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Thread: New to Tuning, MPG tune timing options

  1. #1
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    New to Tuning, MPG tune timing options

    What can I do to clean up and improve efficiency on my stock tune? Is there anything I can do to smooth out some ends to help improve mpg?

  2. #2
    What year truck? What mods have been done?

  3. #3
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    Same question, New to tuning here trying to get more mpg i just recently got the hp mpvi2.
    i have a 2005 chevrolet silverado z71 crew cab.

  4. #4
    Quote Originally Posted by madowns1993 View Post
    Same question, New to tuning here trying to get more mpg i just recently got the hp mpvi2.
    i have a 2005 chevrolet silverado z71 crew cab.
    Wrong section for a Chevy but with the Cummins I?ve had good luck with lower rail pressure, lower timing, lower pilot timing and slightly reduced pilot quantity in the cruise region for gaining mpg, driving habits, weather conditions, road speeds are a couple other major factors

  5. #5
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    First off fix/set your rail pressure compensation tables for both IAT/CT & IAT/Baro, then do the same for the timing correction tables. Smooth out the rail pressure tables, leave the duration alone and then go to work on the main timing tables. ANY time you change fuel pressure once the timing is set, you'll need to readjust the timing in the affected areas.

    I cruise at 16k psi, have minimal pre & post duration events and mainly use them to keep the turbo spooled and exhaust clean. I peaked at 23.3 mpg this past summer and had 5 23+ mpg tanks. 2005 QCSB 4wd, stock height, 33" tires, 21# 4th gen aluminum wheels and AL driveshaft. All hand calculated, fuel tank is vented so I fill up to the filler neck every time.

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    I have a 2006 QCSB with just an intake and exhaust

  7. #7
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    Quote Originally Posted by steve05ram360 View Post
    First off fix/set your rail pressure compensation tables for both IAT/CT & IAT/Baro, then do the same for the timing correction tables. Smooth out the rail pressure tables, leave the duration alone and then go to work on the main timing tables. ANY time you change fuel pressure once the timing is set, you'll need to readjust the timing in the affected areas.

    I cruise at 16k psi, have minimal pre & post duration events and mainly use them to keep the turbo spooled and exhaust clean. I peaked at 23.3 mpg this past summer and had 5 23+ mpg tanks. 2005 QCSB 4wd, stock height, 33" tires, 21# 4th gen aluminum wheels and AL driveshaft. All hand calculated, fuel tank is vented so I fill up to the filler neck every time.
    By fix you mean to set my rail pressure to be around 16k cruising and then how do I correct my timing, lower it? And how do I just smooth out rail pressure tables? Sorry I'm new to this I just dont understand a lot of this stuff. Maybe someone can link me to a good basics guide.

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    Not sure on linking in other threads here but...here is what I've learned, plus other useful info in there with recommendations.

    https://www.cumminsforum.com/forum/3...s-learned.html

    Novice tuner here so keep that in mind.

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    Quote Originally Posted by steve05ram360 View Post
    Not sure on linking in other threads here but...here is what I've learned, plus other useful info in there with recommendations.

    https://www.cumminsforum.com/forum/3...s-learned.html

    Novice tuner here so keep that in mind.
    So say I wanna start with rail pressure, what table do I use and do I just set each one or. I'm looking under Main Injection Limits and all I see is Low pressure limit and Baro limit A, B, and C. For timing I would do my rail pressure then go and advance my timing by .25* until I get it to build boost good but still keep it clean.

  10. #10
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    Limits aside, you want to do your compensation tables to the rail pressure, timing and baro first, then smooth out the rail pressure tables, leave the duration alone for now, then work on timing. The thread has info (IIRC) on what tables to address based on altitude. There is a pic of a table in there that shows what the pressure is at various altitudes, then go look at the tables that tell you what tables are accessed based on baro pressure.

    This will help you get familiar with the tool. I'd suggest leaving the limiters in place until your pretty comfortable with the tool and know what affects what.

  11. #11
    Transient and high pressure are the most commonly used by the ecm for 04-07, have seen low pressure used during idle at first start up

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    When adjusting timing, is it best if I just increment in the crusing area or can I just add to whole table. Still trying to play around with this but I dont know how to properly change the cells lol

  13. #13
    You can add lots in the upper power range, the spool area you will want to leave alone or maybe even lower a little, not much being you are stock and cruise region you can try raising. Cruise timing I already pretty high with stock tuning, some spots you can bump up a little. What you do with timing is going to depend on what you do with your fueling though.

