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Honda Accord Fuel and Fuel System Questions

stanwelksstanwelks Posts: 35
Do any of the 06 Accord models require premium gas?

If so, does it matter if it is used or not?


  • thegraduatethegraduate Posts: 9,731
    All Accords since 2003 only require regular unleaded gas...

    Short answer? Regular is fine.
  • master1master1 Posts: 340
    Premium gas is not only more expensive, but it burns faster - it lasts short. The performance will be better, but regular will still be fine.

    Premium costs more to buy, and doesn't last long.
  • louisnlouisn Posts: 110
    On an Accord V-6, I was always under the impression that you get a slight horsepower increase and slightly higher mileage with premium. :confuse: Something about the computer resetting itself for the premium. On most other cars I've been told it's just a waste of money if the car runs OK on regular w/o pinging. :confuse:
  • elroy5elroy5 Posts: 3,741
    I have heard premium gas could improve power, but it takes a few tanks for the computer to get it. Then only one tank of regular unleaded will put it back to square one. I doubt very much if you would notice the difference in any case. Save your money, and just use regular unleaded. It's one of the advantages of owning a Honda. Take advantage of it.

    Buying premium gas when you don't need it is sort of like buying shoes. Huh, you might say. If you wear a size 10 shoe, and you buy a size 12. You get more shoe for the money, but it doesn't do you any good. :)
  • Actually that is not correct!

    Premium gas has additives to ensure better more even burning and is required only for very high compreession engines or older engines with carbon build-up that start pinging.

    Premium gas actually has less power than regular.

    The only reason premuimu might ever appear to have more power is not because of the gas, but rather because the engine is retarding the spark with regular to prevent pinging.

    There was an old wive's tale, which has never bee substanitated, that a Honda design engineer said that you could gain 10 more horsepower by burning premium instead of regular. But it is just that and has never been substantiated or proven for Honda Accord V6 engines.


  • ezshift5ezshift5 West coastPosts: 854
    ....actually, dude named Sasaki, I think was the Honda engineer who equated premium with 10 more HP (and 10 more pounds/feet of torque).

    ...but I'll be damned if I recall where I saw this info....

    Hang in there, MidCow......

    best, ez..
  • Ezshift5,

    I remember that is was in an interview when the V6 7th generation was first introduced. He said it should get more horsepower and then when pinned down it was never proven. An engineer on the design team wanting to make a statement; a design engineer's pipe dream. LOL

    cruis'n on regular in Accord premium in S2000

  • ray_h1ray_h1 Posts: 1,134
    --"Premium gas is not only more expensive, but it burns faster - it lasts short. The performance will be better, but regular will still be fine."--

    Uh, welcome to Thermodynamics 101... Premium gasoline has a higher octane rating. Higher octane fuels burn more slowly - which is why they reduce the tendency for an internal combustion engine to ping (pre-detonate) under load. The additional hydrocarbon content of higher octane gasoline also results in a higher BTU content - more power per unit volume. Since a higher octane fuel is more resistant to premature detonation, the engine can be tuned with more spark advance which also results in more power output. In virtually all modern engines with computerized ignition and fuel delivery, millesecond-by-millesecond tuning on the fly occurs courtesy of pre-ignition information supplied to the engine management computer by knock sensors which detect pinging long before human hearing is able to discern it. If premium unleaded is used in lieu of regular unleaded, there will be some power increase realized since the EMC will respond by advancing ignition timing to the point just shy at which pinging occurs. This does not take several tankfulls to accomplish, either. But, ten hp is a stretch - probably closer to 4-5 hp at the engine output shaft and about 2-3 hp where the rubber meets the road after accounting for parasitic losses through the transaxle's gears and bearings, wheel bearings, and losses due to loaded tire rolling deformation. In short, if your engine operates without audible pinging, the use of premium unleaded fuels is neither necessary nor sufficiently advantageous to justify its 20 cents per gallon premium pricing. Contrary to a persistant urban myth, unleaded premium gasoline does NOT contain more combustion chamber deposit cleaning detergents than unleaded regular gasoline, either. ;)
  • djm2djm2 Posts: 705
    OUTSTANDING posting! -----What is your opinion about fuel additives such as: BG products? -----Best regards. ----Dwayne ;) :shades: :)
  • ray_h1ray_h1 Posts: 1,134
    Since I have no experience with supplementary gasoline additives, I don't have an opinion one way or the other. Your own empirical results are your best guide.
  • bolivarbolivar Posts: 2,316
    I agree totally with ray_h1.

