Estimation of the Cd-reduction

[Gary Palmer]

With the objectives you have of keeping the engine/transmission running, I'd be pretty careful about doing anything in terms of a grill block, or even a belly pan under the engine.

If you do something with the grill, I'd test the daylights out of it. A grill block does seem to make a difference, in terms of mileage and it does seem to take a block of almost the whole grill before I see a temperature increase, on the highway. However, on my 89 Honda it is only turning 3,000 -3,800 if I'm pushing it at 80 mph, or so. However, that is all steady state driving, not mash it to the floor, then let up as late as possible, hammer the brakes and then do it over and over again.

You should check out the aerodynamics of Bassjoo's Honda. His boat-tail added more mileage than any other modification and it might be something you could give a try.