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What air/fuel #'s do I want when tuning?

Discussion in 'General Tech and Maintenance' started by gocivicls, Dec 15, 2003.

  1. gocivicls

    gocivicls Senior Member

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    I am going to the dyno to tune my All-motor LS. I need to know what Air/fuel mixture I should shoot for. Is it 14.3:1 or what?????? Also do I try to obtain a level mixture across the power band??? In other words do I try to maintain the same # across the rpm's? I am tuning with a Generation 1 JDM S-AFC.
     
  2. K2e2vin

    K2e2vin Senior Member

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    i heard some "more powerful" na cars run like 13.9-14.5. it depends mostly on the fuel octane you are using.

    yes. you want the same a/f across powerband. in rare cases do they have different a/f across rpm band(usually turbo cars).
     
  3. phunky.buddha

    phunky.buddha Admin with a big stick Admin VIP

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    I would run a little richer just to be safe- 13.5:1 would be my target. If you're going to be on the dyno anyway, just shoot for max power and figure out what the a/f ratio is at max power, then run that a/f ratio across most of your rev range.
     
  4. gocivicls

    gocivicls Senior Member

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    When I find the A/F ratio for max power, I want it to be safe. What is borderline or what is too lean???? Ex. 13.0:1 or what???? I do not have a knock sensor so I want to get as close to lean as possible without the risk of detonation. :worthy:

    I am using 93 octane at the least.
     
  5. pissedoffsol

    pissedoffsol RETIRED

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    well, a/f isn't everything....

    timing has a LOT to do with detonation, as does the quality of fuel itself
     
  6. gocivicls

    gocivicls Senior Member

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    I really don't know that much about how I can tell if my ignition timing is way off or closer than I think. I know how to check it with a timing gun. But not how to put it at the proper degree to account for cam timing and the a/f mixture. In other words I don't know that much about tuning besides watching the a/f #'s and the hp and torque curves. Any advise feel free to lay it on me.
     
  7. pills_PMD

    pills_PMD Super Moderator

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    typically on an n/a car i will aim for 13.0:1 mixture across the board to get an even a/f ratio. then lean it out roughly 5% or so to see if 13.5:1 will do us any better... if power increases.. go a little leaner.
    however, near redline, i would never suggest going leaner than 13.5:1

    below is a short article i wrote on the basics for tuning hondata... it may help


    http://www.hondaswap.com/~pills/hondatatuning.html
     
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