Grimmspeed CHASE JB400 Turbocharger Kit 2002-2007 WRX / 2004-2021 STI | Quick-Spooling 49lb Compressor | Performance Turbocharger
Overview
The Grimmspeed CHASE JB400 Turbocharger Kit is a high-performance turbo upgrade designed specifically for Subaru EJ series engines, including the 2002-2007 WRX and 2004-2021 WRX STI models. This turbocharger is engineered as a direct OE replacement, offering enthusiasts a robust, quick-spooling option that significantly enhances mid-range power and torque. Ideal for stage 3 builds, the CHASE JB400 delivers instant power gains with proper tuning and supporting modifications, making it a practical upgrade for serious Subaru performance enthusiasts.
Developed over three years of rigorous testing, the CHASE JB400 embodies Grimmspeed’s commitment to quality and innovation. The turbo features proprietary compressor and turbine wheel designs, billet 2618 alloy compressor wheel, and a durable journal bearing CHRA with advanced oil sealing technologies. This engineering approach ensures reliability under high boost and race conditions while maximizing airflow efficiency. The turbo’s compact size and carefully selected A/R ratios balance quick spool times with strong mid-range torque, setting a new standard for EJ engine turbo upgrades.
In real-world applications, the CHASE JB400 turbo has demonstrated the ability to produce up to 440 wheel horsepower and 460 lb-ft of torque on a tuned 2020 STI with supporting fuel and tuning mods. It maintains over 400 lb-ft of torque from 4150 RPM, a range where the stock turbo typically falls off. This translates to a noticeable improvement in throttle response and mid-range power delivery, enhancing the driving experience for Subaru owners who demand both streetability and track capability.
Features & Specifications
This Grimmspeed CHASE JB400 Turbocharger Kit is engineered for Subaru WRX and WRX STI platforms and features a 49 lb/min compressor flow with a billet 2618 compressor wheel. Constructed from high-quality A356 compressor housing and D5S turbine housing alloys, it delivers robust performance and durability for Subaru enthusiasts seeking a reliable and quick-spooling turbo upgrade.
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Brand: Grimmspeed
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Product: CHASE JB400 Turbocharger Kit 2002-2007 WRX / 2004-2021 STI
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Part Number: 123005
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Fitment: 2002-2003 WRX, 2004-2005 STI, 2004-2005 WRX, 2006-2007 STI, 2006-2007 WRX, 2008-2010 STI, 2011-2014 STI, 2015-2021 STI
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Material: Billet 2618 compressor wheel, A356 compressor housing, D5S turbine housing
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Finish: Natural metal alloys
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Construction: Precision machined with journal bearing CHRA
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Origin: Not specified
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Compressor Wheel Size (Inducer/Exducer): 51.2mm / 73.8mm Extended tip, 48 Trim
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Turbine Wheel Size (Inducer/Exducer): 53.8mm / 47mm, 76 Trim
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Compressor Flow: 49 lb-min
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Compressor Inlet Diameter: 2.4"
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Bearing Type: Journal with severe duty 360-degree thrust bearing and twin hydrodynamic bearings
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Compressor A/R: 0.65
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Turbine A/R: 0.88
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Adjustable Wastegate: Pre-set at 15 PSI base pressure
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Power Gains: Up to 440 WHP and 460 WTQ on tuned 2020 STI
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Tuning Required: Yes, recommended for optimal performance
Key Benefits
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Performance: Significant mid-range power and torque gains over stock turbo, enhancing throttle response and acceleration.
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Durability: Robust journal bearing design with advanced oil sealing ensures reliability under high boost and track conditions.
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Fitment: Direct OE replacement for multiple Subaru WRX and STI model years, simplifying installation without major modifications.
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Quick Spool: Balanced compressor and turbine A/R ratios deliver fast spool times for improved drivability.
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Quality: Precision-machined billet compressor wheel and high-grade housing materials provide long-lasting performance.
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Value: Offers a cost-effective upgrade path for stage 3 EJ engine builds with proven power potential.
What's Included
- 1× Grimmspeed CHASE JB400 Turbocharger Kit
- Installation instructions
Installation & Compatibility
Installation of the Grimmspeed CHASE JB400 Turbocharger Kit is moderately complex and generally recommended for experienced enthusiasts or professional installers familiar with Subaru EJ engine turbo systems. The turbo is designed as a direct OE location replacement; however, supporting modifications such as upgraded intercoolers, fuel systems, and tuning are necessary to realize full performance potential and ensure reliability. Special tools for turbo removal and installation, as well as proper torque specifications, are required. Tuning is mandatory to optimize fueling and boost control for safe operation.
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Professional Installation: Recommended
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Modifications Required: Supporting fuel and intercooler upgrades, tuning required
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Verify Compatibility: Confirm fitment for your specific year and trim level before purchase
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