Radium Engineering MPFST, Multi-Pump Fuel Surge Tank

Radium Engineering MPFST, Multi-Pump Fuel Surge Tank

Click here to download installation instructions (PDF)

What is a fuel surge tank?

A fuel surge tank (FST) is designed to prevent fuel starvation to the engine on vehicles with inadequate fuel tank baffling. Fuel is supplied to the surge tank by a lift pump, which in most cases is the OEM in-tank fuel pump.  The volume of fuel inside the surge tank acts as a buffer to always keep the FST pump(s) supplied with fuel, even if the lift pump starves momentarily.

This volume is maintained by the lift 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. The surge tank also provides a quick and easy way to upgade any standard fuel system without opening the stock fuel tank. This is an excellent fueling solution for vehicles installing large demand power upgrades such as forced induction.

Multi-Pump Fuel Surge Tank (MPFST)

Recently redesigned for 2024, the Radium Engineering MPFST is the perfect solution for high power vehicles experiencing fuel starvation during aggressive driving. Multiple high flowing fuel pumps can be used in the surge tank.

NEW FEATURES

In addition to all previous MPFST features, the new MPFST rendition is packed with innovations.
-Up to 3 Bosch BR540 fuel pumps (DW400) 
-Up to 2 Ti Automotive E5LM brushless pumps
-Up to 3 brushless Bosch pumps (DW440)
-Anti-rotation electrical terminals

The outlet from the fuel pumps merge into a single outlet simplifying external plumbing. And because the compatible pumps utilize check valves, staging is permitted.

NOTE: The brushless Ti Automotive E5LM MPFST includes check valves (shown below in green).

The brushless Ti Automotive E5LM MPFST pump outlet merge collector shown below.

This "FUEL PUMP OUTLET" port is 10AN ORB threaded but comes preinstalled with a -8AN male adapter fitting. The "OVERFLOW", "SUPPLY", and "RETURN" ports are all 8AN ORB threaded but come preinstalled with -6AN male adapter fittings. All of these fittings can be swapped out with different sizes (sold separately).

When fuel enters the MPFST through the "SUPPLY" and "RETURN" ports, it gets redirected and runs tangential through the canister creating a swirl pot. This helps eliminate unwanted air bubbles and fuel foam that can affect fuel pump and engine performance. 

The pumps are mounted using an anodized aluminum bracket. All internal wires are gasoline, ethanol, and methanol compliant. The brushless Ti Automotive E5LM MPFST (shown above) utilizes a standard press-in filter sock included commonly with the pump.

All other pumps use the provided stainless steel mesh inlet screen for pre pump filtration shown above. As depicted below, fuel cannot pass between the 3 independent filtration chambers (A, B, C). NOTE: If less than 3 pumps are installed, the empty port does NOT need to blocked off.

The pump power connections are handled with specially designed high-current electrical studs. Necessary ring terminals and hardware are included with every surge tank.

As shown, the underside of the MPFST is suitable for uneven surfaces commonly found in the trunk of a vehicle. 

Stainless steel M6x1.0mm socket head bolts are included for custom mounting.

20-1440 MPFST, PUMPS NOT INCLUDED, WALBRO GSS342 OR AEM 50-1200 OR DW440

This MPFST comes ready for the end user to install 1, 2, or 3 pumps.

PUMP COMPATIBILITY

Walbro GSS342
AEM 50-1200
Deatschwerks DW440

NOTES:

1. There are many other compatible pumps that use this same physical package.
2. Because of the size, 3 pump can NOT be installed if using the optional fuel level switch.

20-1441 MPFST, PUMPS NOT INCLUDED, BOSCH BR540 OR DW400

This MPFST comes ready for the end user to install 1, 2, or 3 pumps.

PUMP COMPATIBILITY

Deatschwerks DW440
Bosch BR540 (does not come with a check valve)

20-1442 MPFST, PUMPS NOT INCLUDED, WALBRO F90000267/274/285

This MPFST comes ready for the end user to install 1, 2, or 3 pumps.

PUMP COMPATIBILITY

Walbro F90000267
Walbro F90000274
Walbro F90000285
Walbro F90000295 (does not come with a check valve)

20-0443-00 MPFST, PUMPS NOT INCLUDED, TI AUTOMOTIVE E5LM

This MPFST comes ready for the end user to install 1 or 2 pumps. 

PUMP COMPATIBILITY

Ti Automotive E5LM

OPTIONS

20-0461 Fuel Level Switch, 1/8 NPT

The Multi-Pump 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 MPFST 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.

NOTE: The level switch is not compatible with 3 Bosch BR540 or 3 Deatchwerks DW400 pumps. These pumps are too big.

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.