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anyone any expiereance with air fuel ratio graphs

Discussion in 'Motors' started by Mattius, 31 May 2006.

  1. Mattius

    Wise Guy

    Joined: 18 Oct 2002

    Posts: 2,092

    Location: Edinburgh

    i had my dads fancy computer doo dah set up to my spitfire tonight and checked the afr on it ranging from 800rpm to 3500rpm, got a kinda unexpected result, heres the graph.
    [​IMG]

    it basically starts at 22.39 afr then goes down to 12.9 afr at 3500.

    now this tells me its running super lean then goes to rich on acceleration.
     
  2. Simon

    Capodecina

    Joined: 21 Oct 2002

    Posts: 24,373

    Location: Berks / Moscow

    That's a Innovate LM-1.

    Probably needs calibrating via a free air calibration. Lambdas voltage doesnt change much either which is odd. Sure it's set up properly?
     
  3. Mattius

    Wise Guy

    Joined: 18 Oct 2002

    Posts: 2,092

    Location: Edinburgh

    hmm maybe i need to re-calibrate yeap its the innovate lm-1.

    the voltage wouldn't change as it blew the cigarette lighter fuse in my spitfire to i had to use the external power adapter.
     
  4. Mattius

    Wise Guy

    Joined: 18 Oct 2002

    Posts: 2,092

    Location: Edinburgh

    right re-calibrated and got a much better readout, still not too sure what i can do to improve it.
    here is the new readout.
    [​IMG]

    the peaks are 1,000 - 2,000 - 3,000 and 6,000 rpm

    as you can see at 6,000rpm the engine is running perfectly.
     
  5. Simon

    Capodecina

    Joined: 21 Oct 2002

    Posts: 24,373

    Location: Berks / Moscow

    What are you using to read the engine speed?

    It seems odd that the LM output voltages are not changing either
     
  6. Mattius

    Wise Guy

    Joined: 18 Oct 2002

    Posts: 2,092

    Location: Edinburgh

    engine speed is just done by matching the revs to the time.

    voltages won't change its being powered by an charger as my car won't power it.
     
  7. Simon

    Capodecina

    Joined: 21 Oct 2002

    Posts: 24,373

    Location: Berks / Moscow

    Doesn't look pefect to me. It looks far too lean. infact 22.39 is the max lambda it will read so something isn't right.

    Check out http://www.innovatemotorsports.com/ And also have a look on the forums.
     
  8. Mattius

    Wise Guy

    Joined: 18 Oct 2002

    Posts: 2,092

    Location: Edinburgh

    mines only at 1.4 lamda, the top one is using afr rather than lambda
     
  9. Jonnycoupe

    Capodecina

    Joined: 19 Oct 2002

    Posts: 13,948

    Location: N.Warks

    Hes on about the lambda voltage to show the AFR not the power supply voltage.

    An engine wont run when its that lean, i suggest you make sure your calibrating the sensor correctly.
     
  10. Mattius

    Wise Guy

    Joined: 18 Oct 2002

    Posts: 2,092

    Location: Edinburgh

    according to the manuals 1.4 lambda isn't that bad. where are the figures of 23 coming from?
     
  11. Jonnycoupe

    Capodecina

    Joined: 19 Oct 2002

    Posts: 13,948

    Location: N.Warks

    [​IMG]

    There

    and 1.46 lambda is 14.7 x1.46 = 21.5 ish on the other graph.

    i take it the other 5 outputs arn't being used and thats whats confusing matters.

    Id throw that manual away if its suggesting a lambda of 1.4 is okay.

    You want lambda of 1 at idle and cruise and about 0.85 at full throttle.
     
  12. Mattius

    Wise Guy

    Joined: 18 Oct 2002

    Posts: 2,092

    Location: Edinburgh

    yeah im only using the one input. hmm back to the drawing board with the engine tuning then.
     
  13. Simon

    Capodecina

    Joined: 21 Oct 2002

    Posts: 24,373

    Location: Berks / Moscow

    Sounds like you need to do some research.

    You need to understand what you are doing before even thinking about tuning an engine
     
  14. Mattius

    Wise Guy

    Joined: 18 Oct 2002

    Posts: 2,092

    Location: Edinburgh

    oh i know how to tune the engine, but this new gauge thing is baffling me.
     
  15. Simon

    Capodecina

    Joined: 21 Oct 2002

    Posts: 24,373

    Location: Berks / Moscow

    Ok cool, try looking on those forums. They helped answer all my questions with my LC-1