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  • Fuel Injectors????

    FI- i have a question abt it. why do it comes in different LBS?? 21lbs? 24 lbs? 30 lbs? why is it different? and i saw someone has 42lbs for turbo system on 3.4.. cud someone explain me this why is it different? increase HP? decrease MPG? or?
    sigpic
    -1992 Red Z34 284
    -1990 TSTE
    -1991 GTP
    -1992 B Z34 parts
    -1992 R Z34 parts

  • #2
    stock DOHC injectors are 24lb iirc. i have 42.5# injectors in mine. my turbo forces more air into the engine.. there for i need more fuel to keep my fuel mixture safe. more air needs more fuel.. less air needs less fuel.. without enough fuel it will lean out and cause the engine to blow... thats it.

    S
    Shane "RedZMonte"
    2004 Corvette Z06 Commemorative Edition -VIRGIN
    1995 Monte Carlo Z34 14.38@101mph, 331hp/355tq
    -Turbonetics T04E Super 60 Turbo, 2.5" Borla Catback, OBDII, 42.5# Injectors
    2004 Subaru WRX STI -Lightly Modded (SOLD)
    1994 Lumina Z34 -VIRGIN (SOLD)
    1992 Lumina Z34-VIRGIN (RIP)
    1992 L67 Lumina Z34 (SOLD)
    1990 Turbo Grand Prix (SOLD)

    Comment


    • #3
      but why do they provide 21 lbs, 30 lbs? suppose if my engine is STOCK (3.4dohc) and i buy 30 lbs, would it be good idea? or no?
      sigpic
      -1992 Red Z34 284
      -1990 TSTE
      -1991 GTP
      -1992 B Z34 parts
      -1992 R Z34 parts

      Comment


      • #4
        No. If you don't have any mods to support more fuel, then there is no reason to provide more fuel.
        -Brad-
        89 Mustang : Future 60V6 Power
        sigpic
        Follow the build -> http://www.3x00swap.com/index.php?page=mustang-blog

        Comment


        • #5
          then how would i know to measure how much FI when i mod? suppose i do want to upgrade it as much as i can as bore walls, bigger intake, twin turbo....... how can i measure for bigger ones?
          sigpic
          -1992 Red Z34 284
          -1990 TSTE
          -1991 GTP
          -1992 B Z34 parts
          -1992 R Z34 parts

          Comment


          • #6
            -Brad-
            89 Mustang : Future 60V6 Power
            sigpic
            Follow the build -> http://www.3x00swap.com/index.php?page=mustang-blog

            Comment


            • #7
              you will need to tune the car for the mods... There are a few guys that can tune OBDI or you can use a aftermarket management system, OBDII conversion or like timg has the splitsecond FTC2 to adjust his fuel/timing.

              you can't just slap in larger injectors and run it. the computer is tuned for a certin size injector.

              When your Twin Turboed then ask the question... Untill then you don't need larger injectors. (period)

              S
              Shane "RedZMonte"
              2004 Corvette Z06 Commemorative Edition -VIRGIN
              1995 Monte Carlo Z34 14.38@101mph, 331hp/355tq
              -Turbonetics T04E Super 60 Turbo, 2.5" Borla Catback, OBDII, 42.5# Injectors
              2004 Subaru WRX STI -Lightly Modded (SOLD)
              1994 Lumina Z34 -VIRGIN (SOLD)
              1992 Lumina Z34-VIRGIN (RIP)
              1992 L67 Lumina Z34 (SOLD)
              1990 Turbo Grand Prix (SOLD)

              Comment


              • #8
                Very well said, just as shane said, more air, needs more fuel. There is no point in increasing the fuel if you have a stock motor, that causes tooo much fuel in the cumbustion chamber and it washes the oil off the cyclinder walls. In doing this, your rings will be fucked very soon. tuning a car requires ALOTTTTTTTTT of research and lots of calls. I mean dam, I have called shane and others about 400 times just to make sure that I am hookin all my shit up (i am in the process of doing an OBD II swap) right. When you spend close to 6 grand in a motor, you dont want to have it blow up. With that said, your stock injectors can handle a beating. I ran my stock injectors to 6 psi every day.


