switching from 87 to 91 - Page 3
  1. Welcome to 9th Gen Civic Forum : 2012 Honda Civic Forums - 9th Generation – General discussion forum for 9th Gen Civic

    Welcome to 9th Gen Civic Forum : 2012 Honda Civic Forums - 9th Generation - a website dedicated to all things 9th Gen Civic.

    You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, at no cost, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, Join 9th Gen Civic today!
     
+ Reply to Thread
Page 3 of 7 FirstFirst 12345 ... LastLast
Results 21 to 30 of 70
Like Tree53Likes

Thread: switching from 87 to 91

  1. #21
    Truck? What truck?! scottyrocks's Avatar
    Join Date
    Nov 2012
    Location
    Isle of Langerhan, NY
    Posts
    27,050
    Quote Originally Posted by Roadcourse View Post
    Why is octane being raised? To get more hp out of little bitty engines?
    No, short answer is to avoid timing retard and less efficient running. R18s are tuned for 91, but the ecu makes it run 'acceptably,' if not optimally, with 87.
    Roadcourse and Silver2Coupe like this.
    'Three pedals or bust!'
    'Come for the cars. Stay for the people.'
    'Part of having the right to free speech is knowing when to not exercise it.'
    ‘Say what you mean, mean what you say, but don’t say it mean.’
    9th Gen Civic POP Crew #6 Hidden Content
    9th Gen Civic LI Crew#1 Hidden Content

  2. Remove Advertisements
    9th Civic
    Advertisements
     

  3. #22
    Platinum Member Silver2Coupe's Avatar
    Join Date
    Nov 2012
    Location
    Illinois
    Posts
    4,053
    Quote Originally Posted by Roadcourse View Post
    Why is octane being raised? To get more hp out of little bitty engines?
    MPG is why. They have to raise the compression to make the engine more efficient and with out the octane being raised it becomes less efficient. 87 octane is for a 8 to 1 compression engine and even with the added timing needed to make power Knock is less of a issue. With a 10.6 compression engine it is mandatory to run efficient. What happens is Knock retard which lower power and efficiency. 87 octane is still in the Civic operating range but as it detunes it can cause damage when it cant detune any more. MBT is what its all about.
    Roadcourse and scottyrocks like this.
    Civic POP Crew #3

  4. #23
    Platinum Member Silver2Coupe's Avatar
    Join Date
    Nov 2012
    Location
    Illinois
    Posts
    4,053
    Quote Originally Posted by scottyrocks View Post
    No, short answer is to avoid timing retard and less efficient running. R18s are tuned for 91, but the ecu makes it run 'acceptably,' if not optimally, with 87.
    Not optimally but acceptable but that also depends on conditions. Compression is the thermostat and for every degree of timing there is a pressure buildup from 20 to 40 psi per degree. Having 32 degrees timing is optimal because just like riding a bike the most use of the fuel is being used and not wasted. Remember pedaling a bike and you stand up forcing the pedals at the same degrees of MBT which the most efficient. If the fuel is more resistant to knock more timing and be added which the computer does automatically and theoretically making more power.
    Roadcourse and scottyrocks like this.
    Civic POP Crew #3

  5. Remove Advertisements
    9th Civic
    Advertisements
     

  6. #24
    Big Pimping!!! qingcong's Avatar
    Join Date
    May 2013
    Location
    Virginia
    Posts
    763
    Quote Originally Posted by Jesstzn View Post
    Good cuz if you rely on the iMid that's not the way.

    Well, without a GPS to measure miles and an accurate gas measuring system, we don't know if our calculations are off or if iMid is off.
    2013 SOP Si Sedan

    Hidden Content

  7. #25
    Big Pimping!!! qingcong's Avatar
    Join Date
    May 2013
    Location
    Virginia
    Posts
    763
    Quote Originally Posted by Spunjer View Post
    and the research cotinues (i'll just write it here so i don't forget, lol):
    marathon - this one was the worst so far. i got 31.8 mpg on their 93 octane
    valero - filled up with this brand right after marathon, and i was pleasantly surprise it gave me the best mpg at this point. 34.8
    right now, i have a exxon. after that, shell....


