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Thread: Timing Calculator how to

  1. #1
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    Timing Calculator how to

    As I get a lot of questions on its use, thought I would make a little tutorial. Standard useage rules apply, use at own risk. Myself or hpt will not be held responsible for any damage resulting from its use.

    This is not a tutorial on how to build a complete tune, this is simply a demonstration of how to use and apply timing calculator. I am using a 2005 LLY file for this that is totaly stock. The numbers are not meant to represent what you should get, just data to use as an example. Timing is applied to all other models in the same fashion.

    For most, a 50/50 calculation will be enough of a economy/performance increase that you will be happy with it. I will show at the end how to tailor the table a little more.

    First, you want to make any modifications to your tune you are going to do, the timing calculator is the last thing you do as it is dependant on fuel and fuel pressure. Then download (click here) and open it(you must have excel for this). You must also have hptuners and your diesel tune file open.

    1. Copy your fuel rail pressure table from here


    2.Paste fuel rail pressure here


    3. Copy Injector Pulsewidth here


    4. Paste Injector Pulsewidth here


    5. Copy Base Injector Timing here


    6. Paste Base Injector Timing here


    7.This shows the amount fuel being injected before tdc with your stock tune.


    8.This is the very top table in the calculator(light purple). This is what you want to take and copy back to the same table you copied out from.


    9.If you wanted to check that the calculator is doing what it is supposed to, take the table from step 8 and copy into the table from step 6. This is what you should see(not required, just a demo to show what is going on)


    10.The area in green is the area the calculator modifies the timing in. The area in purple is left stock. You want the area in purple to stay the same for each table. So, either copy each timing table into the calculator and back to its appropriate table OR just copy the green area and paste that area into each table.


    The following highlighted (pink) are the the tables for each engine you need to modify.
    LB7


    LLY


    LBZ


    LMM


    The timing calculator does not have an advance limiter. The rule of thumb is not to excede 30 degrees. You will have to manually limit the table if you excede this value below what you are reving to. If it hits these values past your redline(stock is 3250) dont worry about it.

    If a 50/50 timing table is what you want to achieve, you are now done.
    Last edited by mecanicman; 05-27-2011 at 03:15 AM.

  2. #2
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    mecanicman -

    You made the point before about the HPT units setting must be to Mertric. Last week I did a LBZ and forgot to change the units setting in HPT. When I realized my oversight, I went back and redid the sheet only to find the results were the same.

    Are any of the calculations really units sensitive?

  3. #3
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    Roger, you jumped in to soon! Now there will be a gap between part one and two! Lol, just teasing. You want the axis scales to match, if they do not then change so they do. Dont have it in front of me right now but I think that only became important in lmm tables.

    If you are reading/using this, do not PM me about it. I am no longer supporting this. Feel free to use at your own risk, but all pms regarding diesel tuning will be deleted.
    Last edited by mecanicman; 09-13-2013 at 06:43 PM.

  4. #4
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    If you are looking to get a little more involved....

    I have posted in the past that 50/50 is a good compromise, there are better settings depending on what you are doing. The following values are approximate but should be close. You would be best to set up scanner and see where your driving falls in the table.

    Follow the set up for the calculator in steps 1-6 in the above post. Scroll back up to the top of the calculator and look at the purple table. In the top left corner is desired percentage of injection. This value can be changed and the table will recalculate for that percentage.

    1.Change percentage of desired injection to 55% and copy out appropriate columns


    2.Change percentage of desired injection to 50% and copy out appropriate columns


    3.Change percentage of desired injection to 40% and copy out appropriate columns


    Now you have a completed table, same as instructions above copy this portion into all main timing tables.
    Last edited by mecanicman; 05-26-2011 at 08:17 PM.

  5. #5
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    Wow very cool mecanicman! Thanks for taking the time to put this together. I will have to give your tutorial a try on brothers lbz.

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    Sorry mecanicman! I wondered why there were gaps in your post. GREAT INFO - Thanks!

    Here is an xls version of your sheet with sample data for those that do not have the newer version of MS Excel.
    Last edited by Roger Ramjet; 05-27-2011 at 03:13 AM.

  7. #7
    Tuner apex2112's Avatar
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    I would like to start off with a big THANK YOU! to Mecanicman I've seen many of your posts and you are always helpful.
    Now to my question, I have watched a tutorial on the Duramax tuner web page http://duramaxtuner-tutorials.com/ it is done with EFI Live but still using the same tables and 50/50 calculator.
    With regards to "if you are looking to get a little more involved" unless I'm misunderstanding what you are showing in the areas of 20 to 50 mm3 it would apear that you would be adding timing. when in the Duramax tuner tutorial they show to reduce timing?
    Also in the duramax tuner tutorial they show to add some timing to the whole base mid and base low tables, is this something you would also recommend?

