Octane

bigred90gt said:

Yeah, Esso is Exxon here, or at least was at some point (not sure if they're still one in the same).



I work for Shell and almost refuse to buy their gas (unless I'm in dire need and they're the only station around). I buy Sunoco for $.30-$.40 cheaper per gallon for the same octane. Even Exxon Chevron and Valero are $.05-$.10 cheaper than Shell.

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Shell is the same price here but it does seem to be a game as the shell station here is filled up by a tanker that advertises Mobil at their building but then has a Sinclair pump in the parking lot and as I mentioned delivers to a shell station. Gets pretty hard to tell. If there is even a difference. I am sure there is supposed to be!

I use only name brand fuel of the recommended octane. 89 for my ram before tuning, 93 octane now. I have gone to the Royal farms near the track for a few gallons when racing late in my Charger( because I was WINNNING!) and the results were poor, ran slower and more knock. Cheaper is not always the best idea. then again My closest Sunoco, unfortunately, has given me bad gas on more than a few occasions. First in my Charger, which took me awhile to figure out, as I would get gas there on the way to the track and not run as well as I should have. In fact I ( well actually Sean) didn't figure it out until I was data logging for Hemifever. he told me it looked like I was buying cheap gas. I switched to BP and Walla all is well.
SO I avoid that particular station, but not Sunoco altogether.
When I had a old beater I put whatever was cheapest/ convenient in it, as I didn't care. IN fact I would put all my old left over gas form the snow blower weed whacker chain saw etc. in it. Now I have to burn it, as my exploder finally did.
My opinion is you get what you pay for and I'm not gonna put suspect or unknown quality fuel in my high end/ high performance vehicles. If I wasn't tuned they be getting 89/91 octane.

My Charger and my Ram will always get brand name 93 octane.

The difference in price simply can't be a factor, If it is then your either way to cheap/ frugal or you have more truck than you can afford.

My vehicles don't technically NEED full synthetic either but they get it.

Not to say I don't use coupons or get my discounts, I certainly do.

I really think, without any evidence, that in the long run getting better than needed pays off.

Especially when I am towing an enclosed trailer with two big Harleys in it threw the mountains in 90 deg heat at 80 mph with the AC on and not a worry. A worry others might have it they ran around on 87 octane and then oh gee I better put some 889 init to tow...but I have half a tank...think it will be ok?

One of the speed shops in Denver did a dyno shootout on a number of vehicles some time back. They tested 85 vs 87, and found they consistently made less power with the 85. Sorry, I can't remember the actual numbers, but it wasn't a huge difference as I recall. So maybe 85 = 87 at a higher altitude, but from their results it would appear it doesn't happen at Denver's altitude.

That said, this isn't a black and white 85 vs 87 (or 89 or 91) issue alone. There are other factors that contribute to an engines output. Beyond the engine design, the biggest is probably weather. Especially with the wacky weather up here. I've seen the DA swing several thousand feet in an afternoon. I have my weather station with me at the track every week and log both the vehicle PIDs and the weather for each pass. From what I've experienced, Ma Nature seems to have more control than the AKI number on the pump.

wink

^^ interesting. I'm in Denver. I run 87 just to be safe. I spend most of my time at 5k elevation but 10k+ is not uncommon a couple times a month.

I didn't realize so many had posted. Thanks. The deal i have is Costco a "Top Tier" gas is 2.69 for 93. Which is cheaper then the 2.75 for 89 at most stations. I know it's pennies really, but will putting 93 in hurt in the engine in the long run?

Trooper2 said:

I didn't realize so many had posted. Thanks. The deal i have is Costco a "Top Tier" gas is 2.69 for 93. Which is cheaper then the 2.75 for 89 at most stations. I know it's pennies really, but will putting 93 in hurt in the engine in the long run?

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You don't really gain anything from running 93 over 89 unless you tune for it. The reason to run 89 over 87 is to reduce the likelihood of the computer pulling timing due to knock.

I'll run 91/93 when towing my travel trailer. Otherwise I run 89, even towing my bass boat.

As for fuels being different. It's quite simple. Yes, almost all of every stations fuel comes from the same distribution centers in an area. It starts life as being equal. As the fuel is being pumped in to tankers is when each companies additive packages are blended in.

so, what makes a top tier fuel? Easy. The additive package. Detergents, stabilizers, lubricants. Cheaper fuel from a non top tier brand is going to have less, if any, additives.

I'm more interested in long term damage from running 93 octane. I realize there will be no gain in performance/mileage per sey but why in my mind pay .10 more a gallon for 89 when can have 93 for cheaper. 89 is not Avaiable at COSTCO. It's either 87 or 93.

Trooper2 said:

I'm more interested in long term damage from running 93 octane. I realize there will be no gain in performance/mileage per sey but why in my mind pay .10 more a gallon for 89 when can have 93 for cheaper. 89 is not Avaiable at COSTCO. It's either 87 or 93.

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Won't be any damage. Run it.

Riccochet said:

so, what makes a top tier fuel? Easy. The additive package. Detergents, stabilizers, lubricants. Cheaper fuel from a non top tier brand is going to have less, if any, additives.

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So...

If you buy 89 from a reasonably modern "Casey's General Store" (the tanks aren't terribly old) and buy a good additive like Redline / Amsoil / Techron you're probably good ?

Trooper2 said:

I'm more interested in long term damage from running 93 octane.

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With octane, as long as you don't have less than what you engine requires, your fine. As others have stated, having more is not a problem, nor does it cause damage.

Murphy Slaw said:

If you buy 89 from a reasonably modern "Casey's General Store" (the tanks aren't terribly old) and buy a good additive like Redline / Amsoil / Techron you're probably good ?

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Many years back the EPA mandated all underground fuel storage tanks be a dual wall with leak detection. If I'm not mistaken, by now all tanks will have been changed as all the grace periods for the old tanks have expired. Old underground tanks that could contaminate fuel are gone.
Fuel additives are probably needed only when fuel contamination is suspected or you don't drive the vehicle much.