avantagg
02-04-2021, 03:10 PM
This is a how-to for the modification of a B8 LPFP housing to retrofit a Walbro 450lph E85 High-Pressure In-tank Fuel Pump. The purpose of swapping out the OEM pump and replacing it with the Walbro 450 unit is to gain more headroom in the fueling system to avoid fuel starvation. Before we begin it should be noted that this modification WILL NOT WORK ON THE B8.5, they came with a different style fuel pump and can be modified with some alternative parts. For this how-to you are essentially removing the OEM pump from the basket and directly replacing it with the Walbro. However THERE IS SOME MODIFICATION to the bucket and basket REQUIRED (I'll cover that below). Thanks goes to Jesus Garduno and Byron Taylor for the guidance and previous knowledge.
The essentials You’ll Need:
• OEM LPFP - You can use your current pump, but I recommend finding a used one, or buying a new one to swap in, it makes it easier to save on downtime and this way you can take your time without having your car off the road too long. The nice thing about buying a new LPFP (https://www.fcpeuro.com/products/audi-fuel-pump-assembly-0580202016) is that they already come with a new filter in the hat. If you don't buy a new pump, I recommend at least replacing your filter (https://www.fcpeuro.com/products/audi-vw-fuel-filter-bosch-8k0201511a), they get pretty filthy after 60k (https://www.audizine.com/forum/showthread.php/616366-Inside-Your-Fuel-Filter?highlight=fuel+filter).
• Walbro F90000274 (https://www.maperformance.com/products/450lph-e85-high-pressure-in-tank-fuel-pump-walbro-f90000274?variant=34940808003&gclid=Cj0KCQiAlsv_BRDtARIsAHMGVSb5kbH1NNDK_xGRbYuC fkj77zW0MBlYk6Uq3XV45uhxhf7inREPsNAaAlNyEALw_wcB)
• Walbro 450 Installation Kit (usually an add on with the listing)
• Hose Clamp 3 1/16 in. - 3 1/2 in. I.D.
• 3 small screws
• Dremmel
Optional:
• GM Metri-Pack 280 Wire Terminals (https://www.napaonline.com/en/p/NW_725157?ref=MA==)
• Terminal Crimping Tool (https://www.amazon.com/gp/product/B08CXL4RFQ/ref=ppx_yo_dt_b_asin_title_o03_s01?ie=UTF8&psc=1)
https://i.imgur.com/bHNM4N5.jpg
I won't go into steps on how to remove the pump from the tank, there are tutorials for that on YouTube (https://www.youtube.com/watch?v=6d_RvkI8m84).
First start by disconnecting the harness from the hat to the fuel pump. Next disconnect the fitting at the fuel filter, you will need to push in on the connection to slide it out. Next unclip the float switch from the bucket and carefully slide it up and out. Now you should be able to pull the hat up and out of the two guide posts on the bucket. Set aside.
Next you will need to disconnect the plastic hose from the OEM fuel pump. Its very difficult to remove, I ended up snapping the nipple off the old pump by accident trying to pull it off with pliers and had to then break up the pieces in the hose with a pair of pliers to clear up the hose end. I think they make a special took to remove this type of fuel hose, but did not know this in advance. It might have also been difficult because I used a brand new assembly and the hose has never seen fuel. Be careful not to damage this hose, you will be reusing it on the Walbro pump.
https://i.imgur.com/3vKJCNJ.jpg
https://i.imgur.com/mRRriJI.jpg
Next you will unclip the bucket top and carefully slide the lid up and off the bucket. There are 4 clips holding it down, be careful they snap easily.
Once the lid is off you will now see the fuel pump sitting in the basket, pull it out of the bucket and set aside.
Now comes the fun part. There are 3 pieces that need some modification for the new fuel pump to sit in place. The bucket lid, the bucket and the basket.
The Bucket Lid:
Using a dremmel, widen the opening on the lid by 3x to allow for the Walbro harness and OEM fuel hose to freely exit the top of the bucket, it may seem like a lot of material to remove, but it made positioning the hose a lot easier.
https://i.imgur.com/UTDZE1k.jpg
The Bucket:
1. Remove the green and white support posts from the bucket, these will not be reused.
2. Remove the rubber check valve, this will not be reused.
3. Using a dremmel remove all of the round pegs on the bottom of the bucket, you want the bottom to be smooth so the filter can sit freely without getting bunched up.
