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Thread: Tow tune attempt, tune review

  1. #61
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    My bad on the Stoich. I just meant for clean efficient ratios. Iam aware that the A/F for diesel is very much leaner than gasoline.

    As for my pilot im baffled, ive reviewed all my logs, and main timing is right where it should be as well as everything else, the pilot pulsewidth goes to 0 at the commanded points as well. However, I did go back and change pilot timing at the point of 0 pulsewidth down to 0 as well. Just to aid notice of deactivation while driving. But on the log it reads 35 degrees. it never really deviates much from that number. Almost like its defaulting for some reason.

  2. #62
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    Here is a log that displays what iam talking about. Nevermind the FCA percentages I dont understand the issue, its always done it.race2 log1.hpl

  3. #63
    Advanced Tuner Jim P's Avatar
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    I haven?t looked at your log yet or seen your tune but... I?m assuming you are shutting pilot quantity off in the upper rpm and total fuel quantity range. Setting pilot timing to zero in its timing tables as a visual aid of pilot injection deactivation is pointless. That?s not how the pilot injection works. Seeing pilot quantity at zero is the only indication you will ever achieve as an indicator it is not injecting pilot fuel. The pilot timing tables are configured to be degrees ahead of main injection with a minimum separation of 3.01 degrees between the end of pilot injection and beginning of main injection. If pilot is turned downward in crank angle degrees to happen sooner and it breaches the minimum separation it will automatically raise pilot timing to achieve the minimum separation.

  4. #64
    Advanced Tuner Jim P's Avatar
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    Also if you have zero pilot quantity commanded, it?s timing is irrelevant.

  5. #65
    Advanced Tuner Jim P's Avatar
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    Let?s make some assumptions to help clear up the understanding of how the pilot timing event works. Assuming setting pilot to occur at 15* at an ungiven point in its timing table, at that point the pilot event injects for a period of 4 crank angle degrees, main event at that point is set at 11*BTDC. The pilot event would begin at 26*BTDC and end at 22*BTDC. Now if you want pilot to occur at that point at 15*BTDC you would set pilot in the table at that point to 4*. 15-11=4, pilot timing is degrees ahead of main event. But we also have another problem here, we are cutting into our minimum separation, so the ECM will push pilot timing up 3* to engine at 18*BTDC. So in order to get our pilot event to occur at that 15*BTDC the main timing event would need to begin at 8*BTDC. Hopefully that clears it up enough.

  6. #66
    Advanced Tuner Jim P's Avatar
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    FYI at lower coolant temperatures your pilot timing coolant correction table may be taking over.

  7. #67
    Advanced Tuner Jim P's Avatar
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    Hard to say without seeing your current tune.

  8. #68
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    I'm on the road at the moment, but when I get home I'll post the tune. I guess my main concern is, am I running too much pilot timing, or is it causing harm running it so far ahead of the main?
    If it is causing harm, or potentially leading up to it, what signs am I looking for? Thank you.

  9. #69
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    This is the tune for the log above. (removed)
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    Last edited by Bigbad151; 1 Week Ago at 05:47 AM.

  10. #70
    Advanced Tuner Jim P's Avatar
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    You got some wildly off pulsewidth numbers for just 50hp injectors.

  11. #71
    That is a lot of timing in the 2000rpm range. I usually am not about 10-12* of main timing at 2000rpm wot.
    06 SCLB. ATS stage 6, ATS Twin cp3, s369sxe, Fass 220, Hamilton 188/220, 110# springs, DDP 220's, ARP 425's, Big valve head, .40 over, 12v rods, balanced rotating assembly, Efi-Live etc.. 770hp 1380tq Tenacity Tuning

  12. #72
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    From my understanding the bbi stage 1's are a 30% over, which I thought equated to 100 hp sticks. Wildly off,how?

    As far as the timing, it is aggressive, but my calculations put the duration at about 55% btdc.
    Is it really that aggressive? Not trying g to come off as a smartass. Genuinely asking. At this time I havent been able to fully take advantage of or get a firm log because my clutch slips. But I can say that the turbo hits 36 psi in less than a second. Recommendations/reasoning?

  13. #73
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    I'm still a newb, but I think your timing is very aggressive. I've never seen a race truck tune, but that's what your tune brings to mind.


    I used DOM's method that I found in another thread. For WOT, 8* at 2000RPM interpolated to 20* at 3000RPM. My truck responded very, very well to that. I've tinkered with it a little bit, but it is a solid starting point.

    Disregard the attachment. Photobucket has made it unreadable. I was trying to include it as an example of what I think of as an aggressive tune.
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    Last edited by Bucket; 2 Weeks Ago at 07:34 AM.

  14. #74
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    My timing table was created using a calculator that I had made for displaying the number of degrees traveled for the designated pulsewidth at a specific rpm. From there I then made a decision as to what percentage of the duration I wanted btdc and atdc. So all the timing values above 800rpms have been calculated out. Not saying they're optimal because of that. Just stating I'm not just slapping any old numbers in there.

  15. #75
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    has anyone modified the correction factors successfully for the pilot timing to aid in controlling/manipulating it?

  16. #76
    Advanced Tuner Jim P's Avatar
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    I know I?ve said it before, on multiple threads, a timing calculator don?t mean squat. What you do with them is literally just slapping any old number in there.

  17. #77
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    Yes you have, and what I have made is a chart to aid me in understanding the changes I am making. As In helping me more readily calculate the degrees being traveled at a specific rpm and duration setting at that rpm. This I feel helps me to reassure my changes aren't going to be catastrophic. But I am ultimately deciding what and where. Helps me speed up the process I stead of handcalcating every area, everytime. From there I make several trial and error changes based off of testing. Please do t feel that your words go unheard.

    That aside I'm still wondering if there is any warrant to modifying g the correction tables for the pilot timing, and what is the safety threshold/symptoms of too much pilot timing.
    The research I have done leads me to believe it is different for every motor. But cannot find any specific data to mine to make me feel confident in answering this myself.