Walbro 255LPH In-tank Fuel Pump DIY Install - 550 Spyder

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Walbro 255LPH In-tank Fuel Pump DIY Install - 550 Spyder

Postby SeductionMotorsports » Sun Aug 28, 2016 7:29 pm

For those who need to install an in-tank fuel pump for performance purposes or heat issues on their Subaru 2.0L/2.5L or any other fuel injected 550 Spyder. Detailed DIY write-up and pictures found here:

http://seductionmotorsports.boards.net/ ... h-retrofit

We also sell a complete kit or can build you a tank specifically for your 550 Spyder.

We came across some fueling issues on the Subaru 2.5L NA powered 550 Spyders. The inline 255lph Walbro fuel pumps were getting too hot to drive in Arizona summers. Temps outside would reach 117-120 and with the radiant heat bouncing off the fuel pumps behind the radiator they were getting hotter than the factory recommendations of 150 degrees from Walbro. We first relocated them. Didn't work. Heat wrapped them... dialed in the thermal management to higher specs than a Nascar... didn't work. Final solution was to retrofit an in-tank fuel pump.

We started with a brand new OEM fuel pump from an Acura. Why? Clean fuel pump hanger, it has a return, and it was easily adapted to fit an upgraded fuel pump from Walbro. The OEM Acura pump is 190lph whereas the upgraded Walbro is 255lph. More flow, means more fueling, resulting in more power.

We will update this thread with pictures over the next day.

We started with 3D scanning the fuel pump hanger so we could waterjet out a stainless steel flange to weld onto the tank.

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Welded on the stainless nuts on the inside of the flange so the pump hanger could easily bolt down to the tank.

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Below is my cheap aluminum scrap waterjetted template we made so we can align the orientation of where the pump when installed would have the lowest point of pickup inside the tank.

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Next we cut out the hole to weld on the new flange for the fuel pump hanger.

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The hole drilled below is for a fuel tank vent. The fuel cap we have on this particular setup was designed to sit flush on top of the tank and below the hood. Not like the original fuel caps that stuck through the hood. Not pictured is the screen and internal vent mechanism we installed.

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Flange welded on.

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Fuel vent line welded on, flared on the end so we can use a specific fuel injection hose clamp.

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Jess TIG welding on the flange.

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Finished up the retro Walbro in-tank installation.

Below are instructions on how to clean out your tank if you had fuel previously inside it and needed to weld on the tank. It will require re-sealing the inside if you clean then weld on it.

HOW TO REMOVE ALL FUEL FUMES TO WELD ON TANK:

1. Remove tank.
2. Remove all fittings and senders, caps, etc.
3. Time to flush the tank. To flush follow these steps:

3A. Fill with water, dump out.
3B. Fill with water, dump out.
3C. Fill with water, dump out.
3D. Fill with water, dump out.
3E. Fill half way with water, light a match and toss it inside with tank half filled with water. Warning, it should breathe fire like a dragon out the holes for a little while.
3F. Fill with water, dump out.
3G. Fill with water, dump out.
3H. Fill with water, dump out.
3I. Fill half way with water, light a match and toss it inside with tank half filled with water. Warning, it should breathe fire like a dragon out the holes for a little while.
3J. Fill with water, dump out.
3K. Fill with water, dump out.
3L. Fill half way with water, light a match and toss it inside with tank half filled with water. Warning, it should breathe fire like a dragon out the holes for a little while.
3M. Flush one final time with water, dump out.

4. Wipe down.
5. Prep all surfaces you need to weld on, remove paint or coatings. Recommend blue scotch bright disc to clean.
6. Clean with acetone.
7. Weld.

Now, if you welded on a tank that you did the water/match cleanse on.. you will need to clean it out before re-coating the inside and installing it. Steps are below:

1. Plug ports (If you have them) on the bottom of the tank.
2. Using a funnel, pour apple vinegar into the tank, slosh around, let sit on all corners to loosen rust.
3. After about an hour or two, flush and repeat.
4. You can also use cleaning vinegar as the second flush step.
5. After you rinse out with water and apple vinegar, time to flush with baking soda and boiling hot water.
6. Boil water, add baking soda.
7. Funnel into tank, remove funnel screen if you have one.
8. Let sit for about 10-15 minutes and slosh around. This picks up the smell, fumes, and left over debris from the previous steps.
9. Empty baking soda and water flush. Flush with hot water until tank is completely empty and clean on the inside.
10. Coat with a coating of hot water mixed with WD-40 to seal the tank or dry and go straight to the POR-15 2/3 stage gas tank coating kit you can buy at any paint supply shop or online. Takes a couple days to properly setup and cure. Follow the instructions on the POR-15 kit.

