Lol it's just a common phrase people used on picket signs when protesting the oil spill in the gulf.

It was nice at the pump though, their gas was cheapest by far for a while...just had to watch out for all the protesters.

 

I wonder if I can get one of those reports?

There are 3 station around my neighborhood. the 2 Mobil station I believed are owned by the same owner. the other BP opened maybe 3-4 years ago. I usually fill up at the BP cuz it's newer and usually a few cents cheaper (even it's bit further)

I also tried no name gas at all kinds of places.

and yea, I agreed that we should only fill up at busy stations. and NOT right after fuel delivery truck finished unloading.

 

Costco buys bulk gas, same as 7-Eleven and your local Try-And-Save gas bars.

Name brand gas (Shell, BP, Texaco, etc. ) get extra additives, as per the pump claims - Techron, V-Power etc.

Different, as in 'not the same', if Costco gets their truck filled at the local Shell terminal, that don't make it 'Shell' gas.....

 

Agree on busy stations and not filling during fuel truck delivery or shortly after.

For those who don't travel during rush hours, the busy stations will be the first to lower prices, but also the first to raise prices. Since they move inventory quickly they are closest to paying current market prices.


Now - a little quick math for you on driving further to save a few cents per gallon.


Assume that in the city you get 16 mpg (on average).
Also assume that gas is $4.00 / gal for premium.

If you drive 1 mile further you spent an extra 25 cents to get there (and 25 cents to get back) for a total of 50 cents.

To recoup this extra cost in travel distance you would have to save 5 cents per gallon on a 10 gallon fuel up, or roughly 4 cents per gallon on a 12 gallon fill.

Now - it's probably safe to say some people go up to 3 miles out of their way for the "cheaper" gas. This equates to 6 total miles (there and back) for $1.50 in extra travel costs.

This means you need to save a whopping 15 cents per gallon on a 10 gallon fill!!


Something to think about as you pass up gas stations on your route because they are a cent or two higher.

 

when I say further its just about 4 blocks ... LOOOOOL

and it's really on my way to work. same direction, rofl.

but there were times that I really travel 2 miles down just to get gas, it's 30 cents cheaper per gallon dude. 10 gallons is 3 bux. LOL

 

This is interesting, fellow chicago rx8 bro. So are all ILL stations the same ehtanol content? like a minimum of 10%? cuz that would make a difference.

 

I've got a local gas outlet down the road that has been advertising 100 octane race fuel. Take that Shell err wait uh....

 

It's suppose to be 10%. There will be variation from brand to brand, station to station and day to day. Base ethanol, at the moment, is cheaper than base gasoline. You figure what a cut rate brand is going to do with that. The big name brands will be consistent over time.

 

got costco gas this week. didn't notice any difference. I have noticed though that everywhere you go premium is 93 octane (illinois/chicagoland) ...Im wondering if finding some 91 octane if that would be cheaper. no one seems to sell it here though! so weird.

 

91 octane is a west coast thing. You won't find any east of the rockies. Octane changes with altitude. You go up into the mountains, the octane gets lower for the same fuel.

 

You're not going to notice a difference. If you got gas with too low an octane, you might notice a difference - although that was much more likely in the days before knock sensors. If you got some bad gas, you wouldn't notice anything until some time later when it damaged something. Like once when I had some bad gas eat through a carburetor float.

A Sunoco station I sometimes frequent had 91 for a while, in addition to 87, 89 and 93. It was only 2 cents cheaper than 93, vs 10 to 15 cents gap between other grades.

Ken

 

91 is a high altitude thing too, it's not unusual to see 85 regular there

Costco gas is as fine as anything else out there, I have run it the most in all my vehicles including racing my RX-8

Costco.com: Costco Gasoline

 

what would seriously happen if I drove on 89? I mean seriously?? I almost want to try it our of curiosity. I've been combing through the threads and there are some really adamant dudes on here who swear by 87...87!! thats regular! So what would happen if I put mid grade in? I drive an 06...so I think thats one of the models with a knock sensor right? seriously...what would happen?

 

Nothing.

Car runs fine on regular.

May get knock if you pushh very hard - my Racing Beat tuned ECU will flash detecting detonation, even on 91 octane.

Untuned, unboosted, regular won't hurt.

 

then why do so many people insist it does? would 89 mid grade be the safer bet?

 

There is 91 Octane gas in NYC. Almost all Sunoco Station has them. a few Gulf Station also has them.

It's usually 10 to 15 cents cheaper than 93, and of course 10 to 15 cents more than 89.

too bad none of the station on my way to work/play were Sunoco/Gulf. otherwise I would use 91 over 93. no point paying so much when you don't need it. right ?

 

My understanding is that retail gas is a blend of various octane rated gasoline, and the more 93 you make, the less high octane stock you have leftover to make 87 with. California uses more premium than other states, so if it was rated at 93, there would be a shortage on 87. So, 91 it is. We pay the same for 91 that everyone pays for 93, though. Typically 20 cents / gal over regular.

 

in California you pay for Regular what everyone else pays for Premium

 

Because octane rating is a measure of air/fuel ignition temperature under pressure, the lower the octane rating is, the lower the ignition temperature and conversely, the higher the octane rating, the higher the ignition temperature.

Rotary engines do tend to produce copious amounts of heat, especially when pushed hard. The engine can and does, in many circumstances, produce engine temperatures that exceed the ignition temperature of low octane fuel resulting in a condition called "detonation". That is when the air/fuel mixture ignites before it is supposed to which can cause catastrophic engine failure.

The safest bet is to use a fuel with an octane rating that meets or exceeds that which is recommended by the manufacturer.

 

^ I'm the same way, I even keep it to the same gas station and pump. 98% of my fuel for the last 4 years (Including my last car) comes from the Chevron up the street from me, pump #11, 93*. It's a newer well kept place, never had a fuel issue. Just wouldn't recommend the car wash.

 

You left something out called tuning. It's the deciding factor of rather 87 works or only 91 or higher works.

You can tune any car that used to run 91 to run on 87 without issues, all you need to back the tuning off.

not to mention, most OEM ECU these days are based on O2 feedback to adjust it's A/F ratio and will adjust itself on the fly.

So unless it's some turbocharged cars that's hard to run on lower Octane, most NA cars can run on 87 without too much issues. Almost all previous Rotary engines ask for 87. RX-8 actually does work with 87, but fuel quality varies greatly between stations, even if it's the same brand. so it's safer for Mazda to just tell people to use 91 or higher.

 

Not so much tepmerature versus a piston engine. More the very high compression is an issue, as it is for all cars that call for premium. Both heat and pressure can cause premature detonation, and with most performace cars its pressure. Most of us are dealing with sompression ratios that top off at about 10, so, yeah, compression.

 

It was an intentional omission. Based upon the comment that I was adressing, I could extrapolate that the poster has a limited knowledge of what octane ratings mean and their importance. Because of that, I could (safely) assume that the poster's knowledge of the intricacies of tuning is nearly nonexistent. I didn't want to further complicate the issue by introducing additional variables that may not be relevant to the poster.

Also, I agree with you... and why I ended stating that the safest bet is to use what is recommended by the manufacturer.

 

As I stated previously...

 

err ok, yep

Safest is not exactly the best, it won't kill your car of course.

I understand your point of view, but I choose to remain silent, Not gonna get into an internet argument cuz it always end up with some ***** cat fight.