    He has a excellent description on gasoline octane. And he is correct about detergents in gasoline.

    There is a Federal mandate on detergents and all gasolines brands and grades should have adequate amounts. Now, this is not to say that some small, unbranded wholesaler might be 'shorting' the additives in his gasoline, but he would be breaking the law, and have someone at the gasoline 'terminal', where the additives are added, in collusion with him.

    I worked 33 years for a major integrated petroleum company. As a computer programmer, but you pick up a lot a info when you are around the oil business for this long.
  • Most of what you say Ray_h1 is true except for one very IMPORTANT exception : " .. .The additional hydrocarbon content of higher octane gasoline also results in a higher BTU content - more power per unit volume. .."

    That statement is completly incorrect. Actually regular unleaded has a higher BTU content.

    The only reason to use premium is because of higher compression engines used to obtain more horsepower from the same engine size. This also happens in older engines with carbon deposit which inreases the effective compression ratio higher than when it were new.

    Check you facts again! You appear to be a budding engineer with some good knowledge. But just to prove my point, I challenge you to find at least one document that quantatively supports your supposition. you won't because such evidence does not exist.


  • ray_h1ray_h1 Posts: 1,134
    --"Check you facts again! ... I challenge you to find at least one document that quantatively supports your supposition. you won't because such evidence does not exist."--

    Wow - such negatory passion... ;) Actually, any introductory organic chemistry or introductory physics textbook supports what I posted. You seem to be intent on reducing a civil discussion about fuel properties to an infantile schoolyard spat, midnightcowboy. Why is that? But to accomodate you this one time, gasoline without alcohol or MTBE as oxygentators is a blend of two hydrocarbon molecules: septane (C7H16) and octane (C8H18). Each grade contains essentially equivalent amounts of various cleaning agents - the exact composition of such as determined by the gasoline blender prior to delivery to stations. The proportion of each basic "gasoline" molecule varies with grade - unleaded premium containing proportionately more octane than does unleaded regular. By simple arithmetic, it should be obvious to anyone who passed 1st grade that each octane molecule contains one more carbon atom and two more hydrogen atoms in its makeup than does septane. Those extra three atoms are fuel, and give off heat when they're burned. So, what part of 91 octane having a proportionately higher makeup of basic combustibles (ergo, a higher BTU content per unit volume) than 87 octane still eludes you?

    (While you're chewing on that conundrum, here's another brain teaser: Diesel #2, somewhere in the range of C16H34, give or take, has an even higher BTU content than any grade of gasoline - but burns even more slowly. Work on that one a while - might keep ya' outa trouble...)
  • larouselarouse Posts: 28
    We just bought a 2006 V6 Accord. One of the reasons we decided for the Accord was the fact that it runs on regular. For us this car has more power than we relly need. In fact, now I think maybe we should have gone with the V4. We use it for regular driving, not for the car races. Who needs more power? Is that a psychological need or what?
  • ezshift5ezshift5 West coastPosts: 854
    ...I would concur. With your perceptual style, the 4-cylinder in a row (no habla V-4) powerplant would've been a good choice.......

