OK, so this article will detail the modifications I made to a Full Blown dual fuel pump hanger for a 2G GSX in order to fit a Walbro 450 alongside a Walbro 255 pump, and also to generally improve the overall design of the hanger.
I bought a Full Blown double pumper hanger used, and I wasn't happy with the sizes of the feed galley, nor the way they chose to pass the wiring through the top. The hanger itself is a nice CNC'd piece, and they chose to simply drill a hole, pass the wires through, and seal the hole off with some type of silicone. I've heard that this is a known leak point, and with my hanger being used, the sealant was a bit loose and didn't look like it would really seal.
First things first, the feed galley (right hand hole in first pic below) is a smallish diameter, with 3/8" NPT fittings for the feed and return lines, and 1/8" NPT fittings coming from the pumps. The hanger comes with 5/16" hose barbs to connect to the pump hoses.
Influenced by some posts that Twicks69 made, I had the idea to drill out the pump feed holes to 1/4" NPT and use 3/8" smooth hose barbs with 3/8" hoses, drill the main feed galley to 11/16" (-10AN is 3/4") and have the feed side tapped for a -10 ORB fitting, since I have -10 lines from tank to rail. I gave the hanger to a friend who works at a machine shop, where he drilled/tapped the pump feed holes out as described above, enlarged the holes around those feeds to be able to get a socket down in there to tighten fittings, and drilled/tapped the -10 ORB threads in the end of the main feed galley. He drilled out the length of the main feed galley to about 1/2" (which is about the size of the inside of a -10 fitting), which I later enlarged to 11/16" with a cordless drill. This first picture is how I got the hanger back, with the 1/2" galley. He had to drill the larger countersink hole in order to get enough room for the chamfer that the o ring seals against. The second and third pics are of me drilling the feed galley to 11/16" and the final product.
When he was drilling the relief holes for the socket access, the bit broke through the top of the hanger, right on the back of the big part where it says "Full Blown" on top. The feed galley is inside there. Little welding and grinding and it's good to go! This area is not pressurized, so I don't foresee any issues with this little mishap.
With the feed side all set, I started looking at the wiring pass through. As mentioned above, I didn't like the cheap-looking sealant solution they used, and I also didn't like the fact that you were supposed to just solder or crimp the bare wires to the car's harness, which would necessitate cutting the wires if you ever needed to remove the hanger again. Best case scenario is you could buy connectors online to interface the wiring neatly, but you're still left with that leaky sealant on the top of the hanger itself! I searched around for a while and finally settled on a triple pump harness from Radium Engineering. I got the both the internal harness and the external harness for triple pumps. I couldn't get just any old bulkhead connector and wiring setup, because everything that goes inside the tank needs to be rated for extended, direct contact with gasoline and/or whatever fuel you're running. To this end, I also grabbed some PTFE heat shrink tubing from Amazon.com for my connections inside the tank. More on this later.
I spent a lot of time measuring and mocking up the placement of the wiring bulkhead, since it's fairly large and the whole hanger is pretty cramped with everything going on. I decided to take a router to the side of the chunk where the feed galley flows, and I took off about .20" to gain extra clearance for the wiring bulkhead. I later cleaned the roughness from the router up with files and sandpaper, all the way to 2000 grit and went over the whole top edge with an 1/8" roundover bit to make it look cleaner.
Then I drilled a 1" hole from top to bottom through the top of the hanger. I made sure that the retainer nut for the wiring bulkhead would clear both the side of the feed galley and the big plastic ring that you screw down to seal the hanger to the tank. From there, I flipped the hanger upside down, used the o ring that comes with the wiring bulkhead to eye up the position, and drilled a 1.25" hole to countersink the bulkhead to clear the fuel level sending unit. I just drilled down far enough until I had about 1/16" or maybe 3/32" left of material for the top of the bulkhead to rest on and seal against. From there I had to shave off the corners of the bulkhead connector, because it was originally square with screw holes in the corners. Few minutes on the grinder and it slid right in! The very bottom of the bulkhead clears the fuel level sender just barely, but it's perfect!
So, feed galley and fittings are set, wiring is set, now on to getting the Wally 450 pump to fit nicely next to the 255 pump. This hanger is originally made for twin 255 pumps, which are the same diameter all the way down the body of the pump. The 400 and 450 pumps are the same diameter as the 255 pumps, but the bottom 7/8" or so is much larger.
I had to cut off the bottom of the bracket that the pumps mount to in order to get the 450 pump to sit straight. I also had to cut the top lips off of the fittings that the pumps connect to, since the 2G tanks are so shallow. I did not use the fittings provided with the hanger, since I prefer the smooth barbs so you can remove the hose without destroying it. My hose barbs may have been a bit longer than the ones provided by Full Blown, so you may not need to shorten them. The tank is about 6 3/8" deep, so your intake socks/filters cannot be any farther than 6 3/8" from the bottom flange of the hanger. The pumps must sit as high on the bracket as possible, while still having room to get the clamps on the hoses. Not that I think you can get them too much higher, but I suppose you do want the socks on the bottoms of the pumps to be pretty much at 6 3/8" to make sure you get right to the bottom of the tank and make sure you can suck fuel even with a low fuel level in the tank. At the end of it, I had to cut off all but about 3/16" of the curved part of the bracket that the pumps mount to in order to get the 450 pump up high enough. The 450 pump also has two barbs on the outlet that I had to snip off as well (not pictured; sorry!). Just make sure your clamps are tight and it won't be going anywhere. Obviously, make sure to clean up any rough edges and clean out all the shavings before you do your final assembly!
