2001SS_stompinsupras

just something to pick your brain. i have an LS1 camaro for my hot rod
i usually run 100 octane because i have the timing set pretty high. To the point, i thought ETHANOL was suposed be higher octane rated, when i use a 93 octane with ethanol i get a horrible knock at high rpm. i think because it burns much faster. if i use 93 octane with NO ethanol the car barley pings. so what gives shouldnt the ethanol gas be better?

Eagle02

iTrader: (20)

You might want to just back your timing down a bit. How high are you running it?

2001SS_stompinsupras

why does ethanol pre-ignite easier than normal gas?

02*C5

iTrader: (1)

Its not, the Ethanol mix is too high and whats preigniting is the gas believe it or not. The difference between ignition points of gas and Ethanol is almost a 100 degrees and that's what happens when your Ethanol mix is too high and you are not set up to run Ethanol.

Gh0st

iTrader: (3)

93 octane with ethanol is ~E5 so theoretically your stoich changes and you may or may not need a teeny bit of additional fueling to run the same timing without knock.

ccrider

iTrader: (9)

ethanol is a higher octane but you need to burn more of it because it has less btu output

2001SS_stompinsupras

thanks 4 help. Another Question, should the higher octane of ethanol balance out for lean conditions, advanced timing, or compression?

if mix isnt lean, and there isnt different flame fronts.

thank u, good stuff

ccrider

iTrader: (9)

iwas looking into running ethanol on my big block, i work at an ethanol plant. you would up the compression for the higher octane and go up about 8-10 jet sizes on a holley carb.what that would be on injectors? you need to add more fuel.

JonCR96Z

iTrader: (33)

It's not necessarily the timing it's the fuel. Stoich on e85 is 9.7:1, compared to 14.7:1 on gasoline. You're effectively running it lean as **** running on a tune that's setup for 14.7 AFR. You need to add about 50% more fuel for e85.

2001SS_stompinsupras

does anyone have a favorite brand gas? such as chevron, BP, whatever and why?

2001SS_stompinsupras

my local 100 octane is $6 a gallon

Gh0st

iTrader: (3)

Your 93 octane with ethanol is NOT a higher octane! It is rated 93 for a reason! It's 93!

2001SS_stompinsupras

i know, just weird to ME that the 93 ethanol blend was worse, i thought it would be better.