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Old 09-27-2018, 03:53 PM   #108 (permalink)
Ecky
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Join Date: Dec 2011
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ND Miata - '15 Mazda MX-5 Special Package
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Quote:
Originally Posted by mpg_numbers_guy View Post
Couldn't you install a switch to disable the hybrid system to prevent forced regen while driving, and enable it for when you wanted to autostop?
All of the car's computers need to reboot, and then you need to clear the CEL. It wouldn't be a simple switch, but rather a process that takes several minutes and is multi-step. Anyhow, once the battery is that bad, the regen is necessary to have the energy for auto-stop. We're talking the final weeks of a battery's life before it does nothing, not months or years.

Quote:
Originally Posted by mpg_numbers_guy View Post
Does lean burn reduce HP output? I was thinking in regards to climbing a hill, because if downshifting to 4th or even 3rd but maintaining speed and lean burn would be more efficient than lugging it up in 5th and having to re-accelerate at the top of the hill.
Yeah, if you lean out by 33% (14:1 to 21:1), you also lose 33% of your power. You're burning 33% less fuel, after all. It's not free fuel saved. It's only useful if you are only running part throttle in a given gear, leaning out let's you run a wider throttle opening and save a small amount by making less vacuum. It might also affect BSFC, but measuring that would be very difficult.

Lean burn would be nearly pointless on a Prius, for instance, because it has effectively infinite gearing. You just slow the engine down more, or toggle it on and off.

There are a few other subtleties where it's useful, like allowing an engine to actually run at a higher rpm at WOT and make the same power - sometimes this is useful, but it's not really low hanging fruit.


Quote:
Originally Posted by mpg_numbers_guy View Post
Are you talking about the guy from IC who runs 120 PSI in his tires?
Yep, he had no lean burn for a long time.
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