Originally Posted by Yachtsman
I came across a post somewhere, Some hot rod builder was due to rebuild is ride but he was a little strapped being as he'd just gone professional and outfitted his shop. He took his old 351 he'd been using for a while and he converted it to E85, He was already running pistons that gave him a compression ratio of 10.1 but he was buying lots of octane enhancer. All he did was drill out his carb jets and re-time he was done. He lived in Minnesota so he could change to pump gas, get 10hp every digit of compression over standard and return a good MPG. Lucky stiff.
The problem with ethanol is the energy density is about 1/3 less than straight gasoline. This means you've got to burn a third more at 100%. I hazard to calculate where E85 would actually fall in more consumption as it turns out by test rather than than computation that while ethanol has a higher natural octane, when mixed with gasoline the mixtures testable reaction in the test engine does not support an octane increase based upon it's percentage makeup with the gasoline. Which is to say that a little bit on gasoline (premium 91 in the states) is highly distructive to ethanol's natural testable Research octane or almost 109. However, its motor octane is only 90, which is close to the RON+MON/2 figure of 91 octane gasoline.
As for raising compresson getting some amazing power increase, I suggest that author read your escaped countryman David Vizard on that subject. In a nut shell no such thing happens at figures like 10hp for a point of compression unless this was big powerful engine to stat with as a point of compression with no other changes (lots more cam timing) is only worth 2 maybe 3% on a good day. So a 10 horse increase would need a 350-500 horsepower engine to begin with.
In case no one's figured out that the petroleum companies haven't figured out the ratio of power increase or more specifically in their interest, mileage increase, before any of us got there with the idea of higher compression being more fuel efficient; please note that the cost difference in the greater grades of gasoline above regular 87 octane more than offsets the lower consumption of fuel by the engine. This includes the cost difference between regular gasoline and diesel. We've already been out-scammed before driving up to the pump.