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10:1 2.8L M20 197whp - Boosted Interest

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    10:1 2.8L M20 197whp - Boosted Interest

    Greetings lads.

    I've been running a NA 10:1 2.8L M20 for the last 6k miles or so. It makes a humble 197whp on a mild pump gas tune.

    I've been dabling with the idea of adding boost. I'm aware that most M20 turbo builds are either stock compression or lower then stock and I'm just over here with my 10:1...

    In my situation what's the best route to take for good linear power?

    The car currently has a 272 Shrick cam in it. I'd be open to running an alternative cam as I'd need to pull the head for the HG and some upgraded fastening hardware.

    I'm here for thoughts, ideas, and prior experience.
    À la folie


    #2
    10.1 is a bit high for pump gas and turbos. Due to that turbos increase the compression ratio in relation to boost pressure. I would say keep it at lower boost, consider e85 or/and meth to combat detonation.

    More info

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      #3
      E85 likes high compression, but it seems like a big hassle to me. Whats wrong with a ~200whp M20?

      btw is that dyno proven? Id love to see what the dyno plot looks like
      Simon
      Current Car:
      -2017 i3 REx, 21st Century E30
      -1975 Alfa Romeo Giulia Nuova Super 1300, the never-ending name & project



      Make R3V Great Again -2020

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        #4
        You will be fine on 10.1:1 as long as you don't go crazy with the timing. O-ring the block or use MLS and ARP studs either way and have a good tune. We have some customers running 25psi on forged v6's with 9.1 to 9.6:1 compression, a local running 8psi on a 10.5:1 s52 that we even tuned with the stock 413 ECU and premium fuel (93 octane here).
        john@m20guru.com
        Links:
        Transaction feedback: Here, here and here. Thanks :D

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          #5
          10:1 is going to be awesome off boost as well, I agree with FF, you'll be fine.

          Definitely o-ring the block, go with a metal head gasket and ARP's. Providing the tune is good, you'll have no issues.

          SILBER COMBAT UNIT DELTA (M-Technic Marshal)
          RTFM:http://www.r3vlimited.com/board/showthread.php?t=56950

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            #6
            to get a linear power curve you will probably need a S/C
            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

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              #7
              10:1 2.8L M20 197whp - Boosted Interest

              Are you the guy who Bimmerheads posted a picture of your Dyno run? Iirc it was a 2.8 stroker that the Dyno showed 197hp.

              Are you on stock internals? Or forged? If your on stock internals I wouldn't run much more than maybe 6-8psi. If your on forged internals then crank up the boost and run E85 or meth.

              I agree with digger though, if your looking for a linear power band run a supercharger. Run ITBs (if you aren't already) and a centrifugal supercharger. Plenty of power all day.
              Originally posted by flyboyx
              how about if i yank the anal beads out of your ass like i'm trying to pull start a chain saw?
              Originally posted by Northern
              beer is my new liver cleanse.

              Henna - '84 Hennarot 325e
              Lola - '89 Schwarz 325is - being saved
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                #8
                Chamber and head design have a lot more to do with this than just a bumped compression ratio. I say rebuild it with lower compression or build another motor.
                2012 Jeep Wrangler 2dr trail rig
                2014 GLI Edition 30
                Various German company cars.

                Comment


                  #9
                  Originally posted by socal-E30 View Post
                  Chamber and head design have a lot more to do with this than just a bumped compression ratio. I say rebuild it with lower compression or build another motor.
                  It is well known the m20 is a Hemi head design with angular squish, and has been proven over and over with all stock internals to make 500+ whp providing fuel and fasteners were upgraded. Bumping compression ~2 points over stock will not change THAT much. just keep the timing curve more conservative over a stock 8.8:1 compression and there won't be an issue. It will actually make more power off boost, make more power with less boost and just be that much more fun overall.

                  People told me years ago that I couldn't put turbos on stock motors with more than 8.5:1 compression and that cams with more than 10 degrees overlap would be bad for boost, but I have done both on cars with GREAT results. As in 500+whp from 3.8l and a mere 1bar gauge pressure on a 9.5:1 motor with a 30+ degree overlap cam to boot.
                  john@m20guru.com
                  Links:
                  Transaction feedback: Here, here and here. Thanks :D

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                    #10
                    Originally posted by digger View Post
                    to get a linear power curve you will probably need a (Roots or Lysholm) supercharger
                    It's linear.
                    Originally posted by Andy.B
                    Whenever I am about to make a particularly questionable decision regarding a worryingly cheap diy solution, I just ask myself, "What would Ether-D do?"
                    1987 325iS m30b34 Muscle car (Engine electrical phase)
                    ~~~~~~~~~~
                    I was born on 3/25…
                    ~~~~~~~~~~

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                      #11
                      Hondas people boost their engines all the time with high compression engines. It's all in the tune.

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                        #12
                        Dodges have 18:1 they boost all day every day it's all in the tune do it. ;)

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