Domestic V8 lovers don't have a leg to stand on!

I use 91 octane in my Rav4 and I'm averaging about 34mpg on cool days nd 30mpg on really hot days. The winter here is good to me on gas. More dense air equals more get up and go. LOL! A turbo powered car should run well on 89 octane, assuming the ECU is tuned correctly and your tune up is up to date. There is a reason why higher compression engines run well on 91+ octane fuels and lower compression engines do well on 89 octane. Higher octane fuel needs the compression to actually burn efficiently, because it doesn't burn as well as lower octane 89. It sounds wierd, but it's true. It's a complicated math sequence on how octane is achieved with various chemicals. I gave you a short version ,of sorts, on how octane sorta works in engines. I can't explain it in tech talk. Sorry.  
How you drive is your buisness. Remember that you're not the only one on the road!

i will admit, all i knew on that was usually high compression engine need higher octane, lower compression don't.

but what you said just changed how i look at it( i understand it more now)  
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"AzulTuning.webs.com" Join and have Fun

The 6g72tt has low compression, but all I know is that the VR4 was made to run on 93 or higher :-\  
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1994 3000gt VR4
nothin wrong with front-wheel drive, I just refuse to own one

I wonder if it's the way the manufacturer tuned it for one of those "just in case you turbo it" moments. Forced induction creates more pressure in the cylinder head and makes thing a little hotter, thus the need for higher octane. You didn't mention that it was turboed or not, but I assume it has more to do with the fact that it breathes a little better than most engines. It is a 4 banger, no?  
How you drive is your buisness. Remember that you're not the only one on the road!

Id bet  

Higher induction flow creates more pressure... so, it's logical to assume that it would require higher octane to eliminate knock. Technology is so cool.  
How you drive is your buisness. Remember that you're not the only one on the road!

ha, yeah, but I just dont like paying the extra $0.30 more per gallon, that adds up.  

I hear you. I have a Stop&Shop card and I get great discounts on premium gas when the points rack up. They have their own gas station in my town. You guys should see about those discount cards from buisnesses like that. It helps and I haven't had any issues with bad fuel or any thing for 7 years. My last fill was .60 cents less per gallon on premium. It was $2.98 a gallon with out the card.
 
How you drive is your buisness. Remember that you're not the only one on the road!