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Thread: How to change tire size on LL8?

  1. #11
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    True, very true.

    Hey any advice as to which values I need to change for my speedo, comp, and shift points to be right?... and by how much? Is it just a straight % of tire diameter change to each of these points or is there some sort of an offset at 0mph?

    Thanks for your feedback!

  2. #12
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    I used the calculator to adjust the speedo and odo. Shift points just start playing with them on the street, try bumping them up by 1mph at low speeds and 2-3mph at higher speeds. Honestly it took me probably 6 months to setup the shift points where I have them now and like it.

    So yes its pretty much a %age value multiplied to the H0101, H0104, and B0205.
    ~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. #13
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    Yeah that's what I was trying to do but it just made the computer read out and speedo read different and worse. I think I'm going to try to figure this out more scientifically now that I have some more time to play with it... first dialing in one parameter then the next... I'll report back here with what I learn.

    thx.

  4. #14
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    I was tuning a P10 tonight for bigger tires and ran across this same problem, the engine would choke to 600rpms and bog big time if I changed H0101 after I used the calculator to compute the theoretical proper values for the tires. Going to hand calc everything and see what happens in the next day or so and report back.
    ~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. #15
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    Any luck?

    I've run several combinations of +50% and -33% for H0101, H0104, and B0205 and still can't make heads or tails of what's going on. It looks like H0101 inversely affects my laptop reading but has no effect on the speedo itself. H0104 seems to have some effect sometimes, but I'm not sure if it's dependent on H0101 or not. I don't see any effects from B0205 whatsoever.

    When I simply change all three or H010 and H0104 by say, +/-10%, the speedo stays the same but the laptop reading gets all out of whack.

    Hmmm.....

  6. #16
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    Its a customers truck so I havent seen it since I posted that last message but what you're talking about seems dead on to what happened for me. I would see the VSS output to the scan tool increase waaaay beyond what it should be while the guage readout would stay the same. I left it stock simply to make sure all the shift points didnt get thrown off big time.

    Thursday looks like its going to be a testing/wash/clay/wax day for me so we'll see then. But I might have to by a license and start on my SS, cant wait to start playing with it!
    ~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.

  7. #17
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    Hmmm... do you think this might be a software version issue? If so, is this the type of thing that can be resolved by loading a different software version or is that generally a bad idea?

  8. #18
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    Has nothing to do with it Im afraid, Paul and Ross have both said that the speedo calculator is really only for the LS1 and its derivatives, there are so many ways to setup the speedo stuff they cant have a universal tool do it. Know it sucks big time but Im at a loss right now. Simply changing to an earlier software wont do anything, we've only gotten a few major revisions to the P10 files and the last one was back in Feb 08.
    ~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.

  9. #19
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    Ha ha oops. I mispoke I meant, would loading a different OS help... my OS is 12579357. I thought I read somewhere of folks flashing to a different OS somehow... or was that not with the LL8?

  10. #20
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    Cant do it with EFILive (last I head HPT couldnt do it either), have to use a Tech II to change OSs then read the new stock tune out, copy tables over, then flash it back in. Doubt Full Flashing will ever be supported for the P10.
    ~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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