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Thread: Fuel Economy and Less Regens

  1. #1
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    Fuel Economy and Less Regens

    I'll just be frank - all of my diesel tuning experience is with much older mechanical adjustments - retarding the pump by loosening some bolts, spinning it by hand and then adjusting some valves - that's about it... Now with that being said, I've been experimenting with my babymax to try and get better fuel economy and fewer regens... I drive right at 180 miles round trip every day so you can see why I'm after this First thing I tried was just killing some tq limits and playing with the dm table a little - got to 28mpg (it was originally 25ish) and regenning every 200 miles... Next thing I did was I tried increasing the vane position 5% - this was like you were driving with the exhaust brake on, so I went the opposite way - opened the turbo up 6% and on top of that retarded the injection timing about 5 degrees... This was both good and bad - regenning went to a 320 mile interval and fuel mileage went to about 29.5 to 30, but the truck is very lazy down low and you have to stay in the throttle especially when you hit any grades - which does put heat into the exhaust and keep the soot burnt off, but wanted to try something else...

    On the current tune I'm fixing to try out I'm trying advanced injection timing with a 5% increase in fueling combined with stock turbo settings - hoping that by getting overall power up that I can get fuel economy up some more...

    Am I doing anything right? What's recommending for this type of end goal?

    I'm after 32or better mpg on the particular stretch of highway I drive...

    Attaching the current test tune and the one where I was getting my best results so far...
    Attached Files Attached Files
    2010 Vette Stock Bottom LS3 - LS2 APS Twin Turbo Kit, Trick Flow Heads and Custom Cam - 12psi - 714rwhp and 820rwtq / 100hp Nitrous Shot starting at 3000 rpms - 948rwhp and 1044rwtq still on 93
    2011 Vette Cam Only Internal Mod in stock LS3 -- YSI @ 18psi - 811rwhp on 93 / 926rwhp on E60 & 1008rwhp with a 50 shot of nitrous all through a 6L80

    No Longer with passion performance auto for good reasons

  2. #2
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    Ok, so I'll know more tonight but as of now tune 3 is really nice - after 82miles of hard hill pulling highway trying to maintain speeds of 70 to 75 mph my average mpg is 32.5 and data is showing a soot level of 4% (was struggling to stay below 30ish% with any tune prior). This tune also pulls hard and keeps pulling hard where the OE would fall on it's face right around 3500rpms or so... Further testing required, but liking this one... This one also doesn't load up on soot during decel or idle like the older ones or the oe one did... In fact anyone with one of these trucks who has stock tires and drives mostly on flat ground at speeds 75mph or less should get in the high 30's on fuel mileage with this one... Just wondering and asking what's safe and best for those who know diesel tuning as mine is still all epa friendly...

    Is anyone willing to share the "ideal" injection timing setting for idle, cruise and light to mid load?
    2010 Vette Stock Bottom LS3 - LS2 APS Twin Turbo Kit, Trick Flow Heads and Custom Cam - 12psi - 714rwhp and 820rwtq / 100hp Nitrous Shot starting at 3000 rpms - 948rwhp and 1044rwtq still on 93
    2011 Vette Cam Only Internal Mod in stock LS3 -- YSI @ 18psi - 811rwhp on 93 / 926rwhp on E60 & 1008rwhp with a 50 shot of nitrous all through a 6L80

    No Longer with passion performance auto for good reasons

  3. #3
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    I am not an expert but if I was trying to get a better burn I would do it with Higher Rail Pressure it will increase Torque and shouldn?t produce soot maybe 2 degrees Timing in Crushing area smooth more or less the map
    It would probably give you a good staring point

  4. #4
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    I tried smoothing things in an earlier version - didn't work out so well. kinda figured these were like gm's DI gas setups and once you start overlapping tables things naturally smooth out... I have been wondering on the rail pressure increase part as that's a really good way to get power out of a gas burner - increase rail pressure and move injection timing as close to spark timing as possible...

    With this being a diesel I was figuring on increasing cylinder pressure to get base engine power up, but how far do you go before you start causing piston and rod damage? On the other side of this I could use pre-injection to raise temps and then inject with piston closer to tdc reducing the extra stress side effects...

