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-   -   DIY: Dual Walbro 450's and Hobbs Switch Install (https://www.jb4tech.com/forums/showthread.php?t=47438)

07tundra 10-15-2017 04:39 PM


Originally Posted by 135iam (Post )
Its because we cant see the photos!!! LOL

looking forward to getting my fuel system upgraded over the winter, thanks for the DIY TEC!!!

Check bimmer boost i think the pics are working there

protecon 10-15-2017 06:06 PM

Rehosted pics and reposted (originals are low res).


Originally Posted by TEC (Post )
I'm not sure what happened to the original post so I'm reposting this. Mod's if you have an issue with this post please let me know.

Share time!

So my goal was to install two Walbro 450 pumps so that I could run e85 and push boost above 17 psi on the stock turbos and in the future possibly run a PI setup. I looked at a few companies offerings but I decided that I could build something that rivaled and even bettered what is currently on the market for a cheaper cost. This is not a knock on any company or their pricing for dual intank pumps but rather my Colt/DSM mentality to do it yourself and learn more about your car in the process.

In the end what was created is basically a bucketless dual walbro 450 setup. While parts of the stock bucket remain, the venturi system is removed which should produce higher flow numbers for the system.

I’m not sure how this forum feels about posting pricing so I will intentionally leave this information out. You can PM me if you want to know where I picked up my parts.

For this build I bought:
Used stock fuel bucket – junk yard
2 Walbro 450 Pumps with electrical connectors (no fuel socks needed)
2 Holley Hydramats (model 16-111) - 15”x3” for Walbro pumps

He took the used bucket and with some modifications came up with this:



What you see are two Walbro fuel pumps in a modified stock fuel bucket with an adapter to hold the pumps in place. Here is a look at the adapter as it was being laid out for use:


The two pumps feed into PTE tubing and a PTE Y adapter. When I decide to go PI I will probably go back and feed only one pump into the stock fuel line and use the other pump to feed the PI. I cut a hole in the top of the fuel pump bucket top and fed through the wiring for the secondary pump.


The main pump uses the stock wiring and is controlled by the DME as is the stock pump. The second pump is controlled by a Hobbs Switch mounted in the trunk.


I am using the “prototype” adapter. I’ve been told that a newer version exists that looks more like this:


My total cost for this project (all in is about $600) is less than what I would have paid another company for their version of the same thing, with the added bonus of being bucketless (higher flow rates) and able to utilize the newest technology being the hydramats which no company currently offers.

I’ve been driving the car with this setup installed and so far it has worked perfectly…no added pump noise and no LPFP fall off from E85 use.

protecon 10-15-2017 06:15 PM

Part 2.


Originally Posted by TEC (Post )
So my goal was to install two Walbro 450 pumps so that I could run e85 and push boost above 17 psi on the stock turbos. I looked at a few companies offerings but I decided that I could build something that rivaled and even bettered what is currently on the market for a cheaper cost. This is not a knock on any company or their pricing for dual intank pumps but rather my Colt/DSM mentality to do it yourself and learn more about your car in the process.

First and foremost, I want to thank 07Tundra (Jose) for his help with this project. All of this would not have been possible without his help.

More on how the dual Walbro 450 pump assembly that I am installing, was created can be found in this thread:

Now, time for the install.

Legal note: I do not assume any responsibility for errors or omissions contained within this DIY. All users of this DIY assume responsibility for any issues or problems that arise from the use of this DIY. This DIY should be used as a supplemental aid only. If you are unsure of your abilities or steps to complete this task you should consult a professional for assistance.

Time needed: 2-3 hours

Tools needed:
Small flathead screwdriver
10mm socket
Lock Ring removal tool (recommended)
Cutting pliers
½” Socket Breaker Bar
25 amp mini fuse
Vent line hose clip (underside)
1/8” Tee
1/8”x1/8” straight hose connector
1/8” Hose x 1/8” NPT Female connector
Zip ties
Old bucket (Homer bucket, Lowes bucket, etc.)

