Blower overdrive increase vs tuneup

Discussion in 'Manton Push Rods Top Alcohol Tech Questions' started by Battleborn, Jul 19, 2018.

  1. Battleborn

    Battleborn Member

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    Hey guys I’ve got a healthy 540 bbc w/an older but fresh Littlefield 1471 hi helix on methanol, wanting to increase my overdrive from 42% to 46%, how much would this lean the motor out? Is there a rule of thumb for overdrive increase vs pill size change? An uneducated guess would tell me to richen it up .005 but I’m still pretty new to this, thanks
     
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  2. Bjs344

    Bjs344 Member

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    .005 or .006 seems pretty close for an average setup. On my 8mm stuff .004 per tooth works well in small windows. For big swings I usually go back to the calculator. I would never take an on kill tuneup and make moves like that, but if you're burning half a thread and not hurting bearings I think you'll be ok.
     
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  3. Sandracer695

    Sandracer695 Member

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    Big difference between a .065 jet to a .060 and .130 jet to a .125
     
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    Will Hanna, WIZBANG and 32 bantam like this.

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