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  • MAF after turbo?

    I'm wondering why (and i realize it's something i should already know) I can't just put the maf after the intercooler. I would think it would be much easier to map with in that position as you could log in 2nd and 3rd gear instead of 4th. Am I wrong? or should i give this a shot so as not to get speeding tickets trying to tune this in 3rd and 4th.
    8.5 custom arias pistons (.020 over)
    eagle rods
    t70 turbo (man was that a squeeze)
    38 mm external wastegate
    mild port/polish
    3 angle valve job
    custom intercooler piping
    twin external intakes with z32 maf
    rad moved back
    3" exhaust with only a resonator
    romulator
    420cc injectors
    custom body work, homemade oil lines and fittings..
    walbro 255lph in-line fuel pump.... and lots of headaches... lol

  • #2
    t70 wrote: I'm wondering why (and i realize it's something i should already know) I can't just put the maf after the intercooler. I would think it would be much easier to map with in that position as you could log in 2nd and 3rd gear instead of 4th. Am I wrong? or should i give this a shot so as not to get speeding tickets trying to tune this in 3rd and 4th.
    You do know that just because the MAF is located before the turbo/intercooler, doesn't mean that it gets any different air flow reading. Once boost kicks in, its still reading the same amount of airflow.
    Originally posted by Andrew84zx
    tell her your car is so fast it will make her panties fly off
    545 RWHP & 540 RWTQ
    VG30ET.com Member

    Comment


    • #3
      yes i know.. but there is a delay between when the airflow meter reads airflow and when the engine recieves it due to the length of the plumbing and the volume of the intercooler-- which is why, in my opinion, that you end up with different afr's in different gears.
      8.5 custom arias pistons (.020 over)
      eagle rods
      t70 turbo (man was that a squeeze)
      38 mm external wastegate
      mild port/polish
      3 angle valve job
      custom intercooler piping
      twin external intakes with z32 maf
      rad moved back
      3" exhaust with only a resonator
      romulator
      420cc injectors
      custom body work, homemade oil lines and fittings..
      walbro 255lph in-line fuel pump.... and lots of headaches... lol

      Comment


      • #4
        try it

        Terrible idea putting those wheels on...

        Comment


        • #5
          well... if i try it i have to change my intercooler piping to adapt to it.. and i'd rather make sure it will work before i do it..
          8.5 custom arias pistons (.020 over)
          eagle rods
          t70 turbo (man was that a squeeze)
          38 mm external wastegate
          mild port/polish
          3 angle valve job
          custom intercooler piping
          twin external intakes with z32 maf
          rad moved back
          3" exhaust with only a resonator
          romulator
          420cc injectors
          custom body work, homemade oil lines and fittings..
          walbro 255lph in-line fuel pump.... and lots of headaches... lol

          Comment


          • #6
            o, nvm.

            I was just trowing out my gunius ideas :lol:

            Terrible idea putting those wheels on...

            Comment


            • #7
              hehe n/p.
              8.5 custom arias pistons (.020 over)
              eagle rods
              t70 turbo (man was that a squeeze)
              38 mm external wastegate
              mild port/polish
              3 angle valve job
              custom intercooler piping
              twin external intakes with z32 maf
              rad moved back
              3" exhaust with only a resonator
              romulator
              420cc injectors
              custom body work, homemade oil lines and fittings..
              walbro 255lph in-line fuel pump.... and lots of headaches... lol

              Comment


              • #8
                I've always heard that for converting to a blow-through MAF the airflow will be correct UNTIL you get into boost, then you will have to correct either the TP scales and fuel/timing maps and/or the VQmap to get it to run correctly under boost. You will also generally max out the maf with less total airflow. Talk to some of the PRO-M guys about it.

                Comment


                • #9
                  actually you'd have the reverse problem I'd think, you could have less total air metered as boost starts to peak, and hardly any as boost begins to fall in say deceleration

                  and if you use a bov you could royally screw with the readings

                  Comment


                  • #10
                    although, if you plumb the bov before the MAF, then you would escape recirc, cause it'd be unmetered.

                    At any rate, yay speed density
                    88ss, MegaSquirted.
                    t3/t4 60-1 cold, stage 3 hot, FMIC
                    450cc DSM injectors, walbro 255
                    http://www.z-toys.com/ Boost gauge and MS info

                    Comment


                    • #11
                      right... ok.. because the air density is different as boost comes in, the maf meteres less than is actually going through. In fact i wonder if it would even see the difference between 5psi and 6 psi? Thanks a lot guys... i'll continue tuning with a flow through and not a blow through!
                      8.5 custom arias pistons (.020 over)
                      eagle rods
                      t70 turbo (man was that a squeeze)
                      38 mm external wastegate
                      mild port/polish
                      3 angle valve job
                      custom intercooler piping
                      twin external intakes with z32 maf
                      rad moved back
                      3" exhaust with only a resonator
                      romulator
                      420cc injectors
                      custom body work, homemade oil lines and fittings..
                      walbro 255lph in-line fuel pump.... and lots of headaches... lol

                      Comment


                      • #12
                        I've often wondered this myself. Centrifugal supercharger kits often blow-through the MAF and don't blow-up (immediately). It might just be an issue of the MAF not being calibrated to handle the higher air pressure / temp and reliably convert it to a true Mass flow reading.

                        It'd be a cool experiment to wire-up a second MAF down stream of the intercooler and log the two against each other.
                        It's RWD in reverse.

                        Comment


                        • #13
                          stop posting and go do it

                          Comment


                          • #14
                            Got a spare? I've got the datalogger.
                            Attached Files
                            It's RWD in reverse.

                            Comment


                            • #15
                              what kind of maf? i've got 2 z31 mafs and you can have one of those.
                              8.5 custom arias pistons (.020 over)
                              eagle rods
                              t70 turbo (man was that a squeeze)
                              38 mm external wastegate
                              mild port/polish
                              3 angle valve job
                              custom intercooler piping
                              twin external intakes with z32 maf
                              rad moved back
                              3" exhaust with only a resonator
                              romulator
                              420cc injectors
                              custom body work, homemade oil lines and fittings..
                              walbro 255lph in-line fuel pump.... and lots of headaches... lol

                              Comment

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