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  • Manifold selection

    Is there any recommended manifold for an e street or fitech type systems, meaning, single plane or dual plane or a certain type to stay away from?

  • #2

    Re: Manifold selection

    given the same distance as carbs in fuel delivery...
    go for the popular carb manifolds for your given engine.
    Previously boxer3main
    the death rate and fairy tales cannot kill the nature left behind.

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    • #3

      Re: Manifold selection

      I'd take a queue from the OEM's.. just like smaller diameter long runner dual planes, long runner EFI manifolds promote a lower rpm torque curve / peak. Same for larger cross section area short runners favoring higher RPM torque peaks.

      Victor Jr.'s get a lot of use. What are your goals?
      Flying south, with a flock of bird dogs.

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      • #4

        Re: Manifold selection

        I think engine masters touched on this, and the dual plane and the self learn efi didn't like to play nice together..
        The dual plane was for low rpm pull on the carb.. I'm not sure it matters on efi that is pushing the fuel.. into the air stream..
        Were the carb needed it sucked into it..

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        • #5

          Re: Manifold selection

          My goals are to get this to consistently run from 0-30 on the streets we drive on. We had gone to a carburetor, it worked better with a spacer, so it made me question the separation in the manifold, which is currently an RPM Airgap. The manifolds that are idle to 5500 have the separator flush with the base of the carburetor. The 1500-5500 have about a 1/4 inch cutout in the middle separator. Over the weekend we pulled the engine since we had a head gasket leak. Tore it down yesterday and the exhaust side is black soot, the pistons and valve are covered in carbon. There were three corner exhaust valves and three spark plugs that were gray white, the rest were all black soot. There is 2000 miles on this combination. I can guess we were incredibly rich with the carburetor. Went to the injection so it would take care of the mixture for us and it has not been better. Going to degree the cam again, we are showing straight up, but this thing has run like its retarded from day one. Maybe the carbon is glowing and firing at odd times when the exhaust is open, maybe the cam is junk, but what I was hoping to find with being off a tooth or set up retarded with the wrong mark has not happened yet.

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          • #6

            Re: Manifold selection

            I'm still newish to this.. but efi.. reads what the engine needs from the o2 sensor and others.. not a signal though a venturi to meter the fuel.
            so other than fuel dropping out of the air, I don't see how a dual plane would help. over an open..
            The dual plane the one side uses only 2 of the 4 injectors.. and the other side the other two.. and if they were set up to work as seperate "banks" I can see it being better at low
            engine speed.. but most of the tbi efi's are set up for the t/b suppling the fuel out of all 4 injectors.. when it's mapping the engine needs/wants..
            it doesn't know you split the intake tract into 2) 4 cyl totally messing with the settings
            Last edited by JamesMayberryIII; August 23rd, 2016, 06:47 AM.

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            • #7

              Re: Manifold selection

              well, Edelbrock said it has to be a dual plane type manifold, so I guess it changes that. Their EFI manifolds with the port injectors are open, but mixing up in the throttle body needs dual plane.

              I think I just figured out the biggest problem, the plug is not in the cylinder, its halfway up, need to get .750 reach plugs. I guess that explains why this burn is so messed up.

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              • #8

                Re: Manifold selection

                EFI systems use the manifold vacuum and intake air temperature to determine how much fuel to put in the engine. The O2 reading is after the fact to see how well it did, so ideally it's tuned right and not reacting based on the O2 sensor reading.

                Being a TBI unit, it'll probably run cleaner and smoother with a dual plane intake, but a single plane isn't going to hurt it as much as it would a carb that requires suction at the venturies. Given your goals I don't think you could go wrong either way.
                Escaped on a technicality.

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                • #9

                  Re: Manifold selection

                  we loosended the converter, getting better performance, but still seems like its not right with this air gap.

                  Have you seen the new Holley sniper fabricated intake manifolds? They sure look like they are single plane into that box and down to the runners.

                  Maybe this huge cam we are running is taking away the advantage of a dual plane.

                  dont know whether to hack out the baffle in the air gap or just get an old Torker to try.

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                  • #10

                    Re: Manifold selection

                    after reading this thread, I would probably lean towards your assessment that the cam profile may be the issue...
                    Patrick & Tammy
                    - Long Haulin' 2008, 2009, 2010, 2011, 2012, 2014...Addicting isn't it...??

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                    • #11

                      Re: Manifold selection

                      Airgap, then slap a two inch open spacer on it....




                      Even better slap a two inch four hole spacer on it......sorry no piccy.

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                      • #12

                        Re: Manifold selection

                        we have a spacer on it already did not make much of a difference, but its a throttle body on top not a carburetor and we are not ready to take that step back yet.

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                        • #13

                          Re: Manifold selection

                          I'd love to try a throttle body on mine tooo 'spensive.

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                          • #14

                            Re: Manifold selection

                            Fitech is 8-900, Holley Sniper is 999, I would not recommend Edelbrock to anybody.

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                            • #15

                              Re: Manifold selection

                              I've already looked at Fitech on Summit....
                              just can't justify even that amount right now.....😕

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