  • ray_h1ray_h1 Posts: 1,134
    Honda's 6-cylinder engine is of the "V" configuration - two banks of 3-cylinders each in planes seperated by a 60 degree angle culminating at the crankshaft centerline - hence the term, "V6". Their 4-cylinder engine is configured as an "inline" design (all four cylinders lined up in a single plane) and would properly be identified as an "I4".
  • larouselarouse Posts: 28
    Thank you for enlightening me in this regard. Now I know why the 4 cylinder engine should not be called a V4, and thank you for your style. From you, I just learned something. From ezshift5, with his sarcastic style, I learned nothing.
  • From Cecil on "the Straigt Dope" :

    Dear Cecil:

    In this time of high gasoline prices, the Teeming Millions need your guidance (well, at least I do). What is the difference between premium and regular gas, and is this difference worth the extra money? I normally put premium gas into my car because I don't mind paying two or three extra dollars at the pump. Am I being scammed by the gas stations, or is the benefit to my car worth it? --Jeff, via e-mail

    Not to introduce a radical concept, Jeff, but have you tried reading your owner's manual? If it says to use premium, my advice is to use premium. If it says regular, use regular. The fact that your note indicates no acquaintance with such matters suggests that you may in fact be a scam victim, assuming by this you mean "someone who believes what he hears in commercials." I have a hard time working up much outrage over this deception, since discovering the facts requires so little effort. If you don't mind paying the extra money for no reason, don't expect the oil companies to suffer any pangs accepting it.

    In most of the U.S., regular gas has an octane rating of 87, midgrade gas is 89, and premium is 91 or 92. (Octane ratings are lower in the mountain west due to the effects of thin air on internal combustion.) Contrary to widespread belief, the octane rating doesn't indicate how much power the fuel delivers; all grades of gasoline contain roughly the same amount of heat energy. Rather, a higher octane rating means the fuel is less likely to cause your engine to knock or ping. Knock, also known as detonation, occurs when part of the fuel-air mixture in one or more of your car's cylinders ignites spontaneously due to compression, independent of the combustion initiated by the spark plug. (The ideal gas law tells us that a gas heats up when compressed.) Instead of a controlled burn, you get what amounts to an explosion--not a good thing for your engine. To avoid this, high-octane gas is formulated to burn slower than regular, making it less likely to ignite without benefit of spark.

    The majority of cars are designed to run on regular gas, and that's what the manuals tell the owners to use. Higher-performance cars often require midgrade or premium gas because their engines are designed for higher compression (higher compression = more power), and regular gas may cause knock. If your car needs high-octane gas, the manual will say so.

    Using high-octane gas in a car designed for regular accomplishes little except more rapid combustion of your money. Some refuse to believe this, claiming, for example, that premium gives the family Toyota better mileage or more power. These people are in dreamland. Others say premium is purer or contains detergents that will cleanse your engine of uncouth deposits. Likewise misguided thinking--government regulations require detergents in all grades of gasoline. (BP Amoco, I notice, asserts that its premium gasoline contains more detergents than legally required; if you think that's worth 20 extra cents a gallon, be my guest.) Some automotive types claim that using premium in a car designed for regular will make the engine dirtier--something about deposits on the back side of the intake valves. I've also heard that slower-burning high-octane gas produces less power when used in ordinary cars. Believe what you like; the point is, don't assume "premium" means "better."

    Occasionally you get some genius who takes the opposite tack--he spends an extra 10 or 20 grand buying a high-performance car, then decides he's going to save three bucks per tankful using regular instead of premium as specified. He figures as long as the engine doesn't knock he's OK. Wrong, carbon monoxide brain. Car engines nowadays contain knock sensors that detect detonation and automatically retard the spark to compensate. The delay means maximum gas expansion occurs when the piston is farther along in its downstroke and thus there's more room in the cylinder head. This reduces peak cylinder pressure, eliminating knock but also giving you less power and poorer mileage.

    You may ask: Don't knock sensors make it hard to tell when an old car needs higher-octane gas? Years ago, when your beater started pinging on grades or under acceleration, that was the sign that carbon had built up in the cylinders, increasing compression, and it was time to switch to high-test. Now the knock sensors compensate, which seemingly might conceal the problem. Don't fret--today's fuel injection systems precisely meter the fuel-air mix, resulting in fewer unburned hydrocarbons and less carbon buildup. If you're still concerned, I'd say it makes more sense to spend $6 on a bottle of carbon clean-out juice than an extra $150 a year on high-priced gas.


  • thegraduatethegraduate Posts: 9,731

    Post of the year nominee, in my opinion! Nice work.

