{"product_id":"radium-engineering-rad20-1120-mazda-20b-primary-fuel-rail-top-feed","title":"Radium Engineering Mazda 20B Primary Fuel Rail Top Feed Conversion","description":"\u003ch4\u003eTop-Feed Fuel Rail Conversion for the Mazda 20B Three-Rotor Engine\u003c\/h4\u003e\n\u003cp\u003eThe Radium Engineering RAD20-1120 is a CNC machined billet aluminum fuel rail purpose-built for the primary injector location on the Mazda 20B three-rotor engine. The 20B runs side-feed injectors from the factory, a configuration that limits fuel delivery when you start pushing power on an already exotic platform. The RAD20-1120 converts the primary injection position to top-feed using the included injector seats, opening up compatibility with the full range of modern top-feed high-impedance injectors without hacking up the factory intake or plenum. Both feed ports are machined as 8AN ORB (O-ring Boss) to accept industry-standard AN fittings, and the billet construction handles the fuel pressures common in built 20B applications running alcohol, methanol, or high-boost pump gas setups.\u003c\/p\u003e\n\n\u003ch4\u003eKey Features\u003c\/h4\u003e\n\u003cul\u003e\n  \u003cli\u003eCNC machined billet aluminum construction for the Mazda 20B three-rotor engine, primary injector rail position\u003c\/li\u003e\n  \u003cli\u003eConverts factory side-feed injector configuration to top-feed using included injector seats\u003c\/li\u003e\n  \u003cli\u003e8AN ORB (O-ring Boss) feed and return ports for leak-free AN fitting connections\u003c\/li\u003e\n  \u003cli\u003eCompatible with all standard top-feed high-impedance fuel injectors once seats are installed\u003c\/li\u003e\n  \u003cli\u003eSupports gasoline, E85, and methanol fuel delivery systems\u003c\/li\u003e\n  \u003cli\u003eDesigned for use in conjunction with the Radium 20B secondary fuel rail (sold separately) for full engine coverage\u003c\/li\u003e\n  \u003cli\u003ePrecision machined in the USA by Radium Engineering\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch4\u003eFitment\u003c\/h4\u003e\n\u003ctable\u003e\n  \u003cthead\u003e\n    \u003ctr\u003e\n      \u003cth\u003eYear Range\u003c\/th\u003e\n      \u003cth\u003eMake\u003c\/th\u003e\n      \u003cth\u003eModel\u003c\/th\u003e\n      \u003cth\u003eTrim\u003c\/th\u003e\n    \u003c\/tr\u003e\n  \u003c\/thead\u003e\n  \u003ctbody\u003e\n    \u003ctr\u003e\n      \u003ctd\u003e1990-1996\u003c\/td\u003e\n      \u003ctd\u003eMazda\u003c\/td\u003e\n      \u003ctd\u003eCosmo\u003c\/td\u003e\n      \u003ctd\u003eType S, Type SX (20B-REW)\u003c\/td\u003e\n    \u003c\/tr\u003e\n  \u003c\/tbody\u003e\n\u003c\/table\u003e\n\n\u003ch4\u003eSpecifications\u003c\/h4\u003e\n\u003ctable\u003e\n  \u003cthead\u003e\n    \u003ctr\u003e\n      \u003cth\u003eDetail\u003c\/th\u003e\n      \u003cth\u003eValue\u003c\/th\u003e\n    \u003c\/tr\u003e\n  \u003c\/thead\u003e\n  \u003ctbody\u003e\n    \u003ctr\u003e\n      \u003ctd\u003ePart Number\u003c\/td\u003e\n      \u003ctd\u003eRAD20-1120\u003c\/td\u003e\n    \u003c\/tr\u003e\n    \u003ctr\u003e\n      \u003ctd\u003eBrand\u003c\/td\u003e\n      \u003ctd\u003eRadium Engineering\u003c\/td\u003e\n    \u003c\/tr\u003e\n    \u003ctr\u003e\n      \u003ctd\u003eRail Position\u003c\/td\u003e\n      \u003ctd\u003ePrimary (Front Rotor Bank)\u003c\/td\u003e\n    \u003c\/tr\u003e\n    \u003ctr\u003e\n      \u003ctd\u003eInjector Configuration\u003c\/td\u003e\n      \u003ctd\u003eTop-Feed (converts from side-feed using included seats)\u003c\/td\u003e\n    \u003c\/tr\u003e\n    \u003ctr\u003e\n      \u003ctd\u003ePort Size\u003c\/td\u003e\n      \u003ctd\u003e8AN ORB (O-ring Boss)\u003c\/td\u003e\n    \u003c\/tr\u003e\n    \u003ctr\u003e\n      \u003ctd\u003eConstruction\u003c\/td\u003e\n      \u003ctd\u003eCNC Machined Billet Aluminum\u003c\/td\u003e\n    \u003c\/tr\u003e\n    \u003ctr\u003e\n      \u003ctd\u003eCompatible Fuels\u003c\/td\u003e\n      \u003ctd\u003eGasoline, E85, Methanol\u003c\/td\u003e\n    \u003c\/tr\u003e\n    \u003ctr\u003e\n      \u003ctd\u003eApplication\u003c\/td\u003e\n      \u003ctd\u003eMazda 20B-REW Three-Rotor Engine\u003c\/td\u003e\n    \u003c\/tr\u003e\n    \u003ctr\u003e\n      \u003ctd\u003eWarranty\u003c\/td\u003e\n      \u003ctd\u003eRadium Engineering Limited Warranty\u003c\/td\u003e\n    \u003c\/tr\u003e\n    \u003ctr\u003e\n      \u003ctd\u003eUPC\u003c\/td\u003e\n      \u003ctd\u003eN\/A\u003c\/td\u003e\n    \u003c\/tr\u003e\n  \u003c\/tbody\u003e\n\u003c\/table\u003e\n\n\u003ch4\u003eWhat's Included\u003c\/h4\u003e\n\u003cul\u003e\n  \u003cli\u003eRadium Engineering RAD20-1120 billet fuel rail (primary position)\u003c\/li\u003e\n  \u003cli\u003eTop-feed injector seats (quantity matches primary rotor bank injector count)\u003c\/li\u003e\n  \u003cli\u003eMounting hardware\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch4\u003eFrequently Asked Questions\u003c\/h4\u003e\n\u003cstrong\u003eWhat engine does the RAD20-1120 fit?\u003c\/strong\u003e\n\u003cp\u003eThe RAD20-1120 is built for the Mazda 20B-REW three-rotor engine. This engine was found factory-installed in the Mazda Cosmo (Type S and Type SX) from 1990 to 1996. It is also commonly swapped into Mazda RX-7 FC and FD chassis for high-power three-rotor builds, and this fuel rail fits the 20B regardless of the chassis it is installed in, as it attaches to the engine itself rather than any chassis-specific mounting location.\u003c\/p\u003e\n\n\u003cstrong\u003eWhy does the Mazda 20B need a top-feed fuel rail conversion?\u003c\/strong\u003e\n\u003cp\u003eThe factory 20B-REW uses side-feed injectors, which are limited in flow rate compared to the top-feed injectors available in the aftermarket. Side-feed options max out well below what a built 20B running E85 or methanol requires at high boost. Converting to top-feed using this rail and included injector seats opens up injector selection to the full range of modern high-impedance injectors from brands like ID, DeatschWerks, Injector Dynamics, and Fuel Injector Clinic.\u003c\/p\u003e\n\n\u003cstrong\u003eWhat injectors are compatible with this fuel rail?\u003c\/strong\u003e\n\u003cp\u003eAny standard top-feed high-impedance (saturated) fuel injector with the correct body length and O-ring dimensions will be compatible once the included injector seats are installed. Commonly paired injectors for high-power 20B builds include the Injector Dynamics ID2000, ID2600, DeatschWerks DW2200, and Fuel Injector Clinic 2150cc and 2650cc units. Confirm injector clip orientation and body diameter against the injector seat dimensions before ordering injectors.\u003c\/p\u003e\n\n\u003cstrong\u003eDo I need to purchase the secondary fuel rail separately?\u003c\/strong\u003e\n\u003cp\u003eYes. This rail covers the primary injector location on the 20B three-rotor. The secondary injector rail is a separate Radium part. For a complete fuel system overhaul on the 20B, both the primary and secondary rails are required. Radium sells each rail separately so builders targeting the primary bank only, such as staged injection strategies, can purchase accordingly.\u003c\/p\u003e\n\n\u003cstrong\u003eWhat AN fitting size do the 8AN ORB ports accept?\u003c\/strong\u003e\n\u003cp\u003eThe feed and return ports are machined as 8AN ORB, which means they use an O-ring face seal on a standard -8 AN threaded port. You will need 8AN ORB to 8AN flare adapters or direct 8AN ORB hose end fittings to connect your fuel feed and return lines. These fittings are widely available from brands like Fragola, Russell, and Aeroquip and are not included with the rail.