The McCully Union 76 on King St. in Honolulu has 100 octane gas for $6. a gallon.

 

They're using a compound known as MTBE (methyl tertiary butyl ether) to raise the octane instead of lead. However, MTBE leaking from underground tanks is also a known carcinogen, so the oil industry is attempting to find or synthesize another octane booster.

 

Wrong. By US federal law, all grades of gasoline must have the same detergent levels, so there is no such thing as "better quality" gasoline. Octane numbers, as explained elsewhere in this thread, measure ONLY the ability of the gasoline to resist pre-ignition (aka pinging or knocking).

Remember how the oil companies used to boast about added detergents in the high-octane grades to "clean your engine?" Notice how all those ads have gone away?

 

1) Gasoline octanes are serial - if you add the two, divide by two, you get the effective octane
2) Detergent additives. Premium fuels have more. Most fuels today have inadequate detergents. Chevron Supreme and Shell's V-Power are adequate, but I still recommend occasional use of a quality cleaner:
The best: Techron, Red Line SI-1/2, Pennzoil Regane.

 

Are you sure of this? I live in Denver, which I beleive is the highest major city in the US (5280ft) and you really have to scurry around to find higher than 91 octane here. A few places have 100 octane for outragous prices ($4.50+/gal). On a side note, I was testing gasolines as I had heard higher octane is better quality but burns quicker, so I went to a Shell that had 112 Octane racing fuel. Only to find from the attendant after I pumped a couple gallons ($5.20 each) that this 112 octane was LEADED gasoline. I did not see any performance increase or decrease, and I hope I didn't mess up the engine.....

Also in Colorado from November-February we have 10% ethanol added to "burn cleaner" apparently in an attempt to keep OZONE clean. This also drops gas mileage considerably in the winter.

 

I was listening to a local car show (in DC) and the guy said just the opposite. To make higher octane they put in an additive that makes the firing later. This actually takes away from the 'purity' of the fuel. If you don't need the higher octane you are just wasting money and actually getting less 'gas'.

Joe

 

I always buy Chevron. It comes with the techron already in it.

 

I just saw the new "Shell V Power" at the pump that supposedly has 5 times the detergents and cleaning agents required by government and will help cleans valves and pistons apparently. Thoughts?

 

Everything is related to compression ratio of your car. Usually you will see heavly modified old sports cars using this. Heavy engine modifications, high dome pistons, 13:1, or higher compression ratio. The higher compression ratio in a car the more horsepower it makes. Why do you guys think a accord has 240 hp and an TL has 270. Look at the compression ratio of the 2 engines. Granted there might be other changes to the engines but it all comes down to compression. My cousin could only use cam2 becuase they were running 13.5:1 or higher compression. They used to sell 104+ octane boost in auto stores for this purpose in a can. If your auto manufacture only calls for 87 octane, putting 93 in it will not benifit any and you will not get better gas milage. If you want that increase the air flow into the intake, ie. K&N filter, exhause mods, etc.

 

Plenty of thoughts, and research:
http://forums.s2ki.com/forums/showth...hreadid=171397

Fact is, the level of detergents has dropped for years, and the govt does nothing to enforce the standards.

And while I am at it, my postings on lubricants:

http://forums.s2ki.com/forums/showth...hreadid=195574

 

Displacement is irelevant? CR is not everything - it works against you in a car with a power adder. I get over 438 rwhp on pump gas and stock pulleys on the Cobra, and its CR is around 8.0. There are many ways to make power. Look at the S2000 - revs, 11.1:1 = 240 HP. But ya gotta work for it - Cobras and Z06's make tons just loafing around. I enjoy the best of both.

 

yes you are correct about displacement. The meaning was if you have 2 identical engines and raise the compression on one, obviously you will get more horsepower.

 

Well, yes. Words mean things.

Then there is airflow - the reason a DOHC with 4 smaller valves can often produce more power than a 2V system - similarly, we have combustion chamber swirl, position of the plug, etc. It all is part of the engineering paradigm.

 

Uh oh. That may have fried your catalytic converter. Might want to check that...

