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| − | == Walbro GSL392 Lift Pump Install ==
| + | Thanks guys, I just about lost it loiokng for this. |
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| − | '''Ongoing discussion about this article can be found by [http://www.dieseltruckresource.com/dev/showthread.php?p=1375932#post1375932 Clicking Here].'''
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| − | ''Original Writeup By PaulDaisy''
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| − | I have an update. From first hand testing and experience.<br>
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| − | My goal was to replace the stock LP with a reliable alternative, and I know everybody is happy with Walbros, so I bought a GSL392. I spent the entire day today, playing with my fuel system and this is what I have found.<br>
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| − | I built a bench test setup that is shown on the picture using all 3/8" fittings throughout (except the stock barbed connector on the Walbro suction end) and Nylon-11 3/8" tubing:<br>
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| − | http://www.ainaco.com/pavel/hunting/GLS392_test_setup.gif
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| − | I re-tapped the Walbro output to 1/8" NPT to allow installation of compression fittings. With this setup, the ball valve on the dump line allowed me to create line resistance. The pressure before the valve was stabilized by the Watts regulator. I ran the GSL392 and noted the pressures it developed, while measuring the flow from the dump.<br>
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| − | I took only a few measurements of the high pressure gauge because they matched the published Walbro flow curve quite well. At 75 psi I measured 48 GPH and at 55 psi I had ~60 GPH flow. At 20 psi the one gallon jug I used for the dump overfilled before I turned to it and managed to pull off the wires, so I could not take accurate time reading since I was busy cussing and spitting, cleaning up the spill.<br>
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| − | If anyone noticed my recent quest to find out what the flow was through the stock engine, you would see the range of suggestions that I got http://www.dieseltruckresource.com/dev/showthread.php?t=137655 <br>
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| − | You can probably guess where I was going with this: if the flow through is 40-50 GPH, I can run this through my regulator and my GSL392 would run at 80-90 psi, well within the design limit, without installing a return line. The point was to run the fuel out of the tank before dropping it to install a second return line, since the tank was full when I realized my LP was dead.<br>
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| − | Anyway, satisfied with bench testing I installed the entire setup on the frame rail. I will take pics tomorrow, I was too busy assembling it all today. I set up the 392 on a relay with a 1N4002 quenching diode, hooked up to the original LP harness.<br>
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| − | Test time!<br>
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| − | I have news for you. There is no 40 GPH flowing through those lines. Not even close. My high pressure gauge read >140 psi when my low pressure on both the Watts and in-cabin mechanical gauge hooked up to the fuel filter read 12 psi! This translates to 10-12 GPH flow at idle, at 12 psi pressure at the fuel filter housing!<br>
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| − | Worried about the health of the 392, I cranked up the low pressure on the Watts regulator to dump more flow. Half a turn of the handle on the Watts and the pressure at the fuel filter was 20 psi. High pressure was 127-130 psi. This means that at 20 psi filter pressure the system flow is about 22-23 GPH!<br>
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| − | I stopped testing here. The 392 is not designed to run at these pressures continually.<br>
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| − | Conclusions:<br>
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| − | 1. The fuel system is very restrictive: at idle, flows through it are about 12 GPH at 12 psi, 22-23 GPH at 20 psi on a stock engine. I suspect the main restriction is the VP44 but I have no proof.<br>
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| − | 2. The only way a stock engine will flow more fuel at <20 psi pressure is if the VP44 uses more fuel under heavy load; this is not flow-through, this is LP delivered flow.<br>
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| − | 3. Anyone running a Walbro 392 with a back pressure regulation setup (standard on Glacier kits) is using about 1/6 of the pump's volume capacity.<br>
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| − | 4. There is no Walbro inline pump I could find that would have low enough flow to not require a bypass at desirable VP44 inlet pressures (~20 psi max).<br>
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| − | 5. Do not use Parker compression fittings with Nylon line. Curvature of the line causes the convex Parker ferrule to turn and compress at an angle. I only used one of these (the 1/8" NPT to 3/8" tube on Walbro exhaust) , the rest are Swagelok. The Swage does not have any issues compressing on any line. Far superior design (I use them at work a lot, so I knew what I was buying).<br>
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| − | Thoughts: when people say that "with bigger LP the VP44 will flow fuel more to better cool and lubricate", it does not look like it will actually do that. The VP will only flow so much, not to say very little, under the design inlet pressures.<br>
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| − | Plans: I think I will drop the full tank and install the bypass. I will route it so that I can add a fuel filter in the future so that my huge recirculation flow is not wasted but used to filter the fuel all the time. I need to find a filter base for that, which preferably would not cost me a lot (Glacier has these but at too steep a price for my liking, although you could make a FASS functional duplicate for less than half the price).<br>
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| − | Hope you find this useful. I am not putting in the parts list because it is not a completed system yet (LP overstressed, must return flow). But it has more gauges for more bragging rights , and the pressure is very easy to control.<br>
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| − | -P
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| − | ----
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| − | It sounds interesting, your PWM project. This might be the way to provide a drop-in LP replacement for all the folks who don't need more performance, just want more reliability. I'll have to think about it...<br>
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| − | Anyway, here are the pictures I promised to post:<br>
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| − | In-cabin mech. pressure gauge:<br>
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| − | http://ainaco.com/pavel/dodge/cab_gauge.jpg
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| − | Frame rail setup:<br>
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| − | http://ainaco.com/pavel/dodge/frame_rail_setup.jpg
