91 or 87 octane?

Discussion in '3rd & 4th Generation 1990-1997' started by cybrstar, Jan 23, 2009.

?

What ocatane do you use?

  1. 91 (Ohh yeah, only way is the performance way!)

    21 vote(s)
    21.0%
  2. 89 (I like it in between)

    9 vote(s)
    9.0%
  3. 87 (Seem to ride just fine)

    66 vote(s)
    66.0%
  4. Who cares, Gas is Gas

    4 vote(s)
    4.0%
  1. vfrcapn

    vfrcapn Member

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    I've been using 76(Conoco_Phillips) for 20 years. With gas prices last year I went down to 87 from 89 and haven't noticed the slightest difference. Great to be only paying $3.00/gallon now. :rolleyes:
     
  2. vfourbear

    vfourbear New Member

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    I became depressed for about 3 days when I put a 20 dollar bill's worth of gas in my bike.

    That is truly not right.

    I'm serious..........depressed. I had to go buy a piece of new gear just bring my spirits back up
     
  3. Maggot

    Maggot New Member

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    Hey Keager for some reason the Quad cities still have 87 octane regular with NO ethanol added. This is the good old stuff. 89 octane and higher in your area is all mixed with up to 10% ethanol. Thats why your 89 octane is less money than the pure gas 87 octane. Go east towards Chicago and all you find is the 10% ethanol/ gas mix in all octanes. If I were you I'd be running the no ethanol / pure gasoline 87 it should produce slightly better mileage. I wish we had this "Real Gas" back home. My son went to School in Rock Island and It took me a long time to figure out why your "regular" was more money than the "midgrade". It was better gas.
     
  4. 7dayclimber

    7dayclimber New Member

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    Most thermodynamics book will tell you that unless your engine is designed to take a higher octane; don't!. Just a drain on your wallet. If it makes you feel better to do so, like they say, ignorance is bliss!
     
  5. soundmaster31

    soundmaster31 New Member

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    Exactly. There is no grey area here fellas...your engine either needs it or it doesn't. There is no improvement by using a higher octane fuel than is required. By quality fuels we mean brands like Shell and BP. Not bargain basement brands like Admiral or Wal-mart.
     
  6. HondaTech

    HondaTech New Member

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    There is no non-ethanol gas to be found in Oregon anymore except on boat docks (boat motors hate ethanol) My favorite part was that with the mandated year round 10% ethanol everyone's fuel economy dropped 10% or more because there are less BTU's per litre of energy in ethanol than gasoline. My wife freaked out because our Element had gotten 25-27mpg all day (pretty decent for a car with the aerodynamics of a brick!) and now we get 22mpg. Of course the geniuses at the capitol decided to make the change right when gas was shooting above $4 a gallon for 87 too so that's rad. Nothing like being forced to use more of a product you are being raped for in the name of the environment.
     
  7. Maggot

    Maggot New Member

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    Honda Tech. If my old memory serves me correct and sometimes it doesn't, Ethanol has about 30% less energy than pure gasoline so if I mix 10% ethanol with 90% gasoline your total energy drop should only be about 3%. So if your mileage drop is more than 3% you may want to look for other causes.
     
  8. vfourbear

    vfourbear New Member

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    FIXT :thumbsup:
     
  9. HondaTech

    HondaTech New Member

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    It has to be the fuel, because both short and long term fuel trim data are normal and it changed basically overnight with the fuel. Saw the same kind of change with all the Hondas coming through the shop too with complaining customers when the Portland Metro area would change over to the oxygenated fuel every winter too.
     
  10. olddudesrule

    olddudesrule New Member

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    87 octane all the time and a half bottle of fuel injector cleaner every 5-10 tankfuls. Runs like a champ. I tried 91 (our hightest here in AZ) and noticed absolutely no difference.
     
  11. Fizz

    Fizz New Member

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    Personally I just put a splash of SeaFoam in every once in a while, more liquid for less price per volume than most fuel injector cleaners.

