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Thread: 2015 GLA45 AMG - Tuning

  1. #1
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    2015 GLA45 AMG - Tuning

    Hi Gurus,

    Hoping someone can help me with understanding how to tune Fuel for my 2015 GLA45 AMG.
    Do I update Temperature Control > Target Lambda?
    - I'm guessing there would be activators and monitors that need to be changed as well?

    Any help would be appreciated.

  2. #2
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    I have a different engine but I'd say Target Lambda is most important by far. I also have Second Fuel which I noticed has kicked in a few times and I don't know how/why that happens. There is also Power Enrichment which I've noticed can have an effect but can also be left alone and Target Lambda does everything I need. It's frustrating because there are no directions on the other things and the explanation in HP is vague or wrong, but Target Lambda is what you need to adjust for sure, then make Second fuel the same or richer in case it kicks in.
    In mine I can adjust Power Enrichment but it doesn't follow the chart. Eg I set it to richen at 80% load and 4kprm and above, but it'll richen everything below that as well. I have to start richening at 5k, then the lower rpms are ok. Is the chart bogus, scaled wrong, broken? Who knows, all I know is it doesn't work right in my car. Other things don't work right either so it's a lot of trial and error. Not sure if HP programmers dropped the ball or what, but it is what it is.
    I also reduce my Exhaust temps. Again, broken because it says Ex temps are disabled, but clearly not. I worry I may overheat my exhaust but not so worried that I don't mess with it. I think I have set to ~200-250F lower than it comes and that nets a big gain in power.
    I believe it's nothing more than a reference chart and somewhere in there, which we can't see, the ECU will look at that chart to estimate temp and pull power if it thinks things get too hot. So you plug in a lower # and it think things are ok and doesn't pull power. That's my theory anyway. Is the exhaust really as hot as the oem chart says? Maybe under the worst conditions, but maybe they also added a buffer. Will said temps actually hurt anything? Maybe under the worst conditions and again maybe a buffer is added. Since people aren't burning up turbos and valves left n right I'd imagine it's ok. Plus all the cars and hotrodders that don't have any such a safety seem to be more or less ok too. If you do cook a turbo then I guess that's the chance you take, which goes whenever you tinker. If I cook a turbo then I'll install bigger ones, which would be such a bummer to have

    Keep in mind that fuel worked as it was, but imo is likely on the very lean end to satisfy the EPA. I can say my Target Chart was, imo, stupid lean and I'd never run an eng like that. In fact I'm surprised it did run like that but I also bet that's why all the limiters like Ex temp exist and why it was in fact pulling power. So in my mind that cart is set to emissions mode. If this theory is correct then richening the fuel will make it run cooler, which means moving the temp limits is safe. By how much is the question, and how much do the temps need to be moved to net max power? All I can say is I lowered temps by 6% and it made a big difference. I then lowered another 6% and it helped, but not nearly as much. So my guess is somewhere in that second lowering is where it's no longer limiting power. Or maybe I'm not making enough power yet to trigger it, who knows. In the end it's your engine and you have to decide how far you're willing to push it, knowing there are risks. I'm used to hotrodding engines with minimal data. I remember when I bought an exhaust temp gauge and narrow band O2 I thought I was high tech. In reality I think I'd still be ok with that, but throw in a knock sensor and I'd be golden. We have all that and more so I think as long as you understand how an engine works you're fine.
    '16 E550 Coupe RWD - C207.373 / M278.922 / MED17.7.3 / 722.909

  3. #3
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    Thank you for the info and agree on everything you stated. I too was very surprised to see how lean they run. Whilst it does the job for EPA and economy, i want some safety margin before turning boost up.

    I adjusted the Fuel > Temperature Control > Component Protection > Target Lambda > Bank 1 & 2nd Fuel but the desired lambda didnt follow the table.
    I then lowered the Exhaust > Temperature > Exhaust Gas Temperature > Estimated Exhaust Gas Temperature, Var 0 hoping this would trigger the activation of the table but again the desired lambda didnt follow the table.
    So decided to adjust Fuel > Power Enrichment and finally got the desired lambda to follow closer to the table.
    i'll make a few more alterations and log for a couple of days before moving on.

    Next steps will be Timing table:

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    You changed all the bank 1 & 2 var tables for fuel & ex temps right?

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    Yes. Bank 1, secondary fuel and exhaust temps. Also the power enrichment.
    From the testing I conducted, all 4 need to be changed to produce the required results.

