INSTALLATION INSTRUCTIONS FUEL SURGE TANK INSTALLATION KIT 1999-2006 BMW E46 COUPE Document# 19-0056 Support: info@radiumauto.com Note: This kit wasn t designed for a FST-R, but can be accomplished. 1. There are 2 common ways to relieve fuel pressure on the BMW. Option 1: Open glove compartment. Rotate the 2 white tabs on the top-inside of the glove box in order to release and swing the fuse box down and remove fuse 54. Start vehicle and allow engine to stall. Turn off car and remove key. Reinstall fuse and glove box. Option 2: There is a Schrader bleed valve found on the factory fuel pressure regulator underneath the vehicle, shown at right. 2. Open Trunk. Remove right side socket housing for tail light. Take out luggage compartment floor trim panel (1). Unclip the two fasteners that secure the plastic battery cover on the rear right side of the trunk. Remove the plastic cover to gain access to the battery. 3. Unscrew and disconnect negative terminal of the battery (G1). Caution: Disconnecting the battery (G1) may cancel the fault memories of some control units. Consequently, before disconnecting the car's battery, always interrogate the fault memories. Investigate stored faults and, once any faults have been remedied, cancel the fault memory. 4. Pull out emergency release mechanism for tank cap a little. Unclip cable (1) from clip (2). Release and fold down each rear seat using the 2 release handles located in the trunk ceiling. Turn rotary clip (1) 90 and remove.
5. Partially release panel for trunk separating wall. Partially pry out outer trim (1) and remove trunk wheel arch trim (2). 6. Locate the M8 bolts that secure the two rear seat lock receivers to the trunk ceiling. Using a 13mm socket, remove these 4 bolts (2 for each side) and discard. Note: the receivers will temporarily be free and loose within the ceiling. 7. Using the included long M8 bolts and washers, secure the fuel surge tank mounting bracket to these rear seat anchor points (as shown). 8. Using 2 of the included zip-ties, secure the wiring harness to the bracket. Temporarily let the fuel surge tank s circular quick disconnect plug dangle, as shown. 9. Using the included M5 bolt and nut, secure the relay and fuse to the single mounting hole located on the left side of the Radium FST mounting bracket.
10. Using the four included M6 bolts, secure the FST to the bracket. Note the keyway of the circular fuel surge tank connector. Insert and press it into the mating connector on the FST. Spin the threaded collar clockwise until it is fully seated and tight. Route the wiring harness around the trunk and down towards the battery. Remove the 10mm battery nuts and connect the "Power" and "Ground" ring terminals to the respective battery terminals. 11. Locate the black fuel pump relay. On USA coupe models (shown), it is located in the trunk on the right side wall above the shock absorber mount. Note: For all convertibles and some foreign E46 M3 coupes, the fuel pump relay is located below the right rear quarter window behind the interior panel. 12. The relay trigger for the Radium fuel surge tank's pump will need to be tapped off the factory BMW fuel pump's relay wire. NOTE: The pump in the main fuel tank will now be used as a low pressure high flow lift pump As shown, unclip the two relays from the wall as a single unit using a flat head screwdriver or special needle nose pliers. 13. There should be two large gauge wires that are red with a white stripe. Reference the specific wire pointed at in the picture. This will be tapped into. It is nearest the "55" molded into the relay connector. To verify this is the correct wire, there should be continuity between this wire and the factory BMW fuel pump's positive wire. 14. Find the Posi-Tap wire connector in the kit. Unscrew both ends. Insert the red/white wire into the slotted area of the one side of the connector, as shown.
