Octane ratings

Discussion in 'General Discussion' started by shorty, Nov 22, 2014.

Car Parts
  1. shorty

    shorty Full Access Member

    Messages:
    2,054
    Likes Received:
    36
    Joined:
    Sep 1, 2012
    Location:
    Emory, Texas
    As most here know we old men are a little slow. In the Dallas area we get 93 octane for our trucks. Driving west to Abilene the max octane is 92 and by the time I get to Midland Texas it is 91 and at some stations it is only 90. I asked a number of people but got no answer. :dontknow: Last week I asked my son, the private pilot, and he said sure he knew why. I thought, oh yeah, here we go. He said when flying as one gains altitude he has to lean out the fuel mixture. Dallas is 430’ and Midland is 2,782’ about sea level. Duh, our engines, as well as any other, need to be leaned out as altitude increase and rather than incorporated that into our computers the "greedy" ole oil companies refine the gas leaner as the altitude increases. Yah, I could have Googled it but as I said, I am a little slow. I’m guessing Caveman is running 50 octane where he lives. :dontknow:
     
  2. Slitherbeast

    Slitherbeast Well-Known Member Supporting Member

    Messages:
    2,283
    Likes Received:
    35
    Joined:
    Sep 10, 2007
    Location:
    Alberta
    :bs::bs: Leaning out from altitude is done by the computer not by the gas pump!
    The area's without highend gasoline anticipate less highend vehicles. No sense providing 94 oct. if there are not enough customers. I think it is just simple marketing.
     
  3. shorty

    shorty Full Access Member

    Messages:
    2,054
    Likes Received:
    36
    Joined:
    Sep 1, 2012
    Location:
    Emory, Texas
    So there are NO "highend" vehicles in Denver Colorado? :dontknow: Bless his heart poor Caveman has been fooled all along thinking he had a "highend" truck. :chain:
     
  4. CaptnCrash

    CaptnCrash Full Access Member

    Messages:
    217
    Likes Received:
    38
    Joined:
    Jul 1, 2014
    Hmmm.. Well mixture control on our trucks as well as late model cars is handled by the O2 sensors and the engine computers. With carbs it was done far less accurately with metering rods and jets or diaphram based enrichment valves.

    Octane has ZERO to do with mixture richness other than higher octane can tolerate leaner mixes without detonation, it has to do with the difficulty you have in igniting the gas. Specifically the higher the octane the harder it is to ignite ! High octane fules are used where cylinder pressures or temps are higher to prevent detonation.

    Your private pilot has a little red handled lever / knob and an EGT guage that he uses to manage mixture since even fuel injected small aircraft piston engines are mechanically controlled and the mixture controller becomes the grey matter between the ears. The 100LL he uses in his airplane is a pretty cool blend and if you mix it 50/50 with unleaded premium makes for pretty good track fuel with carb'd engines. Lead is a tad tough on O2 sensors.

    Generally when octanes are lower at the pump over a larger area it's because of some green weenie rules like in CA you simply find it nearly impossible to find decent gas.

    I'd love to go back to the good old days when permium was 101 octane leaded and was 27.9 cents per gallon. Hell the 27.9 is only about 1/3 of what you pay now just for TAXES on gas. </soapbox> I'd even settle for 101 octane UNleaded now.

    --CC
     
  5. shorty

    shorty Full Access Member

    Messages:
    2,054
    Likes Received:
    36
    Joined:
    Sep 1, 2012
    Location:
    Emory, Texas
    Haha, could be in way over my head. Midland Texas is the heart and soul of oil country. EPA inspectors get thrown into the oil pit when they come inspecting so not sure the "weenie" rules have much effect in the oil mecca.

    Again, Google up octane and the altitude for different locals and there seems to be a trend in higher altitude and lower octane. :dontknow:

    I too remember .21 per gallon and drip was free. Started smoking at .21 per pack and quit at $1.25. Stopped drinking when 24 cans of Coors was $4.50 but back to the octane. I have no clue what it was at .21 cents per gallon. Guessing drip was around 60 or so as it did make most cars knock. Just can't tell any difference in 90 octane when motoring in West Texas from 93 here in Big D.
     
  6. oldcolt

    oldcolt Striker Heads and Cam Supporting Member

    Messages:
    2,771
    Likes Received:
    161
    Joined:
    Jul 14, 2008
    Location:
    Calgary, AB
    We are at 3500' here and can get 94 no problem. I think it just comes down to marketing in certain areas.
     
  7. sself510

    sself510 Full Access Member

    Messages:
    18
    Likes Received:
    0
    Joined:
    Aug 10, 2013
    I live in Odessa Tx, and I know of 2 places that carry high octane gas. There is a stripes off 1788 that carries 92 octane, and there is a gas station off of 1936 that carries 93 octane. Not sure of any places in midland, but there is a performance shop called MPH that carries race gas, both leaded and unleaded. I typically get 105 and mix it, just to make sure.
     
  8. redice2

    redice2 New Member Supporting Member

    Messages:
    1,228
    Likes Received:
    0
    Joined:
    Jul 30, 2006
    Location:
    upstate NY
    if in abilene go on 20 to clyde mobil station there has 93 octane :D
     
  9. bwellmaker

    bwellmaker Full Access Member

    Messages:
    297
    Likes Received:
    11
    Joined:
    May 22, 2006
    Location:
    Long Island NY
    UIH,

    Higher octane, the more it can be compressed before spontaneously it ignites.

    That being said, Lower octane at altitude because the air is less dense.

    B
     
    Last edited: Nov 22, 2014
  10. shorty

    shorty Full Access Member

    Messages:
    2,054
    Likes Received:
    36
    Joined:
    Sep 1, 2012
    Location:
    Emory, Texas
    What I figured. thanks
     
  11. shorty

    shorty Full Access Member

    Messages:
    2,054
    Likes Received:
    36
    Joined:
    Sep 1, 2012
    Location:
    Emory, Texas
    Can't PM you but I think you can PM me. I am in Mid/Odessa each month. Lets get together.
     
  12. redice2

    redice2 New Member Supporting Member

    Messages:
    1,228
    Likes Received:
    0
    Joined:
    Jul 30, 2006
    Location:
    upstate NY
    i will be in abilene during at least a couple of weeks in december :)
     
  13. shorty

    shorty Full Access Member

    Messages:
    2,054
    Likes Received:
    36
    Joined:
    Sep 1, 2012
    Location:
    Emory, Texas
    I can meet up on the 2nd of Jan as I will be going to Midland for that night and Sat the 3rd.
     
  14. redice2

    redice2 New Member Supporting Member

    Messages:
    1,228
    Likes Received:
    0
    Joined:
    Jul 30, 2006
    Location:
    upstate NY
    by then i am hoping to be back home here in NY. going down to clean up wife's family house and with any luck put it on market and make it back home by christmas.
     
  15. sself510

    sself510 Full Access Member

    Messages:
    18
    Likes Received:
    0
    Joined:
    Aug 10, 2013
    Ok, sounds good, you can shoot me a text @ (432)2609778. I should be available anytime.