What gas companies have 91 Octane ? I usually see Plus that is
89 or Premium that is 94.

 

Just use the 94 octane, or, if you are a bit anal, use half 89 and half 94.

 

Come out west and you'll never see more than 91 from any company..

 

The manual calls for 91 octane, so that is the minimum you should use.

 

I heard the West Coast only has 91 octane due to some stupid limits on octane levels. For example, Mobil sells 93 octane except on the west coast where the same name gas is only 91.

 

Even here on the east coast Sunoko has stopped making 94 ultra and is now 93 ultra.

 

I'm not a chemist, but I did hear an explanation once of what the point is with the octane rating. I believe the only issue is that the higher the octane, the higher the 'threshhold of combustion'. Raising this prevents the gas/air mixture from igniting before the spark fires due to the compression in the cylinder. If you use low octane gas on a car with high compression (like the TL), you'll tend to get 'pre-ignition', which means the gas explodes before the spark fires (i.e. before the piston gets to the top of the cylinder). This is a bad thing because it tries to push the piston back down, when it's still coming up. It results in a metallic pinging sound on hard acceleration.

Somehow (I don't know how), Acura modifies something about the way the engine runs (maybe the spark timing?) to compensate if you're not using the correct gas.

Summary: If the car doesn't need high octane gas, it doesn't buy you anything (i.e. you're wasting your money).

If the car needs it, you should use it, but you needn't use anything higher than what's required. If you use higher than what's required, you still achieve the desired result. So if you use 91, 92, 93, 94 or higher in the TL, it works fine. If you use 91 in a non-type S RSX, you're wasting money.

If there's someone out there who knows more about this, please correct me. I believe, however, that this is a materially correct answer.

 

Up until recently there were some Unocal stations (Madero Road in Mission Viejo comes to mind) that sold Unocal 100 at the pump (I used it for my GN). It was expensive, but you could get it.

 

Wow. How much did it cost?

 

High octane controls preignition (pinging) and you're right. Other than controlling pre-ignition it doesn't do much. The motor has knock sensors that detect preignition and will retard timing to try and compensate but of course retarding timing reduces HP. It also depends on your climate. Like here in SoCal it's been really hot lately, 20-30F above normal in a lot of areas. If you're driving in a hot climate, it can contribute to detonation, as does high loads (fast starts of hill climbs).

IMO, if you liven in a moderately cool climate, don't live in hilly terrain which puts a long consitant load on the car, you should be able to get away with running 89 without detonation.

However, you also have to ask yourself this. Just how much are you saving. Here in SoCal, gas prices are typically .10-.15 per grade with say 87 at $2.15, 89 at $2.25 and 91 at $2.35. So if you fill up on with 14-15 gallons, you're only looking at $1.50 to $3.00 per tank difference to run 91. Then comes how much to you fill up. I commute 50 each way to work so I'm filling up way more frequently than most people and it still comes out to about $6/wk extra for 91.

 

The last time I got it at the pump was when I went racing in Vegas. It was a little under $4/gal (I think $3.95) on I think Flamingo and I went out of my way...most places were were $4.15/gal, but that was when their gas price for regular unleaded was only about $1.65.

In SoCal I've seen it for as cheap as $2.75 if you buy it by the drum (when prem 91 was $2.17/gal) and that's not bad at all. But then they get nearly as much again for delivery if you don't pick it up yourself.

But from my understanding ConocoPhillips which bought the Unocal refineries and I think even their service stations is no longer making these "race" grades anymore.

 

 

In case you didn't realize, airplanes run on 100 octane Low Lead. That Unocal stuff was probably aviation fuel.

 

Or it just had the same octane.

 

They actually pump 103 at a station about 3 miles from my house. A lot of my friends running turbos use the stuff. Not sure on cost exactly, but I believe it is about $4-5 per gallon.

 

Amoco, Mobil and Exxon all sell 93 octane in the Northeast.

 

Stations around here have 87, 89 or 93 octane. I remember years ago that Sunoco had a switch on the pumps that would blend the grades, depending on what octane you wanted. Seemed like a good idea since only 2 grades would be required and the desired octane could be anywhere between the low and the high.

 

Isn't 89 fine....in the grand scheme of things???

 

Why does higher octane cost more? Does it take more time to refine it?

 

Not for the TL. Its compression ratio is too high. You'll get pinging as explained above, which can potentially damage the engine. Honda compensates for this by changing the timing, but it's an imperfect solution, designed to be used if, for some reason, you can't get a tank of 91 octane gas.

 

In the 'old days', lead was used to raise the octane of gas (which is why gas was leaded). Once they required unleaded gas (in the 70's??), I assume that it requires removing some more stuff from the crude oil, resulting in less gas per barrel of crude, hence a higher price. This is just a guess, but perhaps they add something to raise the octane like they used to add lead.

Anybody know something about this?

 

Union 76 has 92 Octane (at least here in the Tacoma, WA area).

FWIW, if you're in the neighborhood cheapest Premuim at $1.22/gal at 76
station at DuPont exit off I-5. Price goes up if you're not in the neighborhood.

 

Unocal 100 is not aviation fuel. Unocal 100 is/was unleaded fuel, not low lead.

