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-   -   IS THERE A FORMULA FOR CARB SIZE? (https://www.racingjunk.com/forums/showthread.php?t=30354)

JEFF69Z28 05-06-2011 08:13 AM

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.

Scooterz 05-06-2011 09:48 AM

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.

fast75vega 05-06-2011 09:50 AM

tci carb calculator

http://www.tciauto.com/Content/Stati...ieSupport=1#13

TheYellaBrick 05-06-2011 06:47 PM

OOOoooo. nice bunch of formulas !! THANKS !! :D :D :D :D

TheRabbit 05-07-2011 05:13 AM

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.

fast75vega 05-07-2011 06:04 AM


Originally Posted by DrivingMissDD
OOOoooo. nice bunch of formulas !! THANKS !! :D :D :D :D

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:


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