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Hot Rods Air-Fuel Ratio Meter

Discussion in 'The Hokey Ass Message Board' started by earlymopar, Jul 11, 2019.

  1. earlymopar
    Joined: Feb 26, 2007
    Posts: 1,016

    earlymopar
    Member

    I'm interested in what others may have and / or may recommend regarding a reasonably-priced air-fuel ratio meter (not a dash-mounted gauge but a hand-held meter).

    Thanks much,

    - EM
     
  2. squirrel
    Joined: Sep 23, 2004
    Posts: 43,196

    squirrel
    Member

    Do you intend to add a bung for an O2 sensor, or do you want to just poke a sniffer into the tailpipe?
     
  3. NAES
    Joined: Dec 24, 2008
    Posts: 434

    NAES
    Member

    I have used the AEM unit in the past but it's a dedicated dash mounted gauge, not a handheld. Seemed to work just fine but I never really scienced the deal out.
     
  4. Atwater Mike
    Joined: May 31, 2002
    Posts: 9,701

    Atwater Mike
    ALLIANCE MEMBER

    JUST ADJUST TO A 15:1 MIXTURE...:D

    Exhaust Gas Oxygen (ego meter) LOL Ego meter?
    Little 'headroom' for the good lookin' guy?
     
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  5. Truck64
    Joined: Oct 18, 2015
    Posts: 3,450

    Truck64
    Member
    from Ioway

    I looked a while for a used Innovate LM-1, these come up for auction now and then. Depends on what you mean by inexpensive. The LM-2 is around $225 new, it does double duty as an OBD-II scangauge for late model off-topic cars and trucks with an adapter cable.

    I found it easy to use and reliable. Many carburetors aren't setup anywhere close to where they might be. If you drive very much it should pay for itself fairly quickly. One long road trip for sure.
     
    dan31 likes this.
  6. sdluck
    Joined: Sep 19, 2006
    Posts: 2,178

    sdluck
    Member

    Correct Timing and fuel mixture go hand in hand.
     
    Truck64 likes this.
  7. Mike VV
    Joined: Sep 28, 2010
    Posts: 1,560

    Mike VV
    Member
    from SoCal

  8. Kan Kustom
    Joined: Jul 20, 2009
    Posts: 2,287

    Kan Kustom
    Member

    I am interested in what is available also. With this many guys on this forum, there is a lot of R and D that has been done with different experience and equipment.
     
  9. lumpy 63
    Joined: Aug 2, 2010
    Posts: 923

    lumpy 63
    ALLIANCE MEMBER

    I was taught to read spark plugs.
     
  10. gimpyshotrods
    Joined: May 20, 2009
    Posts: 16,140

    gimpyshotrods
    Member

    With today's modern fuel, reading plugs is far from accurate, and borders on impossible.

    You were taught with fuel that no longer exists.

    I have cars out there that are perfectly tuned, 500-times-a-second, for mixture and timing, that show little or no deposits on the porcelain, in 1000 miles.

    If they did show anything but a faint deposit, it would be a sign of malfunction.

    If you are still seeing the same deposits that you have all along, you are leaving both efficiency AND performance on the table.
     
    Texas Webb, dan31, DesmoDog and 3 others like this.
  11. lumpy 63
    Joined: Aug 2, 2010
    Posts: 923

    lumpy 63
    ALLIANCE MEMBER

    You are assuming that all the cars I work on run pump gas . And not really seeing how air fuel meters and 02 sensors are HAMB friendly.
     
  12. gimpyshotrods
    Joined: May 20, 2009
    Posts: 16,140

    gimpyshotrods
    Member

    As you are me.

    Non-pump gas is not the same, either, and my point is still correct.

    I don't see how today's interstate highways are HAMB friendly, but here we are.

    Today's fuel, and all other automotive chemicals, for that matter, are not HAMB friendly, if we are to extend your pedentry forward.
     
  13. lumpy 63
    Joined: Aug 2, 2010
    Posts: 923

    lumpy 63
    ALLIANCE MEMBER

    Damn...now i gotta go find a dictionary....:rolleyes:
     
    HemiDeuce, Texas Webb, dan31 and 3 others like this.
  14. brigrat
    Joined: Nov 9, 2007
    Posts: 4,783

    brigrat
    ALLIANCE MEMBER
    from Wa.St.

