Tony and all; I'm sorry, I don't believe that the alcohol raises the octane. If it did, it would be Sunoco 95 or something. It does burn hotter, which is why alcohol fueled engines have everything in the combustion chamber chromed, to withstand the heat. It doesn't help gas much tho. Bottom line is that when you burn anything you get X amount of BTU's out of a given amount of fuel. And when you cut the Gas by 10% by adding Ethanol, you cut the octane, period. We are paying more for less and having to buy more to go the same distance, period. So, in our high performance engines, we just aren't getting the power (BTU's) we once did. It's just that simple. You must compensate for the crap we are getting, being sold as gas. I'm sure this will start arguments, but you can't get out more than you put in, basic physics. Ray On Aug 19, 2007, at 1:07 PM, Tony Rinaldi wrote: I asked the question from many people: Why do I have to advance the spark with this new lower octane fuel? Did not get a reasonable answer, until I asked Thomas White from Whitehall Restoration (Hopkinton, MA) when I met him at Carlisle last summer. He said that the increased alcohol had higher octane and was more volatile. The new gas burns hotter in hot weather and would do the opposite in cold weather. So, there it is. Maybe if your car is running like crap, in hot weather, when it never happened before: ADVANCE the timing?? You all play nice now. Regards, Tony Rinaldi [Non-text portions of this message have been removed] To send a message to this group, send an email to: Chrysler300@xxxxxxxxxxxxxxx For list server instructions, go to http://www.chrysler300club.com/yahoolist/inst.htm For archives go to http://www.forwardlook.net/300-archive/ Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Chrysler300/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/Chrysler300/join (Yahoo! ID required) <*> To change settings via email: mailto:Chrysler300-digest@xxxxxxxxxxxxxxx mailto:Chrysler300-fullfeatured@xxxxxxxxxxxxxxx <*> To unsubscribe from this group, send an email to: Chrysler300-unsubscribe@xxxxxxxxxxxxxxx <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/