    After driving home tonight and fighting some pretty good headwinds and driving rather "aggressively" to get back to the house for a family thing fuel economy dropped to 30mpg, but soot stayed at 4grams until I got more into the back roads country and city stop and go driving at which time the soot level went to 15 percent - so definitely have more to work on around idle and coast area fueling events... I'm going to keep experimenting with some things - think it's headed in the right direction anyway...

    Also may understand why the oe didn't run a setup like this - although it's better everywhere else - NoX does increase about 50ppm with tune 3 under load - otherwise seems much better...
    2010 Vette Stock Bottom LS3 - LS2 APS Twin Turbo Kit, Trick Flow Heads and Custom Cam - 12psi - 714rwhp and 820rwtq / 100hp Nitrous Shot starting at 3000 rpms - 948rwhp and 1044rwtq still on 93
    2011 Vette Cam Only Internal Mod in stock LS3 -- YSI @ 18psi - 811rwhp on 93 / 926rwhp on E60 & 1008rwhp with a 50 shot of nitrous all through a 6L80

    No Longer with passion performance auto for good reasons

  5. #5
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    Does anyone know what the different modes are or under what circumstances they may be used? Best I can tell is that mode 0 or 1 is your primary fueling mode while modes 3,4,9 and 10 are different regen modes? Why does it have so many? I've tried several different things and attaching the best I've been able to come up with for putting out the least amount of Nox while still producing power and economy... Hard driving I've been getting around 32mpg while easy driving you can get in the high 30's on good flat highway... Fixed lots of the transmission issues and have gotten it to where it gegens every 350 to 550 miles depending on how much town driving I mix into it...

    Things I'm thinking about doing right now is to change the axis for tq on the fueling table and fine tune idle fueling more while still maintaining light throttle fueling... I just don't want to edit things too much more from this point without knowing for sure what the different tables are? Doesn't seem to be a whole lot of help in the diesel world even on the efi forums, soooo... Would love some info even through a pm would be nice.

    Due to the issues these motors have I'm trying to keep fuel knock to a minimum as it also shows the best efficiency...

    Another note - injectors are over fueling/leaking again - seems to be every 40000 miles for me and from all of my research people are having issues every 20 to 40000 - hoping there's an updated part to fix this issue by now... Funny thing is though unless you drive at high speeds with light throttle - you wouldn't ever know you had an issue...
    Attached Files Attached Files
    2010 Vette Stock Bottom LS3 - LS2 APS Twin Turbo Kit, Trick Flow Heads and Custom Cam - 12psi - 714rwhp and 820rwtq / 100hp Nitrous Shot starting at 3000 rpms - 948rwhp and 1044rwtq still on 93
    2011 Vette Cam Only Internal Mod in stock LS3 -- YSI @ 18psi - 811rwhp on 93 / 926rwhp on E60 & 1008rwhp with a 50 shot of nitrous all through a 6L80

    No Longer with passion performance auto for good reasons

  6. #6
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    Another question - Pilot fueling - Good thing or bad thing? The earliest tune I pulled from my truck while gm was making changes had very little pilot fueling and honestly probably got the best fuel economy of the gm cals - the one I posted above was this earliest version while this one has gm's revisions - I added to the pilot fueling, but haven't seen any difference although it's possible some is there as we are just talking ms of fueling... Any benefit to more pilot fueling?


    Also haven't tested it yet, but added to post fueling just to try and get regens to take less time...
    Attached Files Attached Files
    2010 Vette Stock Bottom LS3 - LS2 APS Twin Turbo Kit, Trick Flow Heads and Custom Cam - 12psi - 714rwhp and 820rwtq / 100hp Nitrous Shot starting at 3000 rpms - 948rwhp and 1044rwtq still on 93
    2011 Vette Cam Only Internal Mod in stock LS3 -- YSI @ 18psi - 811rwhp on 93 / 926rwhp on E60 & 1008rwhp with a 50 shot of nitrous all through a 6L80

