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Thread: DCOE Choke Measurement

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    Pit Crew Decade Plus User MK1_Oz's Avatar

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    DCOE Choke Measurement

    If I have a Weber 50 DCOE then the bore through the carby is 50mm. I then put a choke in there that is say 42mm. Where is that 42mm measurement on the choke? Is it the thinnest point? The pic below is a slice through a choke...

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    Re: DCOE Choke Measurement

    its the narrowest internal point

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    Re: DCOE Choke Measurement

    I am trying to draw up a 50 DCOE Weber. The air inlet is sized at 50mm but what size is the outlet (where the butterfly is)? A 45 DCOE is 45mm inlet and 40mm outlet but I don't want to just assume a 50 DCOE is 50/45....
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    Re: DCOE Choke Measurement

    The number in 40DCOE, 45DCOE etc is a reference to the throttle-plate diameter.
    So a 50DCO has a 50 mm throttle-plate (butterfly)

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    Re: DCOE Choke Measurement

    Quote Originally Posted by MK1_Oz View Post
    I am trying to draw up a 50 DCOE Weber. The air inlet is sized at 50mm but what size is the outlet (where the butterfly is)? A 45 DCOE is 45mm inlet and 40mm outlet but I don't want to just assume a 50 DCOE is 50/45....
    ????? dont know where your getting the 5mm difference from, the size is the throttle plate size, 40mm has a 40mm throttle, 45 a 45mm throttle and so on.

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    Re: DCOE Choke Measurement

    Me confused then. I was partly going off a CAD drawing of a Weber 45DCOE that somebody else had drawn verified by a couple of 45DCOE parts I have.


    A 36mm 45DCOE choke measures 45mm across at the inlet side, chokes down to 36mm at its thinnest then increases to 40mm at the outlet suggesting a 40mm throttle plate.

    A 45DCOE inlet trumpet is 45mm across its internal diamter which agrees with the choke.


    I don't have my 45's off the car in order to be able to measure the throttle plate. Not challenging anybody, just trying to match up info....
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    Re: DCOE Choke Measurement

    The choke will measure 45mm od, the trumpet will measure 45mm od to slide into a 45mm carb, the choke is radiused from 45mm to the where the choke is measured in the middle so 36mm ID, but the radius shape changes towards the throttlw plate for airflow and to create a venturi, its always thicker on the outside, are you sure youre not looking at it the wrong way around? ie. youre thinking the outside is the inside?
    Last edited by Erikmex; 30-06-2019 at 11:05.

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    Re: DCOE Choke Measurement

    nope measured it as above...
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    Re: DCOE Choke Measurement

    This should help explain what you mean.
    Attached Thumbnails Attached Thumbnails dcoe_dimension_gaskets.jpg‎  

    Regards,
    Kevin

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    Re: DCOE Choke Measurement

    Quote Originally Posted by djaminhi View Post
    This should help explain what you mean.
    thats a 40mm carb, 40's and 45's were made from the same casting body, which is why the throttle end is smaller than the intake and why aux vents for 40's have really thick walls

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