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Thread: Scaling Question

  1. #11
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    That is where the math gets tough for me. He scaled the 90 lb/hr injectors at 63.4920 in B4001, instead of 44.4 (reading out of the inj table from the mfj
    He then set B3671 to 21.57 instead of 28.4 (14.20 X 2, running approx 10% Ethanol) then he copied in someone elses VE tables then modified them. This maybe OK but it is a nightmare for me since he is busy and has not had the time to finish the tune. I will post the current tune and three runs (scans)on the mile at the Silver State Classic Challenge. I would like to get the MAF working to smooth out the driveability.

    miving on 3.ctzSO-3.efiMAF 0n-2.efiSO 1.efi
    Last edited by lbl866@aol.com; September 27th, 2018 at 09:10 AM.
    LBL866

  2. #12
    Joe (Moderator) joecar's Avatar
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    Quote Originally Posted by lbl866@aol.com View Post
    That is where the math gets tough for me. He scaled the 90 lb/hr injectors at 63.4920 in B4001, instead of 44.4 (reading out of the inj table from the mfj
    He then set B3671 to 21.57 instead of 28.4 (14.20 X 2, running approx 10% Ethanol) then he copied in someone elses VE tables then modified them. This maybe OK but it is a nightmare for me since he is busy and has not had the time to finish the tune. I will post the current tune and three runs (scans)on the mile at the Silver State Classic Challenge. I would like to get the MAF working to smooth out the driveability.

    miving on 3.ctzSO-3.efiMAF 0n-2.efiSO 1.efi
    What was rail pressure measured to be (with manifold reference hose temporarily removed)(this is important to get this measurement!!!)...?


    so he scaled the 90 lb/hr IFR to 63.492 ib/hr... this scaling factor is 63.492/90 = 0.7055

    then AFR scaling: 14.7/0.7055 = 20.84 this is close to 21.57.



    I'll take a closer look at your files over the weekend.

  3. #13
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    Quote Originally Posted by joecar View Post
    What was rail pressure measured to be (with manifold reference hose temporarily removed)(this is important to get this measurement!!!)...?


    so he scaled the 90 lb/hr IFR to 63.492 ib/hr... this scaling factor is 63.492/90 = 0.7055

    then AFR scaling: 14.7/0.7055 = 20.84 this is close to 21.57.



    I'll take a closer look at your files over the weekend.
    I finally figured out how to work the VVE but looks to me like it would be easier to use the 44.4 and the 28.4. The scans would be multiplied by 2 in excel then copied and multiplied in the table. I will leave it as is if you can help me with the numbers. Does the MAF modify the Stoich table or the Base fuel flow. Same goes for the VE. Which table does it modify??? (Logic)
    LBL866

  4. #14
    Joe (Moderator) joecar's Avatar
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    When you scale, you would do one of these:
    a. scale stoich and IFR together,
    b. scale VE, MAF and IFR together,
    c. scale VE, MAF and stoich together.

  5. #15
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    Quote Originally Posted by joecar View Post
    When you scale, you would do one of these:
    a. scale stoich and IFR together,
    b. scale VE, MAF and IFR together,
    c. scale VE, MAF and stoich together.
    I appreciate your help but I am still a little short on understanding a couple of basic things. What I have been missing is understanding the logic in the GM ECM of what the MAF settings in the maf sensor tables use as a reference (Stoich,IFR, or both) or what the VE references (Stoich, IFR, or both) when you change the VE Tables or the MAF sensor tables. I understand a. from above and if I were to use 50 % for IFR ( I must scale the IFR due to the limitations in the E38 and my 90 lb. per hr injectors) and twice AFR , I can then use the tools built into EFI Live to manipulate the VVE and MAF with the help you have already given me and some excel tables I have made. If I were to have unlimited access to a dyno, I might eventually answer my own questions but it would be much simpler for me if you could please provide the answers.
    LBL866

  6. #16
    Joe (Moderator) joecar's Avatar
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    MAF (g/s) and VE (g*K/kPa) are both used to calculate cylinder airmass (g)...

    this means two things:

    a. any table that references g or g/s on its axis will need to be shifted along that axis (this can be tedious).

    b. any tables that add/multiply/time fuel on top of cylinder airmass need to be scaled in the opposite direction.

  7. #17
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    When scaling IFR and doubling Stoich a lot of tables that estimate valve temp and injector temp will be thrown off... So be careful when tuning to account for this.
    "All that is needed for the triumph of evil is that good men do nothing..."

  8. #18
    Joe (Moderator) joecar's Avatar
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    Quote Originally Posted by Highlander View Post
    When scaling IFR and doubling Stoich a lot of tables that estimate valve temp and injector temp will be thrown off... So be careful when tuning to account for this.
    Good info, thanks.

  9. #19
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    Highlander and Joe,
    I have only found the Inj Tip temp and Valve temp used during Cold Start and Dynamics. When you say scale ( I am currently scaled at about 70%) do you mean to scale the comanded AFR ratio to match the scaled Stoich ie. 70%(2 x 14.68). I understand that I would do this for each AFR value in the tables, or do you mean I would scale the Valve Temps and Inj Tips Temps by 70% and move the listed AFR values to the left under the corresponding scaled temps. I have built a excel table that will do the first option (scale each value) like I did with the VE Table.
    LBL866

  10. #20
    Joe (Moderator) joecar's Avatar
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    Quote Originally Posted by lbl866@aol.com View Post
    Highlander and Joe,
    I have only found the Inj Tip temp and Valve temp used during Cold Start and Dynamics. When you say scale ( I am currently scaled at about 70%) do you mean to scale the comanded AFR ratio to match the scaled Stoich ie. 70%(2 x 14.68). I understand that I would do this for each AFR value in the tables, or do you mean I would scale the Valve Temps and Inj Tips Temps by 70% and move the listed AFR values to the left under the corresponding scaled temps. I have built a excel table that will do the first option (scale each value) like I did with the VE Table.
    Which scaling scheme are you using (a, b or c)...?


    If you're doing a (stoich and IFR), then you do stoich*n and IFR/n, i.e. on the stoich AFR and the IFR...


    you should have fueling units set to EQR, so you should not see AFR units anywhere, except for stoich AFR.

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