Radium FCST-X, Fuel Cell Surge Tank


Since 2010, external Radium Engineering fuel surge tanks have been an excellent way to eliminate fuel starvation that occurs in racing. To simplify plumbing and packaging, Radium Engineering introduced the first to market Fuel Cell Surge Tank (FCST) in 2013. The current generation of the FCST is still a great cost-efficient solution and is available here. This FCST quickly became the preferred fuel system for the competition vehicle market and professional racing. 


The features listed below carry over from previous fuel cell surge tanks.
-Merged single 10AN ORB female threaded outlet. All pumps use check valves that prevent back-flow.
-One-way fill valves (355LPH each) allow fuel in, but not out, keeping the surge tank full.
-Multiple fuel pump options including gerotor, turbine, and brushless DC motor pumps.
-Hermetically sealed high-current stainless steel electrical studs capable of handling all pumps.
-Simplified servicing eliminates sealing washers and fuel cell retaining brackets.
-Full CNC aluminum construction with anodized surfacing for superior corrosion resistance.
-Fuel compatibility: leaded and unleaded gasoline, methanol, ethanol, E85, etc.
-Optional fuel surge tank level switch and diagnostic LED failsafe port.
-Rollover vent valve protection 

In addition to all previous FCST features, the new FCST-X rendition is packed with innovations.
-Fast lift and surge pump access (9 bolts total)
-Integrated lift handle for fuel pump servicing
-Compatible with up to 4 brushless fuel pumps
-Up to 4 Bosch BR540 fuel pumps (DW400) 
-Up to 3 Ti Automotive E5LM brushless pumps
-Up to 4 brushless Bosch pumps (DW440)
-Compatible with 16AN inlet mechanical pumps
-Easily swappable pump modules (sold separately)
-Lightweight surge tank with increased volume
-Compatible with shrouded level sensors
-Designed with less potential leak points
-Improved fluid control for quick filling
-Optimized internal fluid management
-Enhanced roll over protection
-Anti-rotation electrical terminals

To install a Radium Engineering FCST-X into a fuel cell, the following criteria must be met:
1. The fuel cell must have the industry standard 6"x10", 24-bolt flange opening.
2. The opening must be on the top face of the fuel cell (i.e. not a side face).
3. The cell depth must be at least 7.7" (196mm) measured from the outer top face to the internal bottom face.

A lift pump scavenges fuel from the bottom of the fuel cell and pumps it into the 2L surge tank. Inside the surge tank canister, up to 3 EFI fuel pumps can be used to feed high pressure fuel to the engine. If the lift pump starves, the volume inside the surge tank canister will keep the surge tank pumps fed and the engine supplied with fuel. The return from the fuel pressure regulator is also routed to the surge tank canister to help keep it full.

There are 3 fill valves integrated to the bottom of the surge tank. These 1-way FKM fill valves are sealed shut unless the fuel level in the cell rises above the fuel level in the surge tank. If this happens, each fill valve opens and sends 355LPH of fuel (1065LPH total) into the surge tank until fuel level reaches an equilibrium. 

Excess fuel in the surge tank simply overflows back into the fuel cell. This dynamic sequence is all done inside the safety of a fuel cell.


The fuel pump outlet port is signified by the "PUMP OUT" engraving. It uses 7/8"-14 threads making it compatible with all 10AN ORB fittings. The FCST-X comes standard with a common 10AN ORB to 8AN male adapter fitting. 

The external "RETURN" port is used for low pressure fuel returning from the FPR. This port uses 3/4"-16 threads making it compatible with all 8AN ORB fittings. The FCST-X comes standard with a common 8AN ORB to 6AN male adapter fitting. 

The "VENT" port is tapped with 1-1/16"-12 threads making it compatible with all 12AN ORB fittings. The FCST-X comes standard with 20-0934 which uses a common 8AN male outlet fitting for standard fuel filling. However, 20-0535 can be purchased separately with a 12AN male fitting for quick fill dry break systems that require a high-flow vent.

The following comes standard with every FCST-X variation.
-Anodized aluminum 6x10 plate
-Anodized aluminum surge tank pump hat
-Anodized aluminum lift pump hat
-Anodized aluminum service handle
-Anodized aluminum level sensor plate
-Anodized aluminum surge pump bracket
-Stainless lift pump mounts (shallow and deep)
-Lift pump and surge pump fuel filters
-Anodized aluminum 8AN roll over vent valve
-FKM refueling rollover protection seal
-FKM 6x10 24-hole sealing gasket
-8AN ORB to 6AN male return fitting
-10AN ORB to 8AN male pump out fitting
-2AN ORB fuel level switch plug
-FKM 1-way fill valves (x3)
-Anodized aluminum acorn nuts
-Electrical wire ring terminals


**NOTE: FCST-X does not come standard with pumps, if you would like to add pumps please contact us**