The Radium Engineering Fuel Hanger Surge Tank (FHST) is a drop-in aftermarket fuel pump solution for maximizing power potential. The FHST system independently supplies fuel to the port injectors, while the direct injection system remains undisturbed using the OEM fuel pump. The surge tank functionality ensures that a fuel reserve is kept trapped around the aftermarket fuel pump to prevent fuel starvation.

HOW THE FHST WORKS

The OEM system contains a fuel pump, fuel pressure regulator (FPR), fuel filter and multiple venturi jet pumps (not shown in diagram above). In factory form, the OEM fuel pump supplies fuel to the engine through the fuel filter which has an integrated FPR. This pressure regulated fuel is also used as the driving force for multiple venturi jet pumps. These OEM venturi jet pumps transfer fuel from opposite ends of the fuel tank to the OEM pump basket keeping it full.

The Radium FHST drops into the LH opening of the fuel tank which is the opposing side of the OEM fuel pump on the RH side of the fuel tank. It does NOT disrupt any aspect of the OEM fuel system and still uses all OEM fuel level sensors. Fuel is still supplied to the engine using the OEM pump, OEM filter, OEM FPR, and OEM venturi jet pumps. The FHST uses a separate pump outlet and return inlet making it ideal for an independent port injection or custom fuel system.

The FHST canister is supplied with fuel from the 3 following sources:

1. The LH OEM venturi jet pump now fills the FHST canister first and then the overflow bleeds into OEM fuel pump basket, just like factory.
2. The returning fuel from the aftermarket FPR (included in 20-0867-03 and 20-0867-05) enters the FHST canister through a diverter (shown below) to prevent aeration and fuel foaming.
3. The three 1-way fill valves at the bottom of the surge tank flow 355LPH each (1,065LPH total). As depicted, they allow fuel in, but not out.

PLUMBING

Shown above is a common plumbing scheme for Lamborghini Gallardo LP and Gen1 Audi R8 (Type-42) vehicles. This includes Radium Engineering 20-0865 and 20-0867-03 or 20-0867-05. For Lamborghini Huracan and Gen2 Audi R8 (Type-4S) vehicles, consult with your tuner to get the most out of this system.

ELECTRICAL

The custom designed 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 and the OEM level sensors. Furthermore, the in-tank wiring is insulated with high quality chemically resistant ETFE. A relay kit, such as 17-0031, is recommended to drive this new internal FHST fuel pump.

PUMP COMPATIBILITY

This system requires a single aftermarket fuel pump (sold separately). The following aftermarket fuel pumps are verified to be compatible with the FHST:

• *Walbro F90000267
• *Walbro F90000274
• *Walbro F90000285
• *Walbro F90000295
• *Walbro GSS342
• *AEM 50-1200
• **Bosch BR540
• **Deatschwerks DW400
• **Deatschwerks DW440 (brushless)
• **Protec 11928 (brushless)
• **Fuelab 49614 (brushless)
• *Ti Automotive BKS1001 (brushless)

*Sock filters are provided in this kit (20-0860) for these pumps. **Sock filters are included from the fuel pump manufacture.