  8. #8
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    I too found and used those instructions a couple years back. There is nothing wrong with them, I used them with good results. I dont find the diesel to be as effected by transitions as a gasoline engine, so the smoothing seems pointless to me. You are loosing timing for no real reason. If you disagree, or do find that you can feel the step, it will not hurt. The video shows reducing timing to make the engine quieter. If you are living at sea level and put the 50/50 table in you may notice the engine is louder when driving at low speed. You can do the reduction if the noise is an issue. However if you are at medium/high altitude and compare the tables they work out pretty close in the lower areas. I find the LB7's get noticably louder with the calculator, the rest not so much(depends on your sensitivity to it I guess).
    In my testing(admitedly with little conducted at sea level) the trucks performance and economy picks up significantly with the timing calculator applied as is. I have a lot of trucks out there reporting back to me on fuel economy and the settings I showed seem to be delivering the best results. The reason I show it this way is it is easy for people to see, delivers good results, and I consider it to be very safe. There may be better settings out there that I am not aware of, I have simply posted what I have tested and proven to work for your typical commuter/pulling vehicle. I know from expieriance trying to make big power changes things a little.
    So, to answer your question, no I do not recommend those settings. If you want to apply them they will not hurt. If you discover something in the tune you dont like such as noise those settings can help. Its all about setting it up to your own tastes.
    Last edited by mecanicman; 05-28-2011 at 05:04 PM.

  9. #9
    Tuner apex2112's Avatar
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    I haven't tried any of the timing changes yet, the tune is for my fathers truck it's basically 20/20 tune with some tcc changes and he's pretty happy with it currently getting about 21 mpg in flat Florida. he doesn't tow with it just a work truck with about 800/1000 pounds in the bed.
    If i wanted to make changes outside the straight 50/50 what would I need to log?
    I've included a config file that I made anything I should add or delete?
    Thanks

  10. #10
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    Did you get all of that to log with the LB7? Sometimes they are cranky and not all those pids will work for me. Anyway, for the purposes of timing go for a drive with your father. Have him drive normally and watch the timing histogram you have set up. You are basicly looking to see what columns he hits under normal driving, this is the area I set up 55/45 for best economy. Have him drive a little more agresivly such as passing and see where he hits in the table. This area I set at 50/50. For some people when you say this they are to the floor so I just split the remaining area into to equal sections. Anything past your 50/50 set to 40/60.

  11. #11
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    Ok can you take a look at the new timing tune I made just so I know I'm doing it right, also included the old tune.
    I just always thought that in higher rpm high mm3 the timing number would be higher.
    In a log I did with the old tune at say 3000 rpm and 89 mm3 I see 16° main injection timing but when looking at new timing tune at that area of the timing table it would be 14°

  12. #12
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    You have applied the timing calculator correctly from the tune you had. However your old tune has had the area in purple I highlighted to leave stock messed with it looks like. Every table has 4.2 in top, the tables from stock lb7's I have all show different values. It is not required, but if you have your stock tune still I would recommend using those tables to start with. The low speed timing tables can effect your idle, may idle fine now but a road trip to different altitude may change that.

    You were concerned about less timing. To clarify, the calculator is achieving a specific amount of fuel before and after top dead center(tdc). So, in the fuel economy area any time the truck is in those cells 55% of the fuel is going in before the the piston hits tdc and igniting with compression ignition. 45% continues to be put in after ignition and increases cylinder pressure. You are maintaining this ratio of fuel distribution thru this range. You can get away with more before tdc in this area because the injection pulse is so small.
    In the area you set to 40/60 the injection pulses are getting larger. It is safer to shift some of that injection timing to after tdc to avoid hydraulicing(stock or small tunes this not a concern, only bigger tunes). But you are also trying to increase power and by adding more fuel after tdc to increase cylinder pressure creating a lot of torque.

    The calculator will give you a very safe and effective timing table based off of fuel. It is not a maximum effort racing timing set up.


    PS:I just wrote this as an explanation, I see you did not use the 40/60 in the setup.
    Last edited by mecanicman; 05-30-2011 at 04:58 PM.

  13. #13
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    Yes this tune was based off the 20/20 Mcrat tune, in which it had you copy the timing table from the base low to the other timing tables and just zero areas for idle to help keep it quiet.
    I will go back and start from the stock timing tables, as well as apply the 40/60 to the high mm3 areas.
    Thanks for your patience while I was trying to wrap my head around this.

  14. #14
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    No problem. By the way, the 40/60 in not required. The 50/50 will work quite well. Some people just want a little more. The different hand helds offer multiple tune levels. It is possible setting it up this way to get good economy when driving normally and still run like a banshee when you get into it.

  15. #15
    Tuner apex2112's Avatar
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    The current tune on the truck is mild,was looking to have a little more when you get into it.the fuel milage is good but we could always ask for more.
    My dad had another tune that was stronger but it limped the trans, so we pulled it out.

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    I am working on a LBZ tune. The owner asked for cruise mileage and lots of full throttle power. With that in mind and your post, mecanicman, you inspired me to make a change to your Excel file. I expanded the % input cell on the upper left to 3 cells with corresponding colored areas in the power band. Here is the result.

  17. #17
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    Nice job Roger! And so it grows....

  18. #18
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    I hate to ask this but I downloaded the timing calculator you had a link to and it has different increments on the rpm, and etc etc compared to my trucks values. (05 LLY) I noticed the pictures you have are just like mine, but the calculator is different, and I dont want to mess anything up when i do plug in my values

  19. #19
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    Look across the bottom of th spreadsheet, there are 3 different pages. Choose the page that shows your model and all should be well.

  20. #20
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    Quote Originally Posted by mecanicman View Post
    Look across the bottom of th spreadsheet, there are 3 different pages. Choose the page that shows your model and all should be well.
    Doing an LMM, I applied the calculated area to the pilots you have highlighted in the pic but noticed that another write up by someone else says not to. Did I misunderstand your post or is applying the new values to the pilots just a preference?
    99 T/A WS6, original LS1 turbo