Results 1 to 15 of 15

Thread: Speed Density Tuning

  1. #1

    M157/M278 Speed Density Tuning

    Has anyone had success tuning the speed density tables? Are there power gains available, or is it unnecessary to change?

    Most importantly, do these tables need to be adjusted in response to other changes made to the tune?
    Last edited by Schnell; 02-09-2022 at 10:40 PM.

  2. #2
    Advanced Tuner
    Join Date
    Jan 2022
    Location
    Southern California
    Posts
    348
    All I can tell you is everything on that page is the same between my stock file and aftermarket OE Tune. But who knows what OE modded that HP Tune can't see. My guess is there's tons more stuff in the ECU but HP only shows up the most relevant for power?
    I wish there was a way to see it all. and I don't just mean power stuff, but everything. Soooo many things I want to change, and I probably have the tools to do it but don't know how... Like Vediamo & Monico, but no clue how to get it do what I want.
    '16 E550 Coupe RWD - C207.373 / M278.922 / MED17.7.3 / 722.909

  3. #3
    Advanced Tuner outlaw_50's Avatar
    Join Date
    Nov 2020
    Location
    United Arab Emirates, AlAin
    Posts
    204
    Quote Originally Posted by chevota View Post
    All I can tell you is everything on that page is the same between my stock file and aftermarket OE Tune. But who knows what OE modded that HP Tune can't see. My guess is there's tons more stuff in the ECU but HP only shows up the most relevant for power?
    I wish there was a way to see it all. and I don't just mean power stuff, but everything. Soooo many things I want to change, and I probably have the tools to do it but don't know how... Like Vediamo & Monico, but no clue how to get it do what I want.
    Winols + Damos is what your seeking
    Xstages Motorsport

    Tuning inquiries:

    ECU, TCU, CPC Online Tuning
    Whatsapp: +971503383340
    Email: [email protected]
    Insta: @xstages.motorsport
    www.xstages.com

  4. #4
    Advanced Tuner
    Join Date
    Jan 2022
    Location
    Southern California
    Posts
    348
    outlaw; thank you for that. I downloaded the free demo at some point, I think last year, and like HP Tuner it gave me a headache trying to figure it out, only worse.
    With no guarantee it'll work on my car, how to use it, or price, I passed on it like I did with misc other programs. Your suggestion that it's what I need is really the only information I have on it.
    I don't suppose you know what it costs?
    Damos is an add-on or what? More $ I assume?
    I don't suppose it can also do non-engine stuff like prevent the exterior lights from coming on when I unlock or lock it? Or opening the door? Turn off Eco Stop. Adjust the turn signal from three blinks to one? Stuff like that. And if it can, how on earth does a person find what bit of code does that? Is there some guide? I suppose, like HP, there is nothing.
    I have no idea where things like that stored, I'm just guessing it's the ECU.
    '16 E550 Coupe RWD - C207.373 / M278.922 / MED17.7.3 / 722.909

  5. #5
    Bump for speed density tips. Would like to understand how to tune this section.

    Main goal is to fix a lean condition and ensuing high STFT (at idle only) running E85. Adding fuel under injector slope and Inj PW don't seem to apply after the car comes to a stop and idles for a short time. Something changes and I can't see what it is with the scanner PIDs we have available. The channels are very limited.

    @engineer@hpt

  6. #6
    Advanced Tuner outlaw_50's Avatar
    Join Date
    Nov 2020
    Location
    United Arab Emirates, AlAin
    Posts
    204
    post log and tune to check where you could fix it
    Xstages Motorsport

    Tuning inquiries:

    ECU, TCU, CPC Online Tuning
    Whatsapp: +971503383340
    Email: [email protected]
    Insta: @xstages.motorsport
    www.xstages.com

  7. #7
    Advanced Tuner
    Join Date
    Jan 2022
    Location
    Southern California
    Posts
    348
    I believe Schnell and I have the same problem so I'll post a good example log from today.

    At 5:23:14 you can see the Inj PW drops from .40 to .30 and trims shoot up to correct it.
    idle issue.hpl
    I can't say what is happening but my guess is switching to an oem fuel map we can't see, which does not include Slope or Inj PW Multiplier changes we make.

