{"product_id":"grimmspeed-22-25-subaru-wrx-fa24-equal-length-header","title":"GrimmSpeed Equal Length Header | 2022-2025 Subaru WRX (FA24) (GRM113401) (GRM 113401)","description":"\u003ch3\u003eGrimmSpeed Equal Length Header | 2022-2025 Subaru WRX\u003c\/h3\u003e\n\u003cp\u003eUnlock more from the FA24 turbo system with the GrimmSpeed Equal Length Header for the 2022-2025 Subaru WRX. Engineered specifically around the factory twin-scroll turbocharger, this header improves exhaust flow while maintaining the equal runner lengths that are critical to proper twin-scroll operation.\u003c\/p\u003e\n\u003cp\u003eGrimmSpeed didn't simply replace the factory manifold with larger tubing. The entire header was engineered around runner length, bend angle, collector geometry, flange sealing, ground clearance, and long-term durability. The result is a true equal-length FA24 header designed to improve flow without sacrificing the factory skid plate or requiring an ECU tune just to install it.\u003c\/p\u003e\n\u003ch3\u003eWhy Equal Length Matters on the FA24 WRX\u003c\/h3\u003e\n\u003cp\u003eThe FA24 WRX uses a twin-scroll turbocharger, which relies on properly timed exhaust pulses from opposing cylinders. Maintaining equal-length runners helps preserve that exhaust pulse separation and allows the twin-scroll system to operate as intended.\u003c\/p\u003e\n\u003cp\u003eGrimmSpeed CNC bends and trims each runner to achieve less than 1% variance between the longest and shortest tubes. This provides a true equal-length design while keeping runner bends and transitions as consistent as possible.\u003c\/p\u003e\n\u003ch3\u003eEngineered for Better Exhaust Flow\u003c\/h3\u003e\n\u003cp\u003eAt the center of the design is GrimmSpeed's low-restriction 304 stainless steel cast merge collector. Rather than joining multiple fabricated sections together, the cast collector creates smooth transitions between the runners and turbo inlet while allowing GrimmSpeed to precisely control runner spacing and merge angles.\u003c\/p\u003e\n\u003cp\u003eThe runners are constructed from 1.75-inch, 14-gauge stainless steel tubing and use single-piece bends wherever possible. Reducing unnecessary welds and internal steps helps create a smoother exhaust path while also eliminating potential failure points.\u003c\/p\u003e\n\u003ch3\u003eHeavy-Duty 304 Stainless Construction\u003c\/h3\u003e\n\u003cp\u003eThe header uses 304 stainless steel throughout, including the runners, flanges, collector, and badge.\u003c\/p\u003e\n\u003cp\u003eThe cylinder head flanges are CNC cut and faced from 1\/2-inch-thick 304 stainless steel. Their additional thickness helps maintain flange flatness and provides a strong sealing surface for the exhaust manifold gaskets.\u003c\/p\u003e\n\u003cp\u003eThe runners are welded to the flanges on both the inside and outside. GrimmSpeed then finishes the internal transition to create a rounded entry from the cylinder head into the runner for smoother airflow.\u003c\/p\u003e\n\u003ch3\u003eFeatures\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eDesigned for the 2022-2025 Subaru WRX FA24DIT\u003c\/li\u003e\n\u003cli\u003eTrue equal-length runner design\u003c\/li\u003e\n\u003cli\u003eLess than 1% runner-length variance\u003c\/li\u003e\n\u003cli\u003eFull 304 stainless steel construction\u003c\/li\u003e\n\u003cli\u003e1.75-inch 14-gauge stainless steel runners\u003c\/li\u003e\n\u003cli\u003eCNC-bent and trimmed tubing\u003c\/li\u003e\n\u003cli\u003eLow-restriction cast stainless steel merge collector\u003c\/li\u003e\n\u003cli\u003e1\/2-inch CNC-cut and faced stainless steel flanges\u003c\/li\u003e\n\u003cli\u003eRunners welded inside and outside of the flanges\u003c\/li\u003e\n\u003cli\u003eSmooth internal transitions for reduced flow restriction\u003c\/li\u003e\n\u003cli\u003eNo ECU tune or recalibration required for installation\u003c\/li\u003e\n\u003cli\u003eMaintains factory ground clearance\u003c\/li\u003e\n\u003cli\u003eClears the factory skid plate without spacers\u003c\/li\u003e\n\u003cli\u003eInstallation gaskets and hardware included\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eGrimmSpeed Dyno Testing\u003c\/h3\u003e\n\u003cp\u003eGrimmSpeed performed back-to-back Mustang dyno testing against the factory FA24 exhaust manifold using a 2022 WRX 6-speed. Testing included the factory calibration, a COBB Stage 1 OTS map, and a custom JRTuned calibration.\u003c\/p\u003e\n\u003cp\u003eOn the stock tune, GrimmSpeed reported average torque gains of more than 15 lb-ft across the powerband, with gains reaching approximately 35 lb-ft during spool below 3,000 RPM. They also reported an average increase of nearly 11 WHP, with some of the largest horsepower improvements occurring between approximately 4,000 and 5,500 RPM.