Moparts Tech Archive
Fuel System
Carb flow test
fast68plymouth Moparts Member Posts: 2791 From: so burlington,vt usa Registered: Aug 2000 posted 07-06-2002 09:35 PM first, let me say right up front that this is by no means the definitive carb flow comparison test. i dont have a flow bench with enough capacity to flow test a carb, all barrels simultaneously, at the industry standard pressure drop. IMO, thats the only way to really compare carbs. in any case...this is a set of results from several different carbs, all tested by the same operator, on the same bench. the test procedure is done flowing one barrel at a time at a pressure of 10" h2o. you add up the results from all the barrels, convert that number to 1.5"Hg(20.4" h20), and thats the "dry flow". when the motor is running, fuel will be introduced into the flow path. since the fuel displaces some of the area in the venturi, the flow will be reduced. how much of a reduction of flow depends on how much fuel is being introduced. what this means is that jetting influences the "wet flow" capacity of the carb. an A/F ratio at WOT in the mid-high 12's will result in a loss of flow of about 8%. this is what i use to determine "calcuated wet flow", 92% of the dry flow. perhaps if this generates enough interest Carl can add it to the tech archives, and i can add to it as i get more carbs to test. Holley carbs: dry----CWF----carb 743.8/684.2--4778-2/700DP-stock 838.3/771.2--4779-2/750DP-stock 845.4/777.8--4780-1/800DP-stock 934.0/859.2--4781-2/850DP--no choke tower 838.2/771.1--80508-2/750VS-stock 834.6/767.8--3310-2/750VS-stock(downleg) modified Holley Carbs: dry----CWF----carb 984.4/905.6--CFS 905, ported 850DP annular 976.5/898.4--BG 9380S3 annular 912.2/839.2--Proform body w/HP baseplate 931.3/856.7--PRH 950HP, Braswell boosters, blended and polished venturi, BG baseplate BG Claw/Demon carbs: 1000.7/920.6-BG Gold Claw "1025" downleg 964.1/886.9--BG Gold Claw "825" downleg 980.5/902.0--BG Gold Claw "750" annular 980.4/901.9--BG Silver Claw "1000" downleg 947.7/871.8--Speed Demon 850DP Carter/Edelbrock carbs: 647.4/595.5--69 383 AVS-stock 617.9/568.4--Comp series 625 AFB 767.1/705.3--Comp series 750 AFB 756.2/695.7--Ebrock 1407 750 647.6/595.8--Ebrock 1406 600 --------------------------------------------- All info provided by member fast68ply.
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