Lamda value on e75. And e85

In the AFR course the wordpad file showed that E85 is stoich at AFR 9.8:1. Does that mean instead of targeting the pump gas 14.7:1 I should be targeting 9.8:1? A few well known tuners in my area tune E85 around 14.7:1 or maybe a tad richer than that. Is there a certain reason for this? Also do you have to change the stoich if your ethonal content is constantly changing from the various gas stations available?

Please re watch the module that discusses the importance of the stoichiometric AFR setting on a wideband meter - https://www.hpacademy.com/dashboard/courses/understanding-afr/setting-the-stoichiometric-afr/

If they're tuning E85 to 14.7:1 then they simply haven't adjusted the stoich setting to 9.8:1 to suit the new fuel - this is very common by the way. Tuning E85 at 14.7:1 would be the same as trying to run on gasoline at 22.05:1. I can assure you that the engine would not even run if you tuned this lean.