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Thread: changing from dcoe 40's to 45's?

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    changing from dcoe 40's to 45's?

    I have some twin 40's on my pinto that are jetted as follows

    idle 45f8
    main 145
    a/c 180
    32mm chokes

    can someone offer any advice on jet and choke sizes based of my 40's

    running a Newmans ph4 276 deg cam, ported injection head, standard valves,

    I have a big valve head for the car but currently using it for auto testing and don't want to pull it apart just yet.

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    Re: changing from dcoe 40's to 45's?

    36mm chokes, F11 or 16 etubes, 145 - 155 main, 45 - 50f8 idle, 180 Ac, then stick it on a rolling road

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    Re: changing from dcoe 40's to 45's?

    Could give a starting point for jetting but my advice is with that cam don't use 45's.

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    Re: changing from dcoe 40's to 45's?

    i dont see an issue with 45's, dellorto used to recomend trying 45's on a standard engine!

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    Re: changing from dcoe 40's to 45's?

    I may just leave it for now and save the 45’s until I have built my other engine up.

    Would you not recommend the 45’s cause I may loose low down grunt?

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    Re: changing from dcoe 40's to 45's?

    All depends on what chokes youre using, ive ran a set of 45's on a std Pinto with 34mm chokes and it was very torquey. Theres certainly a fair bit to gain from going up from your 32mm chokes, a Pinto needs 34's at least.

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    Re: changing from dcoe 40's to 45's?

    45's mean going up in choke size, 36mm chokes are too big for a std cam or a Newman 276 cam.
    Using 34 mm chokes in the 45's will mean gaining a few bhp on top end and loosing low range torque.
    When the application is autotest you don't need the extra few bhp on top end.

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    Re: changing from dcoe 40's to 45's?

    Quote Originally Posted by Miniliteman View Post
    45's mean going up in choke size, 36mm chokes are too big for a std cam or a Newman 276 cam.
    Using 34 mm chokes in the 45's will mean gaining a few bhp on top end and loosing low range torque.
    When the application is autotest you don't need the extra few bhp on top end.
    Thanks for this.

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    Re: changing from dcoe 40's to 45's?

    Im not sure why you think using 34mm chokes in a 45 will lose low down torque?? 36mm chokes work well in a std Pinto.

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    Re: changing from dcoe 40's to 45's?

    for an uprated pinto you should not use 40ies at all.....a well jetted 32/36 does the job up to 150HP....more than that...go to 45īs...

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    Re: changing from dcoe 40's to 45's?

    40’s massively outperform a 32/36, I’ve ran 40’s on really torquey fast road engines, far far smoother than a 32/36 or 38DGas, it’s not just about peak power. Swapping from a twin choke to 40’s on an engine with a fast road cam is like night and day. Granted they only really flow enough for about 150hp but will produce a much nicer low to mid range and idle than a twin choke single

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    Re: changing from dcoe 40's to 45's?

    Quote Originally Posted by Erikmex View Post
    40’s massively outperform a 32/36, I’ve ran 40’s on really torquey fast road engines, far far smoother than a 32/36 or 38DGas, it’s not just about peak power. Swapping from a twin choke to 40’s on an engine with a fast road cam is like night and day. Granted they only really flow enough for about 150hp but will produce a much nicer low to mid range and idle than a twin choke single
    i'd agree on that

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    Re: changing from dcoe 40's to 45's?

    Quote Originally Posted by Erikmex View Post
    40’s massively outperform a 32/36, I’ve ran 40’s on really torquey fast road engines, far far smoother than a 32/36 or 38DGas, it’s not just about peak power. Swapping from a twin choke to 40’s on an engine with a fast road cam is like night and day. Granted they only really flow enough for about 150hp but will produce a much nicer low to mid range and idle than a twin choke single
    From what I've drove I agree yah.
    What chokes you recommend on 40's here?

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