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Thread: Injector End Angle Tuning

  1. #11

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    Quote Originally Posted by 81 TransAm View Post
    Yes, I tuned it when it was hot. When cold I run it a little richer until it warms up, and it seems to be happy this way.
    One way is do an Advanced 2D Table and an IEA Offset. X is RPM Y is PW. Make the first row your idle PW and 0 across. Then make the rows above that the difference in crank degrees (positive) between that PW and your idle PW. Doing it this way would keep your PW beginning always right at exhaust close regardless of how wide the PW is (cold start or AE). Of course above a certain RPM you DON'T want to do this. Just keep those columns 0.

    You know what would be really nice? If Holley had a "start PW at exhaust lobe close" check mark on the IEA table. That would eliminate doing work on two 2D Tables. Also have a spot for "until xxxxxx RPM" where it just switches back to the table. Another option is why not have the IEA table Y axis as pulse width instead of MAP?
    Last edited by allan5oh; 06-10-2018 at 03:20 PM.

  2. #12

    Default IEA Tuning: MAP vs IPW

    Does it not make a heck of a lot more sense to use IPW (injector pulse width) as the y axis on the IEA table? The MAP sensor always lags what is actually happening in the port. If it didn't there would be no need for TPS or MAP AE. However IPW does account for AE! Let me give you an example:
    - Engine has an exhaust valve close of 10° ATDC.
    - Tuner has determined he wants to avoid injecting fuel while the exhaust valve is open at all costs lower in the power band to avoid fuel during overlap. See this thread: https://forums.holley.com/showthread...d-Angle-Tuning
    - 1.9 msec IPW correlates to 9.7 crank degrees at idle.

    So to inject at the end of overlap ignoring port velocity:
    Valve closes at -170 (Holley IEA table reference)
    IEA set at -160 due to 10° PW

    Now what happens when the throttle is pushed? TPS AE kicks in and adds fuel but the MAP sensor hasn't responded. We could easily have 10° to 20° of injection off idle or even more during overlap. A Y axis of IPW fixes all of this. On a well tuned engine (base fuel and AE) the IPW is a better indication of what is going on in the ports during transients. Steady state does not matter because the MAP sensor always catches up.

    A question. At the same rpm say 5000. If VE increases this also means port velocity increases by the same amount correct?
    Also, why doesn't the IEA calculator have port cross section? I would think this is vital for calculations.

  3. #13
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    Like everything about tuning, compromises have to be made. TPS EA does add fuel but my fuel table is tune pretty good and I use very little TPS AE. Your idea does sound interesting, I may try it out. I have not found a way to change the X or Y axis.
    Last edited by 81 TransAm; 06-13-2018 at 07:20 PM.

  4. #14
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    After doing some testing using an Advanced 2D Table for IEA Offset I can say it seems to work very well. I always had a very stable AFR trace at cruise. Now it is even a little better. It flatlines at my target of 14.7 AFR. It can sit there for 10 to 30 sec on a flat road before it blips a little then back to flatline. On my display I put IEA & IPW side-by-side so I could see the IEA change as the IPW increased as load increased. On my table, I didn't worry about an IPW over 10 ms and anything over 3000 RPM. All I wanted over these settings was to get the fuel in the cylinder before the intake valve closed. This is what I ended up with.
    Allan5oh, very good suggestion, it work well for me and I'm going to keep doing it this way.
    EDIT: To hard to see screen shot, so I added my Global File in case anyone wants to see it. I'm using V5.
    Last edited by 81 TransAm; 06-17-2018 at 01:37 PM.

  5. #15

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    Thanks for following up. What about tip-in off idle and cruise? I think that's where the biggest gain is optimizing IEA. Did you notice warmup was a bit better? You might be able to pull some coolant enrichment out. A datalog of tip-in would be nice too. It seems like there's always a lean blip (slight misfire).

    Another thing you could do is have two Advanced Tables and have them overlap on the X axis. I haven't tried it yet. More resolution.

    There's now three things they can improve with their IEA scheme. A lot of tuning issues can be related to sub-optimal IEA settings. I wish Mr. S2H would chime in. He doesn't want to give away all his secrets though.
    Last edited by allan5oh; 06-17-2018 at 03:09 PM.

  6. #16
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    Quote Originally Posted by allan5oh View Post
    A lot of tuning issues can be related to sub-optimal IEA settings.
    I agree. It made a big difference in my tune.
    My cold starts have always been very good. But it does feel a little better if I start it cold and put it in gear right away, without waiting for it to warm up a little. On a steady cruise when I go to accelerate a little, you can see the IEA increase as the IPW increases. With the old setup, it would not have increased the IEA under these conditions.

  7. #17

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    Just wanted to add, I don't think the Y axis needs to be anything above 20 IPW:
    @ 5000 RPM 100% DC is 24 msec
    @ 6000 RPM 100% DC is 20 msec
    @ 7000 RPM 100% DC is 17.1 msec
    @ 8000 RPM 100% DC is 15 msec

  8. #18
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    I just looked at some datalogs and my WOT IPW is around 15 msec. But in the winter time, I have some cranking IPW at around 30 msec. I probably could tweak my scale a little.

  9. #19

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    You could just do a simpler 1D graph for Cranking Fuel above 20 ms. Just have to make sure the two tables aren't cumulative and if they are compensating. Another thing, I bet Advanced Control can be set higher when IEA is optimal.

  10. #20

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    I have yet another thought. If one wanted to gain X axis resolution with two maps. Have the RPM two furthest right columns on the low RPM map match the two columns in the high RPM map. Have the furthest right column in the low RPM map as 0° IEA and the furthest left column in the high RPM map as 0° IEA. The computer should blend between the two maps and the resulting IEA should be fine. It's just like an extended map.

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