Step 1: Prep

TIP: Your fuel gauge should be at ¼ tank or less. Less is better in this case…believe me.

Start by removing the fuel cap to release any pressure in the system.
Next remove the 20 amp mini fuse for the fuel pump (position 70), this will be replaced later with a 25amp fuse


Step 2: Seat Removal

Next remove the passenger side back seat (E92) or rear seat (E9x) (e92 shown in pics)


Pull up on front edge of the rear seat. There are two clips on both sides. This may require a bit of effort so pull like you mean it lol.

Under seat clip



Once you have the seat removed place it to the side and pull back the black mat.



Step 3: Fuel Pump Removal

Use a 10mm socket to remove the four nuts to expose the fuel pump lock ring.
TIP: MAKE SURE TO NOTE THE ORIENTATION OF THE CAP (the arrow points towards the front of the car, as well as the dimple)


Once you have the lock ring exposed, you will need to disconnect the two plugs located on top. The plugs have a small lever on the side which must be pressed in to release the plugs from the cap.


Once you have the plugs removed, you will need to disconnect the vent lines. The vent lines have a small lever (blue in the picture) that must be pressed in in order for the vent lines to be removed.


Once you have all the lines removed, it’s time to remove the lock ring. The small vent line can be tucked out of the way between the fuel tank and the body.


The larger vent line, however, will be your constant enemy in getting this project done as it always seems to get in the way.

TIP: Your best bet it to get a piece of string to wrap around the head of the larger vent line and then wrapping the other end of the string around the seat hook under the seat back in order to get the vent line out of the way.


TIP: I found this tool on Amazon for a bit over $10 shipped (with Amazon Prime). It works flawlessly to remove the cap and to tighten the cap. No need for a $40 tool.


If you are using the tool above or similar tool, align the lock ring teeth with the tool. Put your breaker bar on the top of the tool and turn counter clockwise to remove the lock ring. Steady, strong force wins the race here.


After removing the lock ring you are now ready to remove the fuel pump.
Lift the top of the pump enough to access the vent line. This vent line is short, be careful not to pull the head of the vent line out of the vent tube when trying to get the vent line off.


protecon 10-15-2017 06:23 PM

Part 3.


Originally Posted by TEC (Post )
Removal of this clip will probably take up most of your time and be the bane of your existence. There are two teeth on both sides of the clip that must be dislocated in order to remove the vent line.

TIP: I recommend buying a spare one and having it on hand in case you get frustrated and decide to just break it in order to get it off.

In order get this clip out you must push on both exposed sides of the clip a bit at a time. You cannot simply push one side out and then the other as it will lock in the teeth on the opposite side. Both sides of the clip must move together as much as possible.

Once you have the vent line detached, you can disconnect the fuel pump and fuel level clips on the underside of the bucket cap.

Hopefully you have a tank that is near empty. Pour as much of the fuel in your fuel bucket back into the tank before you try to remove the fuel bucket.

To remove the bucket, pull up on the bucket until you feel resistance, then rock the bucket towards the passenger side door to get the fuel level float out with the bucket.

Set fuel pump assembly in your old bucket (homer bucket).

Step 4: Dual Fuel Pump Install

Your new setup (if you decided to copy my setup) is quite a bit larger than the original pump. This part is a little tricky but don’t let it get the best of you, take your time on this part and things will go smoothly.

First, connect all of your wiring as shown previously, if you are using a similar set up as described earlier. Make sure your fuel pump and fuel level connections are connected and tight. You do not want to have the need to dig back into the tank again to fix something.

Next, fold your fuel pickup pads in half in order to be able to get them into the tank. Do not fold them under but fold them up so that once in the tank the pads are able to lay out to their full length. Now, turn the assembly on its side to put the fuel level float into the tank first. Then turn the tank upright and ease the folded pickup pads into the tank. The assembly should drop right in after doing this.