4. Open up the hole where the old check valve was. Drill out two other holes where the old pegs were. This will allow for more fuel to flow into the bottom of the bucket.
https://i.imgur.com/tGBt9Oh.jpg
https://i.imgur.com/oElC3Mj.jpg
https://i.imgur.com/3uQH0zm.jpg
The Basket:
Remove the OEM pump through the top of the basket by sliding the metal band off the bottom of the plastic housing. It's on there good, it will take a small flat head screwdriver to pry off. Once the band is off you should be able to push up from the bottom side of the pump to pop it out.
The bottom of this plastic housing will now need modification for the new pump to be able to slide up and into it properly. With a Dremmel cutting wheel and sanding pad, carefully execute the following:
1. Cut bottom of basket out
2. Remove feet from the basket side bottom
3. Cut a small vertical slice on the bottom of the basket cylinder to allow the opening to be widened for pump insertion
4. Smooth out the bumps on the inside edge of basket cylinder. This will prevent the pump from slipping.
5. Insert Walbro Pump into basket bottom and secure in place with hose clamp, leave some overhang so the filter can sit properly on the pump once it is placed into the bucket. Insert filter on pump.
6. Next you will need to secure the bucket lid to the basket. There are 3 small holes on the lid that line up with the posts coming off the top of the basket. Carefully insert screws through those holes and into the posts, use a drill and widen the holes if needed. This plastic is hard and it cracks easily.
7. Test fit the pump basket in the bucket, and make sure the lid snaps down without too much force, I had to readjust my pump position in the basket several times because the filter was getting scrunched on the bottom of the bucket. Make sure the filter pickup is near one of your bucket holes.
https://i.imgur.com/8hFvyfc.jpg
https://i.imgur.com/8ys3vt9.jpg
https://i.imgur.com/94wcvf9.jpg
https://i.imgur.com/AEUES6g.jpg
https://i.imgur.com/YRSK8KU.jpg
https://i.imgur.com/kgICSBq.jpg
The Wiring:
Cut off the harness clip that connected to the OEM pump. There's a blue wire and two black wires. These will connect to the red wire and black wire on the Walbro pigtail. The Walbro kit comes with butt connectors. You can use these or solder and heat shrink. I chose a factory style solution by depinning the clip on the Walbro pigtail and then crimping new terminal pins onto the OEM wiring. Grab a few extra pins if you choose this route, I messed up a few times as I had never used a barrel crimper before. Next insert the bucket hat back onto the bucket and connect the female end of the fuel line to the filter.
https://i.imgur.com/dsmnDR6.jpg
https://i.imgur.com/4s7kRPq.jpg
https://i.imgur.com/98ZBDSn.jpg
https://i.imgur.com/zUaJRqC.jpg
https://i.imgur.com/Wm8eqzk.jpg
You now have an upgraded fuel pump capable of 750 HP and will hopefully no longer encounter fuel starvation! I will post some before/after data when I get a chance, I'm hoping Byron might have some soon as well.
The essentials You’ll Need:
• OEM LPFP - You can use your current pump, but I recommend finding a used one, or buying a new one to swap in, it makes it easier to save on downtime and this way you can take your time without having your car off the road too long. The nice thing about buying a new LPFP (https://www.fcpeuro.com/products/audi-fuel-pump-assembly-0580202016) is that they already come with a new filter in the hat. If you don't buy a new pump, I recommend at least replacing your filter (https://www.fcpeuro.com/products/audi-vw-fuel-filter-bosch-8k0201511a), they get pretty filthy after 60k (https://www.audizine.com/forum/showthread.php/616366-Inside-Your-Fuel-Filter?highlight=fuel+filter).
• Walbro F90000274 (https://www.maperformance.com/products/450lph-e85-high-pressure-in-tank-fuel-pump-walbro-f90000274?variant=34940808003&gclid=Cj0KCQiAlsv_BRDtARIsAHMGVSb5kbH1NNDK_xGRbYuC fkj77zW0MBlYk6Uq3XV45uhxhf7inREPsNAaAlNyEALw_wcB)
• Walbro 450 Installation Kit (usually an add on with the listing)
• Hose Clamp 3 1/16 in. - 3 1/2 in. I.D.
• 3 small screws
• Dremmel
Optional:
• GM Metri-Pack 280 Wire Terminals (https://www.napaonline.com/en/p/NW_725157?ref=MA==)
• Terminal Crimping Tool (https://www.amazon.com/gp/product/B08CXL4RFQ/ref=ppx_yo_dt_b_asin_title_o03_s01?ie=UTF8&psc=1)
https://i.imgur.com/bHNM4N5.jpg
I won't go into steps on how to remove the pump from the tank, there are tutorials for that on YouTube (https://www.youtube.com/watch?v=6d_RvkI8m84).
