Some Carburetors Used On Mazda Rotaries

Venturi
Rated Primary Secondary Total Area /Bore Secondary
Brand Model CFM Bore Venturi Bore Venturi Bore Venturi Ratio Type Notes
Nikki 12A 300 27.0 20.0 33.0 26.0 2856 1690 59.2% Vacuum
Yaw Nikki 415 27.0 24.0 33.0 2856 Vacuum
Hitachi 13B 27.0 22.0 33.0 26.0 2856 1822 63.8% Vacuum
Holley 4412 500 42.9 34.9 - - 2886 1916 66.4% NA G,H
Weber 45DCOE 45.0 36.0 3181 2036 64.0% NA sidedraft
Dellorto 48DHLA 48.0 38.0 3619 2268 62.7% NA sidedraft
Weber 48DCOE 48.0 38.0 3619 2268 62.7% NA sidedraft
Weber 48IDA 48.0 38.0 3619 2268 62.7% NA downdraft
Holley 1848 465 38.1 27.8 38.1 27.8 4560 2425 53.2% Vacuum C
Weber 40DCOE 40.0 30.0 Note A Note A 5027 2827 56.2% Mechanical A
Holley 1849 550 38.1 30.2 38.1 31.8 4560 3013 66.1% Vacuum D
Carter AFB 500 36.5 30.2 42.9 31.8 4980 3013 60.5% B
Weber 40DCOE 40.0 32.0 Note A Note A 5027 3217 64.0% Mechanical A
Holley 1850 600 39.7 31.8 39.7 33.3 4948 3329 67.3% Vacuum E
Holley 4777 650 42.9 31.8 42.9 33.3 5772 3329 57.7% Mechanical F
Carter AFB 625 36.5 30.2 42.9 36.5 4980 3523 70.7% B
Edelbrock Performer 600 36.5 30.2 42.9 36.5 4980 3523 70.7% B
Notes
General - Diameters and areas are in millimeters.
A - Used in pairs. Sidedraft. Non-progressive secondary actuation.
B - Secondaries are mechanical, but flow begins only after a mechanical air valve opens
C - Modified by Racing Beat for their street port 12A and stock port 12A & 13B intake kits
D - Modified by Racing Beat for their street port 13B intake kit
E - Holley's biggest seller
F - Double Pumper
G - Smaller than 45 Weber, which is generally considered small for a modified rotary. No manifold available.
H - 4bbl carbs are flow rated @ 1.4" pressure drop. 2bbl carbs are flow rated @ 3.0" pressure drop, eliminating CFM comparability between 4bbl carbs & 2bbl carbs. The comparable flow rating is 375 CFM, since this carb is actually half of a 750 CFM 4bbl.
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Last Modified 2003/04/30 © Felix Miata