\u003c\/p\u003e\n\u003cp\u003eWith a Stage 1 OTS calibration, the difference at peak power was smaller, but GrimmSpeed still recorded approximately 10-15 lb-ft of additional low-end torque leading up to peak torque.\u003c\/p\u003e\n\u003cp\u003eDuring custom-tuned testing, the GrimmSpeed header continued to show an advantage during turbo spool, with approximately 5-10 lb-ft of additional torque before 3,500 RPM and roughly 1.6% higher peak torque compared with the factory manifold.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eDyno results are provided from GrimmSpeed's testing and are not guaranteed.\u003c\/strong\u003e Actual results will vary based on vehicle condition, modifications, fuel, calibration, transmission, elevation, temperature, and other factors.\u003c\/p\u003e\n\u003ch3\u003eNo Tune Required\u003c\/h3\u003e\n\u003cp\u003eA major advantage of this header is that an ECU tune is not required simply to install it. GrimmSpeed designed the header as a direct mechanical upgrade for the factory FA24 turbo system.\u003c\/p\u003e\n\u003cp\u003eA properly calibrated tune may still be used as part of a larger performance setup, but ECU recalibration is not required after installing the header itself.\u003c\/p\u003e\n\u003ch3\u003eFitment\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e2022 Subaru WRX\u003c\/li\u003e\n\u003cli\u003e2023 Subaru WRX\u003c\/li\u003e\n\u003cli\u003e2024 Subaru WRX\u003c\/li\u003e\n\u003cli\u003e2025 Subaru WRX\u003c\/li\u003e\n\u003cli\u003eAll supported WRX trims\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eWhat's Included\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e(1) GrimmSpeed Equal Length Header Assembly\u003c\/li\u003e\n\u003cli\u003e(1) FA24 turbo-to-manifold gasket\u003c\/li\u003e\n\u003cli\u003e(1) Pair of cylinder head-to-manifold gaskets\u003c\/li\u003e\n\u003cli\u003e(3) Stainless steel M10x1.25 turbo studs\u003c\/li\u003e\n\u003cli\u003e(9) M10x1.25 flanged nuts\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eInstallation\u003c\/h3\u003e\n\u003cp\u003eGrimmSpeed estimates installation at approximately 2-4 hours depending on the condition of the factory hardware. Installation requires access from underneath the vehicle and removal of the factory underbody panels and exhaust manifold.\u003c\/p\u003e\n\u003cp\u003eA torque wrench, E10 Torx socket, standard metric tools, and extensions are required. GrimmSpeed also recommends having penetrating oil and an M10x1.25 tap available when removing and replacing the factory turbo hardware.\u003c\/p\u003e\n\u003cp\u003eBecause this installation involves the exhaust manifold and turbocharger mounting hardware, professional installation is recommended if you are not comfortable performing this type of work.\u003c\/p\u003e\n\u003ch3\u003eWhy Buy Your GrimmSpeed Header From JD Customs USA?\u003c\/h3\u003e\n\u003cp\u003eA performance header isn't just another part number. How it fits into the rest of your setup matters.\u003c\/p\u003e\n\u003cp\u003eJD Customs USA specializes in parts for modified performance vehicles, and we focus on giving enthusiasts the fitment, technical information, and installation context they need before spending money on a major upgrade. We don't want you guessing about whether a part fits, whether a tune is required, or what actually makes one header different from another.\u003c\/p\u003e\n\u003cp\u003eWhen you order your GrimmSpeed FA24 Equal Length Header from JD Customs USA, you're buying from a performance-focused shop that understands the VB WRX platform and how individual upgrades work together as part of a complete build. If you have questions about fitment, supporting modifications, installation, or how this header fits into your plans for the car, our team is here to help.\u003c\/p\u003e\n\u003ch3\u003eProduct Details\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eManufacturer:\u003c\/strong\u003e GrimmSpeed\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003ePart Number:\u003c\/strong\u003e GRM113401\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eEngine:\u003c\/strong\u003e FA24DIT\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eConstruction:\u003c\/strong\u003e 304 Stainless Steel\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eHeader Design:\u003c\/strong\u003e Equal Length\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eRunner Size:\u003c\/strong\u003e 1.75-inch, 14-gauge\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"GrimmSpeed","offers":[{"title":"Default Title","offer_id":50971248230652,"sku":"GRMGRM113401","price":1029.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/1128\/7276\/files\/92d74dc0cd3daa8daa11edac0e6b91a3L.jpg?v=1786538561","url":"https:\/\/jdcustomsusa.com\/products\/grimmspeed-22-25-subaru-wrx-fa24-equal-length-header","provider":"JD Customs U.S.A","version":"1.0","type":"link"}