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Long slow MS3X build starting soon

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  • #16

    Re: Long slow MS3X build starting soon

    one distinct advantage to building an MS and then going on dragweek is that you will have some very experienced guys to give you a hand on tuning and trouble shooting.
    There's always something new to learn.

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    • #17

      Re: Long slow MS3X build starting soon

      Thats for sure, that is one reason I started looking into MS.
      1968 Plymouth Barracuda Formula S 340 with a 360
      1997 Jeep Cherokee off road toy/driver. lifted, lockers, stroked 4.0

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      • #18

        Re: Long slow MS3X build starting soon

        One tip I've got is that unless it's a purpose built autocross machine, surge tanks are more trouble than they're worth. My Dart used one and the plumbing was excessively complicated and expensive. On my Chevy C10, I just stuck an in-tank fuel pump on the end of the stock sending unit instead.
        I like my surge tanks and cheap fuel external fuel pumps. I've ran the tanks down to maybe a gallon of fuel without issue. The Firebird though may someday get a bolt fuel tank that has an EFI in tank fuel pump, but for now it'll get the surge tank like my other old car converts.
        Escaped on a technicality.

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        • #19

          Re: Long slow MS3X build starting soon

          One tip I've got is that unless it's a purpose built autocross machine, surge tanks are more trouble than they're worth. My Dart used one and the plumbing was excessively complicated and expensive. On my Chevy C10, I just stuck an in-tank fuel pump on the end of the stock sending unit instead.
          That's odd, my customers almost 100% have the opposite experience.

          Most of the guys trying to make an OEM tank work have problems under cornering or braking. Literally more than half of them cannot get this right even after installing fancy sumps, pumps, etc.

          Meanwhile the guys who didn't want to screw around modifying a stock tank, simply set up a surge tank and had zero problems. Probably 12-15 people I've worked with, can't think of one of them who regretted the surge tank setup. MFI and airplane guys do it all the time, they seem to work ok?
          www.realtuners.com - catch the RealTuners Radio Podcast on Youtube, Facebook, iTunes, and anywhere else podcasts are distributed!

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          • #20

            Re: Long slow MS3X build starting soon

            I guess I'll have to see how the modified stock tank works in my truck; it should be up and running pretty soon. It seems to have worked OK for the Nova. Could be we lucked out and the Nova happens to have a pretty good fuel tank for minimizing slosh.

            Have you had any experience with the Aeromotive Phantom setup? Does it work as advertised?
            Last edited by Matt Cramer; January 16th, 2014, 10:50 AM.

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            • #21

              Re: Long slow MS3X build starting soon

              For more basic power levels - is there anything wrong with an externally mounted walbro 255 or similar pump - should work fine with a stock tank, just need to plumb in a return line? (My stock replacement tank for the falcon came with a 3/8" pick up, and a drain plug - the plan is to eventually use the drain plug for the return line)
              There's always something new to learn.

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              • #22

                Re: Long slow MS3X build starting soon

                I ran a $20 junkyard 5/16th Ford pump in the Skylark for a couple years and then a NAPA $85 new equivalent, but at some point I exceeded the HP ability of the one pump, so I installed a second $85 pump that is staged to come on at a certain RPM. It also added redundancy if my main pump fails on me (yet to have an EFI pump fail on me). In some retrospect there are better pumps in the $120 range that would replace the two pumps I am currently using.

                Doing just an external pump with out a good sump or surge tank system would be fool hardy as I tried that in my Thunderbird and right around 1/4 tank it would start stumbling when stopping, accelerating and turning. Added the surge tank with no other changes cured that issue completely.
                Escaped on a technicality.

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                • #23

                  Re: Long slow MS3X build starting soon

                  My fuel system currently is a holley blue that pulls from the stock sender. I don't have any delivery issues with an approximate 450-500HP. Say I added fuel injection and an external walboro pump and made a provision for a return how would this change? I plan on going to a sumped tank anyways but just wondering.
                  1968 Plymouth Barracuda Formula S 340 with a 360
                  1997 Jeep Cherokee off road toy/driver. lifted, lockers, stroked 4.0

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                  • #24

                    Re: Long slow MS3X build starting soon

                    My fuel system currently is a holley blue that pulls from the stock sender. I don't have any delivery issues with an approximate 450-500HP.
                    With a carburetor right?

                    What changes is the injectors need constant pressure to function. The float bowls in the carb dampen temporary uncovering of the fuel pick up. There is what, up to a minute of fuel in a float bowl at low throttle levels? Certainly 10-15 seconds worth, enough to get the pickup covered some to start sending fuel again. And of course the bubble in the line is then vented from the bowl. Where as with the EFI, a minor exposure of the pick up to air will put compressible air into the fuel line and drop the line pressure and cause the injectors to hiccup almost immediately. Or so has been my experience with it.
                    Escaped on a technicality.

