I believe it is safe...

 

as far as i know my engine is stock, but i switched from regular octane to premium over half a year ago. my car runs sooo much smoother and i can feel a slight difference in pedal response. i mean, i just barely have to touch the pedal with premium, whereas with regular i have to press a tad bit more, and it feels a little sluggish. just to make sure it wasn't a mental thing, i let my mom drive it a few times with different octane fuel without her knowing, and the difference was enough to make her notice.

so you're saying i could get the same quality out of 89 octane that i do from 93? i've never went in between, just 87 to 93. i'm not sure i got all this straight, but since my engine's stock, anything above 89 is going to seem the same as 89?

 

The 93 octane fuel is probably cleaner than the regular grade. I would run 93 no matter what... 9.5 doesn't seem too high, but anything over 10 calls for 91 or higher... So go with 93 since you're already doing that.

 

wackos, i cant remember what you drive, and i cant see badges on your sig pic so im going to assume its a 3.8. if its an lt1 thats a different story, it will begin to knock with lower grade gas.

if its a 3.8 you could get away with midgrade just fine. i never fill w/ 87, but here in iowa mid grade has ethanol and is cheaper

 

Your engine doesn't need premium, so using it is just a waste of money.
And using "regular" isn't going to hurt your engine, it just may not perform as well as it can with mid-grade. It's up to you to decide if the slight improvement you get with higher octane is worth the extra cost.
My engine needs premium. I normally fill up at around half a tank, alternate between high and mid-grade, and it runs fine with no pinging.

 

Read:
http://en.wikipedia.org/wiki/Octane_..._octane_rating

 

69, what u said is true of late model cars (which he has). I just wanted to add that older cars or cars run hard can be damaged using improper fuel. because the computer will not have time to (or will be unable to in odler cars) compensate the timing when knock is observed

 

Older cars like mine don't have knock sensors or any type of computer ignition controls that adjusts itself for different octanes.
The tool you use is your ear. If you hear octane knock (like marbles in the cylinders) you either jump the octane up, or manually retard the timing at the distributor.
And trust me, you'll hear it if you have an octane knock. Modern engines automatically get adjusted before you ever hear it.

 

in newer cars the problem is w/ hard acceleration since the computer cant keep up. older cars are easy

 

Yeah, I got my "easy" right here!