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M20 MS2 rev limiter settings (fuel cut vs spark retard fuel cut)

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    M20 MS2 rev limiter settings (fuel cut vs spark retard fuel cut)

    Well i've never thought to much about the way the rev limiter on my car was set up, except for the the rpm, until the other day at an auto-x event. I tagged the limiter a few times and the fan/water-pump/alternator flew off and shredded. I put a replacement belt on thinking it was a freak thing went out for a few more runs, tagged the limiter some more and the belt came off again. It just seems weird to me that it only happens when the rev limiter is hit because it's never happened on the street and the engine will see 6k frequently. The engine in question is a m20b31.

    Current settings:
    spark retard/fuel cut
    max retart (deg) 12
    soft rev limit 7100
    hard rev limit 7300

    I think nando runs
    fuel cut
    soft rev limit 7300
    hard rev limit 7400

    I'm pretty sure nando tags the limiter all the time during auto-x with out issue.

    Would runing fuel cut alone be better and smoother than spark retard fuel cut? Or do the soft and hard limit rpm need to be closer together?

    #2
    I run a very strong retard before the limiter and it really smooths the abruptness of it all. I run spark retard/cut but i feel that the spark retard/fuel cut is the smoothest.
    my limiter is at 7300 and i have zero belt issues.


    7speedshop.com

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      #3
      Thanks kamotors. Mind posting your settings when you get a chance.

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        #4
        Spark cut is no bueno for engines with cast aluminum rockers.

        BMW uses a fuel cut.

        Never had a belt come off.. i bet it has more to do with your pullies and high rpm than the type of limiter you use.
        Build thread

        Bimmerlabs

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          #5
          I think you're probably right about the pulleys and will be addressing that as well. Just wanted to make sure i have my rev limiter set up properly too. I'll make the switch to fuel cut. Though i think i'm going to make it 7,000 soft and 7100 hard. Are you still running the same rev limiter setting on your ms3 as you were on ms2?

          Comment


            #6
            yeah pretty much - I don't think it's called "soft" and "hard" on MS3 though, you set a limiter and a +/- value (usually 100rpm)
            Build thread

            Bimmerlabs

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              #7
              Originally posted by nando View Post
              Spark cut is no bueno for engines with cast aluminum rockers.

              BMW uses a fuel cut.

              Never had a belt come off.. i bet it has more to do with your pullies and high rpm than the type of limiter you use.
              Why is spark cut not good for cast aluminum rockers?
              1986 911 Supercharged Frakenstrat/Stripped
              1987 325is Delphin/Black (Olga)
              1988 M3 Zinno/Natur (Elsa)

              Manual or STFU

              E30 Chapter of BMW Car Club of America
              E30 Oktoberfest 2017

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                #8
                because it makes big bang bang that stresses out the rockers, it also shoots 1 foot flames from the exhaust;)
                I've personally snapped a stock rocker on the limiter with spark cut.


                7speedshop.com

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                  #9
                  Originally posted by kamotors View Post
                  because it makes big bang bang that stresses out the rockers, it also shoots 1 foot flames from the exhaust;)
                  I've personally snapped a stock rocker on the limiter with spark cut.
                  Bet it sounds gangster though
                  - AXIS POWERS - 2JZ E30 Build
                  Current Project - 87 325is 2JZ Swapped with M4 DCT

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                    #10
                    idk why this is being revived but wouldnt the old dizzy m20 engines e.g. 323i be running spark cut via the dizzy ? i remember back in the 90's it used to kick in pretty hard like a small collision lolz until my dad and i disabled it then the next thing was valve bounce hehe
                    89 E30 325is Lachs Silber - currently M20B31, M20B33 in the works, stroked to the hilt...

                    new build thread http://www.r3vlimited.com/board/showthread.php?t=317505

                    Comment


                      #11
                      yup it's an old thread but posts are forever so does it even matter? ;)

                      In the maximum retard setting
                      does it mean spark advance that it's actually at, when soft cut kicks in?
                      or does it mean the maximum advance it is actively subtracting, for example you put 10 it subtracts 10 from *28.

                      I have it set to *0 on retard & fuel cut it's ultra smooth.
                      It doesn't bounce off the fuel cut either it's very nice.
                      Also I've ran spark cut only, for years, and that shit is BEAST.
                      Sounds like a race car but retard&fuel is smoothest/best.

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