Radium FPD-XR Inline Fuel Pulse Damper Kit (20-0200)

High base pressure builds broke the old pulse damper rules, so Radium built the XR.

Injector pulses destabilize rail pressure in every EFI system, but returnless and high-pressure setups push past what standard dampers tolerate. The Radium Engineering FPD-XR Inline Fuel Pulse Damper Kit mounts the extended-range FPD-XR in the fuel line itself, absorbing oscillations with its internal diaphragm across a 40 to 105 psi operating range. Where the standard FPD-R requires base static pressure between 40 and 70 psi, the XR covers the high-pressure territory, including systems like a 72.5 psi BMW E46 M3, and in many installs its vacuum/boost reference line is optional rather than mandatory. Inline placement means it works with fuel systems that have no rail port to spare.

What You'll Feel

• Stable rail pressure on high base-pressure and returnless systems the standard damper cannot serve
• Smoother idle and cleaner AFR traces, especially with high flow injectors
• Placement freedom, since the inline kit installs anywhere in the line rather than needing a rail port
• Simpler plumbing in many cases, with the boost reference line unnecessary when pressure stays within 40-105 psi

Features

• FPD-XR extended range damper: 40 to 105 psi fuel pressure operating range
• Inline kit architecture installs the damper in the fuel line with common fittings
• Internal diaphragm absorbs injector-driven pressure oscillations, measurable through the RPM range
• Vacuum/boost reference port; connection unnecessary when pressure remains within range, required if pressure can fall below 40 psi under vacuum
• Mountable at any angle, including upside down

The Details

Choosing between the FPD-R and FPD-XR comes down to one number: base static fuel pressure. Radium's own worked examples draw the line clearly. A Mitsubishi Evo at 43.5 psi base with a rising rate regulator can run either damper, though the standard FPD-R needs its boost reference connected since pressure climbs to 73.5 psi at full boost. An E46 M3 at 72.5 psi base exceeds the FPD-R's 40 to 70 psi requirement entirely, and only the XR applies. The XR's wider window also relaxes the reference line rules: if maximum pressure stays under 105 psi, the line is optional, though it may still be needed if pressure can fall below 40 psi under vacuum. Beyond damper selection, placement follows the system's evidence: most builds damp at the rail feed, some need multiple dampers, and some benefit from one on the return line. Not compatible with mechanical pumps or the high-pressure side of direct injection systems.

Kit Includes

• 1x FPD-XR fuel pulse damper
• Inline mounting kit with fittings

Applications

• Universal: EFI fuel systems with base static pressure from 40 to 105 psi
• High base-pressure and returnless architectures beyond the standard FPD-R's 40-70 psi window
• Not for mechanical fuel pumps or direct injection high-pressure circuits