Going to be running 600 SC mercs. & they require 92oct. or better. Someone told me 90oct non ethanol is just as good as regular 92 oct w/ ethanol. True or false?

Im no chemist, but the way I understand it, is ethanol is an octane enhancer. So, with the ethanol mixed with the gas, you get 93 octane. However, as its known, ethanol mixed gas can suffer from phase separation. If that happens (old gas), the octane rating of the gas that is left over, will be reduced. I believe that number is 2-3 points when discussing a 10% Ethanol mixed.

So, to sum it up, a fresh tank of 93 with ethanol in it, would have more knock resistance, than 90 octane. At least thats how I understand it from an octane standpoint.

That is true. But Ethanol (by itself)Stoich is almost half that of gasoline....so when added as a % to gasoline, your tune could be thrown off enough where you will run leaner and have a greater possibility of detonation.

So, two different traits from the same substance.

Legally you can only buy 98 % ethanol because if it was 100% ethanol would be a very CHEAP drinkable alcohol as far as choice among whomever for their high and or drink of the day. The 2 % is what will kill you. Anyways 98% ethanol with the 2 % of whatever has a octane rating of 113. Adding 10% = E-10 raises the octane a few points, Some say 2 to 3 points.

If I remember correctly apples to apples E-0 compared to E -10 brings up stoich at 15 to 1 or 15.2 to 1. Yes it will be leaner running ethanol fuel apples to apples - meaning no tuning changes of any sort untouched.

SB you are sounding like a true tuner guy now just by the throwing out the word STOICH. Funny when I have the chance to hang with some of the auto tuners, STOICH is their word choice - like ever other word in their language.

Okay, Lambda then. LOL.

Wonder how those guys tuning for 13.7 AFR with E10 for their blower motors will make out ?

I believe ethanol is typically denatured with poisonous methanol to keep people from drinking it.

Its reporting E-10 at 14.08 to 1 in which is basically 14.1 to 1 that would be richer than the 14.7

I am wondering if that is a misprint as it needs to report E-10 is 14.8 to 1

I swear i remember some guys getting some good results with a skosh of synthetic 2 stroke oil running the 420's
i would say whatever you decide to run double check that your stuff under the carbs will feel the love on the long haul