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Old 05-26-2017, 12:41 AM   #3 (permalink)
ever_green
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Join Date: May 2011
Location: Toronto
Posts: 264

gueff - '19 Mercedes Benz A250 4MATIC AMG
90 day: 30.55 mpg (US)
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Quote:
Originally Posted by Ecky View Post
I'm impressed. What sort of tune do you have? Any chance of running it more on the lean side at part load, and only stoich or rich as it nears WoT, for improved economy?
i have left fueling stock as it's already very good from factory. 14.7-15.2:1 very light throttle. i mostly upped ignition timing in cruise areas and added more intake valve timing cam advance at high rpm. the intake is already very retarded at cruise - there's is about 100* cam retard at cruise! atkinson cycle or whatever it's called. however i found that ignition timing was way too conservative at cruise and 50-70% load area so i bumped it 2-5* knock free. planning on adding 2* total and upping to 89 gas for more power. an extra 1* is a lot of timing on this much compression and advanced cam (high load).
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