The MPFST, FSTR-RA and MPFST-R are different surge-tank configurations. The key decisions are the supported pump count, the exact pump family and whether pressure regulation is built into the tank. “RA” refers to regulator features and should not be treated as a promise of multi-pump capacity.
The three layouts compared
| Model | Pump arrangement | Pressure regulation |
|---|---|---|
| MPFST | Multi-pump; capacity depends on the exact version | Uses an external regulator |
| FSTR-RA / FST-R | One internal pump | Integrated regulator |
| MPFST-R | Multi-pump; check the selected configuration | Integrated regulator |
The FSTR-RA is a single-pump unit. Choose a multi-pump model if the design calls for more than one engine-supply pump; do not buy the FSTR-RA expecting to expand it to three.
Match the part number to the pump
Do not use one pump-compatibility list for an entire model family. Radium publishes separate configurations for different pump packages. A pump that fits one MPFST-R version may require another version or different hardware elsewhere in the range.
Compare the exact pump name, tank part number, optional components and installation notes before ordering from our fuel surge-tank collection. For current compatibility details, use the manufacturer references below.
Decide where the regulator belongs
An external-regulator layout and a tank with integrated regulation use different plumbing arrangements. Draw the fuel path before buying fittings, showing supply, engine feed and overflow, plus any regulator return required by the chosen system.
Use the correct diagram for the exact model. The presence of an integrated regulator changes the route; it does not remove the need to return excess fuel to the main tank where specified.
Check capacity beyond the number of pumps
Choose pumps by their flow at the required pressure, fuel and voltage. Then check lift-pump delivery, electrical capacity, line restrictions and how the pumps will be controlled. Adding pumps without designing the supply and wiring can leave the original limitation unresolved.
If staged operation or a fuel-level switch is planned, review the pump-specific restrictions before ordering. Physical fit and correct operation are separate checks.
Choose the layout that suits the build
- Considering external pressure control? Review the appropriate MPFST configuration.
- Need one engine-supply pump and integrated regulation? Review the FSTR-RA.
- Need multiple pumps and integrated regulation? Review the appropriate MPFST-R configuration.
Confirm dimensions, mounting access, included fittings and pump inclusion for the selected listing. Use our FST installation-planning checklist to turn the chosen layout into a complete parts list.
Manufacturer references
- Radium MPFST specifications and pump configurations
- Radium FST-R / FSTR-RA specifications
- Radium MPFST-R specifications and pump configurations
Related guides
- Fuel surge tank buying guide: what to consider
- Radium Surge Tank vs Fuel Cell: Picking the Right Fuel Delivery Upgrade
- Radium Engineering FST Guide: Fuel Surge Tank Setup
Help choosing your parts
RadiumShop UK is an authorised Radium Engineering distributor. Contact us with your vehicle, model year, engine, fuel type and intended use for help identifying suitable parts. Check the product page or ask us to confirm availability before arranging delivery or collection.
