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Thread: Tow tune attempt, tune review

  1. #81
    Jim do you have a recommended number for how far pilot is advanced from the main? I know its fuel dependent and wont be the same for every truck but a starting point might be good for those of us who dont have the ability to log pilot timing. I have encountered a pilot rattle a few times and am faced with it now in certain areas of my tune.

    Seems like if its advanced too far it might ignite prior to TDC and it needs to be retarded some...

  2. #82
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    Personally I?ve had best results keeping pilot timing at 15*BTDC and tapering pilot quantity down as load and rpm goes up. I?ve used it for the 04.5+ 5.9L and in the 6.7L. I?ve never experienced too early combustion cycle creating the popping that others have described having. Typically it?s something those with an 03-04 will battle versus 04.5+. I?ve had pretty good results from stock to more higher power built trucks with the pilot event I like to use.
    Last edited by Jim P; 02-05-2020 at 12:24 PM.

  3. #83
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    Been quite some time since I actually looked at what I use on the 5.9 but if I remember correctly it?s at 1.97mm3 or so at idle then tapers down to zero as it goes towards the upper rpm/fuel quantity cells and it?s timing held at 15*BTDC till main timing reaches around 12*BTDC and begins pushing pilot timing upwards but pilot quantity is near off by the time that happens.

  4. #84
    In the stock file the pilot quantity goes up with demand and timing is way beyond the 15* mark as demand climbs. 20+ easily...

    What I hear is probably not encountered much... I am cutting RP down to offset some of the other mods I have and when RP goes too low, pilot does not seem to have the duration to prevent what I call the pilot rattle. to counter this I've increased pilot qty which is counter productive to what the goal is. I may just have to bite the bullet and ditch it again all together. The last time I was successful at NOT increasing pilot qty I pulled timing back vs advancing it. That got rid of it and brought power up a noticeable amount since the pilot event was not fighting the main.

    anyways...

  5. #85
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    I take pilot quantity away as rpm and load goes up as there?s a point where pilot really has less of an effect in the upper rpm/load range. As pilot quantity is pulled away, what you are pulling away from pilot moves into the main event to maintain that commanded total fuel quantity. Same holds true when pulling away post injection quantity.

  6. #86
    Quote Originally Posted by Jim P View Post
    I take pilot quantity away as rpm and load goes up as there?s a point where pilot really has less of an effect in the upper rpm/load range. As pilot quantity is pulled away, what you are pulling away from pilot moves into the main event to maintain that commanded total fuel quantity. Same holds true when pulling away post injection quantity.
    wouldnt main duration need to be modified then in the above case?

    Once upon a time I did an rpm based pilot removal, at 1800ish rpms I killed pilot as an audible reminder for me to shift. Maybe its worth it for me to do the same again and add in a fuel demand cutoff... meaning say above 30 mm3, cut pilot but after a desired rpm target.... hummm...

    maybe better to just ditch it all together.

  7. #87
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    Why would you need to modify main duration for it? You are commanding a base total fuel command through the accelerator pedal, you have the pilot and post event quantities defined in tables that account towards the total fuel quantity commanded, remainder is the main event and the entire works is regulated by governors to control final total fuel quantity output required to maintain a given rpm. Pull away desired quantity from the pilot or post it?s just going to move to the main event quantity for meeting the desired total fuel quantity. In the case of moving towards a single injection event like a VP44 truck you begin losing in cylinder heat for the main event to more readily ignite, ignition delay rises so timing and rail pressure will need to go up to help combat the increased ignition delay. More rail pressure will help lower ignition delay back down some and many other things like helping keep it clean out the rail pipe but timing still needs to be raised as well, not to the degree that a P-Pump truck runs at though. My 2010-2012 pure single event tune the RP starts at around 9kpsi and 8.5* of timing and is the absolute lowest timing goes. The pure single event tune I built for stock to 50hp injectors for an 04.5+ 5.9 is quite similar. None of them have main duration adjusted for removal of pilot and post, duration is turned up in the upper end of quantity and RP.

  8. #88
    Quote Originally Posted by Jim P View Post

    Why would you need to modify main duration for it? You are commanding a base total fuel command through the accelerator pedal, you have the pilot and post event quantities defined in tables that account towards the total fuel quantity commanded, remainder is the main event and the entire works is regulated by governors to control final total fuel quantity output required to maintain a given rpm.