TIP: Make sure that your fuel level float moves freely and is not stuck underneath the fuel pick up pad or the edge of the bucket once the fuel pump assembly has been lowered into the tank.

[Below: The top of the bucket is not assembled in order to take clear pictures]


Next, you will need to modify your fuel feed line.


Remove the end piece on the fuel feed line carefully. You will need to remove the clamp and heat the tubing a little in order get the end piece out. DO NOT USE AN OPEN FLAME TO HEAT THE END PIECE!!

Once you have removed the end piece, push the hose from your fuel pumps into the fuel feed line. Use a clamp to secure the lines together.


Re-attach your vent lines and ensure that all your connections are tight.
Next, push the top of the bucket down onto the tank. Make sure the top of the fuel bucket has a lip that aligns with the top of the tank. Put the top fuel pump ring on while holding the top of the bucket down. Turn the ring clockwise by hand until you feel the screws catch. Continue turning the ring until you feel enough resistance to need the lock ring tool to turn the ring enough to get it back to its original position.


Note that there are teeth missing on the top lock ring. The large vent line should center in between the missing teeth. This is your indication that you have tightened the lock ring down enough.

The fuel pump install is now complete. Lets work on the Hobbs switch before we put the rear seat back in.

Step 5: Hobbs switch install


If you are using a pre-assembled harness as shown above this will describe exactly what you will need to install it.

As you can see, one end will need to connect to the fuel pump, the other end will need to be connected to the battery and a ground, while the last end of the harness will need to be connected to a positive boost source.

Before we get started, I need to give credit to jyamona@motiv from which I totally stole the idea to hook up the hobbs switch in the trunk.

Lets layout the harness in the trunk so that you can get a better idea of where things will end up.


Remove the trunk floor in your car and layout the harness.


Pull the end of the harness going to the fuel pump underneath the trunk surround and under the rear seat back.


Put a hole in rubber part of the top of the fuel tank cover.


Then fish the end of your hobbs switch harness through the hole you have made in the rubber grommet.


Connect the harness to the fuel pump.

You are now ready to re-install your rear seat bottom cushion.

Next, remove the accessory compartment on the drivers side of the trunk. Fish the hobbs switch and harness under the trunk flooring.


The exhaust flapper solenoid is accessible through the access panel on the drivers side. Unplug the solenoid and remove the hose that connects to the bottom (not the side hose, this connects to the flapper in the exhaust system)


Connect the hose to the hobbs switch. The hose should be accessible through the hole where the accessory compartment was located that was removed earlier.


Now, you can put the accessory compartment back into place as we are done her.

Next lets move to the other side where the battery is located so that we can connect power to the harness.

Remove the access panel for the battery on the passenger side.

Connect the negative cable to the bolt shown and the positive cable fits neatly in the area shown on the battery terminal.


Tuck the relay and fuse in behind the battery. Put the battery access panel back into place.

protecon 10-15-2017 06:25 PM

Part 4.


Originally Posted by TEC (Post )
Put your trunk flooring back in and you are done here.

Next lets move to the engine bay.

Locate the flapper hose that is connected to the trunk solenoid for the exhaust flap and the hose that connects from the manifold to the diverter valves.



Disconnect the flapper hose from the hose that connects to the brake booster. Cap the tee where the flapper hose has been removed.

Connect the flapper hose with a piece of 1/8” hose using the 1/8”x1/8” straight connector.

Cut the hose that runs between the diverter valves and the manifold.
Insert a 1/8” tee between the flapper hose and the hose that you just cut that connects to the manifold.


Zip tie all the connections and make sure they are tight.

Lastly, make sure you put in your new 25 amp mini fuse into slot 70. Your new Walbro 450 pump draws a bit over 21 amps when running 12~13 volts, so your old 20 amp fuse won’t work.


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