Radium Fuel Hanger Surge Tank - Walbro GSS342 / AEM 50-1200 | 1992-1995 Mazda RX-7 (20-0950)

The FD hides a saddle-shaped tank under that perfect body, and rotary power finds its starvation limits fast.

The Radium Engineering Fuel Hanger Surge Tank (FHST) for the Mazda RX-7 FD replaces the factory in-tank hanger with a true surge system: up to 3 aftermarket high pressure pumps plus 1 lift pump living in the stock FD tank, feeding through a unique integrated 1.85L surge tank that completely eliminates fuel starvation. This 20-0950 version fits the Walbro GSS342 255lph, AEM 50-1220, and pumps sharing that form factor. No grinding, bending, or modification of the trunk floor sheet metal is required, and low profile fittings come preinstalled: an 8AN male on the 10AN ORB feed port and a 6AN male on the 8AN ORB return port, simplifying aftermarket AN plumbing from day one. Pumps sold separately.

What You'll Feel

• Fuel starvation completely eliminated through the integrated 1.85L in-tank surge tank
• Rotary-appropriate delivery headroom, scaling to 3 surge pumps for single-turbo and E85 builds
• A stock trunk floor untouched, with no grinding, bending, or sheet metal modification
• AN plumbing simplified by the preinstalled low profile 8AN feed and 6AN return fittings
• Continuous surge filling by the dedicated lift pump, independent of tank slosh

Features

• Replaces the factory FD RX-7 in-tank fuel pump hanger; drop-in installation
• Integrated 1.85L surge tank; supports 1, 2, or 3 high pressure surge pumps plus 1 lift pump
• 20-0950 pump compatibility: Walbro GSS342 / AEM 50-1220 class
• 10AN ORB feed port with preinstalled low profile 8AN male fitting; 8AN ORB return port with low profile 6AN male fitting
• No trunk floor modification required
• Compatible with all fuel types including E85; pumps NOT included

The Details

The two-stage architecture is what separates an FHST from a simple hanger: the lift pump continuously fills the 1.85L canister from the tank at large, and the surge pumps feed the engine from that always-full reservoir, so cornering, braking, and quarter-tank track sessions never uncover a pickup. Pump count follows the build, with one surge pump covering most street power, two supporting serious E85 single-turbo builds, and the third slot reserved for staging ambitions, each pump wanting its own Radium DIY wiring kit so current delivery matches flow ratings. Radium's companion feed kits for the FD (sold separately) complete the plumbing with an integrated high-flow filter in stainless or microglass. Verify pump family against your version before ordering, since the 20-0950 fits Walbro GSS342 / AEM 50-1220 class only.

Kit Includes

• 1x FHST fuel hanger surge tank assembly with integrated 1.85L surge tank
• Preinstalled low profile 8AN feed and 6AN return fittings
• Provisions for up to 3 surge pumps and 1 lift pump
• Fuel pumps NOT included

Applications

• 1992-1995 Mazda RX-7 FD3S (stock fuel tank)
• 20-0950: Walbro GSS342 / AEM 50-1220 class
• Companion FD feed kits with integrated filter sold separately