    I need ~32% more fuel at idle compared to the oem fuel map, so when this mode kicks in it drops fuel by ~25% and it takes the same ~32% more to bring it back.
    If my fuel needs are only 10% greater, which it is with pure pump gas, then that's the difference you see when this happens.

    My Speed Density settings are oem. The entire tune can be oem and this plays out exactly the same.
    My LTFT are negative so my STFT won't peg 25, if you were wondering.
    '16 E550 Coupe RWD - C207.373 / M278.922 / MED17.7.3 / 722.909

  8. #8
    The tables are of MAP in kPa, with rows being IAT and columns being ECT. I'm logging fuel trims with the same row/column values but not sure why they don't go up to full operating temperature. Maybe because the tables aren't used at operating temp?

  9. #9
    Advanced Tuner outlaw_50's Avatar
    Join Date
    Nov 2020
    Location
    United Arab Emirates, AlAin
    Posts
    204
    Quote Originally Posted by chevota View Post
    I believe Schnell and I have the same problem so I'll post a good example log from today.

    At 5:23:14 you can see the Inj PW drops from .40 to .30 and trims shoot up to correct it.
    idle issue.hpl
    I can't say what is happening but my guess is switching to an oem fuel map we can't see, which does not include Slope or Inj PW Multiplier changes we make.

    I need ~32% more fuel at idle compared to the oem fuel map, so when this mode kicks in it drops fuel by ~25% and it takes the same ~32% more to bring it back.
    If my fuel needs are only 10% greater, which it is with pure pump gas, then that's the difference you see when this happens.

    My Speed Density settings are oem. The entire tune can be oem and this plays out exactly the same.
    My LTFT are negative so my STFT won't peg 25, if you were wondering.
    Sorry still didnt have a chance to check the log as I dont have my laptop on me

    But have you tried changing the Desired Fuel Pressure where you are having the lean issues?

  10. #10
    Advanced Tuner
    Join Date
    Jan 2022
    Location
    Southern California
    Posts
    348
    Fuel pressure makes zero difference. I thought that at first since psi drops at idle by a similar %, but locking it at full psi doesn't do anything at all. Plus the psi change and fuel change are usually not at the same time.
    '16 E550 Coupe RWD - C207.373 / M278.922 / MED17.7.3 / 722.909

  11. #11
    Advanced Tuner outlaw_50's Avatar
    Join Date
    Nov 2020
    Location
    United Arab Emirates, AlAin
    Posts
    204
    try sensor bias or change the first cell of PE table on the upper left corner to something richer

  12. #12
    Advanced Tuner
    Join Date
    Jan 2022
    Location
    Southern California
    Posts
    348
    I think what is happening is when it shifts into this mystery mode is it's simply ignoring any Slope or Inj Pulse Mult settings.
    I thought it was the Ethanol content but only because I have been setting the Slope to match. If I need 30% more fuel and set Slope +30%, then mystery mode goes that % lean and trims go to 30. With the same 30% fuel need but I only add 15% Slope, then mystery mode is 15% off and trims go to 15.

    I guess that rules out a lot of things but doesn't tell us wth it is >: |

    So this past week I've been running less Slope and it's less of an issue, but LTFT are high. I assumed if the system faulted to Open Loop then Slope would save me, but in cold start open loop Slope is not adding extra fuel so I can only assume the same under full load. If so, then adjusting Slope is completely pointless and I should let LTFT deal with my extra fuel needs.
    Why does Slope even exist if it's only works in closed loop where it's not needed?
    '16 E550 Coupe RWD - C207.373 / M278.922 / MED17.7.3 / 722.909

  13. #13
    Have you found a way to tune STFT & LTFT to be 0% or around that?

  14. #14
    Advanced Tuner
    Join Date
    Jan 2022
    Location
    Southern California
    Posts
    348
    Mr AT:
    Yes and no. I can use Slope to get the average ~0, but it also moves around a lot, like +-10 as I drive and that is not as easy to adjust for. You use "Inj Pulse Mult" to bring that spread down. I tried it once out of curiosity and I only made things worse.

    I believe the problem trying to fine tune it is data flow. The data we see in the Scanner is delayed, and the O2 reading is delayed on top of that, which in turn means the trims are at least that much delayed. So in my attempt to fine tune I'd see xx rpm and xx Inj PW and xx Trim so I would adjust the Inj Pulse Mult to correct it, but the trims were really from some earlier moment so my adjustment usually just made them worse.

