Product Overview
What makes Radium FPDs unique?
Along with having the flexibilty of using common fittings, Radium Engineering FPD's use a vacuum/boost reference port which allows for proper fuel pulse damper performance even at elevated fuel pressures. This becomes essential for boosted systems that use a 1:1 rising rate fuel pressure regulator.
What is the difference between FPD-R and FPD-XR?
The FPD-R (green top) is slightly shorter than the FPD-XR (black top) allowing it to be used in space-contrained applications.
WHICH DAMPER DO I CHOOSE?
The FPD-R (Fuel Pulse Damper-Range) and FPD-XR (Fuel Pulse Damper-Extra Range) both have unique base "static" fuel pressure requirements:
FPD-R base pressure requirement = 40 - 70psi (static)
FPD-XR base pressure requirement = 40 - 105psi (static)
Base pressure is the fuel pressure measured when the fuel pump is running WITHOUT a vacuum line connected to the regulator.
IMPORTANT: The ranges above are base static fuel pressures only. Any dynamic fuel pressure created by a rising-rate FPR outside of this range is acceptable, but only when the base "static" fuel pressure is set within these ranges and the vacuum/boost reference line is connected.
Example 1:
Vehicle: Mitsubishi EVO
OEM Base Static Fuel Pressure: 43.5psi
Boost Pressure: 30psi
Rising Rate Pressure Regulator? Yes
Can I use a FPD-R? Yes. Even though fuel pressure is 73.5psi at full boost, the FPD-R will work because the base static pressure was set within the 40-70psi requirement. However, the vacuum/boost reference line must be installed.
Can I use a FPD-XR? Yes. Also, the vacuum/boost reference line does not need to be installed since maximum fuel pressure does not exceed 105psi.
Example 2:
Vehicle: BMW E46 M3
OEM Base Static Fuel Pressure: 72.5psi
Boost Pressure: 20psi
Rising Rate Pressure Regulator? Yes
Can I use a FPD-R? No. Base static fuel pressure exceeds the 40-70psi requirement.
Can I use a FPD-XR? Yes. Also, the vacuum/boost reference line does not need to be installed since maximum fuel pressure does not exceed 105psi.
Features
1. Male Fitting Selection:
a. The 8AN ORB versions seal using a FKM O-ring.
b. The 3/8" NPT variations seal with the tapered pipe threads.
2. Vacuum Port Orientation:
a. Because 20-0178 and 20-0179 use tapered threads (NPT), the vacuum port can be clocked to the desired location.
b. Even after tightened, the newest 8AN ORB dampers (20-0776 and 20-0777), will swivel permiting the vacuum port to be clocked 360 degrees. 20-0776 shown below.
3. This product is safe for use with all fuel types including alcohol blends such as E85.
Included
-Anodized and laser engraved aluminum top, R=range or XR=extra range
-Anodized aluminum body with male threads, 8AN ORB or 3/8" NPT
-Stainless steel hardware
-Rubber vacuum hose, 4mm ID
-Vacuum hose Y-fitting 
Part number 20-0776 shown above. Part number 20-0777 shown below.
ADD-ON: 14-0600 6AN ORB Male to 8AN ORB Female
This fitting adapts the fuel pulse dampers to connect directly to a 6AN ORB fuel rail.
Simply screw this 6AN ORB adapter directly to the 8AN ORB fuel pulse damper fitting.
