Stop in for a cup of coffee

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Ok guys, I need help wrapping my head around something and I didnt want to make a thread. So explain to me why when you use a carb sizing calculator it gives your what your ideal carb size is.. For example my engine is spec'ed to use a 625cfm carb. Ok now you have a factory 340 six pack and from my research is around 960cfm total.

I was running a 750 on my car and it ran good, but when I threw on a 600cfm carb it was much more responsive..Regardless of that, what I dont understand, how is it possible to oversize a carb?? Why could I not run a 800cfm carb on my car and have it run like a six pack? Is what Im saying making sense?
 
straightlinespeed said:
Ok guys, I need help wrapping my head around something and I didnt want to make a thread. So explain to me why when you use a carb sizing calculator it gives your what your ideal carb size is.. For example my engine is spec'ed to use a 625cfm carb. Ok now you have a factory 340 six pack and from my research is around 960cfm total.

I was running a 750 on my car and it ran good, but when I threw on a 600cfm carb it was much more responsive..Regardless of that, what I dont understand, how is it possible to oversize a carb?? Why could I not run a 800cfm carb on my car and have it run like a six pack? Is what Im saying making sense?
Click to expand...
How do I select the correct CFM carburetor for my application?
Answer: The carburetor CFM is a very critical choice in your build. Too large will cause low RPM issues and a rich condition. Too small will restrict the engine performance at high RPM. A simple formula is commonly used by our techs to select the proper CFM:

(Cubic inch of engine X Max RPM) / 3456 = maximum CFM required

Ex. (350ci X 6500RPM)/3456=658.28 CFM (a 650 CFM would be ideal for this application)
 
might just get a 5 dollar craving box from the bell ...taco bell

its really a deal, a burrito supreme, chulupa thingy, nachos, and a taco ....oh yea and don't forget it comes with a pop.

All that individually ...would be way more money and that will last me a day and a half
 
ScampMike said:
How do I select the correct CFM carburetor for my application?
Answer: The carburetor CFM is a very critical choice in your build. Too large will cause low RPM issues and a rich condition. Too small will restrict the engine performance at high RPM. A simple formula is commonly used by our techs to select the proper CFM:

(Cubic inch of engine X Max RPM) / 3456 = maximum CFM required

Ex. (350ci X 6500RPM)/3456=658.28 CFM (a 650 CFM would be ideal for this application)
Click to expand...
I get that part, but when a 340 engine is running 3 carbs for a total of 960cfm @ WOT, how does it function properly?? Now granted I dont know if all 3 carbs open together or not, but that is what Im trying to understand.. It doesnt make sense to me.
 
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