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Miller WAR tune help/feedback needed please

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    Miller WAR tune help/feedback needed please

    I'm struggling to get this turbo setup running right, and considering this is my first foray in to tuning, there's tons I don't know. I've read this book front to back, and while it has some good info on how fuel injection systems work, it says zero about tuning.

    The setup is an OEM k27 turbo system off the old 745i cars, bolted on to my otherwise stock m30b35 motor. 36lb/hr bosch white injectors, Miller MAF/WAR, OEM downpipes, 2.5" single exhaust (I know, a bit small).

    The current symptoms I'm experiencing are:
    - Very rich, rough cold starts until engine temps hit about 130F. Lots of black smoke, stumbling, AFRs in the low 10s.
    - Once warm, it coughs and sputters above 4k rpm, but AFRs stay in a reasonable range (12s to 14s)
    - The engine dies completely if I go to WOT; just a total shutdown. AFRs go to max (over 22) when this happens.
    - Warm idle normally sits about 14.5, but if I rev the engine the idle will stay rich for 5-10 seconds and then come back to 14.7 after sitting there a bit.

    Would anyone mind taking a look at this tune and giving me some observations/pointers/advice? Thanks R3v!

    Also, here's a video of the symptoms: https://vimeo.com/135318837

    #2
    Hiya. I don't have any WAR experience, but I have plenty in playing with standalone ECU's.

    - Sounds like too much warm-up enrichment. Does the WAR chip have a table for extra fuel percentage vs. coolant temp? Or something similar? You're going to want to reduce the WUE in the temp ranges that are problematic for you.

    -AFR's in the 12's are quite rich for an N/A engine. For reference, my M20B25 never saw anything richer than 13.2 and it pulled noticeably harder than the factory tune. Increasing fuel beyond that did not increase power. What does your ignition timing look like in the problem areas? I'm having trouble opening your download, I don't have any programs that know how to handle .mpc files. As a general rule of thumb, at a fixed RPM, moving up in load (atmospheric pressure in the intake manifold/more throttle) requires decreasing ignition timing. On a similar note, for a fixed load, moving up in RPM requires more ignition timing until peak torque, where you would then pull a few degrees afterward or simply run a fixed timing from peak torque to redline (depending on what the engine likes).

    -Does it matter how quickly or slowly you make your way to WOT? If it goes off-the-charts lean (22 on the gauge) when you romp it, but then it recovers, you need more acceleration enrichment. MS has a table for precisely this - you can choose to run the AE algorithm from either your TPS (ideal) or your MAP sensor inputs. Again, I've never seen the WAR interface so I don't know the specifics of your software.

    If you can lollygag your way to WOT and it still goes way lean, then your main fuel table is not delivering enough fuel to keep up. Increase your high-load fuel values a little at a time until the engine will actually r3v. I know exactly what you mean when you said you gave it throttle and it completely shutdown. I ran into it with my first few drives on the MS unit. There's simply not enough fuel to support combustion.

    -When you blip the throttle at idle, the air inside the intake manifold becomes very choppy and turbulent, and skews the readings to your MAP sensor or whatever sensor the WAR uses to measure the amount of air being consumed. This will make the ECU hunt in the map erratically for a brief period while trying to supply the correct amount of fuel. If the engine is not tuned well at high load, low RPM conditions and in lower-load-than-idle, low RPM conditions, it will take a few seconds for the air to smooth out inside the manifold and for the sensors to start reading reliably again.

    * By lower-load-than-idle I mean the conditions you would see while engine braking (closed throttle, but higher-than-idle RPM). Increased RPM helps pull a stronger vacuum (ie lower load) inside the intake manifold.

    A 2.5" exhaust is a good size for your setup. From 30 seconds worth of research, it seems like the consensus is a 2.5" single exhaust will not bottleneck power until 350 to the crank or so. Apparently you need to be making north of 400 horse for a 3" exhaust to truly shine. YMMV of course.
    Last edited by EatsHondas; 08-05-2015, 07:09 AM.
    1989 325i Lachssilber Sedan
    5-Speed Swapped
    M30B35 Swapped
    MegaSquirt MS3X

    1987 325i Lachssilber Sedan
    260k OEM Automatic Daily Baby

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