Radium Engineering FST, Fuel Surge Tank, Single Pump

Click here for volumes & dimensions (PDF)

A fuel surge tank (FST) is designed to prevent starvation to the engine on vehicles with inadequate fuel tank baffling. The surge tank also provides a quick and easy way to upgade any standard fuel system without the need to modify the stock fuel tank or pump. It is also an excellent fueling solution for vehicles installing large fuel demand power upgrades such as forced induction.

HOW AN FST WORKS

The volume of fuel inside the surge tank acts as a buffer to always keep the FST pump supplied with fuel. This volume is maintained by the main fuel tank's pump as well as the fuel returning from the fuel pressure regulator. Excess fuel in the surge tank is returned back to the vehicle's main fuel tank. 

PLUMBING

All adapter fittings on top of the FST are 6AN (9/16"-18) male.

1. The internal FST pump directly feeds the fuel rail(s), through the green 6AN bulkhead fitting. The pump outlet fitting is available in -6AN male size only.
2. The 3 black (interchangeable) 6AN ORB fittings are used for the following. 
a. Fuel entering the FST (from the lift pump)
b. Fuel overflowing and leaving the FST (to main tank)
c. Fuel returning from the fuel pressure regulator

NOTES: 

1. An internal flow deflector prevents fuel foam and aeration on all 3 ports.
2. The pumps mount internally using tubing that is gasoline, ethanol, and methanol resistant. 
3. The overflow to the main tank is a requirement on all installations. Tanks without return ports will need customization of the hanger top or filler neck to create a port for the overflow.

ELECTRICAL

The stainless electrical studs easily handle the high current demand that compact multi-pin bulkhead connectors lack. These serviceable connections are hermetically sealed and impervious to all standard and exotic fuels. Non conductive anodized aluminum acorn nuts are provided to prevent any accidental short circuiting. Electrical hardware is included for the fuel pump. Furthermore, the in-tank wiring is insulated with high quality chemically resistant ETFE. Relay kits, such as 17-0031, are recommended to drive these new internal fuel pump. 

PUMP COMPATIBILITY

This system supports the following fuel pumps (sold separately):

*Walbro F90000267
*Walbro F90000274
*Walbro F90000285
*Walbro F90000295
*Walbro GSS341
*Walbro GSS342
*Walbro GSS341
*AEM 50-1000
*AEM 50-1200
*AEM 50-1220
**Bosch BR540
**Deatschwerks DW400
**Deatschwerks DW440 (brushless)
**Deatschwerks DW810 (brushless)
**Protec 11928 (brushless)
**Fuelab 49614 (brushless)
*Ti Automotive E5LM (brushless)

*Sock filters are provided in this kit for these pumps.
**Sock filters are included from the fuel pump manufacture.

INCLUDED

-Extruded anodized aluminum 1.5 liter canister
-Removeable O-ring sealed billet aluminum caps
-6AN O-ring fittings (other sizes found HERE)
-Corrosive resistant stainless steel hardware
-Stainless clamps for 39-45mm diameter pumps
-Large and small ID pump connections
-Plug and Play pump wiring
-Pre fuel pump sock filters
-Anti-rotation Electrical Terminals

MOUNTING OPTIONS

The fuel surge tank can be installed almost anywhere in the vehicle. However, mounting near collision prone areas, heat sources, or moving parts such as suspension components should be avoided. NOTE: The FST can be mounted anywhere from vertical to horizontal. Choose a bracket below that best fits the application.

Floor and Wall Mount: This bracket is laser cut from aluminum and powder coated black and can be mounted on the side or bottom of the surge tank.
Frame Mount: Because this bracket has a 90deg formed bend and is cantilevered, it is constructed from steel for superior strength. It is not only nickel plated to resist corrosion, it also allows for components to be grounded to the spare hole in the bracket. This assumes the bracket is mounted to an electrically conductive material such as a steel frame.
Angled Mount: This mounting bracket is used for vehicles that may have a limited mounting height. It can be mounted on a floor and against a wall. This bracket is made from laser cut aluminum and powder coated black.

CLICK HERE FOR MOUNTING DIMENSIONS

LEVEL SWITCH OPTIONS

20-0461 Fuel Level Switch, 1/8 NPT

The fuel surge tank comes standard with a 2AN ORB plug in the "level switch" port, as shown below. 

When the plug is unscrewed, this 1/8" NPT fuel level switch can be installed from underneath, as shown below. 

When fuel level in the FST drops by 20% or more, a switched signal can be sent to a unit such as a dashboard mounted indicator or programmable ECU input for safety purposes.

The level switch is constructed of corrosion resistant stainless steel compatible with all fuel types. It includes 24" long, 20AWG flying leads. Polarity can easily be reversed by removing the E-clip and flipping the float. Apply PTFE thread sealant to the tapered 1/8" NPT threads when installing.

20-0519 Fuel Level Switch Plus Diagnostic Indicator

If the 20-0519 Fuel Level Switch Plus Diagnostic Indicator can be used as a visual reference for fuel level. When the fuel level switch is triggered, the signal is sent directly to the LED.

While often not practical to be viewed while driving, the indicator can be used for diagnosing a potential fueling issue.

20-0519 includes all of the items shown in the following picture.

NOTE: To purchase the diagnostic indicator by itself, click this link 20-0508 Fuel Level Diagnostic Indicator. But know that the 20-0461 fuel level switch is necessary for the diagnostic indicator to work.