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stock fuel injector rate??

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  • stock fuel injector rate??

    any1 knows the stock fuel injector rate or cc/hr on s14?
    are they upgradable?

    ty:idea:

  • #2
    240 cc @ 3 bar fuel pressure.

    you dont touch fuel delivery components unless you have the air intake to match it.
    air intake increase comes only from hardware changes like: cams, flowed head,
    supercharger or turbo etc.

    low fuel rate injectors are desirable for a well running engine (they produce a finer spray
    with less amount of fuel "falling out of the air". having big droplets are detrimental to
    performance). It also doesnt make sense to double the capacity, and
    then have to half your injector pulse to get back to decent AFR -- this gives up system
    resolution (of your ECU) and all hardware has to work within certain limits with finite
    resolution.

    John

    Comment


    • #3
      'upgradeable' in the sense that you can increase fuel pressure up to 5 bar instead of the 3 they are rated at.
      S14B20, S14B23
      BOSCH P/N 0 280 150 201 236.5cc/min @ 3 bar
      0.42 BSFC - Est. HP Duty Cycle 80% 42.9; 95% 50.9
      0.47 BSFC - Est. HP Duty Cycle 80% 38.3; 95% 45.5
      0.52 BSFC - Est. HP Duty Cycle 80% 34.6; 95% 41.1
      0.57 BSFC - Est. HP Duty Cycle 80% 31.6; 95% 37.5
      Impedance Low

      here are some more injector flow data:


      Comment


      • #4
        I just got a set of RC injectors for my car rated at 250, thats what thay recomended and thay work grate , i am vary happy with them and the best part was i got all 4 new for $315.00 and thay even came with a chart on what the frlow rates where .

        Comment


        • #5
          Originally posted by John
          240 cc @ 3 bar fuel pressure.

          you dont touch fuel delivery components unless you have the air intake to match it.
          air intake increase comes only from hardware changes like: cams, flowed head,
          supercharger or turbo etc.

          low fuel rate injectors are desirable for a well running engine (they produce a finer spray
          with less amount of fuel "falling out of the air". having big droplets are detrimental to
          performance). It also doesnt make sense to double the capacity, and
          then have to half your injector pulse to get back to decent AFR -- this gives up system
          resolution (of your ECU) and all hardware has to work within certain limits with finite
          resolution.

          John
          John,

          Sorry to thread hijack, but I have a duty cycle question. On my Motec setup I was getting "duty cycle error" during WOT runs. I checked the log at at WOT approaching max RPM the injectors were reaching 95 duty cycle. I bumped the fuel pressure to 5 bar and now they only get to 85.

          Do you think that is adequate or would you go to a larger injector? The current injectors are 32lb/hr (336cc/min).

          What do you think? Is 85 too much?

          Comment


          • #6
            At 85% duty cycle you're pretty much at the limit. I think it's recommended to aim for a maximum duty cycle of about 75 to 80% (to avoid burning out the injector coils over time).

            The injectors in my Opel 16v engine are at 85% at peak torque, and I've been running the engine like that for about 50,000 miles with no problems.

            If you go too large with the injectors, you end up not being able to get a decent idle due to fuel drop-out as John mentioned. As well as a maximum duty cycle there is also a minimum. (Around 5% I think).

            If the minimum duty cycle gives too much fuel at idle then you'll never manage to get a smooth emission test friendly idle mixture.

            Basically, you want to run the smallest injectors you can get that cope with maximum-torque rpm (a duty cycle of up to 80% or so).

            Also note that the flow rates quoted in literature refer to a specific fuel pressure. If you increase the fuel pressure, the flow rate will not increase in a linear way.

            John probably has more solid proof of this and possibly numbers to back it up.
            Steve
            Scottish Cecotto

            Comment


            • #7
              well,on the autronic ecu you can run as large injektors you want,no problems at all!
              I run rochester type,465cc injektor.
              I think it have somting to do,how "fast" your ecu are

              Comment


              • #8
                I don't agree. If the injector at it's smallest setting is squirting in more fuel than the engine needs, then it'll run rich regardless. (I'm talking for idle).

                Unless of course if you are now running sequential injection.
                Steve
                Scottish Cecotto

                Comment


                • #9
                  Does anyone know the flow rate and impeadence for the stock sport evo injectors?

                  Thanks

                  Steve
                  Sport Evo No.47

                  My Sport Evo Restoration

                  Comment


                  • #10
                    Ironhead,
                    336 cc/min at 3 bar or at 5 bar?
                    you have a 2.5 with 284/276 and no airbox right?

                    does your motec tell you where and when this
                    "error" happens? and did the AFR lean out when
                    this happened or remain on target?
                    I dont believe you have a problem
                    at all with 85% duty cycle. The "error" in the log
                    is a good thing to warn you that you are about to
                    to max out the injector and go lean.
                    Also, have you alread converted to sequential mode?
                    In this case it is logical that you can run out of injector
                    at high rpms unless the ECU automatically switches
                    back over to a group or banked. then you probably
                    have to get the injection phase right.
                    what happened to the Lenz, you finally gave up?


                    yngve: first I believe you are running a much
                    too large injector for your engine as you are not
                    making that much hp, and secondly, it has
                    nothing to do with "how fast" your ecu is.
                    stock motronic is not limited to small injectors
                    due to any kind of ECU clock rates. the system
                    scale up with the injectors and AFM used.

                    the injectors are low impedance (below 10 ohms.
                    I believe 5 ohms but Id have to look it up)

                    PS Steve, estimate for
                    new injector rate is: sqrt(newpressure/oldpressure)*old injector rate. if you flowbench them then you know what is
                    going on.

