Combine the two cups of sugar and first two cups of water in a small saucepan over high heat just until the water boils. Stir until all the sugar dissolves and remove from heat. Let cool to room temperature.
In a large punch bowl or pitcher, combine the simple syrup, 2 1/2 cups lemon juice, 2 cups frozen passion fruit pulp (still frozen and broken up into chunks), 4 cups water and 4 cups ice cubes. Stir well to combine and leave in the refrigerator to chill for at least 1 hour (up to 4). Note that it will be very strong at first; the ice will melt so that come time to serve it, the lemonade will be perfectly chilled and balanced. Stir before serving.