    Something to keep in mind with the correction tables if you decide to play with them is the ecm doesn?t use all the tables all the time, most are used only under certain conditions.

  14. #14
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    Quote Originally Posted by Tony Bushmin View Post
    When adjusting timing, is it best if I just increment in the crusing area or can I just add to whole table. Still trying to play around with this but I dont know how to properly change the cells lol

    I would recommend finding a route that has varying loads (flats and different grades) that you can repeat without traffic. Once you have that, make some notes mental or whatever for the speeds. Start by logging it as is (do this every time before doing any tuning) for a reference starting point. Log it and pay attention to areas of smoke and timing rattle. When done with the route, save the log file and look at the timing. Pull back for smoke, advance for rattle.

    Make small changes and repeat the route, log it and repeat. ONly make the changes to the cell areas you identify as smokey or rattle.

    Get the areas you use squared away, then repeat the process but focus on calculated load (CL) values. Adjust timing in the areas your watching and note the CL to lower those numbers. The lower the better.

    I'd also recommend doing this AFTER setting the compensation tables. Any change to the fueling will require timing changes.

    FWIW, with my manual trans truck and my tuning, I am able to use RPMs down to 1000 without the trans complaining and was able to get 22 everyday during the summer (20's now in the colder temps). That is however with light weight wheels and an aluminum driveshaft (good for approx 2 mpg). All tanks hand calculated with a tank vent kit installed, meaning fuel shuts off at the fill neck.

  15. #15
    Quote Originally Posted by steve05ram360 View Post
    Pull back for smoke, advance for rattle.
    One needs to be careful with this one, the way it reads is if you have smoke, reduce timing and if you have rattle, advance timing. Depending on fueling, load, etc. pulling back timing can lead to more smoke and advancing timing can lead to more rattle. Too low of rail pressure can cause haze/smoke. There are many different variables that do come into play that give same results as something like smoke and rattle

  16. #16
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    Quote Originally Posted by Jim P View Post
    One needs to be careful with this one, the way it reads is if you have smoke, reduce timing and if you have rattle, advance timing. Depending on fueling, load, etc. pulling back timing can lead to more smoke and advancing timing can lead to more rattle. Too low of rail pressure can cause haze/smoke. There are many different variables that do come into play that give same results as something like smoke and rattle
    I feel like I have an understanding of timing in BTDC and ATDC but when you guys say advancing or reducing I get confused. So if I have, say for example -5* Main SOI and I change it to 5* am I reducing because -5* is ATDC and 5* is gonna be BTDC. And then if I go from 5* Main SOI to 3* I am advancing? I think I got that right or maybe backwards.

    I was reading up on an old thread and made quick tune for practice
    https://forum.hptuners.com/showthrea...ghlight=timing
    I changed main pw by 20% and smoothed like you said and then did rp at the mm3/rpm I believe I typically cruise at and filled a big hole at the top end under 3000rpm/65-120mm3 then I just used the timing calculator at 40% with no changes because I'm sort of stuck and I kinda want to run it and log it and see what it does as is. Let me know what you think Thanks!

    eco_1.hpt

  17. #17
    Quote Originally Posted by Tony Bushmin View Post
    I feel like I have an understanding of timing in BTDC and ATDC but when you guys say advancing or reducing I get confused. So if I have, say for example -5* Main SOI and I change it to 5* am I reducing because -5* is ATDC and 5* is gonna be BTDC. And then if I go from 5* Main SOI to 3* I am advancing? I think I got that right or maybe backwards.

    I was reading up on an old thread and made quick tune for practice
    https://forum.hptuners.com/showthrea...ghlight=timing
    I changed main pw by 20% and smoothed like you said and then did rp at the mm3/rpm I believe I typically cruise at and filled a big hole at the top end under 3000rpm/65-120mm3 then I just used the timing calculator at 40% with no changes because I'm sort of stuck and I kinda want to run it and log it and see what it does as is. Let me know what you think Thanks!

    eco_1.hpt
    Reducing timing is making it happen later in cycle, advancing is making it happen earlier in the cycle. If you change -5* to 5* you have advanced it 10*. Going the other way, 5* to -5* you are reducing (retarding) by 10*. No need to modify the entire main pw table, unless you are running large injectors and/or injectors are very high mileage. High mileage injectors may benefit from a very very small increase across the board for main pw. You?ll want to increase from 100mpa upwards and 60mm3 upwards. Max load cell, 180mpa and 140mm3, increase that by 20% and blend the rest down to 100mpa 60mm3 into that. In your spool region use timing and rail pressure to help with spool up and keep smoke down. Depending on setup, I?ve found if you start exceeding approximately 1050ish microseconds of main duration too early in the spool up region can cause smoke, raising rail pressure to get the fuel in under a hotter, better atomized spray can help with that, timing will need to be adjusted as well. Timing too high or too low can contribute to smoke.

