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Old 05-02-2021, 11:04 AM   #15 (permalink)
Isaac Zachary
High Altitude Hybrid
 
Join Date: Dec 2020
Location: Gunnison, CO
Posts: 1,954

Avalon - '13 Toyota Avalon HV
90 day: 40.45 mpg (US)

Prius - '06 Toyota Prius
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I once had a 1972 air-cooled VW Super Beetle that I increased the compression ratio from 7.3:1 to 10:1 and ran it lean, around 16:1AFR (I'm not sure what that equates to lambda since I just went by an AFR gauge. The car ran que well.

One big thing that was necessary was to tweak the ignition. Lean burn needs more advance. So yes, I had an air-cooled car with a high compression ratio running lean and had an ignition timing that was quite a bit advanced more than stock mainly driving up and down steep mountain passes. I didn't run any ethanol in the car though. But I did average 30mpg.

I would think if you have sudden changes in acceleration it's due to ignition timing.
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