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Thread: Best AFR

  1. #1

    Default Best AFR

    I have an '89 Jeep with a 4.2L 285. I installed a Sniper 2300 on it, and I'd like to get the best fuel mileage on it. What should I set my AFR to? Hope someone can help.

  2. #2
    Join Date
    Dec 2009
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    Connecticut
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    http://documents.holley.com/199r10485rev1.pdf (Holley 534-201 Stand-Alone WBO2 Sensor Kit - Suggested Air/Fuel Ratios, Page 6)
    https://edelbrock-files-v1.s3.amazon...ers-manual.pdf (Read pages 4-10 of this Edelbrock EFI tuning manual, it's very good.)
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: Dominator MPFI & DIS, A/C, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/X-pipe/shorty headers, 100HP progressive dry direct-port NOS, 160A 3G alternator, Optima Red battery, LenTech Strip Terminator wide-ratio AOD/2500 RPM converter, FRPP 3.31 gears, Cobra Trac-Lok differential, Moser 31 spline axles, '04 Cobra 4-disc brakes, '93 Cobra booster & M/C, 5-lug Bullitt wheels & 245/45R17 tires.

  3. #3

    Default

    So from what I read, if I want to lean AFR, it's at 13 and I want to go to 14.5-15, I have to advance the timing a bit. I'm at 8, let's say go to 10, is that the way I make it work? Can I use a vacuum gauge? When I change the AFR, will it change the vacuum? I have to advance timing with the vacuum gauge? It has a stock ignition system. Thanks again for your time.
    Last edited by Rdoyle; 05-14-2018 at 10:58 PM.

  4. #4
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    I think you need to hire a professional tuner.
    Remember, the only thing this EFI system self-tunes, is the Base Fuel Table, via the Learn Table.
    You're responsible for everything else, especially the Target A/F Ratio Table & the Base Timing Table.
    A dynamometer is the only real way to determine the optimum ignition timing for your performance engine.
    Most people research it, or just "know" what their engine needs or likes. Especially if it's a popular engine.

    (Please don't type your posts like you're texting. It takes me a long time to edit it. At least use Spell Check before posting.)
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: Dominator MPFI & DIS, A/C, Spal dual 12" fans/3-core Frostbite aluminum radiator, Pypes dual 2.5" exhaust/X-pipe/shorty headers, 100HP progressive dry direct-port NOS, 160A 3G alternator, Optima Red battery, LenTech Strip Terminator wide-ratio AOD/2500 RPM converter, FRPP 3.31 gears, Cobra Trac-Lok differential, Moser 31 spline axles, '04 Cobra 4-disc brakes, '93 Cobra booster & M/C, 5-lug Bullitt wheels & 245/45R17 tires.

  5. #5
    Join Date
    Oct 2017
    Location
    Los Angeles
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    297

    Default

    If I were you I would leave the Sniper as is. Let the ECU Learn for a while as it will adjust to your engine and driving habits. Also, I would start watching videos on YouTube about tuning a Holley Sniper. There are some great videos that will help you, and while your learning the software on the computer let the sniper learn.

    Also, make a copy of your configuration file and start playing around with the copied GCF. Always, keep a good GCF on file so you can upload it back to the ECU in case your tune of your copied GCF file is a bad tune or the engine runs poorly.

    To advance your timing the tool you need is a timing light, not a vacuum gauge. Vacuum gauges are generally used to tune a carburetor, so you don't need a vacuum gauge. The handheld unit will tell you how much or little vacuum the engine produces for your information.
    Last edited by RPnova; 05-15-2018 at 01:59 PM.

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