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High-Flow T4 Divided Turbine Housing for Peak Power G38 Builds
The Garrett G38/GXR38 Turbine Housing Kit T4 Divided / V-Band 1.06 A/R (GRT757707-0044) is the largest A/R option in the T4 divided G38 housing family, optimized for maximum exhaust flow at high RPM in large-displacement or high-power builds targeting the upper capability of the G38-1000 or GXR38-64 supercore. The 1.06 A/R ratio on GRT757707-0044 reduces back pressure at peak RPM, allowing the compressor to reach its maximum efficiency zone on engines generating the most exhaust enthalpy. This housing is best paired with larger displacement engines above 4.0L or builds where maximum peak power above 800 horsepower is the primary objective, with some trade-off in lower-RPM spool response compared to smaller A/R options.
Key Features
- GRT757707-0044 T4 divided / V-Band turbine housing for G38-1000 and GXR38-64 supercores
- 1.06 A/R provides maximum exhaust flow capability at peak RPM for high-horsepower race builds
- T4 divided twin-scroll inlet for manifold pulse energy retention and improved response
- V-Band turbine outlet for clean downpipe interface in custom fabricated exhaust systems
- Stainless steel construction for extreme heat durability in sustained high-boost operation
- External wastegate only for full boost control capability
- Includes gasket kit, V-Band clamp, and mounting hardware
Specifications
| Detail | Value |
|---|---|
| Part Number | GRT757707-0044 / 757707-0044 |
| Compatible Supercores | G38-1000 (938272-5003S), GXR38-64 (934173-5008S, 934173-5009S) |
| Turbine Inlet | T4 Divided (twin-scroll) |
| Turbine Outlet | V-Band |
| A/R Ratio | 1.06 |
| Wastegate Type | External only |
| Housing Material | Stainless steel |
| UPC | Verify with Garrett distributor |
What’s Included
- 1 x GRT757707-0044 G38/GXR38 Turbine Housing Kit
- Gasket kit
- V-Band clamp for turbine outlet
- Mounting hardware
- Note: Supercore sold separately
About Garrett Motion
Garrett Motion engineers turbine housing kits across a spectrum of A/R ratios to enable tuners and builders to precisely optimize turbocharger response and peak flow for their specific application. GRT757707-0044 is the highest-flow option in the T4 divided G38 housing family and is ideal for purpose-built competition engines.
FAQ
What is the GRT757707-0044?The GRT757707-0044 is a Garrett G38/GXR38 turbine housing with T4 divided inlet, V-Band outlet, and 1.06 A/R ratio. It is the highest-flow T4 divided G38 housing and is optimized for large-displacement or high-peak-power builds where reducing back pressure at maximum RPM is the priority.
What engine displacement suits GRT757707-0044 best?The 1.06 A/R housing is best matched to engine displacements of 4.0L and above, or to smaller engines built specifically for maximum peak power output above 800 horsepower where spool response is less critical than top-end exhaust flow.
How does 1.06 A/R compare to 0.85 and 0.95 for the G38?The 1.06 A/R GRT757707-0044 flows the most exhaust gas at peak RPM with the slowest spool, making it suited for dedicated race engines. The 0.95 A/R GRT757707-0043 is more versatile. The 0.85 A/R GRT757707-0042 provides the quickest response for smaller builds.
Does this housing work with an internal wastegate?No. All G38 turbine housing kits are externally wastegated only. A compatible external wastegate must be purchased and installed separately.
Is weld flange for the downpipe included?No. The V-Band downpipe connection requires a V-Band weld flange on the downpipe, which is not included. The kit includes the V-Band clamp only.
What supercores fit GRT757707-0044?GRT757707-0044 fits the G38-1000 supercore (938272-5003S) and the G-XRace GXR38-64 supercores (934173-5008S and 934173-5009S). It is not compatible with G40, G42, or other Garrett frames.
Is GRT757707-0044 standard or reverse rotation?Standard rotation. A separate reverse-rotation housing part number is available for reverse-rotation supercore applications.
What does divided T4 mean for the inlet?A divided T4 inlet has an internal divider that separates the two scroll entries, preserving the pulse energy separation from the exhaust manifold. This improves spool response especially at low to mid RPM compared to an undivided open T4 inlet.
Installation Overview
- Confirm your exhaust manifold has a divided T4 outlet flange matching the GRT757707-0044 inlet configuration
- Prepare the G38 supercore with oil feed/return and coolant fittings before mounting the housing
- Align and bolt the T4 divided inlet to the exhaust manifold flange using the supplied hardware, torquing to spec
- Connect the V-Band turbine outlet to the downpipe using the included V-Band clamp
- Install external wastegate to the manifold or housing dump port
- Prime oil system before first start and complete coolant system bleed
- Perform initial idle break-in before driving under full boost load
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