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High Reving M20?

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    #16
    Good stuff, I've been toying with the idea of a high rever for the past few years. I've had my air share of experiences with 3.0 M20's Not a bad setup when properly built and tuned. I think turboing a 3.0 would be lots of hastles and don't see it being sensable for a daily driver. Thanks for the info guys. 8)

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      #17
      Originally posted by SickE30
      Good stuff, I've been toying with the idea of a high rever for the past few years. I've had my air share of experiences with 3.0 M20's Not a bad setup when properly built and tuned. I think turboing a 3.0 would be lots of hastles and don't see it being sensable for a daily driver. Thanks for the info guys. 8)
      Your post was about if it is possible to build a super high revving turbo M20......., and now you have somehow come to the conclusion, that it is a "lots of hassles" to turbocharge a 3.0L M20??? Are you kidding me?

      Good luck with your high revving daily driver ;)

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        #18
        I had the lightened rockers from korman on my last M20 and even they suggested not to go much higher than 8000rpm as they are still a weak spot due to the loss of material for the eccentric. With the double springs i would encounter valve bounce at around 7300rpm, the motor was totally dead by then though, max power peaked at 6400rpm of which the manifold did have a bit to do with it.

        Even with titanium rods you are going to end up replacing them quite a lot (otherwise they will snap), unlike other metals which have a bit of (for lack of a better word) springy nature to them (where the metal can be placed under stress, move, and still retain it's shape), titanium rods will just crack.

        if you want a super high reving M20, reduce stroke, need a custom crank to reduce throw and longer rods (which will actually make the engine smoother and reduce stress at TDC). Everything would need to be super light in order to reduce mechanical stress, and everything would have to be balanced.

        It would cost a hell of a lot of money for not a whole lot of gain though, you would end up with an engine that makes bugger all torque which isnt exactly usefull for a daily driver.

        Even the Race prepped DTM M3's had a 9400rpm redline and there is a lot less rotating mass in an S14 than there is in an M20.
        Just a little project im working on
        - http://www.lse30.com -

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          #19
          To try make this more searchable and FAQ friendly, perhaps someone could chime in on why revs are not really what you want for a sohc 12valve motor. Besides the obvious cost and weakenss of the platform it's just not "what you want" for power in an m20b25. Money is better spent elsewhere. If you want a free revving motor with power, make sure to change your diff gearing depending on your motor build and if you go with boost a 2.93 is where it's at. Turbo and LTW flywheel seems to be a debate so I will not dive into that section, however; if you're n/a a lighter flywheel will help give that feeling of a free-revving motor. Revs are slighlty over rated these days because of Honda's and v-tec :roll: . Can't use the same recipie for cake and baked fish.

          HTH

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            #20
            Originally posted by e9nine
            Can't use the same recipie for cake and baked fish.
            Awesome.

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              #21
              Originally posted by e9nine
              To try make this more searchable and FAQ friendly, perhaps someone could chime in on why revs are not really what you want for a sohc 12valve motor. Besides the obvious cost and weakenss of the platform it's just not "what you want" for power in an m20b25. Money is better spent elsewhere. If you want a free revving motor with power, make sure to change your diff gearing depending on your motor build and if you go with boost a 2.93 is where it's at. Turbo and LTW flywheel seems to be a debate so I will not dive into that section, however; if you're n/a a lighter flywheel will help give that feeling of a free-revving motor. Revs are slighlty over rated these days because of Honda's and v-tec :roll: . Can't use the same recipie for cake and baked fish.

              HTH
              It's very simple, the engine reaches a point where under it's own power, it cannot physically draw air through the head any faster (or in larger volumes).



              The flywheel works by removing rotating mass which makes the engine more responsive (it has less weight to spin), it doesnt make it rev any higher though.
              Just a little project im working on
              - http://www.lse30.com -

              Comment


                #22
                Definately some misinformation in this thread...

                I have talked to korman and ireland engineering about race motors. First off, a 3.0L m20 is the SAME bottom end as the S50 M3 motor, with the benefit of custom lightweight pistons.

                That stroked bottom end can handle 9,000rpms with the light pistons. The bottom end is NOT the problem on the m20... it is the rocker arms. If you run korman shot peened and polished rocker arms, you can expect to change them 2 or 3 times a year on a street motor that revs that high. They change them every one or two races, and they do rev them that high.

                Second is head flow... you need some serious porting and a short runner intake manifold will help with a nutty cam.

                The high reving motor is actually PERFECT for a turbo. Just get one of those nice electronic boost controllers. Where the head starts to drop off in power, have it add more boost so the HP keeps climbing... of course taking into account turbo efficiency and such.

                With a higher revving motor you can also use a larger turbo and a higher diff ratio.

                Don't forget VERY strong valve springs and titanium retainers.

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                  #23
                  Originally posted by turboe30
                  Definately some misinformation in this thread...

                  I have talked to korman and ireland engineering about race motors. First off, a 3.0L m20 is the SAME bottom end as the S50 M3 motor, with the benefit of custom lightweight pistons.
                  Ok. So if the 3.0 M20 is the same bottom end as the s50, why dont you just go get a 92 non-vanos head and then put a vanos unit on it and call it a day?
                  Way cheaper, way more power. And yes, it will work.

                  NASA MidSouth TT Director / GTS2 #018
                  Mods: Coastal PS Fluid, 10w40 Oil
                  Future Mods: Bosch Micro-Edge Wiper Blades, Painter's Tape, Spark Plugs, Freezer for Nutty Buddys, Adam Nitti CD's

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                    #24
                    I think you mis-understood. The bottom end INTERNALS are the same in the stroker... that is where the crank comes from and the rods are the same length.

                    The block is not the same casting. I like the m20 motor - it's lighter and with a turbo it can make huge power if you set it up right. With the m20 you would get lightweight pistons also.

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                      #25
                      if you wanted 8000-10000 you are talking about a race spec motor that has to have everything checked almost every pass at a drag strip let alone auto X ing. You are talking about a lot of money everything balanced the crank would be forged and knife edged and the valvetrain titanium and thats just a start. If you want high rpms look at my post on swaping to an s2000 motor those rev to 9000 right out of the box.


                      http://www.cardomain.com/ride/657387

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                        #26
                        9,000 rpms with a built lightweight bottom end is not going to be all that unreliable - except the rocker arms. Don't talk out of your ass.

                        You do not need titanium valves, but they would be nice. What you do need is VERY strong valve springs and titanium retainers.

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