If you took that same curve but used time instead of RPM on the X-axis, you'd see that it only takes your car a couple seconds to regain the torque it lost from the secondaries opening up. IMO, that's not too shabby considering it's letting in ~50% more air in! (<---Someone please correct me if that number's way off.)
I'm no tuner, but I'm imagining that's it's damn near imposible to get rid of that secondary induced drop off w/o removing the secondaries...
Nice numbers and nice graph!