15. Find the Weather Pack connector in the kit. This is used to make the kit modular if the main harness needs to be removed. Connect to mating Weather Pack connector in the Radium harness. Strip the insulation of the blue wire back to expose about 3/8" of copper. Insert the wire through the other half of the Posi-Tap wire connector, as shown. 16. Screw the two connector halves together and give the wire a quick tug to make sure it seated properly. Note: There are detailed instructional videos on the internet on how to assemble Posi-Tap wire connectors. The Radium fuel surge tank is now completely wired. 17. Break loose the lug bolts on the right rear wheels. Put the vehicle on a lift or jack up the rear of the vehicle and safely place down jack stands. Remove the right rear wheel. 18. The rear under brace will need to be removed. Using a 16mm socket, remove the 3 bolts that secure the underbrace to the chassis. 19. The underside plastic rear panel that covers the right side of the gas tank will also need to be removed.
20. Once all of the fasteners are removed, the panel will need to be shifted towards the back of the vehicle to unlock it from the chassis. 21. Shown to the right is the aforementioned cover that is to be removed. 22. Pry and fold the front most section of carpet in the trunk towards the front of the vehicle. There is a factory sheet metal hole (shown). However, this is hidden underneath the tar board insulation. From underneath the car, find the aforementioned rubber factory plug near the right rear suspension and pierce it with a blunt object such as a screwdriver. 23. From the top side, pull out the remains of the rubber plug and clean the excess tar board to expose the symmetrical 1 hole. Using the included bulkhead plate, lineup and position the rear most left side hole to the center of the trunk hole. Trace the location of the three remaining circular holes using a marker. 24. Using the marked circles as a reference, drill three 5/8 holes (as shown). Clean up all the drilled holes and be sure they are free of debris. Note: The factory large hole is used as a reference point for lining everything up and allowing the included preassembled hoses to reach.
25. Fold the section of carpet back down. Use a razor blade, such as a utility knife, and make 4 corresponding holes in the carpet. 26. Removing the 40mm ID x 170mm long fuel filler hose, from underneath the car, will free up a little bit of room when inserting hoses through this area. Using a 6mm ratcheting socket, loosen the two hose clamps. Slide the hose back and forth until it releases from the hard tubes on each end. 27. There are 8 hoses included in the kit. Four of them are 24" long and are identical (not shown). These 4 will be used in the trunk. The other 4 hoses (shown at right) are of different lengths and have unique hose ends. These will all connect underneath the vehicle from bulkheads to the top of the factory fuel tank. Two attach to the right side and the other 2 to the left side of the fuel tank. Depending on where they connect, many of these hose ends require an included adapter fitting, described below. 28. The "green" bulkhead fitting is the FST's pump outlet port. For starvation protection, this should be drawing fuel from the FST bottom. This port will route to the factory hose on the right of the fuel tank which normally connects to the stock pump assembly. For fuel starvation efficiency, the top port should route to the main fuel tank's return barb found on the left side. The functionality of the other 2 ports on the FST is not important. 29. Screw short end of bulkhead fittings to each 45 degree hose end with an 11/16" wrench. Note: Unlike tapered threads, JIC (-AN) fittings don't require excessive torque or sealing compound. From underneath, insert these bulkheads through the drilled holes, carpet, and bulkhead plate using the following hole locations: Back right hole = short hose with straight hose end Back left hole = long hose with straight hose end Front left hole = long hose missing a hose end Front right hole = short hose missing a hose end
30. From the trunk, secure each bulkhead fitting with the included bulkhead nuts. Next, all 4 "equal length" hoses will be routed between the fuel surge tank and the bulkhead fittings. Note: The bulkhead fittings were organized into a specific hole to make the slack in the trunk hose's consistent (as shown). 31. An aluminum wrench is recommended for all fittings in the interior to resist black anodize marring. Back right hole = bottom "green" FST fitting Back left hole = rear FST port fitting Front right hole = front FST port fitting Front left hole = top FST port fitting Tighten all fittings in the trunk area. 32. Next, the 4 hoses will need to run over the top of the main fuel tank. From underneath the vehicle, remove the M8 bolt (shown) that secures the large fuel tank using a 13mm socket. Let the large clamp hang. Allow the BMW fuel tank to sag down a few inches just enough to feed the 4 hoses up on top of the right side of the tank. Support the tank. Use the included zip-ties to keep the hoses away from the rear control arm. Remember, the suspension will compress when the vehicle is back on the ground. 33. From inside the cabin, pull up to unclip the rear bench seat and remove from vehicle. Underneath the bench, there are rubber mats. Fold the mats back carefully to expose the 2 metal covers. Remove the four M6 nuts (shown) on each cover using a 10mm socket. It is a good idea to clean each side as they will be dirty. On the right side opening, find the 4 hoses and pull them into view. Route the 2 longer hoses to the left side opening underneath the sheet metal but on top of the BMW fuel tank. 34. Under the left side cover is where the stock BMW fuel system s return hose from the BMW fuel pressure regulator reenters the main BMW fuel tank. To remove the factory pinch clamp found on the return hose, simply use a flat head screwdriver and pry the crimped section up and away, as shown. Discard this "one-time-use" clamp.
