

| Subject: | Re: Use Air Cooled Fuel Pressure Regulator on WBX? |
| From: | neil n |
| Date: | Sun, 20 May 2012 08:31:12 -0700 |
Cool. Thanks David. My gut told me that there might be some issue with both return lines pushing fuel into one inlet. But as you suggest, I could measure pressure. Thanks for explaining. A brass " T " isn't available at my FLAPS, but it does exist of course and is what I would've used. The FPR bracket is easy to bend but maybe only to 45� maximum. Hose routing to accommodate the single inlet type FPR might be difficult. e.g. I found that even "just" moving fuel rail hoses to top of intake, and feed/return hoses over to driver side of firewall presents a challenge. (where will it chaff, wires nearby etc.) A single inlet FPR, with FPR bracket bent to max., at best, (in my minds eye) would still put the return hoses at an awkward angle. The feed hoses to new " T " would need to be curved thus routing them over parts. So theoretically possible but hose routing might make the idea moot? I don't feel like spending more money on a test part but could mock something up I guess. Neil. On Sun, May 20, 2012 at 12:26 AM, David Beierl <dbeierl@attglobal.net>wrote: > At 02:10 AM 5/20/2012, neil n wrote: > >> A " T " would be required at inlet, there would be 2 more hose clamps than >> with the WBX part, positioning it might be a problem, but other than that, >> will the part work correctly? >> > > I haven't done it, Neil, but I don't see any likely issues. The AFC fuel > pump delivery rate is the same, injection pressures same, the venting rate > back to the tank should be the same or less. The AFC system appears to > feed at one end of the system and vent at the other; the later ones feed at > both ends and vent in the middle (or to say another way, feed the two sides > of the engine in parallel) which gives both sides the same inlet fuel > temperature. Doing it that way it becomes more convenient to have two > input nipples on the regulator. The only possible (not likely) issue I see > with using a tee is turbulence/noise/restriction where the two flows are > constricted, meet, and abruptly turn 90 degrees at the tee instead of > feeding into the less constricted turning point inside the regulator. > Since the fuel pump is a positive-displacement type with excess capacity > it's not going to cause *it* a problem, and I find it hard to believe it > would constrict flow enough to cause a problem with pressure regulation. > If you're anal you could test this by installing a tee in place of the > existing regulator and measuring pressure at the test tee (not the one you > installed) while running the pump with a jumper. If you wanted to be even > more persnickety you could then measure the same pressure downstream > (toward the tank) of the new tee and subtract it from the other reading to > get the true max pressure drop across the tee itself at max flow > conditions. We're talking about half a liter per minute flow rates here > at 35 psi net pressure drop in the system and gasoline's not very viscous, > so I really don't see a problem. The tee would have to be fuel and > temperature safe at pressure, of course, and if the return line somehow got > pinched it might see over 100 psi. A metal tee would take care of any > worries there. > > Yours, > David > -- Neil n 65 kb image Myford Ready For Assembly http://tinyurl.com/64sx4rp '88 Slate Blue Westy to be named. '81 VanaJetta 2.0 "Jaco" http://tubaneil.googlepages.com/ Vanagon VAG Gas I4/VR Swap Google Group: http://groups.google.com/group/vanagons-with-vw-inline-4-cylinder-gas-engines
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