    Plus, I've never known what's in those things, are they safe for valve guides, gaskets, injectors, seals, lines? SeaFoam is a pure petroleum product, basically oil.

    Oh yeah, for laughs I once dumped a whole bottle of seafoam into my 4.7 gallon (with reserve) tank and no it didn't smoke.
     
  12. olddudesrule

    olddudesrule New Member

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    Thanks Fizz

    "Personally I just put a splash of SeaFoam in every once in a while, more liquid for less price per volume than most fuel injector cleaners.

    Plus, I've never known what's in those things, are they safe for valve guides, gaskets, injectors, seals, lines? SeaFoam is a pure petroleum product, basically oil.

    Oh yeah, for laughs I once dumped a whole bottle of seafoam into my 4.7 gallon (with reserve) tank and no it didn't smoke."

    I had never heard of SeaFoam until I joined this forumn, and have never seen it on shelves of my local auto parts dealers (not looking hard enough:rolleyes:). I intend to give it a try, but I've never had an issue with using regular fuel injector cleaner. Like anything else, I wouldn't use it to excess, but I don't believe it will damage anything if used properly.
     
  13. Fizz

    Fizz New Member

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    I know for sure Wal-Mart and NAPA carry SeaFoam. Used to be 5 bucks, now it's 8. Jeesh.

    You're right, I doubt any reputable name-brand EFI cleaner will do any foreseeable harm, but I just don't like not knowing what's in it. Also, most fuel injector cleaners do do what they are supposed, perhaps too well? Given that their purpose is to degrease and dissolve varnish/deposits, I can't help but think that during their use they strip off oil film from rings/cylinders, valves, etc. Whereas SeaFoam being a petroleum product (and an oil that is slightly more viscous than gasoline at that) does the same thing while actually being an upper cylinder lubricant.

    I've used fuel injector cleaners in the past adn I have noticed their consistencies, smell and color are completely different from that of SeaFoam... I can only infer that that means there's something different and their methods of action are different.

    Obviously everything I've just said is speculation and doesn't take into account how relatively infrequent EFI cleaner use should be under normal circumstances and I don't have any science to back it up... but there's no denying that at any rate, SeaFoam is cheaper and tried and true for many generations. :thumbsup:
     
  14. carbon

    carbon New Member

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    Hey guys,

    Bit of an obsession of mine is tracking MPG with fanaticism. I own a lot of vehicles, and different vehicles prefer different octanes. I always start with what the manual says, and then I do some testing. My tests are always done on the same stretch of road, and usually with little to no wind in place. On my bikes, I keep a riding journal that denotes how aggressive I've been riding (average speed) terrain, and fill-up specs. Below, you'll find what I've found. I've read some great points being discussed here about higher octanes containing more detergents. I've read that some of my older 70s bikes can run into issues with using high-detergent gasoline. Especially since these motors were designed before federally subsidized corn growers jumped into the gasoline market. However, in over 40,000 miles on 70s Honda motorcycles in less than 6 years, I have yet to encounter one engine specific gas issue (i also manage to keep my carbs pretty clean).

    1990 Ford Bronco - 5.9l v8 FI - Prefers regular. Premium will cause the motor to run hot, as noted by my temp gauge, but mpg is unafected. Mileage is constant at 12mpg whether you're spinning tires in mud or towing a house.

    1991 Nissan Pathfinder - 3.0 V6 - Prefers mid-grade. Manual calls for 87, but I have found using 89 will net me between 24-25 mpg if driven under 60mph. 22mpg using 87. 23mpg using premium.

    1994 Chevy Suburban 6.5L Diesel 2500 - 24mpg if I keep it below 55mph. Diesel is a whole other world of dos and don't dos.

