Three 2bbl throttle bodies

[TVS]

>My next question is, I need a formula to calculate the CFM for a given size
>hole in a throttle body. Does anyone have such a formula. I need to know
how
>large my throttle body openings should would need to be to achieve about
>1000cfm.

Hummm, yes. Take the diameter in inches (we're not all metric!) and square
it. Multiply by 21.8 and then multiply by the square root of the pressure
drop in inches of water. This given the theoretical maximum flow. A carb
flows typically 50-60% of this...

i.e. 1 1/2 inch SU carb. @ 25" of H2O

    21.8 x (1.5^2) x (25^0.5)  =
    21.8 x 2.25    x  5              =  245 CFM.   - but only flows 135CFM @
25" H2O or 55% of the theoretical max.

So 1000CFM from 6 carbs. is 167CFM per barrel. or about 1.7 inches diameter.
 hope this helps, let me know if it doesn't! Toby.



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