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Thread: How to scale the DIC for proper MPG?

  1. #1
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    How to scale the DIC for proper MPG?

    After upgrading my 99 Corvette to 60# injectors, the DIC calculated MPG is off a lot. How can I scale this with my HP Tuners? I found someone has done it with EFLive:


    How can this be changed with HP Tuners?

  2. #2
    Advanced Tuner Phantom's Avatar
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    It can be done but the multiplier you posted above probably had not been added to your OS you would need to send a request to have it added to your OS.

    You can do a work around to get it correct just reset the DIC when you fill your tank and the next time you fill record the gallons used according to the DIC and divide actual gal by DIC gal. 15/16=0.9375 you will take that number and multiply injector flow rate by it then take maf and multiply it by 1.9375. That should correct the DIC and keep the air flow model correct.

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  3. #3
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    Quote Originally Posted by Phantom View Post
    It can be done but the multiplier you posted above probably had not been added to your OS you would need to send a request to have it added to your OS.

    You can do a work around to get it correct just reset the DIC when you fill your tank and the next time you fill record the gallons used according to the DIC and divide actual gal by DIC gal. 15/16=0.9375 you will take that number and multiply injector flow rate by it then take maf and multiply it by 1.9375. That should correct the DIC and keep the air flow model correct.
    A lot of questionable info here

  4. #4
    Senior Tuner eficalibrator's Avatar
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    Quote Originally Posted by Phantom View Post
    You can do a work around to get it correct just reset the DIC when you fill your tank and the next time you fill record the gallons used according to the DIC and divide actual gal by DIC gal. 15/16=0.9375 you will take that number and multiply injector flow rate by it then take maf and multiply it by 1.9375. That should correct the DIC and keep the air flow model correct.
    I disagree.

  5. #5
    Tuner Chevy406's Avatar
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    If you entered the proper values for your fuel injectors you will have very close MPG on your DIC. Sounds like you need to do some more work on your injector tables.

  6. #6
    Senior Tuner DSteck's Avatar
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    WGAF. That's my two cents.



    I'm sure HPT could add that scalar. Submit a request.

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  7. #7
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    wow i need to fingre that table out.. the suburban just went 250 miles on 40 gallons! i must have something off a lot

  8. #8
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    Sorry to bump an old thread. I've been looking around for the same answer. My DIC milage consistently reads 10% better than I really get. I would like to correct that error. I have calibrated my wheel rotations/odometer but the MPG is still consistently off. I have a stock (tuned) 8100 in an '05 YukonXL 2500.

  9. #9
    Senior Tuner Higgs Boson's Avatar
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    Quote Originally Posted by deekster_caddy View Post
    Sorry to bump an old thread. I've been looking around for the same answer. My DIC milage consistently reads 10% better than I really get. I would like to correct that error. I have calibrated my wheel rotations/odometer but the MPG is still consistently off. I have a stock (tuned) 8100 in an '05 YukonXL 2500.
    That happens from the factory too. They always read like 2 mpg high. That's why no one who knows uses the DIC for mpgs.

  10. #10
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    Quote Originally Posted by Higgs Boson View Post
    That happens from the factory too. They always read like 2 mpg high. That's why no one who knows uses the DIC for mpgs.
    Thanks for the reply. Clearly it's factory, and consistent. Every GM I've been in with a DIC has the same error, almost the same % off as well. In my truck I know that when the DIC says I used 29 gallons, I am going to put in 32-33. The error is about the same as my hand calc'd MPG. So it must be a setting somewhere, and if they can write it, we can change it, no? Maybe? Please?

  11. #11
    email support with your request, it can be added.

    The PCM communicates the fuel used to the DIC based on the injector flow rate. If it is out by 10% then your will se a 10% error in the cluster.
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  12. #12
    Senior Tuner Higgs Boson's Avatar
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    Quote Originally Posted by Chris@HPTuners View Post
    email support with your request, it can be added.

    The PCM communicates the fuel used to the DIC based on the injector flow rate. If it is out by 10% then your will se a 10% error in the cluster.
    It would be great to have a scalar as mentioned on all of the GM tunes, especially when they are off from the factory and known good injector data is in the factory tune (one would hope).

  13. #13
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    added to 2.23.592 or later for OS 12606961
    - Cluster Fuel Factor
    - Cluster Inst Fuel Filter Coeff
    It doesn't have to be perfect, it just needs to be done in two weeks...

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  14. #14
    Senior Tuner DSteck's Avatar
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    Can we get this for other applications? I'd love to be able to fix the DIC for my Z06, as well as customer cars since they tend to think they magically get hybrid gas mileage with 114lb injectors.

    (I realize before I said WGAF)

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  15. #15
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    Quote Originally Posted by Phantom View Post
    It can be done but the multiplier you posted above probably had not been added to your OS you would need to send a request to have it added to your OS.

    You can do a work around to get it correct just reset the DIC when you fill your tank and the next time you fill record the gallons used according to the DIC and divide actual gal by DIC gal. 15/16=0.9375 you will take that number and multiply injector flow rate by it then take maf and multiply it by 1.9375. That should correct the DIC and keep the air flow model correct.
    Excuse the ignorance, but what if we're running a 2 bar SD tune, could we multiply the injector table and the VE table instead and get the same results? Tuning newbie here

  16. #16
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    Is this in the newest build for E38's ??
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  17. #17
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    Bump for E38 support!