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    M20 Questions

    I've bought a 87 325E/ES. When I look up the VIN it state the car is an E. Anyway, i have verified that its an m20 and the head has ETA stamped on it. Now my question is that it revs past 7k and everywhere I've looked it states that the rev limiter should be at 4750. Am I mis-understanding or is something weird about the car. Also the cluster's redline I believe is 6500. I will be boosting the m20 (not my first time turbocharging a car, check my project thread to see my eclipse) and wondering If its worth swapping to an m30 or just swap heads build the bottom end/head and boost it. How much TQ does the motor hold stock. Don't want to risk the built motor until I get used to tuning e30's.


    s50 86 325e Project

    S50 - BBS - Recaro - BC Coilovers - Morimoto H1 Retrofit

    Feedback Thread

    #2
    You probably have the wrong tach. The Eta head would never rev that high.

    Swap to an 885 head and boost that M20. ;)
    BimmerHeads
    Classic BMW Specialists
    Santa Clarita, CA

    www.BimmerHeads.com

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      #3
      My first suspicion would be that the cluster has been swapped and a 318 cluster was used. That would result in the tach reading 7125 when the engine was at 4750.
      The car makes it possible, but the driver makes it happen.
      Jim Levie, Huntsville, AL

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        #4
        Obviously I come from obd 2 and technology but I figured the rpms would still read true 1=1. The only reason I believe the head might be rebuilt/built is because the P.O. mentioned something being swapped but wasn't sure what. He abandoned it because he wasn't knowledgeable enough to do the work himself. If I swap the head to an 885head can I keep the eta bottom end? Also does the 885 head due the same I'M TB and other head parts?


        s50 86 325e Project

        S50 - BBS - Recaro - BC Coilovers - Morimoto H1 Retrofit

        Feedback Thread

        Comment


          #5
          search for 885 head write ups, if you use your stock bottom end and a 885 head, its a "budget stroker", commonly called a "2.7i" motor.

          then boost it, 10-12lbs on stock everything, closer to 15 if you use head studs(arp) and a stock HG.
          at 10-12 expect in the 250-280whp+

          happy boosting

          Comment


            #6
            Sounds great for a start. My 2.4 Liter SOHC 4g64 makes 250hp 265tq on 15 psi on a 16G turbo. Appreciate the help.


            s50 86 325e Project

            S50 - BBS - Recaro - BC Coilovers - Morimoto H1 Retrofit

            Feedback Thread

            Comment

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