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                    • #25

                      Re: Long slow MS3X build starting soon

                      so in theory - bigger fuel rails perform the same function as a surge tank?

                      Is your surge tank vented?

                      hm.

                      I'm definitely leaning toward the walbro and 3/8 hard line for feed and return, already have one 3/8 feed for the carb.
                      Then adaptors from double flare to AN, short hoses from hardline to fuel rails off the firewall, and at tank connections.

                      Is it advisable to retain a drain in the tank?
                      I am going to put the return into the existing drain, with a T fitting there I could put a valve or plug to drain the tank it I ever needed to. (switching between E85 and unleaded for example)
                      There's always something new to learn.

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                      • #26

                        Re: Long slow MS3X build starting soon

                        so in theory - bigger fuel rails perform the same function as a surge tank?
                        Huh?!?!? I highly doubt that. The air bubble drops the fuel pressure the moment it hits the pump regardless of the size of the fuel rails. Longer the pick up is exposed to air the longer the duration of the hiccup.


                        There are two ways to do the surge tank. Gary Hart on his Studebaker used a holley float bowl bolted to the side of a retangular surge tank so the surge tank did not need a return to the gas tank and the lift pump would dead head like a carb. Mine are open style and have a return from the surge tank to the gas tank. So once the surge canister is full the lift pump continues to pump at it's nearly unimpeded rate and the excess fuel is returned to the gas tank.

                        I also have my fuel regulator return going to the surge tank, which I think helps my situation on keeping all the heat the fuel picks up in the rails up front with the engine and consumed relatively quickly rather than heating a whole gas tank of fuel and run into vapor lock issues. I'm sure some hot fuel gets back to the gas tank, but not at the rate of a return line from the regulator right to the tank (and making long term heating issues worse the hot fuel is put in the tank far away from the pick up).
                        Last edited by TheSilverBuick; January 21st, 2014, 11:12 AM.
                        Escaped on a technicality.

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                        • #27

                          Re: Long slow MS3X build starting soon

                          I may need a schematic of your fuel system to understand what you're talking about.
                          OEM EFI don't have a surge tank, just a feed and return.... I suppose some OEM big can fuel filters might serve as a resevoir of sorts.

                          (speaking of which - why not use an OEM EFI fuel filter instead of the $$$ aeromotive etc canisters?)

                          But - if the issues are only apparent at low fuel levels - is it too simplistic to keep the tank more full? ;-)
                          There's always something new to learn.

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                          • #28

                            Re: Long slow MS3X build starting soon

                            Correct me if I am wrong, I think the issue is the tank / pick up side. Old carb tanks the pickup uncovers more frequently than new EFI tanks
                            Last edited by Russell; January 21st, 2014, 12:00 PM.
                            http://www.bangshift.com/forum/forum...-consolidation

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                            • #29

                              Re: Long slow MS3X build starting soon

                              Correct me if I am wrong, I think the issue is the tank / pick up deside. Old carb tanks the pick up un covers more frenquently than new efi tanks.
                              Exactly. New EFI fuel pumps are in a big canister in the tank. The intank fuel pump is a large assembly for a reason. Plus better baffling and other engineering tricks versus a tube laying on the floor of a tank that has fuel slosh back and forth by it when it gets low. The size of the filter, like the rails, is irrelevant to an air bubble at the fuel pump temporarilly cavitating the pump.

                              I knew getting low on fuel would be a problem, I just didn't expect the problem to manifest itself as early as a 1/4 tank of fuel, I figured I'd get down to at least a 1/16 before troubles would show up, but not the case. This was a new gas tank and pickup/fuel sending unit so the integrity of it was well known.
                              Escaped on a technicality.

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                              • #30

                                Re: Long slow MS3X build starting soon

                                Air bubbles my lift pump picks up from the gas tank make it to the surge canister, but stick around the top of the canister and eventually make it back to the gas tank to be vented at the gas tank's stock vent. A good surge tank is narrow and tall so the bubbles from slosh and such (which should only occur at WOT and low on fuel) can't make it to the bottom of the canister. The high pressure EFI pump picks up from the bottom of the canister and because the narrow shape of it the bottom should never be exposed to air unless the car is upside down or completely out of fuel*.


                                * and maybe not having a lift pump that can keep up with engine fuel demand over time. My lift pump cannot keep up with the engine demand at WOT, but my rough calculations say it would take eight to ten minutes of uninterrupted loaded up WOT to drain the surge tank enough to expose the EFI pump pick up. So basically the lift pump is just barely undersized.
                                Escaped on a technicality.

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