  • badgerfanbadgerfan Posts: 1,564
    Yes that was a good discussion except for a one point.
    On cars that are designed to run acceptably on regular but will provide more power with higher octane, the use of regular will not necessarily harm fuel efficiency, as your engine is almost all of the time running under very light load. Engines under light load will not sense impending knock, and thus will not retard the spark. Thus, under almost all normal driving conditions with these engines, premium fuel only has an effect on engine timing under high load conditions. In fact, I would guess that premium fuel could actually result in poorer fuel efficiency under light load conditions as it combusts more slowly, though one could probably only measure the differences under laboratory tests, as they would be very miniscule.

    Some people have the misguided notion that car companies design these cars with an "octane sensor" that completely adjusts the engine performance under all conditions. This is simply wrong. They design a knock sensing system that reacts by adjusting timing when the knock sensor senses low level knock. This system reacts to impending engine knock, not to the actual fuel in the tank.
  • ray_h1ray_h1 Posts: 1,134
    This is no doubt NOT the ideal place for the following diatribe, but since it relates to the above Wikipedia article, I'll risk the wrath of moderators and forumners... :blush: An interesting(?), but non-fuel related, point about hydrocracking and paraffins for those who plowed into the Wikipedia articles is that the "sweetest" crudes once avilable on the North American continent were the high paraffin content variety associated with the Pennsylvania region oil fields. These crudes were very low in naphthene content. Naphthenes are great solvents, but poor lubes because they're easily oxidized to form sludge, acids, and varnish, thus, generally undesirable in motor oils. Pennzoil, Quaker State, Wolf's Head, and a few other motor oil brands were blended exclusively from Pennsylavania Grade crude oils. But, paraffins out of a distillate tower have various molecular weight molecules in the viscosity range typically used in motor oils; and at low temps, the heavier paraffins will precipitate out as wax crystals which undesirably thicken the fluid. Pennzoil still has a repuation (undeserved) for being "full of wax" simply because the word "paraffin" seems to be synonymous with "wax" for too many people. All current API spec'd "SM" oils use base oils that have undergone hydrocracking - a form of synthesis in which heavier paraffins are cracked down to a specific molecular weight range under the influence of carefully chosen catalysts and very high heat and pressure. Just as importantly, most of the undesirable naphthenes that are present in crudes brought up from the offshore drilling platforms in the Gulf of Mexico will undergo isomerization, too - cyclical ringed structures are broken and re-arranged as desirable molecular weight paraffin alkanes. (Unfortunately, the Pennsylvania fields are largely played out. Equally unfortunately, the fields with the lowest heavy paraffins and naphthene content in current production are located in the middle east.) These severely hydrotreated base oils are designated by the API as "Group II" and "Group III" stocks. Group IIIs are highest quality severely hydrotrated base oils - the difference being the amount of heat, the type of catalyst, and the time in the hydrocracker. Virtually all current conventional finished motor oils are predominently, if not totally, Group II based - some with varying amounts of Group III added for higher quality. (Those with added Group III content may or may not be labled "Synthetic Blend".) The Group III base stocks are so good that they're qualified as synthetic base oils, even though derived from crude oil. As good as they are, Group IIIs still retain extremely low, but, nevertheless, measurable quantities of waxes and naphthenes. Mobil 1 is the lone, widely available holdout in allegedly* using only Group IV base stocks - those derived from natural gas through multiple polymerization steps to achieve the desired molecular weight. Since Group IV base oils start as a pure gas, there are NO waxes or solvents present in them - unless introduced as comtaminants from an improperly purged storage tank. The rest - Castrol Syntec, Pennzoil Platinum Plus, Quaker State Full Synthetic, et al use Group III base stocks exclusively or some combination of Group III and Group IV base stocks in their full synthetic lines - always along with various additives (there's more to finished motor oils than their base stocks).

