If you are searching for a radium fuel pump, you already know the brand and you already know your platform. The question is not which brand - it is which exact configuration delivers enough fuel to your injectors without starving, surging or leaning out on a hard pull. This guide walks through the pump-related Radium Engineering hardware we hold in the UK, so you can match the right parts to your power target and your tank before you order.
Start with your fuel demand, not your pump
Every pump decision starts with a flow number. Add up your injector size, your target boost, your base fuel pressure and your fuel type, then pick a pump that covers that demand with headroom - not one that just barely meets it at 100 percent duty cycle. E85 makes this worse: it demands roughly 30 percent more volume than pump gasoline for the same power, so a setup that is fine on 99 octane can run out of fuel on corn.
Once you know your litres-per-hour target, the rest of the system falls into place. A high-flow pump in a stock tank is a good start, but forced induction and circuit use expose the weak points fast: fuel slosh away from the pickup, pressure pulses from big injectors, and vent lines that cannot keep up.
In-tank hangers and pump clamps
The first decision is how the pump mounts. Radium offers drop-in hanger assemblies for platforms like the Mitsubishi EVO and Subaru WRX that replace the stock basket with a housing built to hold a larger pump. Pick the hanger that matches your tank and your intended pump body diameter, and check the flow rating - a hanger that chokes a big pump is wasted money.
If you are reusing a factory collector hanger, bore size matters more than most builders expect. The Radium pump clamp for 41-43mm bodies swaps the stock 38-39mm clamp for a two-piece unit that grips a 41-43mm pump - exactly what you need when upgrading a platform like the JZX90 or JZX100 to a bigger in-tank pump.
Surge tanks: MPFST-R and FCST-X
Once you are chasing serious power or track time, a surge tank is the difference between a clean pull and a lean spike out of a long corner. Radium does this two ways.
The Radium MPFST-R fuel surge tank is the compact, multi-pump option. It accepts up to three high-flow pumps, fits common bodies including the Walbro GSS342, AEM 50-1200 and DeatschWerks DW440, and has a built-in regulator that returns low-pressure fuel straight into the tank rather than heating it in the return line.
If you want the surge tank integrated into the fuel cell itself, the Radium FCST-X is a 2-litre surge tank preassembled with one lift pump and one surge pump, with 10AN pump-out. It needs a 6x10, 24-bolt cell flange, so confirm your cell before ordering. Both routes solve the same problem: a constant fuel column at the pickup no matter how hard the car corners or launches.
The pumps themselves
Radium does not force you into a single pump brand, and that flexibility is the point. The MPFST-R and FCST-X list both surge and lift pump options across Walbro, AEM and DeatschWerks. Choose your pump by flow at pressure, not by headline flow at zero bar - a pump rated 340lph free-flow can drop well below that at 4 bar with boost reference on top.
- Walbro - the benchmark in-tank workhorse, available in GSS342 and F90000274 formats across the surge tank range.
- AEM 50-1200 - a common upgrade path when you want more flow in the same footprint.
- DeatschWerks DW440 - the high-flow end of the range, ideal when E85 and big injectors push demand up.
Match the pump to the hanger or surge tank you chose, and size the lift pump separately from the surge pump. The lift pump only has to keep the surge tank fed; the surge pump has to feed the rail.
The supporting hardware that keeps it reliable
A pump is only as good as the parts around it.
The Radium venturi jet pump kit transfers fuel from one side of a saddle-style tank to the other, and ships with different venturi orifices so you can match it to your pump's flow rate. Without it, one side of the tank can run dry while the other still reads half full.
Big injectors also hammer the fuel rail with pressure pulses. A Radium fuel pulse damper absorbs those pulses and stabilises rail pressure, cleaning up idle surge and erratic lean spikes - and the inline and 3/8 NPT versions add a vacuum/boost reference port for boosted systems running a 1:1 rising-rate regulator.
If you are wiring a competition cell, the fuel cell subharness kit uses a sealed bulkhead connector and 26 labelled preterminated 10AWG wires so pit stops stay quick. And for a full race-cell build, the Radium R06A 6-gallon fuel cell is FIA and SFI approved, with a polymer bladder, anti-slosh foam and anodised fittings.
Matching the setup to your build
- Street car, mild tune, stock tank: a correctly sized in-tank pump in a drop-in hanger, with a pump clamp if you are upsizing the body.
- Boosted street or occasional track: add a surge tank - MPFST-R if you want multi-pump flexibility, and a pulse damper to settle rail pressure.
- Full competition build: FCST-X integrated surge tank or an R06A cell, venturi jet pump to keep the pickup fed, and the subharness for clean wiring.
Order the right Radium fuel pump hardware in the UK
Every part above is genuine Radium Engineering stock, held and shipped from the UK - no waiting on overseas freight, no guessing at fitment. If you know your part number, search it directly; if you are still deciding between an MPFST-R and an FCST-X, our surge tank and fuel pump collections break down the flow specs and pump fitments side by side.
Work out your fuel demand first, choose the mounting route second, and build the supporting hardware around it third. Get those three steps right and your radium fuel pump setup will feed the engine cleanly from idle to redline - on pump gas or on E85.
