Does leaner equal increased acceleration/throttle response? | FerrariChat
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Does leaner equal increased acceleration/throttle response?

Discussion in '308/328' started by 4right, Sep 2, 2023.

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  1. 4right

    4right F1 Rookie
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    #1 4right, Sep 2, 2023
    Reduced the idle jets from 65 to 60 this morning. Took the 308 out for a drive and noticed quicker acceleration and throttle response. A few years ago, the carbs were sneezing badly. The local Ferrari dealer installed 70 idle jets and the problem went away. The only challenge was a strong fuel smell and soot on the rear of the car. About a year ago, I reduced the jets to 65 and then today 60. I was expecting the exact opposite, however, it’s actually running and accelerating stronger. Counter intuitive.
     
  2. Rifledriver

    Rifledriver Three Time F1 World Champ

    Apr 29, 2004
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    Brian Crall
    #2 Rifledriver, Sep 2, 2023
    Last edited: Sep 2, 2023
    Why is it counter intuitive? In answer to your question correct mixture equals better power. Rich covers up poor running and makes an out of tune car run better but with reduced power. Lean also reduces power but is more symptomatic. Carbs are never more than an approximation of what is correct. Sometimes too lean, sometimes too rich. Too lean shows symptoms more so many err on the side of rich. A carb will never provide perfect mixture across all modes, they are too crude. Injection can.
    Carbs are best used as museum displays. A quaint reminder of the bad old days in automotive history.

    Idle jets or more correctly low speed jets contribute nearly nothing to hard acceleration. Their influence fades away at over 1/4 throttle and is very slight even then.
     
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  3. 4right

    4right F1 Rookie
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    #3 4right, Sep 2, 2023
    Thanks Brian, don’t understand the rich setup then as it’s running better at 60 than 70. If they were trying to cover something, they went too far.
     
  4. Rifledriver

    Rifledriver Three Time F1 World Champ

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    #4 Rifledriver, Sep 2, 2023
    70 is awfully big for a 308. Most came with 45 or 50 and in flow capacity 70 is huge.
     
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