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Thread: Tow tune attempt, tune review

  1. #41
    Advanced Tuner
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    Jan 2018
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    If running post injection with intentionally making main EOI end well past TDC you need to consider the post event timing as well. By the time it injects you could potentially run into a situation of not having the heat required in the cylinders to ignite the post event for it to do its job.

  2. #42
    Tuner in Training
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    Jul 2019
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    I have eliminated the post injection. Do not feel I'm prepared enough to optimize the use of it yet. These study's you mentioned, and search suggestions that would lead me down the right path of them? Thank you again for your patients and time. Has anyone Installed an in cylinder pressure transducer? Any ideas as to how. I hate guessing, and feel I really need relative data to truly grasp all of the variables.

  3. #43
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    Without a modified head you won?t get a pressure transducer installed. Not really needed going that far. Just make small changes, drive and see how it does and make more small changes till you get your desired results. Pretty much what everyone does including those with access to a dyno only with a dyno you can see what it does to torque output for a given fuel quantity.

  4. #44
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    Google ?effects of pilot timing? and things of that nature and you?ll find research articles that give real world results of findings on things like fuel consumption, emissions, cylinder pressure, etc. Don?t take it all as a written in stone but as a guide of what happens when things are changed to get better understanding of what things do. Experimenting and logging your engine and reviewing will show you what?s going on when you make changes as well and is the only way to get towards your desired results.

  5. #45
    Tuner in Training
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    I am going to be diving into the Pilot effects soon, using my tried and true method, tune it, log it over a decent span using cruise and evaluate against other logs on the same route. If you have hilly terrain to haul the load across, you could do the same to dial in the tune, generally low calculated load numbers are the best.

  6. #46
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    Yep, aim for results the give less engine load, throttle input, commanded fuel for a given speed

  7. #47
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    I find 15*BTDC for pilot works quite well

  8. #48
    Tuner in Training
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    Jul 2019
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    I'll experiment with the 15 degrees jim, right now I have an 18 taper to 3 degrees. At 3 degrees pilot I turn it off.
    As far as load calculations I was hesitant to utilize this because of inferred inaccuracies.
    I originally was lead to believe this when experimenting with vp tunes. Which utilize more duration than my tow with pilot tunes. They have given lower load percentages.

    Quick thought. In 6th gear wot I feel it pull sluggish, but as I lift off the throttle, I continue to feel it pull till a certain point. Could this be an indication of too much timing up top causing negating torque?

  9. #49
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    That?s not what actually happens with pilot timing. You can set it relative to main injection SOI or absolute to TDC, stock is relative to main SOI and isn?t the same as absolute to to TDC. There is a minimum degrees of separation from the end of pilot event to the beginning of the main event, stock it is 3.01*. If the main event runs into the pilot event it pushes the pilot event to occur earlier in the cycle to maintain that minimum separation. The only way to shut pilot off is to kill the injection quantity above or below the desired rpm and total fuel quantity.

    Log desired rail pressure against actual rail pressure and see if at 100% throttle your rail pressure is keeping up with desired. One of the possibilities of the truck feeling sluggish at 100% throttle and stronger at 90% throttle comes from not being able to maintain rail pressure.

  10. #50
    Tuner in Training
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    Jul 2019
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    Jim how were you able to change your pilot table to absolute degrees? Iam already aware of both of those facts already. I've been listening.lol
    I calculated to the best of my ability the degrees of duration, then added 3 degrees for event separation, and calculated off of main event timing where my pilot would have to be to achieve 18 degrees btdc, not before msoi. It took quite sometime. And yes I eliminated the pilot in certain areas in my duration tables. Because a 0 on the timing map is only a set point not a Quantity. I'm getting there, slower than my truck but moving forward I hope. You all have been very helpful.

  11. #51
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    HPT doesn?t have the option to make the pilot relative or absolute, at least not that I remember seeing. UDC Pro has it. I made a spreadsheet that does all the math to give the pilot timing values needed to make it a set degrees BTDC, as much as however the main event will allow at least.