 

My advice would be to run one of the good fuel system cleaners I recommended in another post - those winter fuels can leave tenacious deposits on the injector pintles.

The reason you lose mileage is that the specific thermal output of those winter fuels when burned is lower than straight gasoline. So you lose power, and use more fuel - one wonders if that results in equal pollution? Mindless bureaucrats - look what MTBE did to California - it has polluted waterways.

 

In New England at least, Sunoco sells 91 octane (one step below their premium). I only buy it when its cheaper than any other brand's premium (which are generally 93 octane).

 

make sure you bitch if your engine is damaged or your performance suffers because you are unable to understand that acura recommends 91 octane. be sure to blame everything but yourself.

 

In the on line brochure for the 04 TL we recieved from a dealer it specifically says that 91 Octane is recommended, but "gasoline with an octane number lower than 91 may be used with reduced performance".
Does that mean I can use 89 or even 87 octane? I'm not a race car driver and don't need the super performance that the TL is capable of.

 

There is no such thing as quality, but normaly premiun gas (91 and above) have cleaning adidtives etc...

In simple terms octane rating is nothing more than what % of octane is on the gas you buy. For example 91 octane rating has 91% octane fuel and 9% hepatane fuel. Octane has a good tendency to withstand a certain amount of compression before detonation. Unlike hepatane (cheaper to make) has less tendency to witstand compression, but cost less. In other words if the car does not need more than 89 octane, then anything over 89 won't make a difference. Don't forget that if you put more than requiere, there is a sparkplug that would detonate the fuel no matter what higher rating you use. Now, there is a problem when an engine requires 91 octane and you use a lower grade, this will cause premature detonation cause by compression, cars now a days have sensors to detect this and adjust as mention before.

For gas rated a 100 + octane, that means 100% octane + additives that withstand even higher compression than octane alone, or other type of fuel that uses the octane rating for comparison.

 

I have read from some car writers just the opposite. The no-knock chemicals in higher octane do not give performance, and therefor, in a minute manner, degrade the performance.

Joe

 

I normally use 89 octane and it works fine. I have noticed that if I use 87 octane and I have the cruise control engaged, the car will downshift more often when going up a hill.

 

I use to work at a gas station and we sold 87-89-91.... Now thats cool and all, but only one truck show's up to fill up the gas station..... I think its all a hoaks

 

The normal progression here in the DC area is 87-89-93. The standard for super unleaded was generally 92 octane until around 1992 or 1993, when 93 became pretty much universal. Sunoco were the exception, carrying 87-89-93-94, with the 94 costing about 3¢ a gallon more than the 93. I had NEVER seen 91 octane anywhere until last month, when I stopped at a Sunoco in Fairfax and found that the 94 was gone--they now sell 87-89-91-93. I was going to try the 91 but at the time I was concerned that it might not be a good idea since I normally run the car on 93 since that's the only thing available elsewhere; I've since been told that this would not be a problem, but I haven't passed a Sunoco when I've needed gas recently. Sunoco are still the only major brand carrying 91 octane around here.

Back in the days when leaded fuel was still available, before they came out with the 89 octane unleaded, my father used to mix 87 and 92 because his 1982 Accord ran rough on just 87. It worked fine, but then all the stations phased out the old pumps with the dials on them and mixing became a lot more of a hassle so he quit doing it.

There is a place down in Gordonsville carrying 110 octane racing fuel. A friend stops there on his way to football games in Charlottesville because he has a gasoline-powered blender that runs on the 110 octane. (I believe he modified the engine, hence the need for the high octane.)

 

I've been using 87 from day one without any performance issues. Now and then i throw in 89 octane. I don't push the engine hard and it runs fine - no pings and great mpg bout 28 to 30 on average highway so I guess octane levels apply more to those race car types?

 

I use 87 regular here in N.E. with an occational 89 octane- no performance degradation. Engine compensates

 

I'm sorry, but this is complete bullshit. You will achieve NO mileage benefit using 89 octane on a car designed for 87. There is not "efficiency" gain. You do not get the money back in mileage. The Geo Metro will get the same mileage no matter what you put in it. Don't waste your money or the earth's resources. It takes more crude oil to make a gallon of super than regular.

