RenGen

I know this is an age old debate and you always get 50% people saying there's no point putting in premium unless your engine need it, and the other 50% saying it helps you get more power and efficiency, and only a couple dollars more per tank fill so why not - but is there any solid answer?

for example a lot of people told me my 06 gt is tuned for 87 from factory so putting higher is pointless and can even cause pre-detonation, but say for my friends 1987 camaro 2.8 v6, since those were not as computerized as modern cars, would he benefit from high octane?

we have been working on it together and got it running good (well as good as chevys can run :P) but he decided to put 89 octane in it, and even i agree with him that it seems to idle a lot better and the hesitation is gone from when you push the gas pedal to when the engine revs.

edit; also btw before he went to 89 he put in a tank of "non oxygenated gas", so could that have helped do you think? or is it because he went to 89 octane? is non oxygenated or the regular gas from gas stations better for cars? is non oxygenated what they had back in the 60s?

also the weather has gotten a lot colder here lately too (30 degrees)...so could that be why its idling better? I have heard a few times in my life that cars run better in cold temperatures but idk how true that is. i do love how my exhaust sounds in the cold though <3

jz78817

the only (ONLY) thing a higher octane rating denotes is the fuel's ability to resist auto-ignition under compression. if your engine isn't experiencing pre-ignition/detonation (pinging/"spark knock") on 87, then going up to 93 gets you nothing.

it is pointless so long as the engine doesn't require premium. I don't remember if the 3V 4.6 did. But no, putting in a higher-than-needed octane will NOT cause any harm. It'll just be a waste of money.

(now, there is sort of an "exception" here; the 5.0 Coyote in the 2011+ Mustang can run fine for its entire life on 87 octane gas. Ford just doesn't guarantee it'll make full rated hp on 87 because the engine management will run more conservative ignition timing if the knock sensors detect anything. )

not really, because that thing is such a low-compression wheezer of an engine that it probably could deal with lower than 87 octane (assuming the chambers don't have carbon deposits or hot spots."

octane rating won't affect this at all.

this, however, might affect idle quality and throttle response. "non-oxygenated" gas probably means "no ethanol." Oxygenated gasoline, as the name says, contains additives which bring additional oxygen to the mix; ethanol is one such additive. Thing is, if you add oxygenates to the fuel, the fuel:air mix has to be richer than it has to be with straight gas. Modern cars can account for this thanks to the lambda sensors, but an older carbureted car has to be manually tuned for it. Oxygenates weren't that common in the '80s so yeah, running straight gas in your friend's car might make it run a little better.

yourmom6990

Agreed, you're wasting your money unless your engine is tuned to run a higher octane.

Here's an article that explains:

http://www.nicoclub.com/archives/gas...ane-myths.html