First start by disconnecting the harness from the hat to the fuel pump. Next disconnect the fitting at the fuel filter, you will need to push in on the connection to slide it out. Next unclip the float switch from the bucket and carefully slide it up and out. Now you should be able to pull the hat up and out of the two guide posts on the bucket. Set aside.
Next you will need to disconnect the plastic hose from the OEM fuel pump. Its very difficult to remove, I ended up snapping the nipple off the old pump by accident trying to pull it off with pliers and had to then break up the pieces in the hose with a pair of pliers to clear up the hose end. I think they make a special took to remove this type of fuel hose, but did not know this in advance. It might have also been difficult because I used a brand new assembly and the hose has never seen fuel. Be careful not to damage this hose, you will be reusing it on the Walbro pump.
https://i.imgur.com/3vKJCNJ.jpg
https://i.imgur.com/mRRriJI.jpg
Next you will unclip the bucket top and carefully slide the lid up and off the bucket. There are 4 clips holding it down, be careful they snap easily.
Once the lid is off you will now see the fuel pump sitting in the basket, pull it out of the bucket and set aside.
Now comes the fun part. There are 3 pieces that need some modification for the new fuel pump to sit in place. The bucket lid, the bucket and the basket.
The Bucket Lid:
Using a dremmel, widen the opening on the lid by 3x to allow for the Walbro harness and OEM fuel hose to freely exit the top of the bucket, it may seem like a lot of material to remove, but it made positioning the hose a lot easier.
https://i.imgur.com/UTDZE1k.jpg
The Bucket:
1. Remove the green and white support posts from the bucket, these will not be reused.
2. Remove the rubber check valve, this will not be reused.
3. Using a dremmel remove all of the round pegs on the bottom of the bucket, you want the bottom to be smooth so the filter can sit freely without getting bunched up.
4. Open up the hole where the old check valve was. Drill out two other holes where the old pegs were. This will allow for more fuel to flow into the bottom of the bucket.
https://i.imgur.com/tGBt9Oh.jpg
https://i.imgur.com/oElC3Mj.jpg
https://i.imgur.com/3uQH0zm.jpg
The Basket:
Remove the OEM pump through the top of the basket by sliding the metal band off the bottom of the plastic housing. It's on there good, it will take a small flat head screwdriver to pry off. Once the band is off you should be able to push up from the bottom side of the pump to pop it out.
The bottom of this plastic housing will now need modification for the new pump to be able to slide up and into it properly. With a Dremmel cutting wheel and sanding pad, carefully execute the following:
1. Cut bottom of basket out
2. Remove feet from the basket side bottom
3. Cut a small vertical slice on the bottom of the basket cylinder to allow the opening to be widened for pump insertion
4. Smooth out the bumps on the inside edge of basket cylinder. This will prevent the pump from slipping.
5. Insert Walbro Pump into basket bottom and secure in place with hose clamp, leave some overhang so the filter can sit properly on the pump once it is placed into the bucket. Insert filter on pump.
6. Next you will need to secure the bucket lid to the basket. There are 3 small holes on the lid that line up with the posts coming off the top of the basket. Carefully insert screws through those holes and into the posts, use a drill and widen the holes if needed. This plastic is hard and it cracks easily.
7. Test fit the pump basket in the bucket, and make sure the lid snaps down without too much force, I had to readjust my pump position in the basket several times because the filter was getting scrunched on the bottom of the bucket. Make sure the filter pickup is near one of your bucket holes.
https://i.imgur.com/8hFvyfc.jpg
https://i.imgur.com/8ys3vt9.jpg
https://i.imgur.com/94wcvf9.jpg
https://i.imgur.com/AEUES6g.jpg
https://i.imgur.com/YRSK8KU.jpg
https://i.imgur.com/kgICSBq.jpg
The Wiring:
Cut off the harness clip that connected to the OEM pump. There's a blue wire and two black wires. These will connect to the red wire and black wire on the Walbro pigtail. The Walbro kit comes with butt connectors. You can use these or solder and heat shrink. I chose a factory style solution by depinning the clip on the Walbro pigtail and then crimping new terminal pins onto the OEM wiring. Grab a few extra pins if you choose this route, I messed up a few times as I had never used a barrel crimper before. Next insert the bucket hat back onto the bucket and connect the female end of the fuel line to the filter.
https://i.imgur.com/dsmnDR6.jpg
https://i.imgur.com/4s7kRPq.jpg
https://i.imgur.com/98ZBDSn.jpg
https://i.imgur.com/zUaJRqC.jpg
https://i.imgur.com/Wm8eqzk.jpg
You now have an upgraded fuel pump capable of 750 HP and will hopefully no longer encounter fuel starvation! I will post some before/after data when I get a chance, I'm hoping Byron might have some soon as well.