Radium Engineering FHST Extension Add-on Audi R8 Type-4S Lamborghini Huracan

20-0868

20-0868 FHST EXTENSION ADD-ON

• 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

NOT compatible with Audi R8 Gen1 Type42 or Lamborghini Gallardo.

The Radium Engineering Fuel Hanger Surge Tank (FHST) is a drop-in aftermarket fuel pump solution for maximizing power potential. This system works in conjunction with the OEM fuel pump system to provide reliable fueling for direct and port injectors. It's sophisticated design uses venturi jet pumps to ensure all fuel is scavenged from the fuel tanks.

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.

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).

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