 

Not entirely true. The better the quality of the gas (higher octane rating) you use will directly effect your gas mileage. It makes the engine more efficient. So, it's true that it costs more, but you get some of that back in the extra miles traveled. Something to consider. Personally, I use premium in any car that has a high compression ratio as the TL does and 89 octane in everything else. Never use 87 octane. You save some $$ but you lose gas mileage and increase engine wear over time.

 

Go check what the dealers put in. They use 87 from their own farm tank. You would only need 91 or better to see max performance from engine.

 

Burning higher octane fuel has all the benefits mentioned in prev. threads... However, in burning lower octane fuels - when it detonates prematurley, it leaves very high carbon deposits on the cylinder wall and piston heads.

Not Good....

 

Quick Q. I thought the same thing, but ever heard that Sunoco uses two tanks (high and low) and mix together to have all their octane oils...

Anyone knows this?

Thanks.

 

Finally filled my car up today driving home from lunch after my AP Biology exam :p

I had to buy 93 octane at Mobil and it was about 2.40 a gallon

 

The differences in the octane of the west coast vs the east coast are because of altitude differences. The west coast is closer to sea level and therefore the air pressure is higher. The air here in the east coast is generally thinner and combusts much more easily therefore requiring a higher octane rating. Remember octane retards combustion.

I'm not completely sure my explanation is correct but I know its because of altitude.

Exceptions are due to the actual elevation you are at. You can be in the mountainous regions of california and have higher octanes there.

 

It doesn't have anything to do with altitude. The problem was 2 fold. High demands for premium fuels in California and CARB increasing emissions standards for Cali fuel blends (wanted to get away from the environmentally harmful Methyl-tertiary-butyl-ether. As emissions requirements for fuel blends increases, they wanted to use ethanol, but during testing the CEC (California Energy Commission) found that it was easier to make premium gas with ethanol, switching away from MTBE which was found to pollute ground water, if they dropped the octane level requirement for "premium" 1 point. As such, they sent out a survey to all the Cali refineries to see if they would make the new ethanol blend at the new octane rating. Most of course responded yes, thus the switch was made and we're stuck with the new ethanol 91 octane blend.

 

Trust an old chemical engineer, mixing different octane gas works just fine.

 

Very strange since here in the midwest we have 92 octane premium that's 10% ethanol blend. We've had ethanol in nearly every grade of gas for close to 20 years.

Maybe the base stock is part of it, since I do know that compared to other parts of the country you'll seldom find a car exhaust that has the rotten egg smell in the upper midwest. But other areas... pew

 

i was driving to las vegas yesterday from san diego...saw 100 octane from a 76...didn't get it =)

 

AV-Gas

 

We also have oxygenated blends, if not oxygenated all the time. Perhaps other "clean air" B.S. additives contribute to this issue. It's also an issue of capacity as I read. The article I had read a while back specifically mentioned that the midwest has MUCH lower demands for premium fuels and a MUCH higher demand for 87, I'm assuming because of the "distribution" of types of vehicles people are buying, and the ease of getting ethanol. Being hydrophillic ethanol is difficult to transport, so cost of getting it to SoCal may also be an issue. The problem was meeting demand and it was easier to meet the demand with ethanol if they dropped the octane a point.

 

Yep, west coast (CA at least) has only 91 as premium. Nothing higher than that. It used to be 92 a few years back. I've been driving for 15 years here and don't recall ever seeing 93/94.

 

Yup. A Friend of mine drives a Gas Tanker Delivery truck and says alot of the newer stations only (here in CA) get 87 and 91 delivered and will mix their own 89. Those that dont have the right equipment to do so pay to have 89 hauled in but he said even then, the 89 is just 87 and 91 mixed at the refinery.

Now that I know the TL reccomends 91, I'm gonna have to remind him to call me everytime he "drops a load" in Simi Valley where I live.
I wonder how much a 50 gallon drum and a hand pump costs....

 

The "quality" of the gas does not have much to do with the octane rating. The octane rating just signifies the number of octane molecules per some unit of measure (I can't recall what that unit of measure is at the moment). From the stand point of selling gas it really doesn't make sense to have different refining levels either. Most gas sold is 87 grade. People will form opions on different gas companies based on what grade gas they use. Following this logic it would make sense to refine 87 octane gas the best possible way to earn the reputation of having good gasoline. If a gas company refined higher grade gasoline through a better process, they wouldn't benifit from it all that much and they would get a reputation from allot of the population for having poorly refined gasoline.

 

I recently saw 100 octane gas at a Mobil station in Connecticut. It was $5.00+ per gallon. It was called CAM2 or something and was labeled "racing fuel." I'm pretty sure that putting this in the TL would not improve performance at all and could actually, over a long period of time, damage the engine that is not made to "handle" such high octane fuel.

I was tempted to put some in to see what happened, but then I started thinking rationally.

Don't waste your money.

 

91 Octane is dependant of what elevation of the city is at. Out here in SLC, UT, we don't have anything higher than 91. You will probably find the same situation in cities like Denver also. I don't recall what is the specific reason for this, but I think the higher octane is not as efficient burning in the high elevation because of the lack of oxygen. Also quarter mile times are lower up here because of the lack of oxygen compared at sea level.