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Thread: ETC Table Question

  1. #1
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    ETC Table Question

    Hi -

    What exactly is "effective area inch2"? Is there a way to log/tune this table? I noticed there is a built in calculator for ETC Effective Area.

    Aside from changing TB, any reason to tune these tables? If so, how would you go about doing it?

    Thanks!
    TB Pic.PNG

  2. #2
    Senior Tuner CCS86's Avatar
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    Whether you should touch it or not depends on who you ask.

    I tune it heavily on a forced induction car.

    Effective area is a value that helps the PCM figure out how far to open the throttle. Pedal position and RPM give you a driver demand torque. Torque inverse tables turn that into a desired load, which gets converted into a desired MAF rate. And finally, the desired MAF gets converted into an ETC angle through these throttle body tables.

  3. #3
    Senior Tuner veeefour's Avatar
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    Quote Originally Posted by CCS86 View Post
    Torque inverse tables turn that into a desired load, which gets converted into a desired MAF rate. And finally, the desired MAF gets converted into an ETC angle through these throttle body tables.
    Nope, LOAD is calculated from SD, SD model works in conjunction with MAF.

    Torque gets calculated form LOAD. Torque model is only a virtual dyno.

    Desired Torque is compared to ETC model and the TB angle is set.

  4. #4
    Senior Tuner CCS86's Avatar
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    Quote Originally Posted by veeefour View Post
    Nope, LOAD is calculated from SD, SD model works in conjunction with MAF.



    What's your basis for this?

    In my observation SD is used to estimate MAP, and act in a predictive sense to fill in the MAF sensor's transient error/lag.





    Quote Originally Posted by veeefour View Post
    Torque gets calculated form LOAD. Torque model is only a virtual dyno.

    Desired Torque is compared to ETC model and the TB angle is set.


    Describe this "comparison". You are saying that somehow the TB tables directly convert torque to an ETC opening. I don't agree.

  5. #5
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    Being new to the Ford world I'm full of dumb questions but is it possible both of you are right and it just depends on the ECM code?

    Mines a 2004 F150 with a 5.4 3V motor if that makes a difference.

    In the scanner I have two MAP PIDS but both always show zero. I've noticed that some mustangs will read calculated map but mine doesn't. I've added a GM one bar to log map though. Anyways I notice if I change maf airflow to voltage it changes the "Airload" calculations without changing "engine load". In fact they were really far apart from each other. Since than I've adjusted my SD table. I'd just take my lambda error percentage and flip it around. So if I showed -3.5 in a cell I'd change it to +3.5 before id paste special into my ECM file. I'm not 100 percent sure but I really didn't notice any fueling changes. What I did notice is my "Air load" and "Engine Load" are now matching.

    I have an idle problem. Truck runs good but idle it shakes the whole truck. Yes it has thumper cams w/lock outs & imrc deleted but I feel it's an idle issue. Current idle is 800rpm. If I barely touch the throttle the engine smooths right out. If I lower idle to 700RPM and barely throttle it to 800RPM the engine smooths out. This leads me to believe it has to do with idle. I'm thinking tunning my etc table is what I need to do but I don't know what I should log, set up as a histogram, or really adjust.

  6. #6
    Senior Tuner veeefour's Avatar
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    CAI's are not worth the money - marginal gains for 2x higher IAT's no thanks. The only reason we use them is to fit something that OEM filter doesn't like bigger TB.

    COLD AIR? And here is where it gets confusing. How the hell aftermarket open filter element is called "cold" as you have lower IAT's with stock filter? Bollocks.

  7. #7
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    Weird I tried editing my question on the CAI and it deleted???

    Anyways, yes, I realize and agree that there not worth the money. I don't have the stock an this intake was purchased a long time ago by the previous owner. My question is though since the MAF is moved closer to the filter could that cause problems?

  8. #8
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    Well I changed intakes. The intake I went to is sealed and moved the MAF back towards the throttle body. It helped slightly with idle but what it helped the most with is transition fueling. AFR stayed more consistent between points. For Idle I started to throw more at it. I purchased a locked SCT X3 from ebay to do some datalogging. With that program I was able to log effective area, inferred manifold vacuum, and throttle body vacuum. I logged those two against TB position actual. I did this in open loop with torque control, airflow switch, IPC, and cylinder air prediction shut off. Once I had my values I used the TB calculator built in with HPT, turned everything back on, and flashed it. When I started the truck it idle hunted for a little bit and stabilized. The idle was 200 times better. Also, my idle learning actually started to go into the negatives. Vs before it would keep going into the positive. I adjusted the idle airflow down by what the LTIT were reading and idle is 99.9 percent perfect. I just have to work on the idle airflow in drive.

    Don't know if this is the right or wrong way to do things but so far no limp modes, wrench lights, or anything related.