    No Longer with passion performance auto for good reasons

  7. #7
    Tuner JaegerWrenching's Avatar
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    The modes are probably injection configurations based on many factors, from engine temp, Cold, warm, hot, to intake air temp, again cold, warm, hot, to fuel pressure Low, med, high. You're probably missing tables which allow you to pick when and how these modes are chosen, and i'm sure The data logging isn't quite up to par with showing what modes your truck is currently using. It'll say it's in mode 1 or 0 when it's actually using one or multiple simultaneously. Here is the Ford truck example of modes and these are not easy to log to know which one it's using. The scanner always says mode 0 which isn't true. Modes.PNG

  8. #8
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    Yes, the scanner is definitely lacking on the diesel side of things. I've been using a different scanner to log exhaust temps and everything else as none of the log data makes sense... Wish we could tell what tables are being used - would make things go a whole lot quicker and neater... Such as today the CEL came on for a Nox sensor that appears to be going bad again on top of everything else that seems to be going bad for a second round on my truck, but anyway truck was running completely different - I know it's just using one of the other tables I've modded in the same manner, but I liked how it ran a lot better - now I just have to figure out which one of those tables it was using, so I can make those my main tables :/ I've got a completely left field tune I'm running right now that calls for more fuel but actually uses less if that makes any sense - still can't figure out how turning fuel up slightly and increasing torque a small amount can drive down overall fuel consumption so much - I'm up to 33mpg average and can get easy enough 37 averaging 65ish mph... Was hauling a small load getting that, so we'll see... Don't know the specifics of how much fuel you can add before you start killing the motor - have heard up to 40%? I know I'm leaps and bounds from even 20%, but I haven't heard anything good about the pistons in these motors, so don't want to push much more that what I am. Probably too cautious, but I'm happy right now with how things are...

    I may hookup my efi device and see what it shows differently table wise...
    2010 Vette Stock Bottom LS3 - LS2 APS Twin Turbo Kit, Trick Flow Heads and Custom Cam - 12psi - 714rwhp and 820rwtq / 100hp Nitrous Shot starting at 3000 rpms - 948rwhp and 1044rwtq still on 93
    2011 Vette Cam Only Internal Mod in stock LS3 -- YSI @ 18psi - 811rwhp on 93 / 926rwhp on E60 & 1008rwhp with a 50 shot of nitrous all through a 6L80

    No Longer with passion performance auto for good reasons

  9. #9
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    This is where I'm at - anyone mind double checking things? Including the most recent OE file for easier comparison...
    Attached Files Attached Files
    2010 Vette Stock Bottom LS3 - LS2 APS Twin Turbo Kit, Trick Flow Heads and Custom Cam - 12psi - 714rwhp and 820rwtq / 100hp Nitrous Shot starting at 3000 rpms - 948rwhp and 1044rwtq still on 93
    2011 Vette Cam Only Internal Mod in stock LS3 -- YSI @ 18psi - 811rwhp on 93 / 926rwhp on E60 & 1008rwhp with a 50 shot of nitrous all through a 6L80

    No Longer with passion performance auto for good reasons

  10. #10
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    Glad I found this post. Nice to see you are having good results. I am taking baby steps: Torque management adjustments, increased pulse width by .25 in the 100- 120mm3 from 100 mpa and up and blended. Added a little full pressure 7mpa 1500rpm and up. My results are 35 imp MPG hand calculated. I am new to this platform an still reading everything I can find. I know that the turbo is over its rpm limit at 45psi. Here is some reading from one of the Colorado forums. Please keep sharing info this is great.

    https://www.coloradodiesel.org/threa...analysis.4985/

  11. #11
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    I can get roughly 35 to 37 mpg if I baby it - problem is I drive long distances at high speeds pulling hills and then spending about 15 minutes in stop and go city driving, so I average out to 30 to 33 at the moment... Always looking for room for improvement... I'm going back to an older tunes turbo setup that did the best for me with some minor tweaks to the tcc... I also had an older transmission tune that would hold gears better, but it was only because of engine settings - these things appear to be very dependent on the engine side for how the transmission operates and I really think we're missing some torque tables for that - all I did was turn the fuel up a touch more and the transmission acted completely different - happy with it now almost 90some percent, but wish I could still get it to hold gear longer while lugging the motor more...

