Radium Engineering 20-1989 Surge Tank Extension Kit FCST-X 3.7" 1.2 L

Vehicle Fitment

• Universal (for use with Radium FCST-X 3.7" fuel surge tanks or similarly sized tank systems)

Features

• Extension kit designed to increase fuel surge tank capacity by approximately 1.2 litres.
• CNC-machined aluminium construction provides durable, lightweight upgrade to existing tank module.
• Specifically engineered for mounting to deep-cell designs with minimum 3.7" (≈94 mm) internal diameter and 12" internal depth.
• Provides improved fuel supply stability under high-G, cornering or boosted conditions by increasing available fuel volume in the tank/hanger system.
• Retains existing surge tank features - no change to pump hangers or plumbing required when used as directed.
• Ideal for high-flow, track, drag or endurance applications where fuel starvation is a risk.
• E-fuel/E85 compatible when used in properly configured fuel systems and with matching plumbing components.
• Designed as an add-on module - requires the Radium FCST-X 3.7" tank or similar system for installation.

Specifications

• Capacity extension: +1.2 litres of fuel volume.
• Intended internal tank diameter: 3.7" (≈94 mm) or greater; tank internal depth: minimum 12" required.
• Construction material: Billet/precision aluminium, anodised finish.
• Installation type: Extension module for existing fuel surge tank; designed to fit between pump hanger and tank top plate or as a spacer ring.

Included Components

• 1x Radium 20-1989 extension kit module.
• Sealing ring/gasket for integration with tank or module.
• Mounting hardware kit (bolts, washers) for drop-in or replace-in installation.

Product Description

The Radium Engineering 20-1989 Surge Tank Extension Kit is a performance fuel system upgrade designed for use with Radium's FCST-X 3.7" series fuel surge tanks (or equivalent internal dimensions). By adding approximately 1.2 litres of additional volume to the tank assembly, the kit enhances fuel supply stability during high G-loads, aggressive cornering, or high-flow demands - helping to prevent pump starvation or fuel slosh in competitive or tuned applications.

Installation is straightforward when used with a compatible tank system: the module integrates seamlessly, retaining existing pump hangers, senders and plumbing. Ideal for track day cars, drag specials, turbocharged builds or any performance application where fuel supply reliability is critical, the 20-1989 extension offers a smart way to boost system capacity without the expense of replacing the entire tank or plumbing.