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Thread: Toyota Tundra 5.7 fuel mileage

  1. #1
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    Toyota Tundra 5.7 fuel mileage

    Has anyone been able to get some better mpg out of these? My wife just picked up a 14 platinum yesterday and I was just curious. Been tuning the coyote v8 for about 2 years but have not done any reading about these, does anyone have any info or just a small base tune to try to clean it up? These things are thirsty especially lifted with bigger rims and tires. Thank you

  2. #2
    You can net a little more by retarding the intake cam at part throttle acceleration and cruise (think "Atkinson cycle lite") - the 1600-2000 RPM range up to 40-50% load is the area to focus on the most for daily driving.

    We'd normally want to add exhaust retard at the same time to maintain internal EGR, that's not necessary in most areas with the factory cal; Tundras have some internal logic that limits the amount of overlap permitted and prioritizes intake cam timing, and the stock exhaust tables have more retard than can be used with that logic. Loosely:

    Intake Advance + Exhaust Retard <= 52
    Exhaust Retard = Min(Mapped Exhaust Retard, 52 - Intake Advance)

    Other logic applies, especially in transients, but that's the general idea.

    There's more to be had by pushing that approach to higher loads (60%, and even 70%), but good driveability starts to take more effort. More timing advance to go along with those changes is beneficial as well - adding it to Exhaust Cam Spark Base ("Engine -> Spark -> Advance -> VVT -> Exhaust Cam Spark Base") is a little better approach than adding directly to the timing tables so the timing comes on in response to exhaust cam position.



    There's also a bit to be had by lowering part throttle shift points; the stock cal holds gears quite a bit longer than necessary for casual driving.

    Another, much smaller economy gain can be had by leaning out the PE table a bit, but don't go too far here unless the truck never does any hauling/towing duties and has a diet of good fuel.



    Here's an in-work example of some of those (there are lots of other little things going on, feel free to poke around): Attachment 99117

    Nothing earth-shattering, but enough to pretty reliably net ~0.5-1 mpg around town and on the highway without driving radically different than stock. It's not a finished product, but it should be enough to give you some ideas of how to approach it.
    Last edited by SlowNStock; 05-04-2020 at 11:21 PM. Reason: typos, grammar