Radium Engineering Saddle Fuel Tank Conversion Kit

This innovative fuel transfer system allows the use of two fuel cells for racing vehicles, optimizing fuel capacity and weight distribution. The cells can be mounted strategically for optimal weight distribution and a low center of gravity.

REQUIRED COMPONENTS

Two Radium Engineering Fuel Cells. Different capacity fuel cells can be used. However, the top flanges of each fuel cell must be mounted at the same height.

One Radium Engineering FCST-X Surge Tank. Previous FCST (non-X version) surge tanks are not compatible as they do not have the required lift pump access (FCST-X handle).

At least 3 fuel pumps are required (2 lift pumps and 1-3 surge tank pumps). When purchasing lift pumps, make sure they have integrated check valves on the outlets. Pumps without check valves can cause backflow and malfunction.

Remote fill and vent kit or remote mount refueling kit. Since it includes 1.5” ID tubing, any remote mount fuel filler neck with a 1.5” OD connection is compatible. The system is compatible with standard and dry break refueling systems.

RECOMMENDED

One or two Radium Engineering Fuel Level Sensors. If only one sensor is installed, it is recommended to install it in the active fuel cell. However, two sensors are suggested. NOTE: When two Radium Engineering 0-90 Ohm fuel level sensors are wired in series, a new range of 0 (empty) to 180 (full) ohms is created. If connected to separate inputs of a programmable ECU, the passive side level sensor can also be used to control the passive side lift pump activation/deactivation. This will prevent the pump from running when the passive side cell is empty.

Radium Engineering Fuel Level Switch 20-0461. This component installs into the 1/8” NPT port located on the bottom plate of the fuel surge tank. This can trigger a relay or provide an input to the ECU to control the active side lift pump. When the fuel level float is in the high position (fuel surge tank = full), the active side lift pump can be turned off.

NOTES

The FCST-X rollover valve is removed, and the vent port becomes the overflow for air and fuel to return to the passive side. The rollover valve vent fitting is relocated from the FCST-X to the new fuel cell vent port on the passive side.

Due to the new location of the vent fitting, it is mandatory for the active fuel cell to fill just before the passive fuel cell. Depending on the orientation of the 1.5” OD stainless steel tee for the fuel filler tubing, the refueling hoses can be routed in two ways. This will depend on the location of the vehicle's fill hole.

The tee can be oriented vertically or horizontally to change which fuel cell fills first. Observe how the fuel filler cap (fender mounted) shifts to the opposite side of the system depending on the tee connection orientation. This is based on the path of least resistance (fluid dynamics).

The kit allows units to be mounted in the vehicle both transversely and longitudinally. Fittings and hoses for both configurations are included.

Custom logic will be required to control the passive cell lift pump. This will need to use a resistance signal from the level sensor to know when the passive cell is empty, so that the passive side lift pump can be turned off at that time.

The active fuel cell lift pump can be controlled by the fuel level diagnostic switch. It will activate whenever the surge tank level drops.