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  1. #1
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    J TNT's Avatar
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    GEN 3 4 Crankshaft Mods

    Has anyone offset ground the factory crank down to "2.100 rod size to give a Stroke increase of .154" ?

    And if so does it hold up to 800 HP and 6600 RPM ?

    I know the Viper Crank is known for deflection at high RPM..........
    Last edited by J TNT; 07-29-2021 at 06:43 PM.
    White Mamba ,

  2. #2
    Quote Originally Posted by J TNT View Post
    Has anyone offset ground the factory crank down to "2.100 rod size to give a Stroke increase of .154" ?

    And if so does it hold up to 800 HP and 6600 RPM ?

    I know the Viper Crank is known for deflection at high RPM..........
    1. Never heard about crank deflection at ''high'' RPM
    2. 6600rpm is not exactly ''high''
    3. Get the crank overbalanced 51-53%
    4. Lightweight rods/pistons
    5. Stable valvetrain (lightweight valvesprings/valves/retainers + bigger pushrods)

    That's what I know.

  3. #3
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    buy a Sonny Bryant crank. 40lbs lighter then factory crank and very very good quality. Of course if you do the crank it will snowball. Talk to Kevin at exotic engines if you want to go this route

  4. #4
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    Quote Originally Posted by Aevus View Post
    1. Never heard about crank deflection at ''high'' RPM
    2. 6600rpm is not exactly ''high''
    3. Get the crank overbalanced 51-53%
    4. Lightweight rods/pistons
    5. Stable valvetrain (lightweight valvesprings/valves/retainers + bigger pushrods)

    That's what I know.
    Thanks for the feed back.........
    White Mamba ,

  5. #5
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    Quote Originally Posted by TKO MOTORSPORTS TEAM View Post
    buy a Sonny Bryant crank. 40lbs lighter then factory crank and very very good quality. Of course if you do the crank it will snowball. Talk to Kevin at exotic engines if you want to go this route
    Thanks TKO Motorsports ,

    Kevin and Team Viper member reached out to me and this was basically their response,
    We typically never offset grind the Viper crankshaft. The strength and safety factors on it are marginal as it is.
    I suspected that might be the case but now have good sources confirming..........
    Jay
    White Mamba ,

  6. #6
    Quote Originally Posted by J TNT View Post
    The strength and safety factors on it are marginal as it is.
    I suspected that might be the case but now have good sources confirming..........
    Jay
    Thats good to know.

    I heard that most crank problems are mainly caused by oil starvation (gen1/2/3) causing main bearing's failure, before the swing arm oil pan -which was developped with the competition coupe (2003?)- was made standard for the gen4...

    Few months ago I had a case of oil starvation and bearings failure myself and the crank was still okay. My engine builder said it was a pretty good crank, you just want to make sure the oiling is 100%.

    That being said, I wouldnt grind it, especially not for 700-800whp/high RPM if lightweight parts wouldnt be added to the recipe (to relieve stress on the crank)


 

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