I've always put 93 in my car,cause well thats what I figured it needed after I bumped the timing up a little bit. Someone told me that 89 even with bumped timing was all I needed....

Anyone?

 

i usualy run what i can get away with without pinging. but i am a cheap SOB

 

Me too..maybe I should just try it and see.

 

Just so you know......

89 octane is the minimum that the gas needs to be. I've heard from a reliable source (an employee) that Shell 89 octane usually tests out at 91 octane. I imagine the 93 octave probably tests out somewhere between 94-95.

It's safer for them to be a little high than too low. If it was low, then they'd be quilty of false advertising.

That doesn't mean that it will definitely work. You'll still have to try it and see.

Maybe you can alternate every half of a tank? One time get 89, next time get 93.

 

I have to get high grade or my engine makes alot of noise ;-( stupid high mileage engine!! Love the car though :-)

 

I ran 87 a week ago, notcied a good amount of pinging every shift, went back to 90 and it was all better. I'm running around 6 degrees advanced though with 45 gapping on my plugs.

 

i ran 87 in the wee-o-five

 

any 8 cylinder deserves 93 or higher octane!! If you go to a cheap gas station you can get super for the price of regular at mobil

 

I use to run plain jane gas where ever. Then about a year ago Jim86bird convinced me to run at least silver in my car. So thats what I been running in NJ. Now Rochester is a different story. Gas price up here is out of this world. Regular is like $1.65 where back home the good stuff is the same price. Soooo up here I run the cheap stuff and once n awhile throw down the green and put in the good stuff. I really can honestly say..never noticed a difference....

 

Sorry to be the only one to disagree, but the 305 doesnt have that high of compression to deserve 93. I have put every octane in my car. And i find a little pinging at 87, 93 is overkill, and I think 89 is just right. This is of course if your car is stock like mine and no mods whatsoever basically. Ive only got a K&N. Thats my advise.

 

This might be hard to believe but, I bought my car new in 1990 and in 91 I bought a chip for it and a good exhaust. From the first day I filled it up I put in 93 octane. I remember putting in 91 octane once but to date it has always been 93 octane. The car ran good all the way through 186k miles.

 

hmmmm. it depends on the compression ratio and timing a lot. assuming yalls LO3s ahve stock CR and stock (or close to) timing, then I say you dont need it. i bumped the timing up in my LO3 and still ran 87 with no problems. now the 355...........that takes 93 every time. just wandering why are you guys putting down all that extra cash

 

you cant be too careflul when it comes to me LO3 seems like the littlest thing will set it off or break it! its only like 10 cents more and my baby is worth every penny!
besides i get the cheap kinda super that sells for about he price of regular at a mobil haha

 

Not all gasoline is equal!!!!

There was a post on this before (and I've spent an hour trying to find it, but can't). 93 octane at Exxon is not equal to 93 octane at Shell or Citgo stations. They all have an AVERAGE of 93 octane R + M / 2, but the R + M / 2 method leaves a lot to be desired. It only measures one molecule at each end of the octane spectrum and doesn't include all the molecules inbetween. SOrry I couldn't find that post for you.

 

I have put 110 octane in mine before and it ran really good. I could definately notice a difference. That stuff was 4.99 a gallon though. I would only put like 1 or 2 gallons in there mixed with the 93 octane.

 

Most all gas stations in an area get their gas from the same place.

 

This (reputable as we all say) hometown said if your CAM is high performance you best be runnin' the best gas you can buy. Or too much VOLITILE BOOMS inside the engine.

Ctown

 

Yup. Either way they're all regulated tight by the government on what goes in that they're all basically the same. It's mostly state to state regulated. Seriously though, when was the last time somebody found a difference in either performance, milage, or overall quality? I have yet to read of a controlled test where there are measurable differences. I almost always go to a Sunoco just for habit but if there is cheap 92 somewhere else I'll get that. Save's you a lot of money after a year.
If you've got winaldl you can check to make sure there isn't any obvious detonation. A few counts are usually the ecm doing it's self test so ignore them. You'll most likely see the spark counts go up pretty fast and keep going up in that general map/rpm cell.

 

Well, whilst the majority of you may opt for 93, us wee folk in CA have the option of 91.....89.....or 87............no more 92, and havent had 93 since ive been driving. and gas in So CA is about 180 for 91......grunt and moan all you want where you live...but appreciate it nonetheless. (btw, this isnt mobil prices either!)

 

I've got two choises with unleded fuel... 95 or 98 octaine. usuali i tank 95 but i did notice a smoother ideal and better high-end pulling with 98 with corrected timing. You guys sob about $1.68 per gallon for "super". Over here fuel costs normally about 1.10€ for 95 and about 1.15€ for 98 octaine per liter...

