{"product_id":"hks-extension-kit-w-catalytic-converter-2013-2021-subaru-brz-scion-fr-s-toyota-86-rfd99g","title":"HKS Extension Kit w\/ Catalytic Converter - 2013-2021 Subaru BRZ \/Scion FR-S\/ Toyota 86","description":"\u003ch4\u003e\u003cstrong\u003eExtension Kit with Catalytic Converter for the 2013-2021 FR-S, BRZ, and 86\u003c\/strong\u003e\u003c\/h4\u003e\n\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0743\/4122\/0668\/files\/0cf83df6656aed1bc1c6d4c1f911a30b.jpg?v=1772080138\" alt=\"HKS Extension Kit w\/ Catalytic Converter - 2013-2021 Subaru BRZ \/Scion FR-S\/ Toyota 86\" style=\"float: right; width: 40%; max-width: 300px; height: auto; margin: 0 0 16px 20px;\"\u003e\u003c\/p\u003e\n\u003cp\u003eThe HKS Extension Kit with Catalytic Converter for the 2013-2021 Subaru BRZ, Scion FR-S, and Toyota 86 is the front pipe and catalytic converter section that connects the header to the cat-back exhaust system. It is the correct choice for builds using an aftermarket header that requires a specific front pipe to connect to HKS or other cat-back systems. The included catalytic converter maintains emissions compliance while the extension pipe provides the correct connection geometry.\u003c\/p\u003e\n\u003cdiv style=\"clear: both;\"\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003ch4\u003e\u003cstrong\u003eSpecs \u0026amp; Highlights\u003c\/strong\u003e\u003c\/h4\u003e\n\u003cul\u003e\n\u003cli\u003eFront pipe and catalytic converter unit\u003c\/li\u003e\n\u003cli\u003eConnects aftermarket header to cat-back system\u003c\/li\u003e\n\u003cli\u003eEmissions compliant catalytic converter\u003c\/li\u003e\n\u003cli\u003eCorrect connection geometry for HKS exhaust systems\u003c\/li\u003e\n\u003cli\u003eStainless steel construction\u003c\/li\u003e\n\u003cli\u003eFitment: 2013-2021 Subaru BRZ \/ Scion FR-S \/ Toyota 86\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch4\u003e\u003cstrong\u003e50.8mm Front Pipe, 400 cpsi Metallic Cat, 40mm Flex Bellows\u003c\/strong\u003e\u003c\/h4\u003e\n\u003cp\u003eThe extension kit front pipe uses 50.8mm (2 inch) diameter, matching the rest of the HKS FA20 exhaust system diameters. The catalytic converter core is a metallic substrate design with a cell density of 400 cpsi (cells per square inch), which provides lower exhaust back pressure than the OEM ceramic substrate catalyst while maintaining catalytic efficiency above the light-off temperature. The flex joint section uses a 40mm diameter corrugated stainless bellows rated for 10,000+ flex cycles, the primary fatigue concern for any rigid exhaust connection near the engine mount.\u003c\/p\u003e\n\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0743\/4122\/0668\/files\/8c9a096c26b42fd4d687894f09d26992.jpg?v=1772080138\" alt=\"HKS Extension Kit w\/ Catalytic Converter - 2013-2021 Subaru BRZ \/Scion FR-S\/ Toyota 86\" style=\"float: left; width: 40%; max-width: 300px; height: auto; margin: 0 20px 16px 0;\"\u003e\u003c\/p\u003e\n\u003ch4\u003e\u003cstrong\u003eWhy the Front Pipe Scope Matters for System Consistency\u003c\/strong\u003e\u003c\/h4\u003e\n\u003cp\u003eThe extension kit is the bridge between an aftermarket header and the cat-back section of the exhaust system. When running equal length headers like the HKS33005-AT006, the factory front pipe and cat section may not connect correctly to the aftermarket header's outlet. The extension kit solves this with the correct pipe geometry and a quality catalytic converter.\u003c\/p\u003e\n\u003cdiv style=\"clear: both;\"\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0743\/4122\/0668\/files\/ee94e43184bdecb07eb21cba3ff72414.jpg?v=1772080138\" alt=\"HKS Extension Kit w\/ Catalytic Converter - 2013-2021 Subaru BRZ \/Scion FR-S\/ Toyota 86\" style=\"max-width: 100%; height: auto; display: block; margin: 20px 0;\"\u003e \u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0743\/4122\/0668\/files\/fb575283708d9f58e8d78d98278353ea.jpg?v=1772080138\" alt=\"HKS Extension Kit w\/ Catalytic Converter - 2013-2021 Subaru BRZ \/Scion FR-S\/ Toyota 86\" style=\"float: right; width: 40%; max-width: 300px; height: auto; margin: 0 0 16px 20px;\"\u003e\u003c\/p\u003e\n\u003ch4\u003e\u003cstrong\u003ePairs Naturally with HKS Equal Length Headers\u003c\/strong\u003e\u003c\/h4\u003e\n\u003cp\u003eUsed in combination with the HKS equal length headers and a cat-back or header-back exhaust, the extension kit completes a full HKS exhaust system on the FA20. All HKS exhaust components are engineered to work together and the extension kit ensures the complete system is consistent from header to tailpipe.\u003c\/p\u003e\n\u003cdiv style=\"clear: both;\"\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003ch4\u003e\u003cstrong\u003eThe FT Breakdown\u003c\/strong\u003e\u003c\/h4\u003e\n\u003cp\u003eThe extension kit with cat is the connecting piece for a complete header-back exhaust build on the FA20 FT86. If you are running aftermarket headers and a cat-back, this is what closes the gap between them correctly. The 400 cpsi metallic substrate catalyst in the extension kit is the specification used in OEM performance applications from multiple manufacturers — it provides catalytic efficiency at lower back pressure than the ceramic 600 cpsi converters used in standard replacement catalysts. For a full HKS header-back build where every component is matched for flow, using a high-flow cat at the front pipe is the correct approach.\u003c\/p\u003e\n\u003cdiv style=\"clear: both;\"\u003e\u003cbr\u003e\u003c\/div\u003e","brand":"HKS","offers":[{"title":"Default Title","offer_id":52621066535192,"sku":"HKS11999-AT002","price":282.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0998\/4514\/4856\/files\/ims3jbvh7vil_74b9c1ea-84aa-4017-9a11-5f4f99373e94.jpg?v=1788745176","url":"https:\/\/driveforges.com\/products\/hks-extension-kit-w-catalytic-converter-2013-2021-subaru-brz-scion-fr-s-toyota-86-rfd99g","provider":"Drive Forge","version":"1.0","type":"link"}