Radium Fuel Surge Tank Regulated FST-RA (20-1933)

The new regulated Radium fuel surge tank (FST-RA) is designed for use with one fuel pump to prevent starvation to the engine on vehicles with inadequate fuel tank baffling.

Vehicle Fitment:
Universal Application
• Install Instructions (PDF)

Compatibility:
The FST-R can be configured with fuel pumps from many manufacturers. Refer to the part numbers on the list below for all known compatible pumps.
• AEM 50-1000 (*1)
• AEM 50-1200 (*1)
• AEM 50-1220 (*1)
• AEM 50-1230 (*1,3)
• AEM 50-1235 (*1)
• Walbro F90000267 (*1)
• Walbro F90000274 (*1)
• Walbro F90000285 (*1)
• Walbro F90000295 (*1,4)
• Walbro GSS341 (*1)
• Walbro GSS342 (*1)
• Bosch BR540 (*2,4)
• Deatschwerks DW440 (*2)
• Deatschwerks DW810 (*2)
• Protec 11928 (brushless) (*2)
• Fuelab 49614 (brushless) (*2)
• Ti Automotive E5LM (brushless) (*1,4)

(*1)Sock filters are provided in this kit for these pumps.
(*2)Sock filters are included from the fuel pump manufacture.
(*3)These pumps do NOT feature a check valve. If this is required, purchase 20-1533.
(*4)These pumps do NOT feature a check valve. If this is required, purchase 20-1534.

Overview:
The Radium fuel surge tank is designed to prevent starvation to the engine on vehicles with inadequate fuel tank baffling. The surge tank pump feeds the fuel rail(s). The volume of fuel inside acts as a buffer to always keep the fuel surge tank pump supplied. This volume is maintained by the main fuel tank's (lift) pump as well as the fuel returning from the fuel pressure regulator.

In the case of the FST-R (fuel surge tank, regulated), the regulator is built into the surge tank and recirculates fuel internally. Excess fuel in the surge tank is returned back to the vehicle's main fuel tank.

Installing a surge tank is also an easy way to upgrade the fuel pump of a vehicle without opening or modifying the OEM fuel tank. The FST-R is suitable with all gasoline types including unleaded, leaded, oxygenated, and pre-mixes. Furthermore, they are compatible with alcohol blends of fuel including methanol, ethanol, and E85.

The FST-R houses a single internal fuel pump and has an integrated fuel pressure regulator machined into the top cap. This eliminates the need for an external fuel pressure regulator along with extra fittings and hoses. It simplifies the installation, reduces overall cost, reduces weight, and eliminates potential leak points in the fuel system. Furthermore, this system permits cooler fuel temperatures as the fuel is not returning from the hot engine bay.

Regulator:
RA-series regulators feature the first tool-less pressure adjustment. A jam nut and set screw are no longer required. With a simple turn of the knob, pressure will be increased or decreased. Additionally, there are no inherent air (vacuum/boost) leaks through the threads that traditionally a smoke detector would pick up.

To aid in adjusting pressure, there are incremental detents that provide haptic feedback to the user. Every detent permits 1psi (+/-0.5psi) of adjustment depending on current fuel pressure. Furthermore, RA-series regulators feature a 360 degree swiveling vacuum reference port that is double O-ring sealed. This is the first in the industry. It permits the installer to quickly point the vacuum fitting in any direction with no tools required.

There are 4 interchangeable 10-32 threaded vacuum port fittings provided to cover all scenarios.

Barbed Fitting: A black zinc-plated 3/16" (5mm) barb machined from high strength steel that is compatible with the following vacuum hoses: 5/32" (4mm), 3/16" (5mm), and 7/32" (6mm)
3AN Male Fitting: A black zinc-plated adapter machined from high strength steel that is compatible with 3AN hose ends
Push-To-Connect: A nickel-plated brass fitting with Buna-N O-rings that is compatible with hard plastic 1/4" OD tubing
Vacuum Plug: A black oxide stainless steel screw that is used to maintain a constant (non dynamic) fuel pressure. Beginning in the mid 1990s, vehicle manufacturers started transitioning to returnless fuel systems to lower EVAP emissions. To keep temperatures lower, these regulators are mounted inside the tank and do NOT have the ability to be vacuum referenced. This plug would be required in this scenario.

Ports and Fittings:
The 2 ports on top are for fuel entering the FSTR-RA (from the lift pump) and fuel overflowing and leaving the FSTR-RA (to the main tank). They are interchangeable and feature an internal flow deflector that prevents fuel foam and aeration. The side port is the regulated pressure output and is plumbed directly to the engine. No additional fuel pressure regulator is required. However, a fuel pressure gauge/sensor is required to set and monitor fuel pressure. It can be located anywhere between the FST-R output line and the fuel rail(s).

All three ports are tapped to 9/16"-18 (6AN ORB). Three 6AN adapters fittings are preinstalled to the ports. Additionally, one 6AN ORB fitting that adapts to 8AN male is provided, if needed.

Electrical:
The anti-rotation stainless steel electrical terminals 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.

The FSTR-RA features a built-in electrical strain relief for the fuel pump wires. A billet aluminum dust cap (shown above) is provided to hide all external wires.

Specs & Features:
• Full CNC aluminum construction
• Anodized for compatibility with all fuel types
• Integrated adjustable regulator
• Optional 1:1 vacuum reference
• Electrical strain relief with wiring dust cap
• Flow deflector to prevent foam and aeration
• 6AN fittings including one 8AN (purchase others HERE)
• FKM O-ring sealed interfaces
• Stainless steel hardware
• Anti-rotation terminals

Additional Notes:
This new 20-1933 design replaces these previous Radium Fuel Surge Tank with Regulator (FST-R) part numbers:
20-0133-00
20-0135-00
20-0129-00
20-0130-00

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