{"product_id":"ferrea-endurance-dual-valve-spring-kit-2004-2021-subaru-sti-kt4020","title":"Ferrea 'Endurance' Dual Valve Spring Kit | 2004-2021 Subaru STI (KT4020)","description":"\u003ch2 style=\"font-size:1.2rem;\"\u003eFerrea 'Endurance' Dual Valve Spring Kit | 2004-2021 Subaru STI (KT4020)\u003c\/h2\u003e\u003cp\u003eFerrea Racing part number KT4020 is a performance spring kit for the 2004–2014 Subaru Impreza WRX STi and 1 more listed vehicles.\u003c\/p\u003e\u003ch2\u003eVehicle fitment\u003c\/h2\u003e\u003ch3\u003eManufacturer's vehicle list\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e2004–2014 Subaru Impreza WRX STi\u003c\/li\u003e\n\u003cli\u003e2015–2021 Subaru WRX STI\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eAs written in the product title\u003c\/h3\u003e\u003ctable\u003e\n\u003ctr\u003e\n\u003cth\u003eVehicle\u003c\/th\u003e\n\u003ctd\u003e2004-2021 Subaru STI\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eMake\u003c\/th\u003e\n\u003ctd\u003eSubaru\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eYears\u003c\/th\u003e\n\u003ctd\u003e2004–2021\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\u003cp\u003eWhere the two differ, go by the manufacturer's list.\u003c\/p\u003e\u003cp\u003eEngine, trim, drivetrain and options can change which part fits, so \u003ca href=\"\/pages\/contact-us\"\u003econtact mobileiGo\u003c\/a\u003e with your VIN if you are unsure.\u003c\/p\u003e\u003ch2\u003eSpecifications\u003c\/h2\u003e\u003ctable\u003e\n\u003ctr\u003e\n\u003cth\u003eBrand\u003c\/th\u003e\n\u003ctd\u003eFerrea Racing\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eManufacturer part number\u003c\/th\u003e\n\u003ctd\u003eKT4020\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eCategory\u003c\/th\u003e\n\u003ctd\u003eCylinder Heads \u0026amp; Valvetrain Components\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eType\u003c\/th\u003e\n\u003ctd\u003ePerformance upgrade\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth\u003eShipping weight\u003c\/th\u003e\n\u003ctd\u003e5.0 lb\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\u003ch2\u003eBefore you buy: valvetrain part tips\u003c\/h2\u003e\u003cul\u003e\n\u003cli\u003eCamshafts and valve springs are matched; higher-lift cams usually need stronger springs.\u003c\/li\u003e\n\u003cli\u003eValvetrain upgrades often need a tune and careful measurement of clearances.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch2\u003eFrequently asked questions\u003c\/h2\u003e\u003ch3\u003eWill the Ferrea Racing KT4020 fit my Subaru?\u003c\/h3\u003e\u003cp\u003eIt is listed for the 2004–2014 Subaru Impreza WRX STi and 1 more listed vehicles. Check your engine, trim and options against the fitment table above before ordering.\u003c\/p\u003e\u003ch3\u003eWhat is the part number?\u003c\/h3\u003e\u003cp\u003eThe manufacturer part number is KT4020.\u003c\/p\u003e\u003ch3\u003eDo I need new valve springs with this camshaft?\u003c\/h3\u003e\u003cp\u003eHigher-lift camshafts usually need matching valve springs. Check the camshaft maker's recommendation in the manufacturer description.\u003c\/p\u003e\u003ch3\u003eIs this part new?\u003c\/h3\u003e\u003cp\u003eYes. It is a new part sourced from an authorized distributor.\u003c\/p\u003e\u003ch2\u003eManufacturer description\u003c\/h2\u003e\u003cdiv class=\"tt-mfr\"\u003e\u003cdiv\u003e\n\u003cdiv\u003e\n\u003ch2\u003eValve Spring Kit for 2004-2021 Subaru STI by Ferrea\u003c\/h2\u003e\n\u003cp align=\"justify\"\u003eHarmonics or high frequency fatigue is present in all racing engines and will usually destroy the valvetrain if not controlled. Properly designed valve springs will control the dominant harmonics, provide the needed stability, and reduce valvetrain component wear. Ferrea valve springs are developed from high strength alloys, including premium grade chrome silicon steel.\u003c\/p\u003e\n\u003cp align=\"justify\"\u003eOur springs are heat-treated and stress relieved, which dramatically increases the spring’s life. Our valve springs provide the stability needed for high lift, high rpm racing engines, while minimizing the load loss for today€™s aggressive valvetrain combinations.\u003c\/p\u003e\n\u003ch3\u003eFeatures\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eControls Dominant Harmonics\u003c\/li\u003e\n\u003cli\u003eProvides Needed Stability\u003c\/li\u003e\n\u003cli\u003eReduce Valvetrain Component Wear\u003c\/li\u003e\n\u003cli\u003eDeveloped from High Strength Alloys\u003c\/li\u003e\n\u003cli\u003eHeat-Treated and Stress Relieved\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003cdiv\u003e\n\u003ch3\u003eApplications\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e2004 - 2014 Subaru Impreza WRX STi\u003c\/li\u003e\n\u003cli\u003e2015 - 2021 Subaru WRX STI\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eWhat's In The Box?\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003e16 - Dual Springs (S10098)\u003c\/li\u003e\n\u003cli\u003e16 - Titanium Retainers (E11065)\u003c\/li\u003e\n\u003cli\u003e16 - Seat Locators (SL1051)\u003c\/li\u003e\n\u003cli\u003e16 - Valve Locks (K10074)\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eWarranty\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eFerrea Manufacturer's Warranty\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\u003c\/div\u003e\u003c!-- tt-ap-content v1 --\u003e","brand":"Ferrea Racing","offers":[{"title":"Default Title","offer_id":67821353238847,"sku":"MAP FER KT4020","price":1064.96,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/1639\/5151\/files\/ferrea-racing-fer-kt4020-30338522775622.webp?v=1792539236","url":"https:\/\/www.mobileigo.com\/products\/ferrea-endurance-dual-valve-spring-kit-2004-2021-subaru-sti-kt4020","provider":"mobileiGo.com","version":"1.0","type":"link"}