Hi, I have been lurking around here for a while to gain insight into the tuning of Weber carbs. Sadly, I am not an owner of a GT40 (I wish I could) but have seen some very intelligent and helpful folks posting here.
I have been working in the automotive field for most of my life and have tuned many multiple carb setups but nothing like the Webers. Recently I have been working on a streetrod with a 5.0 liter stroked to 347. We installed four Weber IDF 44 carbs and began the saga of getting them set. A lot of time was spent getting the linkage properly set and synchronizing the carbs. We are now down to jetting and overall driveability. At the present we have idle jets @ 55, main jets @ 135, air jets @ 170. No other changes have been made.
The engine idles great and under full load runs perfect. Problem comes in when under light acceleration we encounter a lean condition around 2200-2500 rpm. It is not a major stumbling of the engine but firing is uneven, not smooth. I tried using 60 and 65 idle jets to cure it but the 60's made no difference and the 65's seemed a bit too rich.
I am thinking I should change the emulsion tubes. Does this sound like a possible solution? Is there anything else I should do?
I have been working in the automotive field for most of my life and have tuned many multiple carb setups but nothing like the Webers. Recently I have been working on a streetrod with a 5.0 liter stroked to 347. We installed four Weber IDF 44 carbs and began the saga of getting them set. A lot of time was spent getting the linkage properly set and synchronizing the carbs. We are now down to jetting and overall driveability. At the present we have idle jets @ 55, main jets @ 135, air jets @ 170. No other changes have been made.
The engine idles great and under full load runs perfect. Problem comes in when under light acceleration we encounter a lean condition around 2200-2500 rpm. It is not a major stumbling of the engine but firing is uneven, not smooth. I tried using 60 and 65 idle jets to cure it but the 60's made no difference and the 65's seemed a bit too rich.
I am thinking I should change the emulsion tubes. Does this sound like a possible solution? Is there anything else I should do?