Plotting 2002 LS6 Cam Lobe Profiles With Different Ratio Rockers
Plotting 2002 LS6 Cam Lobe Profiles With Different Ratio Rockers Can someone plot the 02 LS6 cam lobe profiles with stock ratio, 1.8, 1.9 & 2.0 ratio rockers for me? Im looking to see the effect the higher ratio rockers have on duration
Joined: Apr 2006
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From: Grand Rapids, Michigan
Don't have software to do the plotting, but basically your advertised duration stays the same, your @.050 duration will increase slightly, and you'll have more area under the curve. Also may have valve control issues unless a cam is ground specifically for those ratios. I'd also wager that higher ratios would be harder on the cam and lifters. Wouldn't just specifying a more aggressive lobe accomplish the same thing as a higher ratio rocker? I guess I should ask, what is it you are trying to accomplish?
im doing a bolt on only ls6 build so im limited to the stock cam. with my old car/setup i ran 1.8 yella terras with the ls6 cam and it worked great. this time id like to run an even higher ratio.
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unfortunately i do not know how to calculate what the change in .050 duration would be or how to plot it that is why i posted here for help. i do know how to calculate the difference in valve lift.
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The total advertised duration is 270/282, so for both sides it takes about 30 degrees of duration to get that first .050" of lift, if you go to a different rocker that gets reduced by 5.6% for a 1.8:1, 10.5% for a 1.9, and 15% for a 2.0 rocker.
That means you would gain, at 0.050" lift, 3 degrees of duration for the 1.8:1 rocker, 6 degrees for the 1.9:1, and 9 degrees for the 2.0 rocker.
These values are almost completely meaningless because it doesn't change when the valve opens, just how fast it gets past the magic .050" lift point. Its a hydraulic roller cam, all you are changing is how fast and how far you are actuating the valve.
That means you would gain, at 0.050" lift, 3 degrees of duration for the 1.8:1 rocker, 6 degrees for the 1.9:1, and 9 degrees for the 2.0 rocker.
These values are almost completely meaningless because it doesn't change when the valve opens, just how fast it gets past the magic .050" lift point. Its a hydraulic roller cam, all you are changing is how fast and how far you are actuating the valve.
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Where does one find 2.0 ratio rocker arms for an LS? Not that I'd do that; as even with the right springs I'd be concerned about valvetrain stability along with stress on the lobes and lifter; but I'm curious.
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The total advertised duration is 270/282, so for both sides it takes about 30 degrees of duration to get that first .050" of lift, if you go to a different rocker that gets reduced by 5.6% for a 1.8:1, 10.5% for a 1.9, and 15% for a 2.0 rocker.
That means you would gain, at 0.050" lift, 3 degrees of duration for the 1.8:1 rocker, 6 degrees for the 1.9:1, and 9 degrees for the 2.0 rocker.
These values are almost completely meaningless because it doesn't change when the valve opens, just how fast it gets past the magic .050" lift point. Its a hydraulic roller cam, all you are changing is how fast and how far you are actuating the valve.
That means you would gain, at 0.050" lift, 3 degrees of duration for the 1.8:1 rocker, 6 degrees for the 1.9:1, and 9 degrees for the 2.0 rocker.
These values are almost completely meaningless because it doesn't change when the valve opens, just how fast it gets past the magic .050" lift point. Its a hydraulic roller cam, all you are changing is how fast and how far you are actuating the valve.
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From: switzerland
be aware that rocker geomentry is complicated. a "1.8 rocker" will not maintain that ratio thoughout the whole range, neither will a stock rocker. thats why a comparison calculation is mute. it also makes a difference how high a rocker is installed. furthermore there is the issue of valve bounce to consider (if the valve goes faster up it comes faster down also).
