Hi Buellers,
Come on ... I live in Brazil in Sao Paulo. Here we have a climate where 70% of the year has temperatures above 25 Celsius (77 fahrenheit). Regular gasoline has 27% ethanol and premium gasoline is 25% ethanol and according to Petrobras has 95 octane. I believe that regular gasoline also has 95 octane because of the large amount of ethanol. Taking all this into consideration, I would like to know the recommendation of you to have an engine running rounder. As you know, it has a compression ratio of 10: 1 (recommended for use petrol) and the manual tells you to use gasoline with 91 octane. And to not use gasoline containing more than 10% alcohol. The original map AFR varies between 14.7 (low) to 13 (high). These proportions are to use gasoline with 91 octane. The stoichiometric ratio of AFR for ethanol would be 9,8 correct. But as our gasoline has 27% ethanol, there must be a middle ground to get the best proportion. I have heard also that the O2 sensor original narrowband can not identify this amount of ethanol, hindering the correct reading. I not believe this information, since the O2 sensor le only the oxygen in the exhaust coming out, regardless of the fuel. What you guys advise?
Slightly change the compression rate to use our gasoline? Perhaps change the compression ratio, eg to 10.5: 1 or 11.0: 1 to suit a bit Brazilian gasoline?
Also decrease the AFR values ​​for a middle ground between the ideal for gasoline is 14.7: 1 for petrol and 9.8: 1 for ethanol?

What is the opnion of you? Thanks.