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My boredom = Fuel Rails (390cc DSM)

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  • My boredom = Fuel Rails (390cc DSM)

    Nothing else to do when it's 20 degrees outside except play in the garage. I made some fuel rails in 20 minutes (that's just a poke at an earlier post by someone else)... It has been more like 2 weeks, with working on them 10 minutes here and 20 minutes there.There was a set of 390cc fuel injectors laying around my garage and I decided to try my hand at a little fabrication. I only have the right side put together (still need some finish & touch-up work on the brackets/intake and install Earl's/Russel/Aeroquip line fittings) for now. There isn't more than $50.00 in parts (not including injectors) for both sides, but I can see where the time involved could be costly! I also milled out the lower injector mount in the intake manifold to drop the injector pintle lower into the intake runner to put it as close to the factory injector pintle location.





    Any input or questions from you other fuel rail guys may be helpful!

  • #2
    Nice job!

    Attachment to the lower intake will be interesting as some people will discover it's the hardest part of making the rails. Not only do the tabs need to be cut off, but there are two different lower intakes for the different injector types, and the mounting tabs are the only real difference.

    Are those brackets bolted all the way through the rails?

    How/did you chamfer the end fitting bores? Or do you plan to use o-ring end fittings?

    Are the rail ends tapped for NPT fittings like I think I see there, or -6 AN?

    How/did you ream the injector holes to the correct size?

    Comment


    • #3
      If you were to make several for profit, then it would be a good idea to buy one of these: http://www.rossmachineracing.com/injectortool.html
      1987 300ZX Turbo - http://www.z31performance.com/forum/vie ... php?t=3114
      2001 Tiburon Turbo 60-1 270whp/268tq

      No cupholders? Where am I gonna put my beer????

      Comment


      • #4
        Jason84NA2T wrote: Nice job!
        Are those brackets bolted all the way through the rails?

        How/did you chamfer the end fitting bores? Or do you plan to use o-ring end fittings?

        Are the rail ends tapped for NPT fittings like I think I see there, or -6 AN?

        How/did you ream the injector holes to the correct size?
        Yes, the stainless counter-sunk allen bolts go all the way through the rail to the bracket.

        The 3/8" NPT tap took care of the taper.

        Yes the rail ends are drilled and tapped for 3/8" NPT and I plan on adapting -6 AN afterwards.

        I started with a 1/4" drill bit to set the holes all the way to the 1/2" rail bore, then used an equation from a fuel injection book [ I think it was: D-(T/4) or something close to that - I'll get the right equation later ] to mill the holes for the injector o-rings. Afterwards, lightly pollished the bore finish.

        And Evil, that injector port tool would of made it a lot easier, but $130.00... Remember I'm a cheap @ss Z31 guy :wink:

        Comment


        • #5
          Yea, that's why I said it would be great only for a shop that will produce a LOT of them. Would make their job easier.
          1987 300ZX Turbo - http://www.z31performance.com/forum/vie ... php?t=3114
          2001 Tiburon Turbo 60-1 270whp/268tq

          No cupholders? Where am I gonna put my beer????

          Comment


          • #6
            Evil Z31 wrote: Yea, that's why I said it would be great only for a shop that will produce a LOT of them. Would make their job easier.
            I actually have one of those on the way, funny you should mention it!

            Comment


            • #7
              Looks good... but I could have done it in 15 minutes using only my teeth.

              I like the way you mounted the rails... pro.

              where did you get the fuel rail stock? I like the finned look.
              86 hardtop shell, 93 SC300 engine, 95 soarer bellhousing, 91 supra transmission, 95 Q45 differential hubs and driver's side axle, 1992 300ZX turbo driver side axle and calipers, 2004 350Z Rotors, 87 300ZX front end/hood, 1999 Viper radiator, 1992 Mustang throttle body. Lots of glue and tape to keep it all together.

              Comment


              • #8
                Fuel Injection Specialties, here in SA, got me a foot of that same stock for like $12.

                Here it is on my Tib:
                1987 300ZX Turbo - http://www.z31performance.com/forum/vie ... php?t=3114
                2001 Tiburon Turbo 60-1 270whp/268tq

                No cupholders? Where am I gonna put my beer????

                Comment


                • #9
                  Evil Z31 wrote: Fuel Injection Specialties, here in SA, got me a foot of that same stock for like $12.

                  Damn, that is a good price! Here is where I purchased both of my 12" (1ft.) rails because they were in stock and only a few miles from my house. http://store.summitracing.com/partde...5&autoview=sku


                  And on another note about injector bore sizing in the rail, here is what it says in the Motorbooks International Fuel Injection Guide by Jeff Hartman:
                  When drilling holes and reaming for O-rings, measure the diameter of the O-ring (D) and the thickness of the O-ring (d). The hole should be D-(d/4). A 1 inch O-ring that is .125 inchs thick requires a hole that is 1"-(.125"/4). That works out to a .96875 inch hole.


                  Hope this helps you guys out!

                  Comment


                  • #10
                    Jason84NA2T wrote: Nice job!

                    Attachment to the lower intake will be interesting as some people will discover it's the hardest part of making the rails. Not only do the tabs need to be cut off, but there are two different lower intakes for the different injector types, and the mounting tabs are the only real difference.

                    Are those brackets bolted all the way through the rails?

                    How/did you chamfer the end fitting bores? Or do you plan to use o-ring end fittings?

                    Are the rail ends tapped for NPT fittings like I think I see there, or -6 AN?

                    How/did you ream the injector holes to the correct size?


                    There are 2 Diff lower intake pleniums correct? The injector holes on a 89turbo one seems to be smaller than a 88 N/A. Can you use the N/A is what im wondering? Do oyu have to get some diff rings for it or somthin?
                    89' Turbo-R.I.P. (scrapped)
                    87' NA all parts swapped from 89', Stance, 3.3 long block, hx35w, Injector Dynamics 1000cc, isky cams, pathfinder intake, front mount, megasquirt v3.57 w/MS3X
                    07 Frontier XE <----(turd) daily

                    Comment


                    • #11
                      Black 89Turbo wrote: There are 2 Diff lower intake pleniums correct? The injector holes on a 89turbo one seems to be smaller than a 88 N/A. Can you use the N/A is what im wondering? Do oyu have to get some diff rings for it or somthin?
                      I would assume no one would bother to take the o-rings out of the lower intake before you got it... the inner diameter and injector cap is the same for all years afaik

                      Comment


                      • #12
                        Like I said, if you have a drill press, then you can ream out the lower IM holes from 11mm to 14mm, so it will accept all 14mm o-ring injectors.
                        1987 300ZX Turbo - http://www.z31performance.com/forum/vie ... php?t=3114
                        2001 Tiburon Turbo 60-1 270whp/268tq

                        No cupholders? Where am I gonna put my beer????

                        Comment


                        • #13
                          That looks great but that aluminum is going to soak up heat.
                          Try not to be a Yahoo

                          Comment


                          • #14
                            crowbar wrote: That looks great but that aluminum is going to soak up heat.
                            Yup, but no more than any other aftermarket aluminum fuel rail for any other car out there.

                            What are the stock ones made out of? Are they copper or somthing like that? those ones would soak up heat faster than the aluminum ones would. However, the bigger thicker aluminum ones will hold the heat longer.
                            85 Z31 6.0 LSX turbo 766whp/792wtq
                            04 GTO, LS6, big cam, porting, N20... underway for summertime daily driver.

                            Comment


                            • #15
                              I believe they are brass. Stainless Steel would be a better choice.
                              Try not to be a Yahoo

                              Comment

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