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Thread: Hard Coded MAF limit in LHU?

  1. #1

    Hard Coded MAF limit in LHU?

    Hi,

    I working on a LHU in europe right now, which i cannot get to read the MAF higher the 251-255 g/sec, I already increase the MAF housing diameter and rescaled the MAF table to fit, but still the same limit.

    on the stock housing this is aroun 12kHz, thats why i thought it's maxed out and tried a bigger housing.

    is there a hard coded limit in the OS?


    hope anybody can help me on this.

    Thanks Tobi

  2. #2
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    Turbo discharge pipe on the LHU is very restrictive, less than 2" I think.
    All cobalts with turbo upgrade have bigger discharge pipe 2.25" or 2.5"
    Not sure if would help.

  3. #3
    in the meantime I found out thats not like I said before, driver demand was a little low, so by occassion it run in the same limit and i was wondering about this, now I have it reading 300+ g/s.

    yeah the discharge pipe, i have to enlarge it to 2.25 or 2.5 i think, but I have to search someone who can fabricate it for me.

  4. #4
    hi there,
    made some more mods lately, now i am struggeling a boost limit of exactly 2bar.
    I am running a ZFR7163 now, making real good power now, but I cannot go past 2 bar boost, car seems to cut injection then.
    I experienced this boost limit befor on the stock k04 Turbo, but never looked further for it, because I didn't want to punish the Turbo that bad.

    any input would be appreciated.

  5. #5
    found it

  6. #6
    Quote Originally Posted by dertobi View Post
    found it
    So... What was it that you found?

  7. #7
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    Quote Originally Posted by dertobi View Post
    found it
    Hi) we have the same config and same problem. We cannot past 2 bar boost( can you help us?

  8. #8
    Senior Tuner cobaltssoverbooster's Avatar
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    post your tune file. i am almost 100% positive i know what is happening but i need to see your tune file to confirm my suspicions.
    2000 Ford Mustang - Top Sportsman

  9. #9
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    Quote Originally Posted by cobaltssoverbooster View Post
    post your tune file. i am almost 100% positive i know what is happening but i need to see your tune file to confirm my suspicions.
    Attached Files Attached Files

  10. #10
    you could try to disable map voltageb diag in the pressure diagnostic section, but i always also change a value which is not accessible with hpt, thats why i am not sure if only disabling the diag will work

  11. #11
    just looked a little more in the tune...what are you running GTX42? all your values are far from reality if not running 800-1000hp

  12. #12
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    Quote Originally Posted by dertobi View Post
    just looked a little more in the tune...what are you running GTX42? all your values are far from reality if not running 800-1000hp
    All torque values and other limiters are increased to not interfere with the tuning process. Later, of course, we will bring them to real ones, although they do not affect anything other than the limiters.

  13. #13
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    Quote Originally Posted by dertobi View Post
    you could try to disable map voltageb diag in the pressure diagnostic section, but i always also change a value which is not accessible with hpt, thats why i am not sure if only disabling the diag will work
    Thanks, we will try to find it in winols)

  14. #14
    good luck, took me half a year

    regarding your values: your torque tables, driver demand, etc are way too high, this f***s up the whole trq/load calculation of the ecu.

  15. #15
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    Ok, at this point of view if you make a little change of torque tables, driver demand, etc, then we completely ruined whole torque model. Only stock values are correct. But, the calculated engine torque remains unchanged with the real numbers in these tables or greatly increased in equal conditions.

  16. #16
    you already demand 600kW from the driver demand tables, your peak and brake trq limits are set so high, i suppose the car would command at least 3 Bar boost.

    the calculated torque is dependend on a lot of stuff, first you have to get your MAF reading correct, thats the biggest factor. also AFR, ignition advance,and cam phasing, air temperatures are taken into account in the ECUs actual torque calculation.
    the trick is to get all this right and not just max everything what would limit you out of the way.
    for example if you add 1? of ignition the ecu actually calculates +5Nm of torque, if you have set your desired torque right, so that it is always reachable for the engine, you will see 1? more timing but less boost command... same with cam timing, you can modify it like you want, but if correct you wont see a big difference in torque/power output of the car, because the ecu modifies the other parameters, mainly desired airflow, so desired boost,to achive the desired torque set in the brake torque table.
    it's all about getting the desired and calculated torque exact, not a desired boost, the ecu will demand everything accordingly to achive the Trq goal.

    i "developed" a procedure to get all this very accurate, the ecu shows the exact engine torque and power values like the dyno shows, and the car drives better than ever. rock solid and dead on, every pull under any condition, elevation, temperature etc.
    and well... yes even the stock actual engine torque calcution is off by around 30-40Nm full load

  17. #17
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    We don't use stock boost control system. We use this one: https://sirhclabs.com/product/cortex-ebc/
    WMI system controls by cortex to.
    And that is why we max all this values.
    About maf: eq ratio error no more than 0.2-0.3%
    For sure, your tun very good for different environment conditions. I need to create different boost profiles for cold and hot weather, and for different height above sea level.

  18. #18
    Senior Tuner cobaltssoverbooster's Avatar
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    sorry i got called in for a long work shift and forgot to log back in.
    Another user stated what my thoughts were and that was: the torque model is high. the idea is to overshoot actual by a tad so the computer thinks its achievable. When this is done right the airload commanded matches the actual pretty damn close. it was an issue in the LNF and LDK as well.
    Knock factor is a limiter, and also the boost parameter definitions. if there are obscene numbers then your going to get some issues as well.

    you may encounter issues with that remote boost controller. when the computer figures out it doesnt have control like it should, it will start to freak out. it was a problem early on in the lnf days before we got more ecu unlocked and figured out how to remove the power output learning effect.
    2000 Ford Mustang - Top Sportsman

  19. #19
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    So, we don't have any issues before 2 bar boost. ECU do exactly what i wont at WOT (throttle position, cams angle, ignition angle, eq ratio etc).
    Here is my log file (we adjusted the eq ratio with WMI system ON)
    As you can see, desired boost is always higher than the actual. it is acceptable conditions for ECU if underboost error off.
    For the throttle to remain 100% open, the driver demand (predicted) torque request must always exceed the calulated engine torque (because in my case ECU can't control WG solenoid)
    when we add boost (2 bar) the ECU does not close the throttle, does not reduce the desired boost, the requested torque does not change, the injectors simply turn off and that's it.
    Attached Files Attached Files
    • File Type: hpl 7.hpl (745.4 KB, 18 views)

  20. #20
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    Quote Originally Posted by dertobi View Post
    you could try to disable map voltageb diag in the pressure diagnostic section, but i always also change a value which is not accessible with hpt, thats why i am not sure if only disabling the diag will work
    Thanks!!! It works!