    Silver has also mentioned that fresh tanks of gas are more fuel efficient as stuff hasn't gotten a chance to separate. He'll know more, but I think as the gas gets older in the tank, the MPGs get worse. So unless you're doing the same route everyday and filling up in the same intervals, the results will likely vary even if you use the same brand.
    Silver2Coupe likes this.
    2013 SOP Si Sedan

    Hidden Content

  8. #26
    Question Authority Roadcourse's Avatar
    Join Date
    Nov 2011
    Location
    Dixie
    Posts
    6,424
    Thanks. Learned something today. Didn't realize the R18 needed more than 87. The manual says 87 or higher. There's an official hint from Honda. How long does it take the ecu to learn a different tank of higher octane fuel? Hate to be negative but we will prolly be raped on price for the higher octane when it likely only costs the suppliers a nickel a gallon or so. Vote this bastard in.
    Silver2Coupe and scottyrocks like this.
    Question authority.

    Only the knife knows what goes on in the heart of the pumpkin......unknown

  9. #27
    Big Timer!!!
    Join Date
    Nov 2013
    Location
    Omaha, NE
    Posts
    249
    Quote Originally Posted by qingcong View Post
    Well, without a GPS to measure miles and an accurate gas measuring system, we don't know if our calculations are off or if iMid is off.
    I think the odometers in our cars are fairly accurate. To calculate my MPG, I squeeze every last drop I can into my tank and divide my miles on that tank by the gallons added. This eliminates the chance that the fuel gun stopped filling too soon which often happens and would cause a higher than accurate MPG for a tank. My imid has been about 2MPG higher than my actual MPG. I am also getting better MPG from Phillips 66 gas over BP gas. Best tank = 32.7 Worst tank = 26.3
    2013 ASM Civic Si - Stock
    2013 Ninja 300 EX

  10. #28
    Nooblets Spunjer's Avatar
    Join Date
    Feb 2014
    Posts
    71
    yeah, pretty much the same route everyday. 36 miles round trip from home to work. granted, it's not EXACTLY the same since i have to consider going to town, and some other menial trips. but actually those are minor. i figure it won't be accurate, but at least it will give me a roundabout idea on which brand gives me a better MPG. as roudcourse mentioned, we are prolly gonna get raped with the price here soon (summer), any help i can get to squeeze my gas money would be alright, lol.as far as what The Guru (silver2coupe) mentioned, i did notice that the gas degrade the longer it stays in the tank. the last 150 miles seems to peter out a bit.another thing i forgot to mention; the mileage i've been getting above are more on the conservative side, meaning, i'm going by the iMid, which, as we all know is not as accurate as calculating it (mileage travelled divided by gas used,). on the valero fill up, using the calculation method, my MPG was actually 38.5! not too shabby, really...
    Silver2Coupe and qingcong like this.
    2013 Honda Civic EX-L 4 Dr Sedan W/ Navi
    R.I.P. 2004 Honda Accord EX-LHidden Content

  11. #29
    Community Director Scione's Avatar
    Join Date
    Sep 2012
    Location
    Mount Olympus
    Posts
    3,405
    This is what I get from driving to work this week. E87 all the way!


  12. #30
    Big Pimping!!! qingcong's Avatar
    Join Date
    May 2013
    Location
    Virginia
    Posts
    763
    Quote Originally Posted by 2013SilverSI View Post
    I think the odometers in our cars are fairly accurate. To calculate my MPG, I squeeze every last drop I can into my tank and divide my miles on that tank by the gallons added. This eliminates the chance that the fuel gun stopped filling too soon which often happens and would cause a higher than accurate MPG for a tank.

    Isn't it not recommended to overfill the tank?

    The odometer's reading will vary over the lifetime of the tire. When the tire gets worn down and the diameter gets smaller, the MPGs will start calculating higher because the car thinks you're going more miles due to more tire revolutions.

    As for measuring the gas, I think that each individual tank will vary based on when the pump shots off, but I would think that over time the variations average out, making the total amount of gas used over the lifetime of the car fairly accurate. It's just hard to verify the accuracy of a single fillup without more sophisticated equipment.
    2013 SOP Si Sedan

    Hidden Content

+ Reply to Thread
Page 3 of 7 FirstFirst 12345 ... LastLast

Quick Reply Quick Reply

Register Now

Please select your insurance company (Optional)

Similar Threads

  1. Switching to a different state license?
    By usaf9thgen in forum Water Cooler
    Replies: 8
    Last Post: 02-04-2013, 09:15 PM
  2. Help with Switching Wheels
    By BayLyfe in forum Wheels and Tires
    Replies: 7
    Last Post: 09-08-2012, 04:37 AM

Posting Permissions

  • You may post new threads
  • You may post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Powered by vBadvanced CMPS v4.1.2