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Thread: How to change tire size on LL8?

  1. #1

    Default How to change tire size on LL8?

    How to do i change the tire size on these LL8's, cant find nothing for gear or tire changes in the software?

  2. #2
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    First, make sure you have the latest version of EFLive Scan and Tune software (7.3.3).

    What year LL8? I have an 02, and what you need to do is go into the Speedometer section and change B0205 and B0201. There isnt a calculator, so I dont know how you can figure out what to change them to, but the VSS part is directly related to the gears and tire size...
    ~Erik~
    2013 Sonic RS Manual - 1.4L I4T E78, starting the mods
    2008 TrailBlazer SS 3SS AWD Summit White - LS2 E67/T42, bolt ons, suspension, etc.
    2002 Chevy TrailBlazer LT 4X4 Summit White - 4.2L I6 P10, lifted, wheels, etc.

  3. #3

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    Quote Originally Posted by ScarabEpic22
    First, make sure you have the latest version of EFLive Scan and Tune software (7.3.3).

    What year LL8? I have an 02, and what you need to do is go into the Speedometer section and change B0205 and B0201. There isnt a calculator, so I dont know how you can figure out what to change them to, but the VSS part is directly related to the gears and tire size...
    i changed those..i used the calculator part by getting in just a regular tune that has it, just put in the tire size and gears

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    OK, I think those are the only 2 tables regarding gears and tire size in EFILive now, so if those didnt change anything I think we are screwed unless someone wants to modify hex code.
    ~Erik~
    2013 Sonic RS Manual - 1.4L I4T E78, starting the mods
    2008 TrailBlazer SS 3SS AWD Summit White - LS2 E67/T42, bolt ons, suspension, etc.
    2002 Chevy TrailBlazer LT 4X4 Summit White - 4.2L I6 P10, lifted, wheels, etc.

  5. #5
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    Hey folks! So have you guys had any luck doing speedo updates? The calculator tool looks very nifty but it doesn't seem to be working for me.

    First off, when I dial in any tire size, the {H0104} value jumps from the original 2637.428850 to 1622.523953 regardless of the new tire size, so I'm immediately suspicious that I might be messing something up somewhere.

    Using the Speedo Fine Tuning tab instead, the calculator updated {H0101} fine, but when I went to the Shift Point Correction sheet it didn't seem to be working right yet. It seemed that no matter what I entered, when I pressed "Apply" the percentage box went back to 0% and nothing had been changed. See here:

    and then I would get an error:

    Does anyone know how to get around this?

    Thanks in advance!

    - bret

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    Quote Originally Posted by Whodunnit View Post
    First off, when I dial in any tire size, the {H0104} value jumps from the original 2637.428850 to 1622.523953 regardless of the new tire size, so I'm immediately suspicious that I might be messing something up somewhere.
    You right I notice the same thing and i got myself thinking something is wrong. pcmforless does not even change or touch the H0104

  7. #7
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    Ha, thanks for keeping this alive. I have to admit that I got frusted and gave up for a while. I guess it'd be worth downloading the latest versions and checking it out again. It'd sure be nice to have an accurate speedo again!

  8. #8
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    Unhappy Is there anyone who can help with the speedo parameters?

    Hi folks, I finally decided to shake the bats out of the ol' efi tuner. (I have to take the car in for a smog and speed-sensor errors keep popping up)

    I updated to v7.5.5 to see if this problems been resolved, but haven't had any luck with the Speedo Calculator (or at least lack confidence that it's/I'm doing it right) so I started to attempt the adjustment the old-fashion way, but I think the nomenclature has changed!.

    With v7.5.5 does anyone know what values to adjust to correct for new tires, and by how much?

    My speedo and VSS values are both reading 5.4% low. Intuitively I attempted to lower:
    {H0101} "Vehicle Speed Sensor Pulses per Kilometer"
    {H0104} "Trans Output Shaft Revs/Kilometer"
    {B0205} "Vehicle Speed Sensor Pulses Per Mile On Data bus"
    each by 5.4%, but that didn't seem to work. I don't see the {B0201} ScarabEpic22 mentioned anywhere?...

    I tried changing just {H0101} and {B0205} a different time, but the adjustment didn't come out correct and the car just ran rough after coasting to a stop (hmm.... I'm wondering if H0104 needs to be linearly scaled with H0101 because the Description box states "It will normally be consistent with the equation: H0101=H0102*H0104.")

    Do anyone happen to know if these values tend to be linearly scaled through zero (in a y=mx format) or is there an offset perhaps (such as y=mx+b)?

    Any help will be GREATLY !
    Thanks in advance!

    - bret

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    FYI, I just tried using the Speedo Calculator tool again since I recently updated software and the FlashScan Firmware and Boot Block. I read somewhere that it helps to set Units and the Speedometer Segment in "Configuration Display Units" both to Imperial, so I did that too.

    It looks bugged still though. My speedo readout went down, my computer readout went up (they no longer agreed), and worst of all the car insisted on lugging it in 4th at 900rpm. Basically the shifts were all over the place. Based on what I'm seeing, it seems multiple values must be labeled wrong for the LL8.

    Needless to say, I flashed back to stock. Will the LL8 support ever come around? My old EEC-IV programming was not near this buggy.

  10. #10
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    I changed the speedo settings but didnt bother to use the shift correction stuff. The likelihood of us getting any more P10 support is highly unlikely as it was only used in 1 platform for 4 years. I know there are a lot of TBs out there but when it comes down to tuning, they are a very small percentage of the total.

    So go use the calculator for the speedo and odo correction then setup the shift points by themselves. I also changed TCC lockup to never occur under 45mph in 4th because my 02 would get into 4th lockup at 30mph and continually lock/unlock driving on flat roads because it would gradually speed up causing me to pull my foot off the gas= unlock then relock conditions.
    ~Erik~
    2013 Sonic RS Manual - 1.4L I4T E78, starting the mods
    2008 TrailBlazer SS 3SS AWD Summit White - LS2 E67/T42, bolt ons, suspension, etc.
    2002 Chevy TrailBlazer LT 4X4 Summit White - 4.2L I6 P10, lifted, wheels, etc.

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