Lift is a bad thing and to counter act you need to either add ballast or reduce the lift. If you reduce the lift and decrees drag, isn't that the same free lunch?
Yes and no -- I am making an important but subtle distinction regarding first principles. Reducing lift is
not the same as "creating down force" it is the elimination of an undesirable negative not the creation of a new force pointing in the opposite direction at no cost (ie violation several physical laws)
Cutting loose a boats anchor is not the same as putting up more sail while leaving the anchor out. They may both increase the speed of the boat but different things are going on. In the case of taping the nose you are cutting the anchor chain, reducing a negative that already exists, you are not getting any free energy you are reducing your losses.
I agree with you entirely, NASCAR is an excellent example of reducing drag by cutting internal flow drag by taping off the radiator.
The point several people here are trying to make is that the conception that "down force" in certain situations is some how "free" in terms of drag is a faulty understanding of the physics involved. If that faulty understanding is applied uncritically to other problems it leads to big mistakes both in understanding what is going on and why you should be doing it.
Some folks understand that distinction some do not. Yes the reduction in drag is "free" in the sense that the tape does not cost much and little effort is involved but physically it does not "create" anything new. Lowering front end lift by reducing underhood pressure is not "increasing down force" it is reducing lift. Two very different things that have the same net result
in this case.
For example adding a gurney lip on an inverted airfoil substantially increases down force generated by that inverted airfoil at a relatively small cost in drag, but it is still not "free down force" you do pay a small price in additional drag. That penalty may be much smaller than the drag penalty you would pay for creating the same down force with a bigger wing or a wing with more camber or with the same wing at a higher angle of attack but it is still not free, it is just the least costly of the 4 alternatives to get to the same place.
Going back to your analogy, adding ballast actually creates down force and does not increase aero drag in any way, but it will increase rolling resistance, and bearing losses in the loaded wheel bearings. It also certainly slows down your acceleration to the 2. Again it
appears free but it is not, you are just paying for it at a different window.
Larry