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Thread: $8D RPM Limit Question

  1. #1
    Fuel Injected!
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    $8D RPM Limit Question

    So while poking around at some BINs for $8D, I noticed that in every single "stock" Y-body BIN posted here, using $8D-1227730-V1.XDF the rev limit section appears to be essentially non-functional. That is, the "fuel cutoff engine speed" is set to 10,000 RPM while the "fuel resume engine speed" is 9,500 RPM.

    Now, obviously there's no way a stock L98 is going to spin that high. And I can't imagine GM having the ability to limit the RPM of the engine during normal operation and not using it. So does anyone know what's going on here? I can only think of three possibilities:

    1. All the "stock" BINs on Gearhead-EFI aren't stock, but are modified to remove the rev limiter.
    2. GM did not have an electronic rev limiter on the L98 despite having the ability to do so.
    3. The XDF is wrong, either with what address it's querying or the equation it's using to convert bytes to RPM.

    Anyone have insight?
    1990 Corvette (Manual)
    1994 Corvette (Automatic)
    1995 Corvette (Manual)

  2. #2
    Fuel Injected! ralmo94's Avatar
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    I believe I remember reading something about that being the stock settings in the docs for s_AUJP
    No need to re-invent the wheel. But we can make it better

  3. #3
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    Quote Originally Posted by NomakeWan View Post
    So while poking around at some BINs for $8D, I noticed that in every single "stock" Y-body BIN posted here, using $8D-1227730-V1.XDF the rev limit section appears to be essentially non-functional. That is, the "fuel cutoff engine speed" is set to 10,000 RPM while the "fuel resume engine speed" is 9,500 RPM.

    Now, obviously there's no way a stock L98 is going to spin that high. And I can't imagine GM having the ability to limit the RPM of the engine during normal operation and not using it. So does anyone know what's going on here? I can only think of three possibilities:

    1. All the "stock" BINs on Gearhead-EFI aren't stock, but are modified to remove the rev limiter.
    2. GM did not have an electronic rev limiter on the L98 despite having the ability to do so.
    3. The XDF is wrong, either with what address it's querying or the equation it's using to convert bytes to RPM.

    Anyone have insight?
    GM did not have a rev limiter on that application.

  4. #4
    Fuel Injected!
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    Oh wow, I had no idea. That's...kind of wild, actually.

    I might have to throw one in just for peace of mind, then. Thanks for the answer!
    1990 Corvette (Manual)
    1994 Corvette (Automatic)
    1995 Corvette (Manual)

  5. #5
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    There were speed settings though, and those matched the tire type.

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