  6. #6
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    The way you worded it sounds like you only did bank 1. Im sure you meant 1 & 2, plus 1 & 2 secondary.
    Glad power enrich worked for you. I dont know what its supposed to do on mine.
    So how'd it work out??
    My oem timing is too much so I had pull 3deg at higher load and all the mid range. A little E85 fixed that so I guess it wants ~93 octane vs the 91 available. Point being there was no room to add timing. In my non-tbo tinkering timing wasnt a big deal, if it was 5 neg I couldnt tell, 10 deg maybe. Once I was 30 neg and I could certainly tell but it wasnt as big a deal as it sounds. So chasing a few deg is back burner for me. The limiters are the biggie on mine, just have to figure out which work and which are broken. Like max wheel torque doesnt work for me, some others I have to double the #'s to get them to work.
    Its crazy a 4cyl can make so much power. Cant help but think same tech, power per liter, in my 4.6. Or your eng in a tiny car.

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    They are one hell of an engine! the same in a 4.6 would be next level.
    Only have bank 1. and secondary 1. No bank 2 or secondary 2.
    Power enrich worked a treat. Very happy with where the fuel is.
    Timing seems ok so will leave that.
    The limiters are defiantly a pain.
    I've got a dead spot where in 3rd gear it will boost to about 21psi by 3500rpm then hold at 21psi until 4500rpm.

  8. #8
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    My brain is broken. I knew you had a 4cyl but kept thinkin V8 for the fuel banks 1 & 2.
    If you post hhe tune I can see if its anything obvious. And ideally a good run showing the boost issue

  9. #9
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    Im thinking it might be related to the TCM limiting the torque.
    Current tune and log file attached along with stock file.
    MERC97_STOCK.hpt
    MERC97_TUNEV17.hpt
    MERC97_TUNEV17_Log_File_3rd_gear_pull.hpl
    Any help would be much appreciated.

  10. #10
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    Sorry it took so long but life gets in the way of play time.
    I modded your file more like what I would do if it were my car. I didn't bump them as much as I would in my car because it's not my car, but it still might be more than most would ever try.
    From what I see it's clearly limiting boost, which you can see in the turbo duty cycle. In my car about 55% DC will give max boost up to maybe 4500rpm, then with more flow/rpm it needs more force to hold the wastegate closed which means more duty cycle. If I lower it to 50% I can kiss about a third of my power goodbye. 45% it might as well not have a turbo at all. Point being that you can't assume 10% difference in DC will make 10% diff in boost. Plus this all changes with ex flow, so after ~4500 I lose a little bit of boost/power unless the DC is increased. Not sure what DC I need at max rpm but 60-65% DC is probably all it needs. While I've never tried it, I imagine setting min to 50% and max to 65% will do all I need. Your eng/turbo will be different, obviously, but I bet it has a similar narrow window that is useful and the rest useless.
    Adjusting the min DC won't help your issue, but it can help troubleshoot. So I set my min to 50% first time I messed with it, which was pretty spot on. The problem is it can cause overboost at lower rpm, so be wary. At 55% mine will overboost a good bit below 4k so that's too much. 50% is more on the safe side, but 52% makes a lot more boost than 50%, but also overboost more. So I decided the overboost of 52% was acceptable in order to minimize turbo lag and areas where it would otherwise pull boost.
    I don't think the overboost hurting anything but I don't really know. The only parts that I think are in danger are the intercooler and plastic intake manifold, which now see maybe 50% more boost that it otherwise would. Did they make it with enough safety margin that I'm ok? Who knows. All I know is they do let go on some people but I've never read what psi that was. Your car I don't know about but I'd imagine similar parts are at risk?
    Also note you have a "Manual Control" for duty cycle, which I have too but it doesn't work. Not sure if just doesn't work on my car, all cars with my eng or just another bs thing in HP that doesn't work at all. So if I were you I'd turn that puppy on and see if it follows the #'s. The #'s in its chart look fine/safe as-is so I'd leave them as they are for now. If it does work then great, but know that if the ecu doesn't like it it'll pull throttle to control boost. Frikin frackin stupid computers... Manual throttle control would be the best thing ever, and is possible, but HP certainly doesn't offer it. On a 1-10 scale of things I want HP to do, Manual throttle would not only be #1, it would be 1-8. If I had that + manual boost I don't think I would need anything else, other than a little fuel enrichment, and I'd be done. Instead we have an overly complicated puzzle, a little piece of a Rosetta stone, and not nearly enough tools. It reminds me of what they say about big pharma, that it's much more profitable to treat a disease than cure it. I wonder if similar is happening here?