\u003c\/p\u003e\n\n\u003cstrong\u003eIs this fuel rail compatible with methanol and E85?\u003c\/strong\u003e\n\u003cp\u003eYes. The billet aluminum construction and O-ring sealing surfaces on this rail are compatible with gasoline, E85, and methanol. The injector seats included with the rail are likewise alcohol-safe. For full alcohol compatibility, ensure that your fuel lines, pump, and filter are also rated for the fuel type being used.\u003c\/p\u003e\n\n\u003cstrong\u003eDoes installation require machining or modification to the intake manifold?\u003c\/strong\u003e\n\u003cp\u003eThis depends on your specific 20B intake configuration. This rail is designed to bolt into the 20B engine's primary injector location, replacing the side-feed rail. Depending on whether you are running a factory manifold or an aftermarket intake, minor fitment adjustments may be needed. Consulting a machinist or rotary specialist familiar with 20B top-feed conversions is recommended before installation.\u003c\/p\u003e\n\n\u003cstrong\u003eIs this rail designed for a specific injector spacing or pattern?\u003c\/strong\u003e\n\u003cp\u003eYes. This rail is machined specifically for the primary rotor bank injector spacing of the 20B engine. It is not a generic universal rail and cannot be used on other rotary engines such as the 13B without a different Radium rail designed for that engine. The included injector seats are also 20B primary-specific in their positioning and angle.\u003c\/p\u003e\n\n\u003ch4\u003eInstallation Overview\u003c\/h4\u003e\n\u003col\u003e\n  \u003cli\u003eDepressurize the fuel system and disconnect the battery before beginning work on the 20B fuel rail.\u003c\/li\u003e\n  \u003cli\u003eRemove the factory side-feed fuel rail from the primary injector position, carefully extracting all factory injectors without damaging the intake sealing surfaces.\u003c\/li\u003e\n  \u003cli\u003ePress or slide the included top-feed injector seats into position at each injector bore in the manifold, ensuring full seating and correct O-ring placement.\u003c\/li\u003e\n  \u003cli\u003eInstall the selected top-feed injectors into the rail, lubricating the O-rings with clean fuel or O-ring lubricant before pressing in.\u003c\/li\u003e\n  \u003cli\u003ePosition the rail assembly over the injector seats and press the injectors into the seats, then secure the rail using the included mounting hardware.\u003c\/li\u003e\n  \u003cli\u003eConnect 8AN ORB fittings to the feed and return ports, routing to your fuel system plumbing.\u003c\/li\u003e\n  \u003cli\u003eReconnect the battery, cycle the ignition to prime the fuel system, and inspect all connections for leaks before starting the engine.\u003c\/li\u003e\n  \u003cli\u003eAfter initial startup, verify fuel pressure at idle and confirm no leaks are present before returning the vehicle to service.\u003c\/li\u003e\n\u003c\/ol\u003e\n\n\u003cp\u003e\u003cstrong\u003eWARNING:\u003c\/strong\u003e This product can expose you to chemicals including lead and phthalates, which are known to the State of California to cause cancer and reproductive harm. For more information go to www.P65Warnings.ca.gov.\u003c\/p\u003e","brand":"Radium Engineering","offers":[{"title":"Default Title","offer_id":46000636624975,"sku":"RAD20-1120","price":180.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/1062\/7920\/files\/Radium_RAD20-1120_Mazda_20B_Primary_Fuel_Rail.png?v=1782996193","url":"https:\/\/www.blackopsautoworks.com\/products\/radium-engineering-rad20-1120-mazda-20b-primary-fuel-rail-top-feed","provider":"Black Ops Auto Works","version":"1.0","type":"link"}