I once had that, but I took some Kaopectate and it went away.

 

The reason some states/cities have lower octane is altitude. Their is no or little difference in 85 octane at high levels vs the 87 at a normal altitude. For those of you in Denver, expect the regular unleaded to be 85 octane, but you get the same burn rate as the 87 at 2500 feet.

 

There was a write-up on "top tier gas" as dictated by some auto manufacturers in this month's Car & Driver:

http://www.toptiergas.com/index.html

 

Costco is on Mike's no-no list


Sunoco, Shell, Citgo, Texaco

West of TX - Union 76

The additive package is what makes the difference in "shared" base stock

 

And the best way to get on these lists is to sponsor the lists...
Been there, done that.

Costco has good quality gas locally, and has decent contracts.
When I was with
(brand removed by me, as I recalled my non-disclosure agreement, sorry)
we had Very high quality gas, but it never was highly rated, as the mother company, (who lost their shirt on buying the refinery for 600 million, putting many hundreds of millions in upgrading it, then selling it back for 600 million...)
would not pay to get on lists, or pay for advertisement.
Big mistake. If you don't grease the right wheels, you don't stay in business.

So after they let it go back, some money was spent in the right places, and Amazing, they were highly rated that year. Not one thing changed in the refinery, the source oil was still Venezuela high sulfur crude, no new additives, etc.
It is one of the things that made me too cynical to have any more involvement with the patch.

The best rated gas here in California is Arco. Meets a dozen politically correct goals. Quality just doesn’t seem important.
The rest of your list is not available here, except Chevron, who sells to Costco, and Shell, which costs 15 cents more a gallon. There is a 76 Union across town, (9 miles) but he gets 24 cents a gallon more than Costco, and from knowing him for thirty years, it is not someplace I would recommend…
Chris

 

Great information guys!

These trucks are designed to run on 87 octane. If it doesn't run right
on 87, something is wrong. Anything higher than 87, and you are just throwing your money away (unless you have the ever popular *tune*).

 

I think it would be interesting to see a truely independant study done to test the various brands out there to see which performs and cleans best. someone should contact consumer reports. I trust them.

 

Before the flame war starts, I don't.

I can show you hundreds of their silly, politically motivated mistakes.

Not to mention that they are lab guys combined with pseudo intellectual lit and journalism majors, not real world people.
Guys who actually do things with their hands need not apply at that rag.

I wish it wasn't that way. A true independent non-ideological review service would be worth its weight in gold.

Just for fun, guess which national review magazine called the Renault Alliance a 'Superior automobile, that American makers would do well to emulate' or said ‘The Yugo is the wave of the future.’

Also, rate gas all you want, it doesn't help when the dodo driving the rig dumps the fuel in on top of JP4, or the gas station buys 2 year old gas that has not been stabilized.

Or the graveyard jockey has figured out that to roll the pumps back is easier than cleaning the toilets, but to make the stick reading come out OK, he has to run a couple hundred gallons of water into the tank every night, after he rolls the numbers and pockets the cash...

Even with all that, no company, no matter how reputable can make billions of gallons, from thousands of different oil pools, then scattered across a dozen refineries, shipped from hundreds of holding tanks, into thousands of ground tanks, the same.

Hell, they can’t even make Soda pop taste the same, lot after lot.
Gas is much more variable. That’s why I posted the easy-to-follow way to get a fair shake on gas, and minimize the gamble.
I don’t expect things to be perfect, just workable. Makes life better that way.

Chris

 

I run 87. Your engine is designed to run on that octane rating. If you hear any type of pinging or detonation, then bump it up to 89. Unless you're chipped, then you are just kind of wasting money on stuff like Premium, unless you're chipped for that grade of gasoline.

 

Using a fuel with a higher octane lets an engine with a higher compression ratio operate without having problems with knock. The "knock" associated with lower octane fuels used in high compression engines is due the fuel is detonating prematurely in the cylinder or in the valves. Compression is directly related to power, so engines that require higher octane usually deliver more power.

Some people believe that adding a higher octane fuel to their engine will increase its performance and their fuel economy; this is false - octane only stabilizes n-heptane and does not provide any increased power. All engines perform best when using fuel with the octane rating they were designed for.

To Address the 85 octane fuel:
The term "E85" is used for a mixture of 15% gasoline and 85% ethanol. This is mostly available in the midwest states because ethanol is derived from corn which supports the local economy by providing a market for corn growers to sell their product. The use of ethanol from grain as car fuel has been promoted by government programs. Most states in the corn belt began subsidizing ethanol production from corn after the Arab oil embargo of 1973 and in 1986 the U.S. even began giving ethanol producers a free supply of corn.

BTW: higher priced fuels do not equal higher quality.



If you noticed that all of the higher priced stations (on the right) are those that have heavy national advertising campaigns. They have to pay for those commericals, NASCAR endorsements, golf tournaments, high franchise fees, etc ... somehow.

 

Interesting info Oxlander.

Um one very minor nit pick. The ping is caused by fuel detonating too fast, usually, that is to say it goes off before the piston is at the optimum position for the explosion. Octane boosters slow the explosion in the same fashion as premium gas.

You are, of course, completely correct in saying it won't help if you are NOT advancing the timing. The power comes from the blast taking place at a more opportune moment in the piston/valve cycle.
Detonation is caused by it exploding too early. The bang hits the top of the piston as it goes up, not as it goes down.

The fuel air mix is compressed as the piston nears the top, valves are closed, then the spark is sent. The spark is actually sent long before the piston hits TDC or top dead center, but the kernel or fireball takes a little bit of time to expand, and the piston is on the way back down before the explosion is fully lit.

That's why if you want to crank in more advance (lighting the fire earlier) you better have slower burning fuel so that the piston has the time to make it to the top, before the blast throws it back down. Slow ignition, combined with lots of spark advance equals lots of power.
Set it too advanced and it pings, a little more and it detonates. Hard on the pistons. Very hard.

Put premium fuel or octane booster in, on regular settings, and the timing is set to 'light er off' late, thus the explosion being slightly delayed works against you!

Many report worse gas mileage from higher octane fuel. That would not be surprising.

So it's more than just wasting gas money, you are also wasting power.


One big caveat, the gas you buy local, ain't always good elsewhere. Our local gas is set for 3000-3500 feet. We run great in the higher mountains, but get ping down at sea level, where they sell higher octane juice. But up in the high mountains, they sell nothing but low octane. In the old days of small tanks, and high gas consumption this wasn't too important. Guys who 'commute the mountains' know that they need to buy their gas before climbing back up. The higher octane won't help them at home over 8,000 feet, but if they use the local 85 octane stuff, they will ping when they get down to the beach cities.
So use the indicated gas, and don’t waste money.
Now if you are using a tuner, the indicated gas just might be pretty high octane
Chris

 

thanks guys, 85 it is!

 

Chris and Ox - I would like to thank you both for an extremely educational and eye-opening thread. It seems you both know your stuff when it comes to this!

 

87 octane Mobil.

 

Acutally...Here in Iowa, running 87 costs more than 89 octane. All of the mid-grade (89) fuels are 15% ethanol blend. One of the smatest things that the state did was to grant subsidies for the 15% blend quite a few years ago. Right now 89 octane is running about 7cents less that the 87. (I don't even look at the premium any more)