                    John
                    Last edited by John; 01-16-2005, 04:24 AM.

                    Comment


                    • #11
                      Its not the speed of the ECU but rather the physics of the opening time of the injectors. Once the time goes lower than 1.2-1.0ms then *most* injectors have consistant flow issues due to t getting an opening signal before the other cycle has time to close fully. *Some* injectors are better than others at <1.0ms. I know for a fact that with the LENZ, any other injector besides Bosch @<.90ms have issues with idle control. I have tried a few different injectors/pressures, and the best so far are Bosch 26# @4bar. This combo provides 80% @ max torque and 1.15ms at 1000rpm idle on my motor.

                      T

                      Comment


                      • #12
                        My poynt was only that on the sequential autronic there is no problem running too large injektors! The 465cc where somting I had before i got my s14. They have capasity close to 400hp so to big yes! But no idele problems,and for future mods there is plenty fuel :huh:

                        Comment


                        • #13
                          Originally posted by John
                          Ironhead,
                          336 cc/min at 3 bar or at 5 bar?
                          you have a 2.5 with 284/276 and no airbox right?

                          does your motec tell you where and when this
                          "error" happens? and did the AFR lean out when
                          this happened or remain on target?
                          I dont believe you have a problem
                          at all with 85% duty cycle. The "error" in the log
                          is a good thing to warn you that you are about to
                          to max out the injector and go lean.
                          Also, have you alread converted to sequential mode?
                          In this case it is logical that you can run out of injector
                          at high rpms unless the ECU automatically switches
                          back over to a group or banked. then you probably
                          have to get the injection phase right.
                          what happened to the Lenz, you finally gave up?


                          yngve: first I believe you are running a much
                          too large injector for your engine as you are not
                          making that much hp, and secondly, it has
                          nothing to do with "how fast" your ecu is.
                          stock motronic is not limited to small injectors
                          due to any kind of ECU clock rates. the system
                          scale up with the injectors and AFM used.

                          the injectors are low impedance (below 10 ohms.
                          I believe 5 ohms but Id have to look it up)

                          PS Steve, estimate for
                          new injector rate is: sqrt(newpressure/oldpressure)*old injector rate. if you flowbench them then you know what is
                          going on.

                          John
                          John,

                          The injectors are 336cc at 3 bar....not sure what that equates to at 5 bar. They were up to 95% duty cycle when I was using them at 3 bar. This triggered the "duty cycle error". It was reaching 95% duty cycle above 6500 RPM at WOT. I bumped fuel pressure up to 5 bar, I got no more duty cycle error. Checking the datalog of WOT runs, the injectors at 5 bar were maxing out at 85% duty cycle. The car is set up with sequential injection, 284/276 cams, 2.5L.

                          I am reluctant to switch to larger injectors, because of the potential idle issues (need this car to pass smog) and because I have a lot of 336cc injectors now....I was just making sure the 85% duty cycle was adequate safety margin. The WBO2 log never showed any leaning out even with the injectors hitting 95% duty cycle at 3 bar. I figure I am OK with these injectors...just wanted another opinion.

                          Yes, I gave up on the Lenz and switched to Motec.

                          Comment


                          • #14
                            Originally posted by John
                            Ironhead,
                            336 cc/min at 3 bar or at 5 bar?
                            you have a 2.5 with 284/276 and no airbox right?

                            does your motec tell you where and when this
                            "error" happens? and did the AFR lean out when
                            this happened or remain on target?
                            I dont believe you have a problem
                            at all with 85% duty cycle. The "error" in the log
                            is a good thing to warn you that you are about to
                            to max out the injector and go lean.
                            Also, have you alread converted to sequential mode?
                            In this case it is logical that you can run out of injector
                            at high rpms unless the ECU automatically switches
                            back over to a group or banked. then you probably
                            have to get the injection phase right.
                            what happened to the Lenz, you finally gave up?


                            yngve: first I believe you are running a much
                            too large injector for your engine as you are not
                            making that much hp, and secondly, it has
                            nothing to do with "how fast" your ecu is.
                            stock motronic is not limited to small injectors
                            due to any kind of ECU clock rates. the system
                            scale up with the injectors and AFM used.

                            the injectors are low impedance (below 10 ohms.
                            I believe 5 ohms but Id have to look it up)

                            PS Steve, estimate for
                            new injector rate is: sqrt(newpressure/oldpressure)*old injector rate. if you flowbench them then you know what is
                            going on.

                            John
                            John,

                            The injectors are 336cc at 3 bar....not sure what that equates to at 5 bar. They were up to 95% duty cycle when I was using them at 3 bar. This triggered the "duty cycle error". It was reaching 95% duty cycle above 6500 RPM at WOT. I bumped fuel pressure up to 5 bar, I got no more duty cycle error. Checking the datalog of WOT runs, the injectors at 5 bar were maxing out at 85% duty cycle. The car is set up with sequential injection, 284/276 cams, 2.5L.

                            I am reluctant to switch to larger injectors, because of the potential idle issues (need this car to pass smog) and because I have a lot of 336cc injectors now....I was just making sure the 85% duty cycle was adequate safety margin. The WBO2 log never showed any leaning out even with the injectors hitting 95% duty cycle at 3 bar. I figure I am OK with these injectors...just wanted another opinion.

                            Yes, I gave up on the Lenz and switched to Motec.

                            Comment

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