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Hollowing out your camshafts

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  • Hollowing out your camshafts

    So i was reading the new Evo brochure, and it says they have hollow cams causing them to be 2lbs lighter. Does anyone know what kind of material the the z31 cams are made of?

    I wanna try getting them on a lathe and drilling them out at least as big as the bolt holes. If i can lose 4 more pounds on the rotating assembly that would be great. For every pound lost off the rotating crank assembly is an average of 2.38hp. Since the cams are spinning half as fast, you would gain 1.19hp per pound lost. Remember every pound counts.
    KILL HADJI

  • #2
    Alex86na2t wrote: So i was reading the new Evo brochure, and it says they have hollow cams causing them to be 2lbs lighter. Does anyone know what kind of material the the z31 cams are made of?

    I wanna try getting them on a lathe and drilling them out at least as big as the bolt holes. If i can lose 4 more pounds on the rotating assembly that would be great. For every pound lost off the rotating crank assembly is an average of 2.38hp. Since the cams are spinning half as fast, you would gain 1.19hp per pound lost. Remember every pound counts.
    but rotating mass varies based on the diameter, drilling out the camshaft and losing 1kg (2.2lbs) per side would save you probably on the order of 100 grams of rotating mass, whatever the actual number you wouldn't even feel it turning it by hand

    and if you were going for weight distribution there's plenty of metal on the block that can be ground off

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    • #3
      G-E wrote:
      but rotating mass varies based on the diameter

      and if you were going for weight distribution there's plenty of metal on the block that can be ground off
      Yes, but I have read numerous times the AVERAGE gain per pound is 2.38hp. It is harder to turn a pound of metal 1 foot from center than it is 1 inch from center. Most likely with the cams being so small in diameter compared to something like the flywheel, It would be the lower side of that average. But like i sayed every pound counts. Engine gains work in percentages, and for example if you do this to a stock z31T you probably won't notice anything. But do it to a 600hp Z and it might be really worthwhile. Also it seems so simple, its not like you have to balcance once your done. Also the material the cam is made of seems very dense, so i think you could really lose a lot of weight off it by doing this.

      About the block, it's not really sucking power because it not moving. It is just adding weight to the car, which is not really on my agenda at the moment.
      KILL HADJI

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      • #4
        you are turning the cam with the cam gear, it is already on a reduction drive, seriously go do some calculating regarding what you think you will save in weight at the radius you would drill, accelerated to 1/3 engine speed

        I'm sure theres a site

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        • #5
          Most cams are made from nodular iron, which has been nitrided for a vary hard surface on the outside.

          It is by nature VERY brittle. If you ever drap a camshaft on anything hard, it will probably crack... if not completely shatter.

          It's an interesting idea, but I can't see it making noticeable power gains on even heavily modified engines. You would probably be better off knife-edging the crank counterweights and race-prepping (which really just means you give them a smooth finish) the rods. This has been shown to give upwards of 20hp on race engines and has become standard practice over the years.

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          • #6
            The inside of the cam spins soooooo slow in comparison to the outside of a flywheel.

            But rotating mass, is rotating mass.

            Terrible idea putting those wheels on...

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            • #7
              I bet it takes more effort to accelerate all the coins in the ashtray

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              • #8
                G-E wrote: I bet it takes more effort to accelerate all the coins in the ashtray
                +1^ LOL
                85 Z31 6.0 LSX turbo 766whp/792wtq
                04 GTO, LS6, big cam, porting, N20... underway for summertime daily driver.

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                • #9
                  Jason84NA2T wrote:
                  It's an interesting idea, but I can't see it making noticeable power gains on even heavily modified engines. You would probably be better off knife-edging the crank counterweights and race-prepping (which really just means you give them a smooth finish) the rods.
                  I already have that checked off the list. I am just trying to think of every little thing.
                  KILL HADJI

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                  • #10
                    If you are that dead set on getting that extra .05% HP
                    then you might as well wait until you have gone through enough cam
                    profiles to find that optimum "power" cam before you go through the trouble of hollowing one out.
                    imagination is a virtue

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