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turbocharged 9:1 tuning

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  • turbocharged 9:1 tuning

    Ok, now that I've finally gotten the M30 ECCS working, I now have been starting to tune for a turbocharged 9.1 compression.

    At first I used a Z32 fuel and timing map because its compression is the closets to mine, at 8.5, the fuel injectors are pretty close in size, and the AFMs are the same. Unfortunately, it gave me ALOT of knock at the point where the turbocharger just begins to spool up, around 2000rpms, and at the point were it isnt high enough to reach positive boost pressure in the manifold. Basically at the same point were i would expect to see zero manifold pressure on an NA, just before the turbocharger starts to take over. I expected this because my turbocharger is going to spool up sooner than those on the Z32.

    So, I started trimming down the timing in the area of the map under boost, at 0 manifold pressure, and down to about -10psi. I know these TPs because I logged the AFM voltage against RPMs and then did the math.

    The highest AFM voltage i get is just below 4 volts, at 9psi boost. So this would be a TP value of 60. this is the highest TP value that i can reach at 9psi.

    Some of the other voltages i have are:

    idle 700 1.18
    no load 1000 1.25
    2000 1.56
    3000 1.86
    4000 2.07
    5000 2.22
    6000 2.60

    4th gear pull to 5000 @ 9lbs ~4v

    From looking at the data that I have logged, all the voltages to RPMs under negetive manifold pressure are close to the same, whether the engine is under load or not. This means that the engine doesn't take in more air under load than when under no load. Makes sense to me.

    Anyways, I have gotten the timing down to 15degrees and I'm still getting alot of knock at the point where i step on the throttle and the turbocharger starts to build boost. It mostly stops once the boost reaches maximum.

    Here's the ECCS settings

    K value = 0118, for 380cc injectors (wanna make sure that I'm running alittle rich here) MB injectors
    Null = 4C
    base timing set to 15degrees

    I have found that if i bring the timing down at the distributer all the way till it wont turn anymore, then the knocking subsides. But, this is not how i want to tune the Z. I should leave the distributer alone, set at base timing, and then adjust the timing maps.

    So, i guess what im asking is, do i need to continue to trim the timing down under the above problematic load conditions and see what happens?

    What are other people running with the same setup, turbocharged 9:1 compression

    here's a copy of the current timing map, compared to the orginal.

    [strike:ff0tp92h]1984 300ZXT[/strike:ff0tp92h]
    [strike:ff0tp92h]1986 300ZX 2x2 NA2T[/strike:ff0tp92h]
    2000 Porsche Boxster
    2007 Toyota Yaris

  • #2
    why not try adding fuel instead of trimming timing

    Comment


    • #3
      should i add fuel by changing the K value, void?

      Or by changing the individual cell values?

      I don't have a wideband, so I have the K value set a little rich to begin with.

      I figured out exactly where the low end knock was coming from, at TP values 8-23, or the first three. At these points, the timing is just too high for the onset of boost. I know lowered them all by a magnitude of about 15 and the knocking stopped. The engine now feels a little more sluggish at the lower end, but it doesnt knock anymore.
      [strike:ff0tp92h]1984 300ZXT[/strike:ff0tp92h]
      [strike:ff0tp92h]1986 300ZX 2x2 NA2T[/strike:ff0tp92h]
      2000 Porsche Boxster
      2007 Toyota Yaris

      Comment


      • #4
        so add more fuel where it's knocking and smoothly add a bit to the surroundings.... there's something wrong if like you say you have to kill your timing and crank the dist fully

        Comment


        • #5
          I'm really suprised that youre hitting boost at a tp of 8-23. You really shouldnt be in boost until about your 47 column. Something doesnt sound right. Are you sure you're modifying the correct ignition map? There are two and maybe its using the other map.

          Comment


          • #6
            I really hope you guys will continue this dialog, as I am turbo a 86 NA.

            Please throw in as much remedial info and you feel free to give.

            Comment


            • #7
              I'm guessing your fueling is way lean under boost. You're not tuning using a widebad, are you? That's the only reason I could see you needing to run timing advance as low as 15 degrees with just a little boost. I'm also not sure on your tp calculations... have you done column testing to confirm? This is with premium fuel?

              That's one very strange looking timing map IMHO. I would get your fueling squared away before you adjust it too much more. This is the timing map I have been working with on my 8.5:1 engine:


              All of the tp readings will change depending on temperature (as maf voltage does) but from memory boost comes in around 41-48 TP; 10PSI is about 65-69TP; I hit a max of about 107 TP when the maf voltage maxes out at ~18PSI. This tune is always run on 93 octane fuel with 11.60 AFR's and I never hear any audible knock.

              Comment


              • #8
                I figured it out. Apparently, after a little more review between Stinky and I, I come to find out that I was tuning the wrong timing map. The knock and primary timing maps are reverse of each other compared to the Z32.

                Now that I'm using the right timing map, it runs great with the stock Z32 timing.
                [strike:ff0tp92h]1984 300ZXT[/strike:ff0tp92h]
                [strike:ff0tp92h]1986 300ZX 2x2 NA2T[/strike:ff0tp92h]
                2000 Porsche Boxster
                2007 Toyota Yaris

                Comment


                • #9
                  Stinky wrote: I'm really suprised that youre hitting boost at a tp of 8-23. You really shouldnt be in boost until about your 47 column. Something doesnt sound right. Are you sure you're modifying the correct ignition map? There are two and maybe its using the other map.
                  I never said that I was hitting boost before column 47. I was merely stating that before that column the turbo is spooling up, but not fast enough to overcome atmospheric pressure.
                  [strike:ff0tp92h]1984 300ZXT[/strike:ff0tp92h]
                  [strike:ff0tp92h]1986 300ZX 2x2 NA2T[/strike:ff0tp92h]
                  2000 Porsche Boxster
                  2007 Toyota Yaris

                  Comment

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