A fuel surge tank is an auxiliary reservoir between the main tank and the engine's fuel supply. It gives the engine-supply pump a local reserve when fuel temporarily moves away from the main pickup. It supplements the main tank rather than replacing it.
Why fuel starvation happens
During braking, acceleration or cornering, fuel can move away from a pickup, particularly at a low tank level. If the pump draws air, fuel pressure can be interrupted. The symptoms need diagnosing: restricted filters, poor wiring and an undersized pump can also cause pressure loss.
A surge tank addresses temporary pickup interruption. It cannot repair an electrical fault or support an engine indefinitely when lift-pump supply is inadequate.
How the parts work together
| Part | Purpose |
|---|---|
| Main tank | Stores the main fuel supply |
| Lift pump | Feeds the surge reservoir |
| Surge reservoir | Provides a local buffer |
| Engine-supply pump | Delivers fuel towards the engine |
| Regulator and return/overflow paths | Control pressure and route excess fuel according to the chosen layout |
The precise connections depend on the model. Use the manufacturer's diagram rather than treating every port as interchangeable.
When should you consider one?
Consider a surge arrangement when diagnosis points to pickup starvation during the intended use. A car that maintains adequate supply may not need one simply because it has a higher power target.
Check packaging as well as performance: mounting space, service access, line routes, electrical supply and the main-tank overflow connection affect the installation. Decide how the system will be monitored before full-load use.
Choose your next step
This article explains the principle. Use Fuel surge tank buying guide: what to consider for selection criteria, Radium Surge Tank Guide: MPFST vs FSTR-RA vs MPFST-R for the model differences, and Radium Engineering FST Guide: Fuel Surge Tank Setup after choosing a tank.
Browse Radium fuel surge tanks with your vehicle, fuel type and intended pump details to hand. Confirm the exact configuration and whether pumps are included before ordering.
Manufacturer reference
Radium MPFST operating principle, connections and documentation
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.