    Pull away desired quantity from the pilot or post it?s just going to move to the main event quantity for meeting the desired total fuel quantity. In the case of moving towards a single injection event like a VP44 truck you begin losing in cylinder heat for the main event to more readily ignite, ignition delay rises so timing and rail pressure will need to go up to help combat the increased ignition delay.

    More rail pressure will help lower ignition delay back down some and many other things like helping keep it clean out the rail pipe but timing still needs to be raised as well, not to the degree that a P-Pump truck runs at though. My 2010-2012 pure single event tune the RP starts at around 9kpsi and 8.5* of timing and is the absolute lowest timing goes.


    The pure single event tune I built for stock to 50hp injectors for an 04.5+ 5.9 is quite similar. None of them have main duration adjusted for removal of pilot and post, duration is turned up in the upper end of quantity and RP.
    As pilot quantity is pulled away, what you are pulling away from pilot moves into the main event to maintain that commanded total fuel quantity.
    Your quote above says that the duration removed from the pilot event being modified is moving into the main event. I dont see that in my logs. I can modify pilot MM3 at any given point in the tune and the duration tracks with the change, meaning if I go from 300 to 200 us of duration in the main event does not change. With that said, not sure what your trying to say here...

  9. #89
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    You are mixing up what I said. I said nothing at all about duration when talking about pulling away from pilot or post. Duration is nothing but injector open time. Fuel quantities is what I am talking about.

  10. #90
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    https://youtu.be/3icnMv1djeY

    Point proven in this short video...

    AC compressor was cycling on and off but when settled main quantity has gone up by basically the amount that pilot was at.

  11. #91
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    Should I do a video on correction factor tables as well to show they don?t blend with the air density tables or operating modes but rather run off being selected based on how they are configured to be either max wins or min wins and comparing the selected air density table against the correction tables to determine to use either the air density table or a correction table as the table to run off of depending on whether it?s configured for max wins or min wins?

    In an as steady running state as possible like idle it?s very easy to see how tables interact or what happens when you do something like take away pilot.

  12. #92
    Quote Originally Posted by Jim P View Post
    https://youtu.be/3icnMv1djeY

    Point proven in this short video...

    AC compressor was cycling on and off but when settled main quantity has gone up by basically the amount that pilot was at.
    what truck is that on?

    I will do the same test on mine next time I am tuning...

  13. #93
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    Quote Originally Posted by steve05ram360 View Post
    Jim do you have a recommended number for how far pilot is advanced from the main? I know its fuel dependent and wont be the same for every truck but a starting point might be good for those of us who dont have the ability to log pilot timing. I have encountered a pilot rattle a few times and am faced with it now in certain areas of my tune.

    Seems like if its advanced too far it might ignite prior to TDC and it needs to be retarded some...
    https://www.tytlabs.com/english/revi...3_009hotta.pdf

    This paper has some interesting information. Fig. 7 concerns pilot timing under light load and low RPM. I believe main injection timing is 4 deg ATDC. ISFC (indicated specific fuel consumption) goes down as pilot timing gets closer to main injection event. I don't suggest that the actual numbers in the graph will work for our engines. But it makes sense that having the pilot event closer to TDC when under light load conditions would result in better fuel economy when the main injection event is short and around TDC (to a point).

    Also note the different injection quantities in Fig.7. Varying pilot injection quantity doesn't change fuel consumption all that much. Fig. 4 shows much the same, but doesn't go as low in pilot injection amount.

    I've read other papers on pilot timing. One of them found that best fuel consumption for their small diesel engine was at 17 deg BTDC...very close to Jim's 15 deg number.

    Pilot injection is something that I haven't touched yet. It is next on my list. I think to start off I'm going to modify the low load areas. I'm going with 10% of main injection quantity at 15deg before main injection.

  14. #94
    Quote Originally Posted by Bucket View Post
    https://www.tytlabs.com/english/revi...3_009hotta.pdf

    This paper has some interesting information. Fig. 7 concerns pilot timing under light load and low RPM. I believe main injection timing is 4 deg ATDC. ISFC (indicated specific fuel consumption) goes down as pilot timing gets closer to main injection event. I don't suggest that the actual numbers in the graph will work for our engines. But it makes sense that having the pilot event closer to TDC when under light load conditions would result in better fuel economy when the main injection event is short and around TDC (to a point).