I bought a Full Blown double pumper hanger used, and I wasn't happy with the sizes of the feed galley, nor the way they chose to pass the wiring through the top. The hanger itself is a nice CNC'd piece, and they chose to simply drill a hole, pass the wires through, and seal the hole off with some type of silicone. I've heard that this is a known leak point, and with my hanger being used, the sealant was a bit loose and didn't look like it would really seal.
First things first, the feed galley (right hand hole in first pic below) is a smallish diameter, with 3/8" NPT fittings for the feed and return lines, and 1/8" NPT fittings coming from the pumps. The hanger comes with 5/16" hose barbs to connect to the pump hoses.
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Influenced by some posts that Twicks69 made, I had the idea to drill out the pump feed holes to 1/4" NPT and use 3/8" smooth hose barbs with 3/8" hoses, drill the main feed galley to 11/16" (-10AN is 3/4") and have the feed side tapped for a -10 ORB fitting, since I have -10 lines from tank to rail. I gave the hanger to a friend who works at a machine shop, where he drilled/tapped the pump feed holes out as described above, enlarged the holes around those feeds to be able to get a socket down in there to tighten fittings, and drilled/tapped the -10 ORB threads in the end of the main feed galley. He drilled out the length of the main feed galley to about 1/2" (which is about the size of the inside of a -10 fitting), which I later enlarged to 11/16" with a cordless drill. This first picture is how I got the hanger back, with the 1/2" galley. He had to drill the larger countersink hole in order to get enough room for the chamfer that the o ring seals against. The second and third pics are of me drilling the feed galley to 11/16" and the final product.
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When he was drilling the relief holes for the socket access, the bit broke through the top of the hanger, right on the back of the big part where it says "Full Blown" on top. The feed galley is inside there. Little welding and grinding and it's good to go! This area is not pressurized, so I don't foresee any issues with this little mishap.
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With the feed side all set, I started looking at the wiring pass through. As mentioned above, I didn't like the cheap-looking sealant solution they used, and I also didn't like the fact that you were supposed to just solder or crimp the bare wires to the car's harness, which would necessitate cutting the wires if you ever needed to remove the hanger again. Best case scenario is you could buy connectors online to interface the wiring neatly, but you're still left with that leaky sealant on the top of the hanger itself! I searched around for a while and finally settled on a triple pump harness from Radium Engineering. I got the both the internal harness and the external harness for triple pumps. I couldn't get just any old bulkhead connector and wiring setup, because everything that goes inside the tank needs to be rated for extended, direct contact with gasoline and/or whatever fuel you're running. To this end, I also grabbed some PTFE heat shrink tubing from Amazon.com for my connections inside the tank. More on this later.
I spent a lot of time measuring and mocking up the placement of the wiring bulkhead, since it's fairly large and the whole hanger is pretty cramped with everything going on. I decided to take a router to the side of the chunk where the feed galley flows, and I took off about .20" to gain extra clearance for the wiring bulkhead. I later cleaned the roughness from the router up with files and sandpaper, all the way to 2000 grit and went over the whole top edge with an 1/8" roundover bit to make it look cleaner.
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Then I drilled a 1" hole from top to bottom through the top of the hanger. I made sure that the retainer nut for the wiring bulkhead would clear both the side of the feed galley and the big plastic ring that you screw down to seal the hanger to the tank. From there, I flipped the hanger upside down, used the o ring that comes with the wiring bulkhead to eye up the position, and drilled a 1.25" hole to countersink the bulkhead to clear the fuel level sending unit. I just drilled down far enough until I had about 1/16" or maybe 3/32" left of material for the top of the bulkhead to rest on and seal against. From there I had to shave off the corners of the bulkhead connector, because it was originally square with screw holes in the corners. Few minutes on the grinder and it slid right in! The very bottom of the bulkhead clears the fuel level sender just barely, but it's perfect!
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So, feed galley and fittings are set, wiring is set, now on to getting the Wally 450 pump to fit nicely next to the 255 pump. This hanger is originally made for twin 255 pumps, which are the same diameter all the way down the body of the pump. The 400 and 450 pumps are the same diameter as the 255 pumps, but the bottom 7/8" or so is much larger.
I had to cut off the bottom of the bracket that the pumps mount to in order to get the 450 pump to sit straight. I also had to cut the top lips off of the fittings that the pumps connect to, since the 2G tanks are so shallow. I did not use the fittings provided with the hanger, since I prefer the smooth barbs so you can remove the hose without destroying it. My hose barbs may have been a bit longer than the ones provided by Full Blown, so you may not need to shorten them. The tank is about 6 3/8" deep, so your intake socks/filters cannot be any farther than 6 3/8" from the bottom flange of the hanger. The pumps must sit as high on the bracket as possible, while still having room to get the clamps on the hoses. Not that I think you can get them too much higher, but I suppose you do want the socks on the bottoms of the pumps to be pretty much at 6 3/8" to make sure you get right to the bottom of the tank and make sure you can suck fuel even with a low fuel level in the tank. At the end of it, I had to cut off all but about 3/16" of the curved part of the bracket that the pumps mount to in order to get the 450 pump up high enough. The 450 pump also has two barbs on the outlet that I had to snip off as well (not pictured; sorry!). Just make sure your clamps are tight and it won't be going anywhere. Obviously, make sure to clean up any rough edges and clean out all the shavings before you do your final assembly!
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