    With yours opening the wastegates as much as it is it's certainly able to make more boost, it just isn't allowing it. Deciphering how to allow more boost has not been easy for me. I mean I can get more super easy, but getting how much I want across the board, not so much. It's such a pita that I'm once again considering making my own boost controller because the computer clearly isn't capable. Or I'm not capable of figuring it out, but either way I can't keep the turbo duty cycle where I want it all the time. I also noticed it varies day to day, or during the day. I get good boost on a run, then I floor it later and I'm down 20%. Why I may never know. This is also super frustrating because I may have a good tune but discard it if it felt like running low when I tested it.

    So go through the tune and see what I did, then decide if you want to run it as-is or tweak it however you like, but lets see what happens and go from there.
    Also know that I have no experience with your eng, and not much experience with HP period, but I do know engines. So keep in mind this tune is from some rando guy on the net who is not a professional tuner. While I would jump right in and floor it, I suggest you ease into it, like put in in 3rd at say 3k and slowly floor it, or maybe floor it for a second and stop, check the data, push it more etc. I can't imagine anything bad happening but it doesn't hurt to ease into it. I'm sure you know all this but I feel I should mention it.

    I also attached a pix of all my PID's, some of which I think you should add. Eg cyl knock avg, actual throttle position, horsepower, front/rear wheel speed, manifold psig. The wheel speed is virtually pointless because of the slow data I mentioned, but it does show obvious wheel spin if you have 2wd. If awd then never mind.
    I also like boost to read from ambient (psig), which is just boost minus ambient. Some may say it's pointless but it's easier for me to relate. So I have two gauges for boost, psia and psig. I avg the knock sensors to give me one value for easy reference, and I can easily look at the PID's on the left to get more details. HP, psig and retard avg are all math functions. If you need I can explain how and send you mine to look at.

    Note the "Driver Input" pix I attached. I had to raise the crap out of these # to get it to work, but you don't have that chart at all. Maybe MB decided it wasn't needed, or maybe HP didn't add it. If the latter I'd imagine you're F'd. I know my car would be.
    The "Max Desired Load" is important too. I didn't bump yours up much but I had to more than double my #'s to get it to work. Not sure if things like this are just my car or what, but I see others will only bump a little, like 5% or 10%. That 10% would do nothing for my car.
    Then there's Torque to Load which is also important, and I believe I need to bump mine further than I have it but when I do I get a torque error and shutdown. It doesn't stop the eng but it's no better than putting it in neutral. Have to pull over right then and a restart will fix it, but I load a different tune because I don't want a repeat. A surprise shutdown is not good when you're on the freeway... Fyi when you test, might want wary of where. Oddly enough, my shutdowns only happen at low rpm and low load, not in the range of the chart. But like the Power enrichment I mentioned in a previous post, the charts don't always do what they say.
    So my Torque to Load limit is ~17% higher than stock, any higher, shut down. I also noticed that the lower % torques are more sensitive. If say I bumped 50% by 5%, shutdown. Who knows if yours will do that, but I set it to a conservative #. The 90 & 100% lines are also flat across where the oem has a large drop at 2500. So this should help your issue. It may also make too much boost, especially at the 2500-3k mark, but only one way to find out.
    For me this Torque to Load chart is far more sensitive than any of the others. If I drop the #'s in the bottom row by 10% I'll lose more than 10% power. All the other charts 10% doesn't do much, if anything.
    The Optimum Torque chart also causes a shutdown if I go too far, but it's limit is about 10%. Not that it matters because I can't tell the difference between oem and +10%.
    Next to the Optimum Torque chart is "Min Efficiency". I see you changed that and I left it alone. Mine oem settings were 1.00 in all cells, which is where I left it. I have no idea what this is and the description is of little help. I've never tinkered with it but maybe I should? I'm curious why you did and if maybe you know what it does? I would set yours to 1.00, or at least higher than it is, and see what happens, but up to you.

    MERC97_TUNEV17 chevota.hpt

    PIDz.jpg
    Max Desired Load.jpg
    Driver Input.jpg
    '16 E550 Coupe RWD - C207.373 / M278.922 / MED17.7.3 / 722.909

  11. #11
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    Quote Originally Posted by MERC97 View Post
    Im thinking it might be related to the TCM limiting the torque.
    Current tune and log file attached along with stock file.
    MERC97_STOCK.hpt
    MERC97_TUNEV17.hpt
    MERC97_TUNEV17_Log_File_3rd_gear_pull.hpl
    Any help would be much appreciated.
    Hi I try to check it when i am at home. I have A45, maybe we can share something.