    Also note the different injection quantities in Fig.7. Varying pilot injection quantity doesn't change fuel consumption all that much. Fig. 4 shows much the same, but doesn't go as low in pilot injection amount.

    I've read other papers on pilot timing. One of them found that best fuel consumption for their small diesel engine was at 17 deg BTDC...very close to Jim's 15 deg number.

    Pilot injection is something that I haven't touched yet. It is next on my list. I think to start off I'm going to modify the low load areas. I'm going with 10% of main injection quantity at 15deg before main injection.
    Thanks for the link, I'll read it tonight. As for the lowest BSFC & the pilot timing... since I am not able to log pilot timing... my conclusion is BFSC goes down once the ignition point of the pilot event is ATDC. A few weeks back I dropped pilot qty enough to push that ignition point to BTDC while tuning, power went down noticeably and I had a slight rattle. All i did to fix it was bump pilot qty back up, which brought the duration up and presumably pushed the ignition point past TDC. Leaning towards ditching it in a way where its not in play under the cruise zone or just ditching it all together.

    When you get to messing with the pilot event, make a mental note of what typical timing rattle sounds like. Assuming a quiet tune is in place with no timing rattle, go halve your pilot with no other changes and take it for a spin. I dont know why but the pilot rattle is slightly different than the main event rattle. It may be because mine has the fueling reduced so much, IDK.... keep in mind mine has a lot of rotational mass removed, wheels, driveshaft, pulleys e-fans & elect water pump. On top of that, I have a manual trans.

    On Jims video... i think when the pilot is removed, load is going up enough to get the extra fuel added into the total mm3 demand. I expect that he would need to advance the main event some to bring that load back down. If he redid the video with calc-load & main timing visible along with the other gauges it would shed more light on it.

  15. #95
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    Your perception of how load on these ECM?s is calculated is off. It is very very largely tied to the maximum commanded total fuel set in the air density table you are running off of for the given rpm you are currently at. Simply increasing allowable fuel in these tables alone will yield the result of what would appear to be lower load.

  16. #96
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    The video was on a 2012 but that?s irrelevant to the point as it?s the same on the 5.9?s.

  17. #97
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    Way my tuning is currently set up there is no point in showing calculated load at idle or high idle because it will just read 0%

  18. #98
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    Here's screenshots of the pilot event I used on one truck.

    Pilot.png

  19. #99
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    Here?s solid proof that if you take away or add to your pilot or post event it takes away from or adds to you main event. Total fuel injected is a combination of all 3 events and on the the 5.9, your fuel axis in tables and in tables like fuel limit are total fuel, not event. This is done on a 6.7 but same holds true on a 5.9. The key differences on this between the 5.9 and the 6.7 is that the 5.9 is regulates the engine speed through fuel based control while the 6.7 regulates engine speed through torque based control. With the torque based control I can have direct control of the total fuel quantity much better than can be achieved with the 5.9.

    Note I did make an error in the video when I said I?m going to set my main event to 10mg/stroke, I set total fuel quantity to 10mg stroke. Achieving 10mg/stroke on the main event is achieved by completely removing the pilot and post event. Making everything nice number with no .xx makes it very easy to see clear as day that when the main event is the only event running and is running at 10mg/stroke, when I add 1mg/stroke to pilot it drops the main event to 9mg/stroke to maintain the desired total fuel quantity of 10mg/stroke and so on.

    Hopefully you can see in the video that calculated engine load does not decide the fuel quantity. Calculated engine load is basically and simply relative to % of total allowable torque based on operating mode for the 2010+ 6.7 and total allowable fuel quantity based on air density mode on the 5.9. I hate to say it but much of how you think this engines ECM?s is quite incorrect.

    https://youtu.be/eF-k2Ss_YNA

  20. #100
    Thanks for the input... That last video shows it clear as day... I will continue to experiment and learn as I go... cause & effect.
    Last edited by steve05ram360; 02-13-2020 at 03:46 PM.