-Series I housing upgrade. Only verified G38 and GXR38-compatible turbine housings should be used.
• The 0.85 A/R housings prioritize earlier boost response and may increase turbine inlet pressure as airflow and power rise.
• The 0.95 A/R housings provide the broadest general balance between response and turbine-flow capacity for many street and track applications.
• The 1.06 A/R housings provide additional exhaust-flow capacity and may reduce turbine inlet pressure at high engine speed, with some reduction in low-speed boost response.
• The open-scroll V-band housings are generally the simpler choice for custom single-turbo systems because they do not require a true divided manifold and pulse-preserving wastegate arrangement.
• The divided T4 housings should be used with a properly divided manifold and an external-wastegate arrangement that preserves the intended pulse separation. Installing a divided housing on an undivided manifold does not provide the same twin-scroll behavior.
• No internally wastegated G38-1000 configuration is currently listed by Garrett. An appropriately sized external wastegate system is required.
• Garrett’s current G38 product materials do not identify oil-feed, oil-drain, or coolant fittings as included. These components should be treated as application-specific purchases.
• Turbine-inlet flange or clamp, turbine-outlet weld flange and clamp, external wastegate, wastegate springs, oil and coolant plumbing, intake plumbing, charge piping, exhaust manifold, downpipe, boost-control hardware, and application-specific fasteners are not included unless separately stated.
• Garrett turbo-speed monitoring systems 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.