    Say if you can log over 475Nm of torque 4500+rpm! It seems to be some TCU limit. It can go over 500Nm short time around ~3500-4500rpm. If you can do it, there is something that i can't understand.

  12. #12
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    @MERC97

    Hmm

    I did check it through and there is couple of things i would changed back. It think they are little bit dangerous. Turbo PID (P and D), change those back. Same with torque while sifting and first gear torque limit, to be safe . I have lover or stock. My m133 can do 3rd gear 80-120km/h 2.0-2.1s. you did 3s. So there is something to get it quicker . You should get it going around 2,4-2.5s with the OEM turbo.

    I can make one version for you, if you want (for science [free]). maybe it will help you. I started to editing it, but didn't finish it yet.

    You have to add more PID's for the scanner. TPS, lambda values, rail pressure, injection and others. You can add more latency to the pid's (right click on the pid list) you will not have to refresh so often. Like oil temp, water temp so on.. 500-1000ms should be fine.

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    Thanks for the help guys.

    @chevota, Epic write up and appreciate the level of detail. I reviewed the tune you supplied. There was some items i wouldnt touch but "Sent It" anyways. Here is the 3rd gear pull. looks to be same issue. I didnt want to mess with the duty cycle as ive noticed 4th gear pulls dont limit the boost at the same rpms.
    CHEVOTA - 2nd gear pull.hpl
    CHEVOTA - 3rd gear pull.hpl

    @Makeclick, Agree with you about the TCU limiting torque which looks to happen in 2nd and 3rd gear. Not sure if its a reference to wheel speed, gear selection or something else.
    I'm grateful if you would like to work your magic on a tune for me. The 475Nm does seem to be the torque limit.

    For Scanner PIDs:
    Polling = 10ms for all except temps and Baro pressure
    Throttle = Commanded Throttle Actuator (SAE)
    Fuel Commanded = Equivalence Ratio Commanded (SAE)
    Fuel Wide Band = WB EQ Ratio 1 (SAE) (2)
    (i have a dedicated screen mounted to monitor performance while driving)
    MERC97.Layout.xml
    MERC97.Channels.xml
    MERC97.Charts.xml
    MERC97.Gauges.xml
    MERC97B.Charts.xml

    Math Parameters:
    BOOST.MathParameter.xml
    POWER KW.MathParameter.xml
    TORQUE Nm.MathParameter.xml

  14. #14
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    Hi again

    There is TPS sensor also. Inj pw is important too. If you use inj PW multi to adjust fuel, you will need it.

    Here you go, but please. test it for caution! log STFT, labda and boost. Please, run it many runs... everytime higher and higher rpm, so you can see everything looks ok . And don't blame me, if you brake something! I tried to make it even safer than your version.
    MERC97_TUNEV17 Be careful_do_not_just_use_TEST.hpt

    Maybe this going to be something you will hate, but maybe it will give you different perspective of tuning for this brain melting ECU .

  15. #15
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    @MERC97

    Any news? would be nice to look some 3rd or 4th pull. Did it boost more?

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    @Makeclick
    I've been running the tune for a week now and its defiantly better.
    Boost is higher and drivability is excellent.
    Log for 3rd gear pull.
    18.08.2022 Log File - 3rd gear pull.hpl

    Log for Race Start.
    18.08.2022 RACE start.hpl
    There is an issue with race start when shifting into 3rd gear, seems to just cut throttle for a few seconds due to hitting a limiter (probs the 475 as discussed).
    Do you get the same with your A45?

  17. #17
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    Quote Originally Posted by MERC97 View Post
    @Makeclick
    I've been running the tune for a week now and its defiantly better.
    Boost is higher and drivability is excellent.
    Log for 3rd gear pull.
    18.08.2022 Log File - 3rd gear pull.hpl

    Log for Race Start.
    18.08.2022 RACE start.hpl
    There is an issue with race start when shifting into 3rd gear, seems to just cut throttle for a few seconds due to hitting a limiter (probs the 475 as discussed).
    Do you get the same with your A45?
    Hi

    Naah... I don't get that. I didn't copy all my changes. I don't like it. There is some other limiter. You have to add the Throttle position sensor. I bet it will limit, even your commanded throttle is 100% the TPS % can be lower.
    Maybe it is something to do with airflow limit or exh temp?

    You can add little bit more load to lower rpm range (in torque to load map), but don't add more to upper, because your WG is too high all ready.

    This is only for testing, if you found the limiting factor
    You can test this too add +2 or +3 to 3500-5500 intake valve. I think this will make it lot better. It will raise combustion ratio and torque, but it will calculate less. You ass will think other vice . You may need to add more fuel.