    *Mobil used to adverise that their Mobil 1 line was blended exclusively from PAOs (Group IV) with select esters (Group V) added as lube quality enhancers (esters have a natural affinity for metals and will retain a lube film after the oil has drained back into the sump) and engine seal conditioners (esters will swell seals - a job previously carried out by the solvent-like naphthenes present in lower quality base oils - the lone desirable quality of naphthenes in motor oil). Mobil's no longer claiming that PAO exclusivity. I have no idea whether their back-pedaling wording change is significant or not. Some (not myself) on BITOG have tentavely explored the heresy that the "standard" Mobil 1 full synthetic line (vs. Mobil 1 EP) may now carry some Group III content. Their reasoning is that PAOs are very expensive to polymerically synthesize because of the multiple steps involved.
  • I use regular as recommended, most of the time. There is a consideration though, when gas PRICES are up. If you know when gas is delivered at a particular station and the tanks (in the ground) are filled, no problem. If not you might run the risk of putting deposits into your tank that can clog your injectors bad. It happened to me with a car I had. My tank was low, I got gas from a slow filling pump, (gas in the station tank was no doubt low) and within minutes my car was running badly. People tend to put regular in their cars before premium (even if premium is recommended) when prices run up. Just a thought.
  • elroy5elroy5 Posts: 3,741
    This is how I (and Consumer Reports) view using premium gas when it is not necessary. Using premium gas when your car is designed to run on regular is like buying size 13 shoes when size 10 shoes will fit perfectly. You are getting more shoe for the money, but it's not doing you any good.
  • patpat Posts: 10,421
    Hahaha - great analogy!
  • ray_h1ray_h1 Posts: 1,134
    )) " might run the risk of putting deposits into your tank that can clog your injectors bad. It happened to me with a car I had. My tank was low, I got gas from a slow filling pump, (gas in the station tank was no doubt low) and within minutes my car was running badly." ((

    Your experience was justifiably unsettling, but several points you may not have considered:
    1) An inground tank with a low fuel level is more likely to have pumped WATER into your car's fuel tank. (Since water is heavier than gasoline, it settles to the bottom of the tank.) Both the station's pumps and your fuel system have very effective fuel filters to trap solid contaminants, but limited ability to trap water. Station personnel are responsible for servicing the equipment, but not all are equally attentive. Car owners can be notoriously lax in regular fuel system maintenance.
    2) If the station personnel were lax enough to allow their regular-grade tank to run low enough to cause problems, what assurance do you have that the same might not have been true of their high octane tank?
    3) How can you be sure that your car didn't have an anomoly that was about to become apparent regardless where or what grade of gasoline you purchased?

    I've learned the hard way to seek out national brands* of gasoline and trade where there're cars lined up to purchase fuel. Generally, those stations have a high turnover rate and consistently acceptable quality fuel. Unless I'm in dire straits, I steer clear of unbranded mom-'n-pop convenience store gasoline.

    *which can be as cheaply priced as the no-name brands. I use BP "ARCO" and Total "Valero", though I draw the line on Citgo gasoline and lubes for political reasons.

    (curious observation: British Petroleum owns the "ARCO" and "Castrol" brands - cheap gasoline, expensive motor oil. Chevron Oil Co. owns the "Chevron Supreme" motor oil brand - relatively pricey gasoline, cheap motor oil [and a very good one]. Go figure.)
  • 1) An inground tank with a low fuel level is more likely to have pumped WATER into your car's fuel tank. (Since water is heavier than gasoline, it settles to the bottom of the tank.)

    Why would the level of the tank change the chance of getting water? Full or empty, wouldn't the water still be at the bottom?

  • elroy5elroy5 Posts: 3,741
    Honda, Chevrolet, and some other car makers recommend using Texaco/Chevron gasoline, for their detergent additives (Techron). I use Texaco because they are easy to find when we are out of town.
  • bolivarbolivar Posts: 2,316
    Don't you know about the ingenious 'floating pickup' that keeps the water out of the gasoline?
  • bolivarbolivar Posts: 2,316
    Please give me a page number, or even a section name, in my Honda or Chevrolet owner's manual where they 'recommend Texaco/Chevron gasoline'.

    I've currently got one of each of these brands, and I've never personally seen this in either of their manuals.....
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