    Their about as traditional as Bluetooth and there's plenty of pages on that subject...........................smileyface
     
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  15. I used an Innovate on my car for Drag Week, then moved it to another off topic Italian car. I liked it so much I got another one for my Model A after I rebuilt the motor.

    As long as you use an analog gauge it does not stand out as too modern.

    Great tool, plus gauges are cool.
     
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  16. gimpyshotrods
    Joined: May 20, 2009
    Posts: 16,140

    gimpyshotrods
    Member

    Tradition is just peer pressure from dead people.
     
  17. gimpyshotrods
    Joined: May 20, 2009
    Posts: 16,140

    gimpyshotrods
    Member

    I don't leave the gauge or sensor in the car. Once tuned, it all comes out.
     
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  18. scrappybunch
    Joined: Nov 16, 2011
    Posts: 280

    scrappybunch
    Member
    from nj

    I've had the F.A.S.T. handheld for several years. I sure wish I had it 40 yrs ago!
    What is amazing, engines that were so called professionally dyno tuned, were way off. Seen plenty of carbs cruising at 60mph with 11 :1 ratios. Full throttle even richer. I would get them to 15:1 at cruise, and the mpg would increase by 8 mpg.
    Oh, and the Q-jet is an amazing street carb, part throttle mixture adjustment is simple as turning a screw.
     
    gimpyshotrods likes this.
  19. GaugePod.JPG This is in the off topic car, but it blends right in.
     
  20. Truck64
    Joined: Oct 18, 2015
    Posts: 3,450

    Truck64
    Member
    from Ioway

    That was exactly my experience, I experimented and found a carbureted OHV V8, just like the literature claims should be able to cruise on level ground at around 15.5 to 16.5 AFR without misfire or running hot. If it won't, there's something else going on and needs investigating. Another area of surprise for me was discovering the ignition timing is normally in the 45° to 50° BTDC area at cruise, maybe more. Vacuum advance was the only way to achieve this before computers took over ignition duties.

    The trick to optomizing performance and respectable economy is to measure and re-adjust when necessary the AFR while under acceleration/load. Lean AFRs under acceleration or load is bad stuff will roast valves, too much timing will put holes in pistons or maybe bust a ring land. So using 21st century tools on old iron doesn't bother me. The old timers only figured it out by trial and error, sometimes only by breaking stuff. I don't need or want to re-invent the wheel.

    Reading spark plugs is very tricky and takes experience, getting good feedback from an O2 sensor gave me the confidence to push things much farther out than I otherwise would have and also discover maybe those engineers knew what they were doing, it's amazing how much fuel is wasted straight out the tailpipe without a good tune-up. I honestly didn't think it was possible for an engine to run "OK" and still be that far off the beam.

    Somebody here mentioned they had a really good side gig going in the '70s by tuning carburetors for customers, and they were very happy. I believe it.

    Jetting and the different carb circuits and how they interact with each other is very commonly misunderstood. The AFR should to be "curved" to supply the correct quantities of fuel at idle, cruise, and wide open throttle sort of similar to the way a distributor is with ignition timing.
     
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  21. scrappybunch
    Joined: Nov 16, 2011
    Posts: 280

    scrappybunch
    Member
    from nj

    Can I give you a virtual hug?
    Of course not.

    But it is cool that a post 1965 manufactured tool will make for better tuning.
     
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  22. Truck64
    Joined: Oct 18, 2015
    Posts: 3,450

    Truck64
    Member
    from Ioway

    I think I have the confidence now to tune a carb/engine by only reading the plugs. Even using an O2 sensor, there's no getting around the fact the plugs are a window to what's really going on inside the engine, they don't lie if you know what to look for. It's possible to have an over reliance on sensors, tuning is an art as well as science.

    The AFR meters are only an average of four cylinders typically. They also only read O2, so they can give confusing results. For example if there is an ignition defect or spark plug is misfiring, an O2 sensor will indicate a false lean condition. There also can't be any exhaust manifold leaks, etc.
     
    Just Gary likes this.
  23. scrappybunch
    Joined: Nov 16, 2011
    Posts: 280

    scrappybunch
    Member
    from nj

    It's just like any other tool in your box. There is a time and place for it.

    Now if you really need to tune, five gas analyzer is the way to go.
     
    Truck64 likes this.

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