 

Ok, you guys are killing me now. Yes, the engine compensates, but how? It retards the timing! As soon as it detects pinging, it retards the timing. This will reduce your torque, HP, and gas mileage. Whether you can detect it or not is another issue, but that is what happens.

 

I am able to get Sunoco 94 ultra here in Virginia. Where do you live?

 

Where is the Sunoco you visit? I live a few miles east of Springfield Mall. The Sunoco at Fairfax Circle dropped the 94. (I haven't been to the one off the Fairfax County Parkway near Sydenstricker recently to check on them.) My brother's 1974 Beetle seems to prefer the 94, so if there's a place around that still has it, I'll pass it on to him. Thanks.

 

i think that you may have misunderstood what "dcarlinf1" was trying to say.... because you said the exact same thing just one line down. he was refering to the tl engine being less efficent then it could be if you use a lesser octane. so by using a lesser octane fuel the tl would lose power and mileage. and the higher octane restores power and mileage. but using a higher octane fuel in a car not designed for it, will not give an increase performance or mileage.... it can keep the engine running better, as higher octane fuels do come with higher then required cleaners. now the honda accord has a compression ratio of 10.0 to 1. this is still a fairly high compression ratio. although it doesnt require premium fuel (86 or above). i dont think it would hurt using a higher grade fuel. especially in warm (hot) climates. hilly areas (more load on engine) or if you drive it like you stole it. also if you mod an engine premium gas should follow to ensure engine life as mods increase the thermal stress an engine will see. it may not help produce power/mileage, but it wont hurt it either and it may make it run more consistanly.

i always used midgrade or higher in my 280zx which called for just 87, not that it needed it, just the difference in cost was so small that i didnt care, and i thought it might help a bit. later as i added headers, a cam, intake, high flow exaust, bumped the timing, and changed the fuel maps, im sure the higher octane helped as the car was nor producing more heat and power then stock. my contour svt (car just before the tl) and the tl both use premium, they get nothing less then that. when florida got hit by the four hurricanes this year, fuel was hard to come by everyone bought up what the stations had. some only had 87. i parked the tl and drove my f350 until gas became more avaliable. it runs on diesel (60 gallons of it)

in an engine, designed for 91+ octane (like the tl) it is important to use that octane. although you can use a lesser octane. the engine will dial back the timing to compensate. the more you advance the timing the more power that you can make (to a point). advancing the timing refers to firing the plug before top dead center (tdc) and how many degrees (on a rotational plane) before tdc the plug fires. the fuel/air mixture gets ignited just before the piston stops moving upward. this allows the mixture time to burn, as it burns this mixture will expand from heat and drive the piston downward. pri-ignition is the combustion of the gas/fuel and the drving of the piston downward before it ready (still on its upward stroke). A VERY VERY BAD THING. this combustion is controlled by the spark plug and timing. if you lower the octane the engine will fire the timing closer to tdc to protect the engine, but you in turn lose power and efficiency. higher octane gas is also less volitile.

 

The real danger from using fuel with too low of an octane rating in an engine calling for a higher grade fuel (say using 87 in an engine rated for 91+) is detonation. Now virtually every gasoline engine produced today is controlled by a computer which, among other sensors, has an anti-knock sensor(s), so the chance of detonation occurring is significantly minimized.

For those of you who may not know what detonation is or who may believe it to be the same thing as pre-ingnition (ping), which it's not, here you go. Detonation occurs when an unburned portion (pocket) of the fuel/air mixture explodes in an engine's cylinder. As you all know, fuel is burned in internal combustion engines.. it is not "exploded". An explosion of fuel/air in a gasoline engine will almost always destroy the engine. Anyway, this happens because of generally three things: 1) ignition timing that has been advanced much too far; 2) using a fuel with an octane rating too low for the specs of the engine (timing and mechanical compression ratio); 3) a mixture which is too lean (rarely happens with today's engines). Granted there are other factors which could cause this, but these are the primary ones.

