Focus Fanatics - View Single Post - Regular Unleaded Gas (stock) vs Premium Unleaded Gas (tuned)
View Single Post
Old 03-27-2012, 07:51 PM   #47
Outlaw5.0
Focus Enthusiast
 
Join Date: Mar 2011
Fan#: 84300
Location: Canton, MI
What I Drive: 2011 Ford Focus SES

Posts: 394
FF Reputation: 1 Outlaw5.0 Good Standing Member
Buy-Sell-Trade Rating: (0)
Tom is correct. If the computer senses any knock, it will start to retard timing. Yes our cars will knock slightly on 87 octane, its not uncommon to see the computer retard timing by 2-4 degrees. The use of midgrade or premium fuel will make sure the timing stays at full advance. Now granted with premium fuel there is room to add a few degrees of timing at WOT. For a untuned Focus, 89 octane in most cases is good enough.
Outlaw5.0 is online now  
    Reply With Quote