There are several advantages to this unique system:
1. The FHST independently supplies fuel to the port injectors, while the direct injection system remains undisturbed using the OEM fuel pump. Because of the high pressure spikes created by the mechanical high pressure fuel pump (HPFP), the Huracan/Type 4S restricts port injection fuel rails using an orifice fitting that makes upgrading the port injectors not very efficient. Now that these fuel systems are separate, these 2 restrictive fittings will no longer be used.

2. The surge tank functions to ensure that a fuel reserve is kept trapped around the aftermarket fuel pump to prevent starvation. Unlike the OEM fuel system, which uses a small single pump collector in the RH tank, this system uses an additional (surge tank) collector in the LH tank to prevent pump cavitation at high power levels.

FEATURES

-Drop-In Installation
-Brushless Fuel Pump Compatibility
-Fuel Starvation Protection
-Additional Port Injection Potential
-Prevents Cavitation in High Power Applications
-High Current Electrical Hardware
-Compatibility with Popular Fuel Pumps
-Anodized Aluminum Construction
-Gasoline, Methanol, and Ethanol Compliant
-Fuel Resistant Tubing and Wiring
-Stainless Steel Hardware

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⁽³⁾
*Walbro F90000274⁽³⁾
*Walbro F90000285⁽³⁾
*Walbro F90000295⁽³⁾
*Walbro GSS342⁽³⁾
*AEM 50-1200⁽³⁾
**Bosch BR540⁽⁴⁾
**Deatschwerks DW400⁽⁴⁾
**Deatschwerks DW440 (brushless)⁽⁴⁾
**Deatschwerks DW810 (brushless)⁽⁴⁾
**Protec 11928 (brushless)⁽⁴⁾
**Fuelab 49614 (brushless)⁽⁴⁾
*Injector Dynamics BPC1000 (brushless)⁽⁴⁾
*Ti Automotive BKS1001 (brushless)⁽⁴⁾

⁽³⁾Sock filters are provided in this kit (20-0860) for these pumps.
⁽⁴⁾Sock filters are included from the fuel pump manufacture.

HOW THE FHST WORKS

The OEM system contains a fuel pump, fuel pressure regulator (FPR), fuel filter and multiple venturi jet pumps (not shown below). 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:

• 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. This OEM jet pump was flow tested at Radium Engineering to be 302LPH (max)
• The returning fuel from the aftermarket FPR (included in port injection plumbing kit) enters the FHST canister through a diverter (shown below) to prevent aeration and fuel foaming.
• The three 1-way fill valves at the bottom of the surge tank flow 355LPH each (1,065LPH total).

NOTES

• The early and late fuel tanks are slightly different. For the later GEN2 R8 (Type-4S) and Huracan, the FHST resides just above the OEM jet pump and fuel level sensor. On these cars, we recommend running a 1/2 tank (minimum) for track use.
• For the GEN1 R8 Type-42 and Gallardo, this is NOT required. The FHST sits at the very bottom of the factory tank allowing all the fuel to be drawn into the FHST through these valves (shown).

PLUMBING

Shown is a common plumbing scheme for Lamborghini Gallardo LP and Gen1 Audi R8 (Type-42) vehicles. This includes Radium Engineering 20-0865 port injection kit and 20-0967-XX plumbing kit.

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.

20-0868 FHST EXTENSION ADD-ON

This extension kit permits an additional 0.2L (7oz) of fuel using a 1.5' (39mm) deeper canister.

COMPATIBILITY

Audi R8 Gen2 Type4S
Lamborghini Huracan LP580-2
Lamborghini Huracan LP610-4
Lamborghini Huracan LP640-4
Lamborghini Huracan EVO
Lamborghini Huracan STO
Lamborghini Huracan Tecnica

Because of fuel tank depth, this kit is NOT compatible with Audi R8 Gen1 Type42 or Lamborghini Gallardos.

As shown below, an extension section mounts between the canister and the bottom cap. It strategically locates the bottom area of the FHST to clear the fuel level sensor. 

Longer tubing and a longer pump bracket are included to keep the fuel pump inlet at the bottom of the surge tank. Also a stainless steel mount is provided to secure the OEM venturi jet pump out of the way.

INCLUDES

• Canister, Mid Section
• Canister O-rings, FKM (x3)
• Convoluted Tubing, Large ID
• Convoluted Tubing, Small ID
• SS Venturi Jet Pump Mount
• SS Pump Bracket, Extended
• SS EFI Clamps, Large ID (x2)
• SS EFI Clamps, Small ID (x2)
• SS Socket Head Screws (x6)
• Thread Forming Nuts (x2)
• Zinc-Plated Steel Screws