Below are pictures for reference for cleaning your fuel cell:

Apple vinegar:

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Pour into tank using wide-mouth funnel:

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Slosh vinegar around, leave tank on all sides to dissolve rust:

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Use magnet to remove any metal debris inside the tank you can see from cutting or drilling on the tank. Easiest to do this method when tank as fluids inside it:

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If you want to scrape the tank sides, rig up a towel with tape on your magnet so the magnet pulls debris to the rag and you can wipe down the inner tank walls:

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Boil water, add baking soda:

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Remove funnel screen if needed:

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Empty flushes into containers and properly dispose of it... (Looks nasty cause the apple vinegar is apple cider colored)

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Flush is complete. Use a gas tank sealer such as POR-15 fuel cleaner/sealer 2-3 stage kit.

WALBRO IN-TANK FUEL PUMP RETROFIT CONTINUED...

After you have the flanges all welded on, tank cleaned, sealed, coated.. it's now time to modify the fuel pump hanger and set it up for your tank. Steps are show with pictures below:

1. Take the fuel pump hanger, and remove the 190 LPH fuel pump since you will be upgrading it to a 255 LPH Walbro fuel pump.

Stock unit pictured:

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Walbro 255 LPH pictured next to the stock 190 LPH fuel pump... almost exactly the same in exterior dimensions.

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We are using the upgraded Walbro fuel pump installation kit witch comes with an upgraded in-tank fuel filter bag as well:

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2. Remove the speed nut off the OEM fuel pump. We need to get the rubber end cap off to use on the Walbro pump. (Keeps the pump from vibration and grounding out)

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Speednut pictured below. You will destroy the old one by removing it.. these are about $0.05 at the local hardware store, you need the 1/8" ID speed nut to replace it. One does come in the Walbro installation kit if you purchased that however along with the new fuel line, filter, and hose clamps as pictured:

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3. Time to measure where you need your fuel pump hanger and bag filter to sit inside the tank. You want the filter to sit at the lowest point inside the tank so fuel is constantly feeding it. To do so, stick a ruler in there at the angle you need. You're going to bend the hanger bracket to mimic this angle.

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You will need to make 2 relief cuts in the hanger so you can bend the hanger to bottom out the filter bag where needed, as pictured: (Use a band saw for a clean cut. Metal snip shears will work as well)

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Bent to our measurements:

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4. Take end cap off OEM pump and swap onto the Walbro before installing the filter bag and speed nut.

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Installed onto Walbro 2225 LPH:

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Speed nut installed (Trick to get this little guy on... use a socket and tap with mallet lightly once until it's secure and flush):

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5. Use zip cable ties to secure pump to bracket. Plug in clip. You will need to cut down the feed line hose to fit then secure with supplied hose clamps:

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6. Fold up and slide into tank:

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7. Using GASOLINE grade teflon tape (yellow, not white), wrap all the bolts that will secure the fuel pump hanger into the fuel pump hanger tank flange:

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8. Repeat teflon and gasket installation for the fuel pump sender. Remember to set your fuel pump hanger setting before installing, use this link for a DIY on that step:

http://seductionmotorsports.boards.net/ ... ng-install

Picture for reference:

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9. Install tank and wire up fuel pump. Complete!


More pictures for references:

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NOTE: If using hose clamps, please make sure you are using FUEL INJECTION hose clamps and not worm-gear hose clamps, picture for reference:

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Zip cables ties holding fuel pump secure:

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Disclaimer: Reader assumes all responsibility for any alterations and modifications to their vehicles. http://www.SeductionMotorsports.com or the author of the DIY thread you are reading is not liable for any damage to your vehicle (or yourself) as a result of documented instructions. The threads contained in this forum are for informational purposes only and should not be followed by non-experienced mechanics. If you are unsure of what you are doing, please consult a qualified mechanic.
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Builder of 550 Spyders, SM550 Spyder Outlaws & 356 Coupes
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