FST Fuel Surge Tank Standard for Deatschwerks DW400 9-401 Radium Engineering - USA-RAD-20-0257-00 - A fuel surge tank (FST) is designed to prevent fuel starvation to the engine on vehicles with inadequate fuel tank baffling. The FST fuel pump(s) directly feed the fuel rail(s). The volume of fuel inside the surge tank acts as a buffer to always keep the FST pump supplied with fuel. This volume is maintained by the main fuel tank's pump as well as the fuel returning from the fuel pressure regulator. Excess fuel in the surge tank is returned back to the vehicle's main fuel tank. The surge tank also provides a quick and easy way to upgade any standard fuel system without the need to modify the stock fuel tank or pump. This is an excellent fueling solution for vehicles installing large fuel demand power upgrades such as forced induction. All Fuel Surge Tanks Include: -Extruded and Machined Aluminum 1.5 Liter Canister -Bright Dipped Anodized and Laser Engraved Housing -Removeable O-Ring Sealed Billet Aluminum Caps  -6AN O-Ring Fittings (8AN can be purchased separately HERE) -Circular Bulkhead Electrical Connector with 24" Flying Leads -Corrosive Resistant Stainless Steel Hardware All pumps mount internally using gasoline, ethanol, and methanol resistant wiring. For dual-pump configurations, each pump is wired independently. All hoses are submersible and E85 safe. The pump outlet fitting(s) are available in -6AN male size only (shown in green). The other ports can be adapted to other -AN sizes using adapters (sold separately). How to Select Your Fuel Surge Tank Configuration Determine if your application will require one or two pumps. This is based on determining how much fuel flow the engine will need. Next, select the fuel pump model that will be used from the options shown. If you are unsure which pump will be best for the application, CLICK HERE for an unbiased performance test of some of the fuel pumps we offer. CLICK HERE for a easy to read side-by-side comparison of all the fuel pumps we offer.   Deatschwerks DW400 9-401 Pump This surge tank comes in a single version only. NOTE: The Bosch equivalent (P/N: BR540) does NOT have an integrated check valve. Instruction PDF