So this is what happens. The spark plug ignites the mixture, starting the burn a bit too early in the ignition stroke. The fuel used is too low in octane (anti-knock additives). As the expanding flame front from the burning fuel spreads across the combustion chamger, it super compresses the remaining unburned fuel along with the fact that the internal cylinder temperatures are rising extremely fast and a LOT! Because the remaing unburned mixture is of a lower octane rating, it cannot ward off the inevitible (heat and pressure), and instead of waiting to be burned like the other portion of the mix, it explodes. THIS is detonation.

 

Sunoco in Woodbridge VA. corner of Smoketown Road and Minnieville Road. Near Potomac Mills mall.

 

I have to disagree with you on this. Higher octane fuel DOES give a more efficient burn, thus you will see slightly better gas mileage in vehicles designed to take only 87 octane. This was discussed in detail on local car guy Pat Gauss' weekly radio program last year.

 

I'm sure they were selling aviation fuel at a gas station on the side of the road. Just in case I wanted to pull up in my Cessna and fill up on my way home. Riiiiiiiiiiiiiiiight.

Think 1st, post 2nd.

 

Started talking to a guy at the gas station who has the same car as me (04 TL). Then I noticed that he was pumping regular (87) gas into it. Told him I always use Premium and Acura recomends at least 91 Octane. He insisted that he uses regular without any problems or performance issues. Now I see someone in this thread stating that he does the same. Am I wasting money using higher octane???

 

The ECU will retard timing enough so that you won't get detonation. Although, you won't be experiencing the full 270hp you would see with 91+ octane.

 

Thanks. I filled up at a Sunoco on Quaker Lane near Shirlington last night. Not only had they gone to the 87-89-91-93, they even had a sign up saying "New Octane/Same Quality."

I filled up with the 91 for the first time last night and I am not noticing any difference in the car's performance. Can't say whether I will make this my regular fuel, though, because there are a few Exxons around where 93 octane is cheaper than the 91 there (without driving the 10 miles down to Woodbridge, where it is lots cheaper). I won't go below the 91, though, notwithstanding some of the commentary on this thread. Even if buying the premium unleaded were to be a waste of money in the end, it's not all that much money. Call it cheap insurance. I probably waste more money on food that spoils in the refrigerator as leftovers before I get around to eating it.

 

the guy you were talking to is a dumbass.... plain and simple

use 91 at a minimum unless its absolutly needed to use less (ie out of gas and only 87 is available)

 

To mporter410;

You wrote,

"I have to disagree with you on this. Higher octane fuel DOES give a more efficient burn, thus you will see slightly better gas mileage in vehicles designed to take only 87 octane. This was discussed in detail on local car guy Pat Gauss' weekly radio program last year."

I have to say I disagree with this assessment and is at least the second thing I've heard Pat Goss say about which I take issue.

Higher octane fuel contains anti-knock additives which make it able to ward off pre-ignition and detonation in high-compression engines and/or with initial timing advanced quite a bit more than the factory specification. Burning this fuel in a lower-compression engine with stock timing is not only a waste (which he has said on numerous occasions and which I totally agree), but can actually being the process of raising your compression ratio because of more unburned deposits finding a home in your combustion chamber. I ran some tests some years back with a '94 Honda EX (8.8:1 compression) where I used a slightly higher octane. Not only did I notice a slight drop in performance, but my mileage decreased.

I suspect what Mr. Goss was talking about might have been the higher levels of detergent packages in higher octane fuel.

Oh the other thing I heard him say which I completely with was a comment he made on MotorWeek that clutches in cars usually don't last more than 70,000 miles. Hell, if you can't get at the minimum, over 100,000 miles from a clutch, you're doing something VERY wrong.

 

Aviation gasoline is 100LL. The LL means it's low lead, not "0"lead. Aviation fuel is definately not sold at a pump. Even being low lead, it's got a huge amount of lead and is illegal to use in any road vehicles. Using aviation gasoline in any of todays automobiles will ruin the engine...trust me, I know from personal experience! When I graduated from school, I worked at a local airport as a flight instructor. My boss who owned the facility, used 100LL in his Lincoln since it was cheaper and more convenient than filling up at the local gas station. After a year or so running this stuff, his engine required a top overhaul due to lead deposits on the valves. It's OK to use it in a racing engine, but not in a modern car.