    You mind posting your tune at the moment?
    2010 Vette Stock Bottom LS3 - LS2 APS Twin Turbo Kit, Trick Flow Heads and Custom Cam - 12psi - 714rwhp and 820rwtq / 100hp Nitrous Shot starting at 3000 rpms - 948rwhp and 1044rwtq still on 93
    2011 Vette Cam Only Internal Mod in stock LS3 -- YSI @ 18psi - 811rwhp on 93 / 926rwhp on E60 & 1008rwhp with a 50 shot of nitrous all through a 6L80

    No Longer with passion performance auto for good reasons

  12. #12
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    That read was actually a lot of what I was looking for - thank you... By the time my truck shifts its commanding right at 23 degrees btdc on timing and boost wise I'm running 32psi commanded, so think I'm good everywhere there... When I get more time I'm going to read through the whole write up
    2010 Vette Stock Bottom LS3 - LS2 APS Twin Turbo Kit, Trick Flow Heads and Custom Cam - 12psi - 714rwhp and 820rwtq / 100hp Nitrous Shot starting at 3000 rpms - 948rwhp and 1044rwtq still on 93
    2011 Vette Cam Only Internal Mod in stock LS3 -- YSI @ 18psi - 811rwhp on 93 / 926rwhp on E60 & 1008rwhp with a 50 shot of nitrous all through a 6L80

    No Longer with passion performance auto for good reasons

  13. #13
    Tuner JaegerWrenching's Avatar
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    Quote Originally Posted by GHuggins View Post
    That read was actually a lot of what I was looking for - thank you... By the time my truck shifts its commanding right at 23 degrees btdc on timing and boost wise I'm running 32psi commanded, so think I'm good everywhere there... When I get more time I'm going to read through the whole write up
    You can advance the timing in it to more than they have in their write up and you're going to end up around 26-29* BTDC. EGT's will drop while increasing timing gradually until peak cylinder pressure is just after TDC. It will then revert quickly and start getting hotter as you get too advanced. One big thing they missed in all of this is back pressure and BP ratio. I didn't see it mentioned once, that can really affect a lot of the data also. I'm also very curious how they were measuring heat loss per rotation? That's very hard to do and if they had a sensor in the head its location in the head is crucial in order to obtain proper data. Same goes for measuring cylinder pressure, it's not all cut and dry just stick it in there. Also check their timing, their ramp in is decent but it's jumpy after 3800rpm while still under acceleration and RPM rise before the shift.

  14. #14
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    Just had a recall done on the truck. Dealership replaced the last sensor in the exhaust and reflashed the PCM. Had the P1478 code. Glad the write up was interesting for you. Data is data! Jaeger has a lot of good points also. Both of you are far more experienced than myself. My tune is far more in the infant stage than what you have. My understanding is when you increase pulse width, it pushes injection later in the cycle. So you have to increase fuel pressure or increase timing. Now timing is confusing for me, therefore have not touched it yet. I am at sea level and was thinking of taking the high altitude SOI map and using it in the low altitude map. Any thoughts on that?

    Colorado speedo fuel pressure 7mpa pulse width .25 .hpt

  15. #15
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    Quote Originally Posted by JaegerWrenching View Post
    You can advance the timing in it to more than they have in their write up and you're going to end up around 26-29* BTDC. EGT's will drop while increasing timing gradually until peak cylinder pressure is just after TDC. It will then revert quickly and start getting hotter as you get too advanced. One big thing they missed in all of this is back pressure and BP ratio. I didn't see it mentioned once, that can really affect a lot of the data also. I'm also very curious how they were measuring heat loss per rotation? That's very hard to do and if they had a sensor in the head its location in the head is crucial in order to obtain proper data. Same goes for measuring cylinder pressure, it's not all cut and dry just stick it in there. Also check their timing, their ramp in is decent but it's jumpy after 3800rpm while still under acceleration and RPM rise before the shift.
    What did you think of the tune so far? I put my older timing table in which is only a little more advanced and my older turbo table. Still fine tuning shifts
    2010 Vette Stock Bottom LS3 - LS2 APS Twin Turbo Kit, Trick Flow Heads and Custom Cam - 12psi - 714rwhp and 820rwtq / 100hp Nitrous Shot starting at 3000 rpms - 948rwhp and 1044rwtq still on 93
    2011 Vette Cam Only Internal Mod in stock LS3 -- YSI @ 18psi - 811rwhp on 93 / 926rwhp on E60 & 1008rwhp with a 50 shot of nitrous all through a 6L80

    No Longer with passion performance auto for good reasons

  16. #16
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    It was ok but found in stop and go traffic the soot level would go up quickly. What tune are you running now? Tune 2. I also pulled the Canyon stage 4 tune from the repository and had a look at that. Thought about reducing everything by 25%.