    The only way to get an accurate reading, imo, would mean going to a steady load/rpm on the Inj Pulse Mul chart, hold that until you know the trims are for that point. Since the car accelerates while doing this, good luck. I guess you'd need a big long steep hill so you could load it but not accelerate. And no cops or traffic to bother you while doing it which is impossible for me. Plus a lot of time collecting data at each rpm and load in the chart, so it's a hard pass for me. Plus, what would all that work net you? Nothing... Just a number on a screen is closer to 0. So imo it's more of an OCD thing. Sure my mild OCD would love it to be 0, but it's way way too much work.
    So I only adjust Slope to bring the average trims closer to 0 and let it move around +-10 all it wants.

    So I would just look at the avg trim and bump Slope by the same %.
    With my oem Slope of 0.01669792 netting trims of ~+10 on Gas, I added 10% which was 0.018367712. It won't accept just any # so just plug in your # and see what it rounds it to. All I remember is I ended up using 0.0185 for Gas. I'm running 30% Ethanol now which needs a Slope of .021, but that causes problems with "Mystery Mode" mentioned in my previous post. A Slope of .019 does not cause a problem so that's what I've been using. I just leave it at .019 if I run Gas or Eth, which just means the trim avg on Gas is slightly negative and on 30% Eth it's ~ +14.
    '16 E550 Coupe RWD - C207.373 / M278.922 / MED17.7.3 / 722.909

  15. #15
    Advanced Tuner
    Join Date
    Jan 2022
    Location
    Southern California
    Posts
    348
    Schnell: My redneck fix for the idle issue (pix). It isn't perfect because as you know the lean issue comes and goes, but overall I have not had an O2 fault out using this and that was the most important thing for me. Driveability is fine.
    My Slope is set to work with whatever mix of Ethanol I'm using, which is ~46% at the moment and I think slope is .022? What's important is the lean out I applied at idle and around it. This forces the LTFT to got up at idle which means STFT never hits 25, which is where my O2 would fault out. I've been doing this for weeks and it's good.
    I learned that changes to fuel need to be loaded and run in closed loop or your cold open loop just may be a disaster. I made this change slowly, like lowering the .975 to .94, .90, .86 etc. I believe if you just went straight from .975 to .800 you would be like 18% lean until you made it to closed loop. Then, I assume from trial and error, it then remembers your previous trim and applies it to your next cold start and you're good.

    I think I mentioned previously that mystery mode attacks STFT harder based on how much slope/pulse width you add. So basically all I'm doing is adding the slope I want to more or less zero out trims above 1500rpm, then subtracting it via the PW table at idle. Note the blending isn't just to blend, but it's get LTFT to ramp up. If you just set the idle rpm cells then LT will either remain low or be too slow to change and when mystery mode strikes the party is over. Then same as you lightly accelerate, say traffic, you don't want to fault out at 1000rpm x 1ms so I have it leaner under a little load too. Beyond 1.5ms it seems mystery mode goes away.

    Are you running pure E85? Because I had mine up to 52% pure Eth last week (counting the E85 + the 10% in the gas) and I started to lose a little fuel psi at that %. I didn't go lean or anything but I figured that's my limit. I also "seem" to dump in more fuel than other people? Based on Inj pulse width that is. I see others scanner runs and they usually stay under 3ms on gas, mine is 50% or more higher. My all the time highest, that I've noticed, is 6.44 on that 52% mix. So I wonder what your pulse width is at peak? I wonder if I were normal and only hit 3ms on gas, then maybe I could use straight E85? Do you watch fuel psi? Have you ever seen it lean out? Of course boost matters too because my pw shoots way up under boost, and I mean a greater % than it should. I've wondered if it's a glitch or what. Sure cyl psi is higher so it's more difficult to get fuel in, but 6.44ms seems excessive.
    Let me know about all that because I'm very curious what yours is doing and it's not like there's many of us to share notes.

    Anyway, here's what I did. This brought my STFT at idle, in mystery mode, to ~5 or so. It doesn't need to be down at .800, .850 works too, it just means the idle trims are higher, like ~12.

    Inj PW 800.jpg
    '16 E550 Coupe RWD - C207.373 / M278.922 / MED17.7.3 / 722.909