We got a 75% fuel tax

 

75 percent that insane i feel you pain.
where do you guys get this 95 and higher octane gas? i never see it sold near me. i live in nJ

 

75 % ... wow... anyways you gotta remember that there is only one tank the gas comes out of at the gas station, not like there is 1000's of gallons of 4 different grades of gas, it is just an additive they add to the gas. And that equasion for the gas grade... it is not for the gas, it is for the additive that is getting mixed with the gas, so yes gas staions may get there gas from the same place, but the gas mixture may be different or the additiave could be different hell the pump that mixes it could be out of calabraition who knows. just my $.02. I use nothing less than 91, depending on the price.

 

Yes there are. I was a pump jockey for 2 yrs at a Shell station. We had three different tanks. The 89 and 92 were 1000 gallon and the 87 was 1750 gallons. They were filled about twice a week.

I agree with that, but it's done elsewhere, not at the gas station.

I can also say that not all stations get their gas from the same location. There's a refinery about 20 miles from me. It's owned by Hout Oil, who is franchised by Phillips 66. They supply gas to (obviously) the Phillips stations, as well as all the other 'off brand' places. I don't think it's all the same formula. It's just all held at the same place. I'm not 100% sure on that though.

I do know the Shells and Amocos each get their own fuel from the Chicago area, each at different locations. They're totally different, and my car shows it.

 

LOL well i guess not all gas stations are created equal... I worked at a real small town sunoco.

 

Crisis, Europeans only use Research Octane Number (RON), that's why you think you have 98 octane. EuroSuper 95 is probably of lower quality than U.S. 93 Premium, and Super98 is similar but doesn't match the "emissions" requirements in U.S. (I think it's leaded in most places -- killing your cat).

In United States they average RON and MON (Motor Octane Number). MON is always lower because the research engine is really forgiving and the motor they used for testing MON starts knocking much earlier.

So Europeans use RON, but in U.S. they use (RON+MON)/2 which is more accurate, hence "lower" octane numbers of U.S. gas. In fact, some types of gas can have a high RON, but a really low RON, effectively making it 87 and giving your engine a really hard time.

Two reasons why gas is more expensive in Europe:

1) the government taxes it much more
2) Small euro-countries can't make bargain deals like U.S. since they spend a lot less oil.

 

Marin you are right about the octaine levels.. but as for leded fuel... i haven't seen it anywhere in the last two yeas. (allmost) all the leded fuel got pull off the (finnish) market because nobody needed it. (thus we are not killing cats around here )

the "regular" fuel around here is advertised as 95 octaine and the "super" is marked 98..

I'm not saying your wrong about the tests (which i know nothing about) but its all about how makes/mixs the fuel around here.. you can tank anything but there is a big difference where you tank preformance wise... fuel prices differ +/- 10% and the truth here is that you get what you pay for... usualy. domestic fuel is better over here than the "import" fuel.. just costs more...

 

I have a friend who has worked at the Chevron Refinery for a while now. He said theres only two places to buy "raw" gasoline after it's refined frome crude then the major gas staion companies buy it then put in their addittives.
So the gas octane wise should be all the same around your area
but the additves and detergents will differ from different stations.
I 've I owned a few Chevy and GM products and found that Chevron is the best for them.

Think about it Chevron is an acronym for "Chevy Run"

 

I use Amoco 93 octane exclusively in my camaro because Amoco is one of the few companies that uses their own gas that they make. They dont have it delivered from the same truck as every other gas station around here. Plus its clear so i assume it doesnt have as many contaminants, lol. Only the best for my baby. In our lo3 engines the cheap stuff wont effect it in the short range at all, only reason i use it is because 93 wont clog the injectors or cause buildup in my engine as easily.

 

for you guys who dont know you want to run the lowest octane pump gas you can get away with unless your running race gas. i read an artical about it they were saying a lower octane will give you a hotter and faster burn.

 

hotter and faster burn... true but hotter and faster = less controled, ie. depeinging on the compression ratio of the engine can be good or bad, low octane + high compression = knock and lots of it.

 

yes i understand it knocks but thats not because it's uncontroled it's because the burn is at it's hottest point thats why when you advance timing it pings because it lights the fire sooner and by the time it releses it pings.

 

ahhh.. heres where the low compression pays off... I use pretty much what ever is flammable at the gas station (usually regular 87) and the engine does just fine on it. With gas being so expensive around college who can afford the good stuff. With the old carbonized 305 i had to use the higher octain fuels because it would knock so much. The carbon build up in the cc of these old motors pushes the CR up and it needs better gas not to detonate.

 

i wouldnt worry about clogging these tbi injectors... The design is much more robust then the crap teh tpi guys get. You could probably run sludge and tar through them and they wouldnt clog. Even my 15 year old 45 pph injectors i have in the parts pile look as new as the day they where made.

 

Yes I agree about the TBI being better as in more reliable and rugged and less sensetive than other fuel inj's.
But I hafta to go with the 93 octane.
I've had brand new four wheelers and dirts bikes and such
and found out it just bearly ran a tad better(if at all) on 93 but it being cleaner burning extended oil and spark plug life quite noticeably.
87 vs. 93 is probably only about 2-3 HP difference on a high power motor (which is unnoticeable by most drivers) I just like 93
because its cleaner burning