                WWW.OverKillEngineeringMotorsports.com

                Comment


                • #9
                  He is very right.

                  You have to be doing a good amount of performance up grades before larger injectors are needed, there times when Bigger Isn't Always Better.

                  Stock, street driven EFI engines using an O2 feedback, closed loop control system rarely exhibit a performance gain simply by installing higher flowing injectors. During closed loop operation, the stock ECU will try to adjust for the greater amount of fuel being delivered. If the replacement injector is not too large (about 10 - 20% greater flow at most) the ECU might be able to make the correct compensation.

                  If the induction system has been left stock and the ECU cannot compensate for the increased fuel volume, unburned fuel will all but pour into the exhaust. This in turn will cause the Check Engine Light to come on, the catalytic converter could overheat and other problems will occur. In applications looking for just a little more performance it my be easier and more cost effective to raise the fuel system pressure to get a 10%-20% fuel flow increase at the injectors.

                  Remember that installing larger flow injectors only has technical merit if substantial modifications have been made to the entire induction system. Plus, the stock ECU will undoubtedly have to be re-programmed for the increased injector fuel flow.

                  Just so you know too the stock injectors for the 91-93 3.4 DOHC is 21lbs/hr and I am still getting all the fuel I need in my two set-ups and I have done major mods in a N/A set-up. It WILL vary for a Turbo set-up, main depending on % of boost, compression, etc, etc.

                  You'll need to get a tuner if your getting serious with the mods.

                  Hope that We've all helped you out!!!
                  1991 Grand Prix STE
                  3.4 DOHC
                  1 of 792 Produced
                  Extensive Mods Done

                  1991 Lumina Z34
                  3.4 DOHC
                  Getrag 284 5spd
                  1 of 30
                  Canadian Z34 Models Made with the Getrag 5spd Wahoooo!

                  1980 GMC Sierra Classic C25 With 18,000 ORIGINAL MILES!!!!

                  sigpic

                  Comment


                  • #10
                    thanks everybody, haynes yes this really helpful, im still new to 3.4 DOHC but i have known by it for years, money talks, it comes to time and now i own 2 Z34, but im selling one, maybe both so that i can sum up to get Z34 w getrag ready then rebuilt my 3.4 dohc sitting on garage floor, rebuilt all high top end performance crankshaft, rods, piston, blah etc.. then reprogram the fuel delivery system to match/fit with twin turbo in it, im considering to add NOS system in it but i highly doubt to add it since it will eat and kill the engine one day so dont want to lose 6 grand like d.o.h.c say.. but as far right now i need to build up the knowledge of 3.4 dohc, deeper than rebuilding if u know what i mean. and yeah id be needing more help from all of you for rebuilding, best advices and etc, hope it can be the WOW, fastest 3.4 DOHC. it will take a while, but worth it

                    do u know how can i reprogram for that OBDII? tips? where do u all live?.. how do we can hook up and do those projectS? via mail? haha
                    sigpic
                    -1992 Red Z34 284
                    -1990 TSTE
                    -1991 GTP
                    -1992 B Z34 parts
                    -1992 R Z34 parts

                    Comment


                    • #11
                      I'm in Canada, LOL

                      If your looking for a a Z34 just so you know I MIGHT be selling mine late summer.

                      Its in it excellent shape, with the Getrag 284.


                      I'm not sure weither I want to or not cause I love that car but I have to many cars!!! LOL
                      1991 Grand Prix STE
                      3.4 DOHC
                      1 of 792 Produced
                      Extensive Mods Done

                      1991 Lumina Z34
                      3.4 DOHC
                      Getrag 284 5spd
                      1 of 30
                      Canadian Z34 Models Made with the Getrag 5spd Wahoooo!

                      1980 GMC Sierra Classic C25 With 18,000 ORIGINAL MILES!!!!

                      sigpic

                      Comment

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