  17. #17
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    This is what I'm running right now - I've actually been using some of the cummins 6.7 for reference as they have a much cleaner idle - they run positive injection timing at idle... It's still a work in progress - gets anywhere from 400 to 500 miles on regens as long as your doing primarily highway / has decent power / gets 32 to 33 on the highway even after the exhaust recal, which you should notice costing you fuel economy now. Still needs trans tweaking - hard to do with our current hpt scanner - lacking a lot on these, so logging with another and making corrections based on data I'm seeing on it...
    Attached Files Attached Files
    2010 Vette Stock Bottom LS3 - LS2 APS Twin Turbo Kit, Trick Flow Heads and Custom Cam - 12psi - 714rwhp and 820rwtq / 100hp Nitrous Shot starting at 3000 rpms - 948rwhp and 1044rwtq still on 93
    2011 Vette Cam Only Internal Mod in stock LS3 -- YSI @ 18psi - 811rwhp on 93 / 926rwhp on E60 & 1008rwhp with a 50 shot of nitrous all through a 6L80

    No Longer with passion performance auto for good reasons

  18. #18
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    Yes HP is lacking a lot. Oh great less fuel economy. I regen every 250miles only on the highway. I am currently looking at the Banks I dash. Can data log and has a lot of PID avalible

  19. #19
    Tuner JaegerWrenching's Avatar
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    Quote Originally Posted by GHuggins View Post
    This is what I'm running right now - I've actually been using some of the cummins 6.7 for reference as they have a much cleaner idle - they run positive injection timing at idle... It's still a work in progress - gets anywhere from 400 to 500 miles on regens as long as your doing primarily highway / has decent power / gets 32 to 33 on the highway even after the exhaust recal, which you should notice costing you fuel economy now. Still needs trans tweaking - hard to do with our current hpt scanner - lacking a lot on these, so logging with another and making corrections based on data I'm seeing on it...
    I think you are doing fantastic especially when you consider the tools you've been given to complete your task. You're doing everything right and i wouldn't change anything. Keep an eye on BP ratio in the cruse region, you can sometimes pick up some by dialing in VGT position a little or commanded boost. Other than that keep messing with main timing until you find a happy spot, log it on the same tune a few times on the same spot for continuity and then if you really want to tinker start to play with pilot and see how it goes. We live in an age where these trucks are more or less just limited by emissions or torque reduction. But most of the time these stock tunes are really close. You know as much as i do and playing with your car over a long period with tons of logs will yield the best result.

  20. #20
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    How much fuel addition starts getting into unsafe territory? I'm running in the 30 to 40 percent addition now showing the best results...

    When you say BP ratio - I assume Boost Pressure to Fuel correct? What would be a good target? I've noticed that I can have fuel knock at times, but the second you hit boost with fuel staying the same the knock goes away - are diesels this sensitive to an air fuel ratio?

    Why is it I can change rail pressure - which I assume raising it puts more of the fuel in at the original soi point - does the engine get quieter?

    What is a good rail pressure target that won't overly stress the pump?
    2010 Vette Stock Bottom LS3 - LS2 APS Twin Turbo Kit, Trick Flow Heads and Custom Cam - 12psi - 714rwhp and 820rwtq / 100hp Nitrous Shot starting at 3000 rpms - 948rwhp and 1044rwtq still on 93
    2011 Vette Cam Only Internal Mod in stock LS3 -- YSI @ 18psi - 811rwhp on 93 / 926rwhp on E60 & 1008rwhp with a 50 shot of nitrous all through a 6L80

    No Longer with passion performance auto for good reasons