  18. #18
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    Quote Originally Posted by Jim P View Post
    One needs to be careful with this one, the way it reads is if you have smoke, reduce timing and if you have rattle, advance timing. Depending on fueling, load, etc. pulling back timing can lead to more smoke and advancing timing can lead to more rattle. Too low of rail pressure can cause haze/smoke. There are many different variables that do come into play that give same results as something like smoke and rattle
    Yeah I'd agree with your statements... the assumption on my part is the changes at the start are minimal from the base HPT tune pulled. With his focus being fuel economy, smoothing out the rail pressure, leaving duration and working on the timing last should give good results. Thats the order I concluded makes the most sense. As you know, as soon as you change the rail pressure in an area of the tune, the ideal timing changes and timing needs to be tweeked to bring it back.

    I think though problems new tuners encounter is what worked well yesterday, may not work quite as well today. This is why I recommend starting with the compensation tables. I've had to go back a few times after getting them set to what works best (slope and amount of change to the parameters -baro, coolant & IATs) Big changes in them are not necessary but if left at default, can cause the tuner to start chasing the tail.

    Example for others... if your tuning and your IATs are at 60~65* and it runs absolutely awesome in all areas used, but becomes smokey as IATs rise, then one would be tempted to go back to the main tables and work on them more. When in reality the timing for IATs could be dialed in better to bring back the awesome running tune. With those tables, your correcting for the main tables by trimming (+/-) timing or fueling.

  19. #19
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    Quote Originally Posted by steve05ram360 View Post
    Yeah I'd agree with your statements... the assumption on my part is the changes at the start are minimal from the base HPT tune pulled. With his focus being fuel economy, smoothing out the rail pressure, leaving duration and working on the timing last should give good results. Thats the order I concluded makes the most sense. As you know, as soon as you change the rail pressure in an area of the tune, the ideal timing changes and timing needs to be tweeked to bring it back.

    I think though problems new tuners encounter is what worked well yesterday, may not work quite as well today. This is why I recommend starting with the compensation tables. I've had to go back a few times after getting them set to what works best (slope and amount of change to the parameters -baro, coolant & IATs) Big changes in them are not necessary but if left at default, can cause the tuner to start chasing the tail.

    Example for others... if your tuning and your IATs are at 60~65* and it runs absolutely awesome in all areas used, but becomes smokey as IATs rise, then one would be tempted to go back to the main tables and work on them more. When in reality the timing for IATs could be dialed in better to bring back the awesome running tune. With those tables, your correcting for the main tables by trimming (+/-) timing or fueling.
    I agree with you that I will never be able to get consistent results without adjusting my iat/baro but I feel that I need to get a good main timing first before I start to mess with anything else. Plus I am still starting out so I am just trying to grasp a lot of these concepts.

  20. #20
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    Quote Originally Posted by Jim P View Post
    Reducing timing is making it happen later in cycle, advancing is making it happen earlier in the cycle. If you change -5* to 5* you have advanced it 10*. Going the other way, 5* to -5* you are reducing (retarding) by 10*. No need to modify the entire main pw table, unless you are running large injectors and/or injectors are very high mileage. High mileage injectors may benefit from a very very small increase across the board for main pw. You?ll want to increase from 100mpa upwards and 60mm3 upwards. Max load cell, 180mpa and 140mm3, increase that by 20% and blend the rest down to 100mpa 60mm3 into that. In your spool region use timing and rail pressure to help with spool up and keep smoke down. Depending on setup, I?ve found if you start exceeding approximately 1050ish microseconds of main duration too early in the spool up region can cause smoke, raising rail pressure to get the fuel in under a hotter, better atomized spray can help with that, timing will need to be adjusted as well. Timing too high or too low can contribute to smoke.
    Okay so I did have it totally backwards haha, so then is -5* before TDC or after, I thought it was after TDC and 5* is 5* before TDC. As far as the pw goes I did just that, I have stock injectors with about 200k on them (2006 5.9 btw) but I have not messed around with anything over the whole map. And so like you said before if I have smoke reduce it (I wonder why that is. Maybe is it because the ignition event is happening way earlier and the fuel is not able to combust) I just did a drive and everything seems fine except I think it might be rattling a little more at idle. I also dont understand how advancing it more will reduce rattle is it because of negative torque.