    2004 Acura TSX 2.4 i4 - 36mpg if I keep it below 60. This tank has never seen regular as the owners manual requires says it premium. Six speed manual really helps. All time best mpg was 45mpg coming south in wisconsin, and hitting the jetstream for over 450 miles. 10 Gallons of gas. Woot

    1975 CB750f - I've spent a lot of time trying to figure this one out (also two different 550s). I seem to get a better mid range response when using a lower octane. Bike is 100% stock. MPG between 40-45 regardless of octane. Premium gives me a better top end and a higher top speed (by almost 8mph - 110mph on 87, 118mph on premium). Some CB riders have a firm belief that CBs like to operate with some gunk in there, so I stick with 87 unless I want to take the old girl up.

    1985 VF500f - 100% stock. Average 50-60mpg. No change in MPG from premium over regular. However, regular will definitely make the bike feel sluggish with no improvements in any part of the power band. So I run premo in this one.

    1989 VTR250 - Interesting little bike. 100% stock If i keep it below 10k, I can get 75mpg. If i ride it like I'm supposed to, I get between 55-65. Premium makes a very noticeable difference in my upper power band, but regular seems to give me more grunt down low. I run regular mostly for commuting, and use premium every so often to clean, and/or haul ass.

    1996 VFR750 - Just got this bike. It's jetted and has a two brothers pipe. I have no idea what the jetting specs are, but it performs and sounds awesome so I have no desire to change anything. PO told me the bike is running rich. The ride home confirms that. Picked up the bike with the gas gauge indicating full, but in my haste I did not check the physical fuel level. Rode 105 miles until the gas light came on. Put 4.5 gallons in, but I'm not sure if that's how much I actually consumed. Based on 4.5 gallons, that's 23mpg for my first fill up. Doing some quick math, I traveled almost 100 miles in less than 50 minutes. So, with less ass hauling, I might be able to double that figure hopefully. My first fill up was with premo.


    Here's some other tidbits I use to guide my gas journey. Only go to busy gas stations. Slow gas stations will have fuel sit for a while, which can cause sediment or lack of bang when you fill up. I also run inline fuel filters on all of my bikes. If I know my bike will be sitting for a few weeks (or more) I put an oz or two of Marvel Mystery Oil in my tank. MMO does a great job at prevent sediment and removing deposits from your carbs. I run this in all of my cars, trucks, and bikes, but not necessarily in every fill up. It does great for both FI and carb'd applications. It has cleared stuck injectors and clogged jets for me before, but your mileage may vary. It's one of the few products I can say works. I also have had great success with SeaFoam, but I've also seen the over-use SeaFoam eat through piston rings. So if you use SeaFoam, or any fuel additive for that matter, be careful and follow the instructions. Japanese motors work on some very tight tolerances; after years of use, gaskets and seals will adjust based on the conditions they are subjected to.

    If you introduce a foreign substance that the motor is not adjusted to, at any stage, you could jeopardize these tolerances through the varying molecular structures found in different substances. For example, we've all heard of how great Mobil 1 synthetic oil is supposed to be. What you may not have heard is how engines that have been broken in and driven for a substantial number of miles on regular oil will not tolerate mid-life switches to synthetic oil. Engine gaskets and piston rings build up tolerances and chemical bonds with the fluids you run your motor with. Synthetic oil has a notably smaller molecular structure than conventional oil. The molecules are physically smaller because they are man-made, and purpose built. For a lot of motors this is a benefit. Smaller molecules adhere to surface areas more effectively and provide a better coating for a lower point of friction. However, if the motor has been conditioned and seasoned using conventional oil, a synthetic oil like Mobil 1 can often slip by these adjusted gaskets and get into places where it doesn't belong (like your coolant routing).

    Driving slower usually means better mpg, but only to a point. You ideally want to find your best operating range and speed for what ever vehicle you are using. Every vehicle is different, based on numerous factors. Gas is more or less gas, but your motor will have a preference. Engineers calculate timing and compression to dictate what kind of gas your motor should run, but bean counters always make the final call. If your vehicle has a requirement for premium, don't go below that. If it can run fine on regular, do some testing and find out if 89 or 93 (what we get here in Chicago) will net you any benefits.
     
    Last edited: Aug 9, 2009
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