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Old 01-02-2020, 05:33 PM   #34 (permalink)
Master EcoModder
Join Date: May 2019
Location: California
Posts: 378

Tahoe 2020 - '08 Chevy Tahoe H
90 day: 20.75 mpg (US)
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Originally Posted by talonts View Post
Honestly, without a separate tank, your (and others') "solution" of filling to the first click, even at the same pump, is generally useless.

I can watch the pulsing of the fuel in the hoses to the fillers on cars and see that the more cars there are filling at once, the more sensitive the shutoff valves are. They can also be temperature sensitive. You'd have to hit a pump when the station is deserted, run your tests, hit it again when deserted, and have the outside temps the same. Even then, there is ZERO guarantee that "first click" will lead to the same fuel level both times.

You either fill the tank ALL the way up, possibly destroying your vapor recovery system (depending on design), or you get a separate calibrated tank/pump to run your tests from.

Edit: Todd Day and I played around with fuel maps on our 90 Talons in the late 90s/early aughts, and while lean burn obviously helps a lot, the fastest gains were from extending the closed loop tables as far as possible, as that helped in all upper rpm situations. Which was very difficult on the stock ECU, as making room for those extended tables required removing other code, that chip was PACKED full for the 90-94s.

I do love your setup though, best of both worlds. I'd love to do the same with an LS/LT motor in the future in a transplant.

You want to basically add any power mod you can that involves volumetric efficiency, as that will boost power AND mpg. Long tube headers probably aren't going to help much at 1-2K, though...
i use the same pump it's pretty accurate since in California it has a return vapor line so all the vapor gets sucked out of the tank
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