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| − | Pressure gauges installed on frame rail at engine idle:<br>
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| − | http://ainaco.com/pavel/dodge/press_gauges.jpg
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| − | 3/8" fitting that replaced the banjo bolt on the filter housing:<br>
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| − | http://ainaco.com/pavel/dodge/fuel_filter_housing.jpg
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| − | The pressure line from fuel filter is adapted to 1/8" to bring it into the cab:<br>
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| − | http://ainaco.com/pavel/dodge/cab_press_line.jpg
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| − | Parts used:<br>
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| − | Surplus Center:<br>
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| − | 1 2140-160 160 PSI 2" LM DRY GAUGE $4.69 <br>
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| − | 1 2140-30 30 PSI 2" LM DRY GAUGE $4.69 <br>
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| − | E-bay:<br>
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| − | 1 Bosch 20/30 amp SPDT 12 VDC relay $5<br>
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| − | 1 Walbro GSL392 gerotor pump with clamps and fittings $114<br>
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| − | MSC Industrial:<br>
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| − | 30' 74203779 .275IDX3/8ODX.050WALL NYLON11 TUBE(CTL)BLACK $23.10<br>
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| − | 1 04254371 1/4NPT X M12 METRIC ISO ADAPTER $4.88<br>
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| − | Swagelok:<br>
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| − | 2 3/8" brass Tee $6<br>
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| − | 2 3/8" NPTM to 3/8" Swagelok tube $3<br>
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| − | 1 1/4" NPTM to 3/8" tube stub (adapts the fuel filter adapter to tube) $2.50<br>
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| − | 1 3/8" Swagelok elbow $6<br>
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| − | 1 1/4" NPTF to 3/8" barb fitting (goes on bypass valve, optional) $3<br>
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| − | 1 1/4" NPTF to 3/8" Swagelok (goes on bypass valve, optional) $2<br>
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| − | 10 3/8" Swagelok ferrule set (did not need any but had for spares) $6<br>
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| − | 1 1/8" to 1/4" Swagelok reducing union (for cab gauge) $3<br>
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| − | 2 1/8" Swagelok cap/ferrule sets (for cab gauge) $2<br>
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| − | 4' 1/8" PTFE tubing (this I had, didn't buy) $10<br>
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| − | Hardware store:<br>
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| − | 1/8" NPTM to 1/4" Parker compression needle valve (cab fuel gauge disconnect) $5 (replace the rubber O-ring on this with Buna-N; I used #3 Viton O-ring)<br>
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| − | NAPA auto parts:<br>
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| − | 5' 3/8" fuel hose $5<br>
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| − | 1 3003 3/8" Napa Gold inline fuel filter $3.69<br>
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| − | 2 5/16" 665-1147 or 665-1989 self tapping frame bolts, pkg of 5 and 10 $5 per package<br>
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| − | 1 3/4" 770-1160 Adel clamps $6<br>
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| − | 4' 1/2" water hose for Nylon hose sheath in the engine compartment $4<br>
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| − | Misc. parts:<br>
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| − | 1 Teflon-sealed needle valve for adjusting return flow (from a friend, any valve will work)<br>
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| − | Wal-Mart:<br>
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| − | 20' 14 gauge wire, black and red, $5<br>
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| − | Blue crimp terminals and 3/8" split loom $5<br>
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| − | The 263A Watts pressure regulator that I used has a Buna-N diaphragm and is designed for water or heating oil pressure control. I had it in my parts box, didn't have to buy it. This actually was part of the reason I did it this way instead of using a back pressure regulator like the one in the Glacier kit. A 26 Watts is the same as the 263 but does not have a gauge fitting (I have two of those but the gauges are neat so I used the 263 for bragging rights)<br>
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| − | The fuel filter housing fittings are all 3/8" throughout, performance gurus will like that.<br>
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| − | I may have forgotten a few small parts. If anybody needs detailed advice, please PM me and I will answer with details.<br>
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| − | Notes:<br>
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| − | The clear housing of the inline filter allows me to see bursts of air bubbles coming in. I am not sure what that is caused by; all clamps seem very tight. With any other strainer with a metal housing you would simply not know this is happening. I will look into this; the truck does not seem to care.<br>
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| − | I have tons of fittings left over; well, I bought way more than I used up simply to save the trip to Denver Valve and Fitting (Swagelok dealer). BTW, they will ship Swagelok to you if you are not local.<br>
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| − | I have probably 15' of nylon-11 left over. This is considering I used it for bench testing and for the return line. You don't need 30' to implement this setup.<br>
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| − | I did not have to drill any holes in the frame. There are perfectly spaced holes in the frame already, forward of the transfer case (you can see the location on the pictures). Same applied to mounting of the pressure regulator: I used existing holes for everything. A Napa 5/16" self tapping bolt with fine thread works great for this.<br>
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| − | The pressure at idle can be set to anything using the Watts. I set it to 17 psi and there is a 2 psi drop across the line and filter (the cab gauge reads 17, frame rail reads 19 psi). At WOT the pressure is 12 psi. At rapid and heavy acceleration it can drop to 10. This is all with high pressure set to 40 psi. If I bump this to 60 psi using the bypass valve, the heavy acceleration does not drop below 13 psi. But 10 is fine with me, so I backed it off to 40 psi to relieve the GSL392.<br>
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| − | I plan to bolt a slightly angled steel shield, like a skid plate, to the bottom of the frame rail to protect the setup from debris kicked up by the tires.<br>
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| − | Hope this helps!<br>
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| − | -P
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| − | --[[User:Iker42|Iker42]] 21:01, 13 March 2008 (EDT)
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