93 or 91 with e10 vs plain 93 gas

[hediki12]

hey ive been doing some searching and all and i cant get a concrete answer. i use bp 93 w/ "up to 10 percent ethanol" and it seems the engine has more counts of knock that does plain 93. is the a draw back from using 93 with e10 vs plain 93? or any other octane that is mixed/diluted with e10./

 

[Bohrn]

if both are the same octane level, the non alcohol fuel will have more energy per unit and will give more power and better fuel economy.

If you have 91 gas and 93 alcohol/gas, the 93 will give better performance on a turbo or high compression engine as it will allow full boost/more timing

 

[Rob10_99]

I thought it was a fedral requrement that all retail gas sales is at least E10? Ill go snoop around.

 

[rstchris]

The dif is most likley in the true octane cause the real octane count can vary slightly from station and truck. If you tune for 1-2 counts on one fuel it would be normal to see it change to 0-1 or 3-4 depending on where you buy. If you stick with a corporate non-franchise station you should get consistant results.

 

[knochgoon24]

Most gas contains 10% ethanol to help emissions.