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  1. #1
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    Another carb question

    When I'm reving my friend's GTT from 2000 till 5000 with a 2/3 throttle (in this case boost is around 6-7psi) first as the acc pumps a bit it gets around 12-12,5 but soon after leans out till 16-16.5.
    If I rev the car with wot than it is around 13-13,5 all the range. (std. boost around 10psi)
    Is this normal from a std. carb or shall I check something?
    Thanks again.

  2. #2
    Non-member SCHWARTZ's Avatar
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    Re: Another carb question

    is this just revving the engine in neutral? as i think the engine would need to be under load to give you a proper reading.

  3. #3
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    Re: Another carb question

    Quote Originally Posted by SCHWARTZ View Post
    is this just revving the engine in neutral? as i think the engine would need to be under load to give you a proper reading.
    No, in 3rd gear.

  4. #4
    Non-member SCHWARTZ's Avatar
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    Re: Another carb question

    sounds like its a bit lean all over then. theres articles on here that explain what the readings should be at, at what rpm, throttle position etc...

  5. #5
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    Re: Another carb question

    Quote Originally Posted by SCHWARTZ View Post
    sounds like its a bit lean all over then. theres articles on here that explain what the readings should be at, at what rpm, throttle position etc...
    I've read trough all articles but I've only found readings at WOT and I haven't found readings for half or 2/3 throttle.
    Maybe I'll try a smaller a/c.

  6. #6
    Committee Member Sparkie's Avatar
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    Re: Another carb question

    you need to make a note of the vacuum readings in relation to the afr readings.

  7. #7
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    Re: Another carb question

    Quote Originally Posted by Sparkie View Post
    you need to make a note of the vacuum readings in relation to the afr readings.
    There is no additional turbo gauge in the car only the one in the instrument panel. So I only know pressure at the carb top.

  8. #8
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    Re: Another carb question

    I've also observed another abnormal behaviour of this car.
    Cruising on a flat road in 5th gear around 3k rpm, boost is around 2-3psi @carb top and the AFR readings are a near constant high 14s than after a while suddenly low 13s. And not only for a moment.
    I have already checked the fuel flow. 1bar at the FPR, running the pump for 40s and it pumped around 1,2l. And the flow seemed to be constant.
    Could it be an air leak? But where?

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