91 octane no ethanol or 93 octane 10% ethanol?
 

I've been using BP 93 octane with up to 10% ethanol.

Just this morning I noticed a gas station I've been avoiding because it is only 91 octane also says no ethanol added. I never noticed this before.

I'm just curious which would be best to run in my car? Is the extra octane worth the ethanol? Discuss.

Read this: http://www.ethanolrfa.org/resource/facts/engine/

...yes
why not? especially in the colder seasons...

I put 98 octane in my stock tuned S/C :)

DOn't know if it helped, but I felt quite faster. And only cost me $8.95/gal at the time

That article cleared things up for me.

Thanks.

placebo...if anything you lost power.

Just trying to save your wallet

Not sure, but it seems sarcastic to me...so hopefully he didn't spend $9/gal.

i know someone who put 110 racing gas in a mostly stock Supercharged Grand Prix. Gained nearly a second, than when he ran 91.

With that said, i am pretty sure that the computers in our cars wont allow the motor to net any more power.

he either was knocking like a mother fucker stock
or he tuned for it

i dont know how many threads there has to be about this, 110 gas doesn't make horsepower by itself, actually if not tuned you will lose power.

Correct me if Im wrong,
but isnt the fuel's octane rateing mostly just
how much the fuel resists detonation/knocking?

IE: Higher octane, higher compresson before it blows up.

yes.

knock resistance/burn rate

OBDII retunes and advances automatically, otherwise when you put race gas in you would run like molasses and put out too many emissions.

:lol: our computers only have a high octane map and a low octane map. it will not advance timing more if it detects more octane.

absolutely incorrect....