35. Shown to the right is how the clamp will be removed using a screwdriver. Next, gently pull the hose off the OEM barb. CAUTION: When running fuel pressures over 5Bar, we've seen instances when the throttle is chopped after a high boost run, the pressure spike after the FPR dislodges the internal connection inside the tank. This prevents fuel from siphoning to the right side of the "saddle bag" tank. The BMW fuel level gauge will not read properly. Fortunately, this should never happen with a FST system. 36. Locate the -6AN male to barb fitting in the kit. Lubricate the barbs with oil and install to the OEM hose, as shown. Next, install the included worm drive hose clamp. Secure the long hose (with the straight -6AN end) onto this fitting. 37. From the left side opening, pull out the hose which does not have a crimped hose end on it. Find one of the small hose clamps in the kit and insert it over the hose. Lubricate both the barb and the inside of the hose liberally. Gently push the PTFE (Teflon) hose over the blue barb. It will be nice and tight. DO NOT FORCE IT AS THE OEM PLASTIC IS BRITTLE! Secure the clamp onto the hose, as shown. 38. Underneath the right side cover is where the original BMW fuel pump hanger assembly resides. To release the factory quick disconnect fitting, simply rotate the connector until both outer tabs can be accessed with a thumb and index finger. First, pull the connector towards the center of the hanger. Next, squeeze the 2 tabs and then gently pull away from the mating tube, as shown. Have a rag handy as fuel will instantly leak out of this connection. 39. From the right side opening, find the short hose that has the does not have a crimped hose end on it. Find one of the small hose clamps in the kit and insert it over the hose. Route the hose around towards the front of the vehicle and insert the PTFE hose over the blue barb (no lubrication is necessary). DO NOT FORCE IT AS THE OEM PLASTIC IS BRITTLE! Secure the clamp onto the hose, as shown.
40. From the right side opening, find the last hose (short hose with the straight hose end). Also, find the male quick disconnect adapter fitting in the kit. Screw and secure the -6AN fittings together, as shown. Insert the Radium quick disconnect male adapter fitting into the BMW female quick disconnect fitting until it fully seats and clicks. 41. Reconnect the battery. The FST must be fully primed with fuel before the engine will start. Remove the fuse located on the Radium mount. Cycle the ignition several times. Wait 10 seconds each time to allow the BMW main relay to cycle. This will activate the lift fuel pump for a few seconds each time. After 3-4 cycles it should be ready to start. Replace FST fuse. Now cycle the ignition and listen for the FST pump to confirm the Radium electrical was performed properly. Start the vehicle. The engine may run rough for a few seconds until all air is bled from the system. 42. Start the engine and INSPECT ALL CONNECTIONS FOR LEAKS! Next, reinstall all parts that were removed. When putting the trunk back together, the rubberized carpet will need to be cut in a half circle, as shown in red. Test-drive the vehicle and inspect again for fluid leaks. If no leaks are found, the installation of the Radium FST is complete.