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  • #31
    um some info if people dont know, a Z32 flywheel bolts directly to the VH45de and can use Z32 clutches and there are group buys for adaptor plates and flywheel spacers for Z32 transmissions. its like $650 bucks for all hardware, adaptor plate and flywheel spacer. Not too bad.

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    • #32
      I'm no expert on the matter, but I believe the reason many force induction motors don't make good NA motors is due to the chamber and quench design.

      A good example I think is the older nissan L series motors. The earleir N series heads had a smaller chamber than the later P series heads. On the N series they used dish pistons, to get the same compression with the later heads they used flat tops, except for the turbo engine wich had dish pistons, to lower the compression for the chamber.

      But think about it, if the chamber volume of the head increased, and they're running a dish piston then the combustion chamber is much more round than the earlier design. And considering the port size, design, shape, and the fact that it's a non-cross flow head they can make some decent numbers. (garrett on HZ is now making over 450 hp on a stock head/cam).

      These kind of numbers are much harder on the older heads, even with extra dishing of the pistons. A gasket solution is a joke if you're really going for performance.

      So now lets look at the obvious opposite. In the L series motor the earlier heads are much more desirable for NA application and the later ones are considered to have less NA potential. This is because when you start raising compression the main way you're supposed to (pistons) then your chamber shape becomes uneven.

      Maybe I'm completely wrong. But if someone can prove me wrong I've love to learn something new. But this is my best attempt at explaining NA chamber design vs FI chamber design.

      Oh, and thanks for the tranny info roastin300.

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      • #33
        I kind of get what you're saying.

        Again i am not saying an NA VG is the best of ideas. I am just asking why it wouldn't work. If i were to build a Z with great MPG, I would put in high compression and the lightest rotating mass i could find. I don't see why it wouldn't run right.

        But still the combustion camber shape does not affect the compression stroke. Just the volume, for example if for some crazy reason you had a cubic CC. It would flow like shit, but during the compression stroke it wouldn't make a difference (because pressure is forced onto all surfaces regardless of shape). And during the power stroke it would be similar to a forced induction engine because of the peak cylinder pressure.
        KILL HADJI

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        • #34
          You're right, it wouldn't effect air distrobution, but it will effect the velocity of the air, plus the main thing is that it'll change the quench and how the flame front spreads. Flame front is one of the most important things in a chamber design, this is the whole reason a hemi was so different in their era. If you're flame front is erratic then this could lead to early detonation.

          I really wish I could find some good tech articles online on the subject, so if anyone does find anything let me know, I'd love to bookmark it.

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          • #35
            Ahhhhh, now i see what you are talking about. I wonder how much of a performance difference it would be between an NA HC engine and a boosted engine which had the same running tdc pressure (preignition).
            KILL HADJI

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