just figured i'd add some useful info from Tuner Badass Greg Banish since I was just reading this portion of a book of his the other day. I'm Paraphrasing but,

basically stoich on pump gas is 14.68 parts air to 1 part fuel. stoich for pure ethonal (which is pretty hard to find) is 9:1 with an octane rating of 129 RON (which is the higher of the two ratings, MON is the other one)

pure ethonal is typically a "research" fuel and thus is typically priced as one.

e85 is typically 85% ethonal and 15% gasoline. adding the 15% gasoline to the mixture greatly helps cold temperature evaporation rates and makes storage less of a concern for water absorbtion.

the blend between ethonol and gasoline results in a stoich balance of a 9.85:1 mass ratio instead of 14.68:1 like gasoline.

therefore a naturally aspirated engine looking to run at lambda ~ .86 x 14.68 (gasoline) would be at a 12.6:1 air fuel ratio

however using ethonal would be .86 x 9.85 (e85) = 8.47:1 air fuel ratio.

this is when lambda = 1.00 = stoich (for whatever fuel you're using) is easier to work with instead of an air fuel ratio you're not used to seeing.

e85 has an octane rating of ~ 105 (R+M)/2

also more useful info from mr greg says F.A.S.T. XFI standalone have the ability to monitor the gm fuel composition (part #12570260) when connected to the auxiliary discrete input. This means a single tune file can be used with premium pump gas as well as a summer blend of e85.

the reason the gas stations switch to e70 in teh winter is because that extra 30% gasoline mixture aids in cold starts as mentioned earlier.

anyways, long story short, whatever fueling you need for your current horsepower set up, basically double it since you're gonna need almost twice the flow volume to get the same air fuel ratio as you would with gasoline.

hope that helps,

one day matt the blue 510 will be alongside your hatch at the drag strip so you besta bee running ~7.5:1 air fuels in that thing, i wanna see -20 fuel lines and 2 x a1000's pumping that shit



Dave