Radium Fuel Surge Tank, Standard Single, Pump Not Included

Radium Engineering Fuel Surge Tank, Standard, Single Pump, Pump Not Included - Part #20-0960

Fuel starvation on a K-swapped Civic or an S2000 shows up as a lean hit in a long corner at a quarter tank, and no amount of fuel pump fixes it, because the pickup is sucking air. A surge tank does: a small reservoir with its own pump that the main tank's pump keeps full, so the engine feeds from a canister that never sloshes empty. Radium's standard FST is the single-pump version, 1.5 liters, built for a 39mm in-tank pump of your choice, and sold here without the pump.

What It Is and Why It Works

The FST is an extruded and machined aluminum canister, bright-dip anodized and laser engraved, with O-ring sealed billet caps top and bottom. The factory tank pump feeds it, the pressure regulator's return fills it, and the pump inside it feeds the engine at full pressure from a reservoir that's always full. The lid carries 6AN male ORB feed and return fittings, and the pump wiring exits through a nickel-plated electrical bulkhead with 24 inch flying leads. Inside, Radium uses PTFE-insulated wire and submersible hose, so the whole tank is E85 and methanol compliant. The 20-0960 fits a single 39mm pump: Radium sells this same tank preloaded with a Walbro GSS342, a Walbro F90000274, or an AEM 50-1200, and this is the tank alone for anyone with a pump on the shelf. Extra O-rings and stainless hardware are in the box.

Specs

Fitment

Not vehicle-specific. Returnless cars (06-09 S2000, most late-model Hondas) need the FST-R with the integrated regulator instead; this tank needs a return line.

What to Know Before You Buy

You need a pump, a bracket, a low-pressure lift pump in the main tank, and lines, and Radium sells vehicle-specific install kits that cover the bracket and hoses for cars like the S2000. Wire the surge tank pump on its own relay and fuse; Radium's 17-0031 kit is the right size. Pick the pump for the power target, not the biggest one; a 450 in a surge tank is loud, and the GSS342 covers most naturally aspirated K-swaps. The factory in-tank pump becomes the lift pump and only has to keep 1.5 liters topped up, which it will do all day. Mount the tank upright and low, and give the return line a straight shot back to the main tank.