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Setting up/Re-designing a Fuel and Ignition Table.

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  • dieselgeek
    replied
    Funny, but I looked at the top of the table and saw 95 and 105, no 100, which is where I'd like to have more resolution. Scott has kinda smirked at me about this this but I'd like to have more tunable data points around the low TPS cruise part of the map and the WOT parts.
    I set it up that way on purpose, as you tend to see WOT atmospheric pressures between 97ish and 103kpa. You can definitely and easily add another row in between, but make sure not to change the 95 and 105 lines. I did that to make sure we had the tune spot on and so it would stay that way as you climb a mountain pass at WOT, the engine doesn't get into an area of the map that's too lean or rich.

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  • CDMBill
    replied
    Funny, but I looked at the top of the table and saw 95 and 105, no 100, which is where I'd like to have more resolution. Scott has kinda smirked at me about this this but I'd like to have more tunable data points around the low TPS cruise part of the map and the WOT parts. I haven't tried that to see if its possible but that is where the action seems to be on a street strip car, or even maybe a Power Tour every other week car like yours.

    Oh and adjusting fuel and spark tables while driving by yourself is like texting while driving. It may fell important but you may not live long or prosper.

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  • TheSilverBuick
    replied
    Cool! I haven't tried leaning it out until it mis-fires, but it is idling with a steady 14:1 AFR. I still have to do some timing optimization at idle still. I modified my rpm bins too some more to change the influences at idle to steady the idle. My first tank of gas heading east will probably have the most changes made to the tune on the fly, hope to have that part dialed in by then. Not much between Ely and Delta.

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  • dieselgeek
    replied
    Situations like yours are exactly why the MS guys came up with "adjustable VE bins" - go for it!

    The only thing I'd caution is, make sure you reset your idle by doing the old "lean it out until it misfires, then richen up until smooth idle" with the engine warm. A lot of times, guys note lower vacuum with a camshaft change, but don't realize they'll pick up a couple more inches by making sure they're running the proper AFR.

    Most of the stuff I work on has HUGE exhaust and HUGE cam, so the AFRs do not register anything but "lots of oxygen" at idle - hence, I tune idle almost alway by ear/feel trying to maximize vacuum there.

    Just get her close, keep track of economy on the trip here, then we'll have a blast tuning all week trying to knock that MPG figure up a couple clicks!

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  • milner351
    replied
    That maybe the best thing about EFI set ups like yours - constantly knowing whats going on in the engine - and being able to make live adjustments that don't require dumping fuel on the intake! Drive safely my friend! Don't spend too much time staring at the laptop!

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  • TheSilverBuick
    replied
    I believe I'm coming in via I-70. Same route I towed the Javelin.

    As for the fuel table, it should go uber rich if nothing else, that's what happens when you climb elevation. I do have an A/F gauge I want to install, but yes I will have my laptop riding shotgun and unless it's like Vegas or LA traffic climbing that hill I'll be watching the engine stat's going up, as well as datalogging it either way.

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  • milner351
    replied
    Randal - I don't see anything wrong with your propsed mapping strategy - but I'd like to hear Scott's input as he has infinitely more experience than I do.

    Can you set up a warning display to alert you if you are running at a "dangerously" lean condition so you can pull over and make some adjustments? I'm assuming you're going to have your trusty laptop on the seat as you drive this monster....

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  • Bamfster
    replied
    Are you coming the northern route?

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  • TheSilverBuick
    replied
    Luckily for me, once I get it set here, my baro calibration should still hold true and maintain AFR's even at "low" elevation At least I don't have to spill any fuel, nor turn the car off, nor even pull over!


    Also, I'm interested to see how my car does on that 11,000+ft pass. My Centurion hated it with the Q-jet. I'll be data logging that one just to see how low the air pressure gets and to capture if my car freaks out.
    Last edited by TheSilverBuick; September 1st, 2011, 03:18 PM.

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  • Bamfster
    replied
    Heck, I thought I had some figuring to do .... I settled on 5 steps richer on the jets and see how it does.

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  • TheSilverBuick
    started a topic Setting up/Re-designing a Fuel and Ignition Table.

    Setting up/Re-designing a Fuel and Ignition Table.

    After successfully datalogging the trip to work I can see I'm using less than 50% of my old VE/Spark table because the engine doesn't pull enough vacuum to use the lower half of the table. So time for a re-design to give me better resolution in the area I do have vacuum.

    So I attached two tables, one is my old one with the MAP/Baro pressures fairly evenly distributed along the y-axis and one I'm going to change too, which has more bins above 60 since this idles at 62 and cruises at 65, and any more loaded up only raises the number (increases the atmospheric pressure in the intake).

    So here is my old VE table. The 60 is halfway up the side, so essentially everything below that isn't used except when coasting in gear and the fuel can be cut down quite a bit.
    Click image for larger version

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    What I'm proposing going to. Which gives me more resolution on the y-axis in the area that I'm actually operating in. (ignore the fueling numbers, they aren't adjusted yet)
    Click image for larger version

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    So I guess the question is there any issues with setting it up this way? With the 2nd baro sensor I shouldn't run into an issue when I go to lower elevation it shouldn't go much below 60 (MAP/Baro) even at idle or cruise. I'm looking at using the same x and y numbers for the ignition advance tables.
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