Results 1 to 6 of 6

Thread: IS THERE A FORMULA FOR CARB SIZE?

  1. #1
    Senior Member DYNO OPERATOR
    Join Date
    Apr 2008
    Posts
    496

    IS THERE A FORMULA FOR CARB SIZE?

    I HAVE A LITTLE MORE COMPRESSION AND A DIFFERNT CAM THAN I HAD LAST YEAR AND THE MOTOR STUTTERS WHEN I LEAVE THE LINE I WAS WONDERING IF I WAS UNDER CARBED.

  2. #2
    Senior Member RACING JUNKIE
    Join Date
    Mar 2006
    Location
    EUGENE,OR.
    Posts
    3,408
    You can run the basics on a common chart by Holley if I remember correctly. It has been awhile since iv'e done it, but I think it was like cubic inches by max RPM ... then it gives you a starting point. from there, it will help fine tune the size needed.
    "I would walk through hell on Sunday before I fear the enemy"

  3. #3
    Senior Member RACING JUNKIE
    Join Date
    Nov 2008
    Location
    Niagara Falls, NY
    Posts
    965
    GOOD PARTS AREN'T CHEAP AND CHEAP PARTS ARE NEVER GOOD.........
    http://img.photobucket.com/albums/v2...lastscan-3.jpg

  4. #4
    Senior Member RACING JUNKIE TheYellaBrick's Avatar
    Join Date
    Mar 2008
    Location
    Emmett, Idaho
    Posts
    7,334
    OOOoooo. nice bunch of formulas !! THANKS !!
    TRUTH is HATE
    to those who
    HATE TRUTH

    God Bless our folks in uniform
    "We the People, have your backs"
    http://www.racingjunk.com/profile/279898

  5. #5
    Senior Member RACING JUNKIE TheRabbit's Avatar
    Join Date
    Jan 2007
    Location
    Augusta, Ga.
    Posts
    2,295
    All the racing math you'll need.
    http://www.wallaceracing.com/Calculators.htm

    BTW
    Air Capacity & Volumetric Efficiency

    Theoretical cfm = rpm x displacement / 3456
    Volumetric efficiency = actual cfm / theoretical cfm x 100
    Street carb cfm = rpm x displacement / 3456 x 0.85
    Racing carb cfm = rpm x displacement / 3456 x 1.1

    I made some of my own Excel spread sheets for carb. size and for gear ratios and tire speed with any transmission and transfer case / chain drive.

  6. #6
    Senior Member RACING JUNKIE
    Join Date
    Nov 2008
    Location
    Niagara Falls, NY
    Posts
    965
    Quote Originally Posted by DrivingMissDD
    OOOoooo. nice bunch of formulas !! THANKS !!
    i know i tried them all with our 3 cars(which are all setup differently) and they are all damn near right on the money :wink:
    GOOD PARTS AREN'T CHEAP AND CHEAP PARTS ARE NEVER GOOD.........
    http://img.photobucket.com/albums/v2...lastscan-3.jpg


Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Copyright © 2005-2016 RacingJunk.com All Rights Reserved.

Designated trademarks and brands are the property of their respective owners. Use of this Web site constitutes acceptance of the RacingJunk.com
Terms of Use, Classifieds Disclaimer, Privacy Policy, and Cookie Policy