Radium FD3S Rx7 Surge Tank Fuel Pump Upgrade ( No Pumps)


Integrated Surge Tank
A fuel surge tank (FST) is the best solution in preventing fuel starvation. Since 2009, Radium Engineering has been designing numerous FSTs for multiple applications. But after some sanctioning bodies banned externally mounted FSTs, Radium built the first production fuel cell with an integrated surge tank (FCST). Because the FD RX7 can experience high lateral Gs, it inherently suffers from fuel slosh. Fortunately, Mazda manufactured a gas tank with a very large bolt flange pattern (similar to the FCST) permitting various upgrading options. 

The custom designed stainless electrical studs easily handles the high current demand that compact bulkhead connectors lack. These serviceable connections are properly sealed and impervious to all standard and exotic fuels. Nylon acorn nuts are provided to prevent any accidental short circuits. Furthermore, the high quality in-tank wiring is insulated with chemically resistant PTFE. Electrical hardware is included for the fuel pump(s), OEM level sender, and OEM temperature sensor.

The lift pump sends low pressure (high volume) fuel in the FST through a special deflector in the bottom of the surge tank canister. The 24 hole diverter evenly disperses fuel inside the canister preventing air bubbles and foaming. When a low demand for fuel is present, the canister will overflow back into the OEM sub tank

The 1" check ball allows fuel into this tight area during acceleration and traps fuel in during deceleration.

For the high pressure pumps supplying fuel to the engine, a bespoke stainless steel triple pump mesh strainer is included for proper inlet filtration.

For a proper FST to function, a lift pump is necessary to maintain volume within the surge tank. This lift pump is located in the rear portion of the OEM sub tank within the Mazda gas tank. Included in the kit is a lift pump mount that snaps onto 3 sides of the OEM sub tank. It also serves as a baffle keeping the lift pump supplied with fuel. Measures were taken to ensure that the lift pump always has fuel to deliver to the surge tank.

Because all compatible fuel pumps utilize integrated check valves, the high pressure pump outlets merge into a single 10AN billet collector.

This system is compatible with the following fuel pumps( not included on this particular variation )


F90000267  ( 450lph E85/Pump Gas) 
F90000274 (450/460lph High Pressure E85/Pump Gas )
F90000285 ( 525lph E85/Pump gas " Hellcat" ) 

-Drop-In OEM Replacement
-Permits 1-3 Surge Pumps plus 1 Lift Pump 
-8AN Male Pump Outlet Fitting
-6AN Male Return Inlet Fitting
-Fuel Starvation Protection
-High Current Electrical Hardware
-Anodized Aluminum Construction
-Gasoline and Ethanol Compliant

-Anodized Aluminum 8AN Male Fitting for Feed
-Anodized Aluminum 6AN Male Fitting for Return
-Anodized Aluminum 8.5mm Barb Hose Ends for OEM Feed/Return
-Anodized Aluminum Surge Tank Canister
-Anodized Aluminum OEM Fuel Sensor Mount
-Anodized Aluminum Lift Pump Baffle and Check Ball
-Fuel Resistant Submersible PTFE Tubing
-Fuel Resistant PTFE Insulated Wiring
-Stainless Electrical and Mounting Hardware
-Stainless Steel Mesh Triple Pump Filter


1. When purchasing "No Pumps Included", the kit will come preassembled as shown above. 
2. There will be enough components included with this option to run all 4 fuel pumps. Depending on the setup, some parts will simply not be used.
3. Because this kit includes a bespoke fuel pump inlet screen, the sock filters that typically come standard with these types of pumps are not required.