With CL engines having a fixed venturi it's been found by experiment that the best fuel draw occurs when the hole in the spray bar is pointing around 10 degrees further down from directly across the venturi. A Fox spray bar has 2 holes but they're not drilled 180 apart so it's only fitted correctly when both holes are pointing slightly down and can't be seen. On RC carbs with the adjustable mid range (like ST and Enya) the spray bar outlet can be turned slightly to match it's position somewhat better to the more angled airflow through the barrel for better (or worse) fuel draw. The Enya carb is better than the ST though because it uses a lever to rotate the spray bar while the engine is running and also has an air bleed for idle. I must admit I've never tried altering the Enya's mid range at full throttle though to see what happens to the mixture but I know it's very effective on the mid range.