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Title: MEVD17.2 N55 - Boost/Load/Torque Limit Post by: waleonboard on November 10, 2023, 08:46:16 AM Hello Guys,
Its my first post here and my first topic. Currently working on a N55 BMW with the MEVD17.2 ECU. Engine is built with a big turbo and all supporting mods so it can easily support over 2 Bar/30 psi relative boost pressure. Car is running on E40-E50 to avoid timing correction on stock timing maps. For some reason the car never requests over 180% load or 2.2 bar absolute pressure. All load ceilings and torque ceilings are raised, pressure limiters raised and i cant find the limiting variable. Also there is no adequate logger that could give me the PIDs like torque limiter or any turbo relating limits. Even the logger from PRJ is limited in this aspect. I did attach my last log file and tune. (Dont wonder about the tune since this is just a base to get the car going) If someone could point me into the right direction it would be great. BTW, car has XHP Stage 3 with torque limiter set to 1000 NM so no limit over CAN. Title: Re: MEVD17.2 N55 - Boost/Load/Torque Limit Post by: prj on November 10, 2023, 10:24:19 AM My logger has no advanced mode on BMW KWP, hence you can't see much. Maybe there's a point to add it, maybe not.
As for your ECU, the answer is simple, you can also see it in logger. psolldr_w max value is 2560, that's because ECU isn't fully 5120. Same for ps_w. IIRC on these you can't request more than 1.5 bar boost, so you're never going to request 2 bar boost on it anyway... As for where you're stuck now, you probably need advanced logger to see it, which there isn't one. I don't think I even have a KWP MEVD17 ECU here. Title: Re: MEVD17.2 N55 - Boost/Load/Torque Limit Post by: waleonboard on November 10, 2023, 11:16:25 AM Thanks PRJ, i figured it will be limited. But even if i will only request 1.5 relative, my issue is that the requested load is not high enough and as you can see the TB being closed. Also wondering how others are tuning big turbos on those with way over 2.5 bar absolute. Is there a patch? I know i can set a switch for commanded boost and but i dont like having no compensation for altitude etc.
Title: Re: MEVD17.2 N55 - Boost/Load/Torque Limit Post by: prj on November 11, 2023, 05:15:58 AM You're probably missing something obvious, since I don't remember having this issue when tuning the higher boosted 2.0 liter engines on F series.
But of course maybe on E-series something is different in ECU. Either way, if you want to figure it out, you need FR and a ram logger... |