Banktoturn,

Have a close look at Simon's Drag Budget illustration. The horizontal axis is labeled "Slow, high lift coefficient." Strictly speaking this doesn't apply to Pylon Racers unless they slow down a lot in the turns. A plane that is banked 80 degrees is pulling about 5 G's or a bit more in a level turn where the fuselage is not contributing lift. If the lift coefficient is 0.1 or 0.2 in the straights and there is not an appreciable slowing in the turns, then the coefficient of lift must be about 0.5 to 1.0 (5 times as great for 5 G's). At these lift coefficients, the induced drag is very high and high aspect ratio is a big advantage. Also when the chord is narrowed and the airfoil % thickness is maintained the frontal area is reduced in the same proportion as in chopping the wing when the resultant areas are the same for the high and low aspect ratio cases.

If you were to base a drag budget diagram on the same speed in the straights as in the turns, the parasitic drag would be more or less constant and the profile drag would be about the same if the airfoil was still operating in its low drag bucket. However, the induced drag would increase as the square of the lift coefficient increase.

Of course there is slowing in the turns but you want to minimize that with the highest aspect ratio that you can get away with structurally.