i have been in racing for several years, i am currently in iraq working as a civillan for the US government for the last 5 years.
thanks Dr Goggles, your tank is one i have ben lookng at for sometime and the way the exhaust exits the rear. the meredith effect could be implemented on the tank exhaust at the rear by using an exhaust augmenter where the exhaust exits the tank, smooth the body panels on the sides of the engine where the air louvers are and replace them with a NACA duct on each side. the large suction action of the exhaust augmenter would be like a vacume cleaner running and pulling cool air in the NACA ducts around the hot engine compartment and out the back, contributing more heat and expanding gasses to the air stream behind the car, filling the void behind the vehicle and increasing aerodynamics.
an earlier post beat me to the punch, it got to late for me last night so today i was going to elaborate about the american and the russian 300MPH torpedos, they use compressed gasses released along the front and sides of the torpedo to lower the drag and increase the speed, the gas bubbles create a boundry layer of gas around the torpdo body, pushing the water out of the way, water being many times more viscous than air and subsequently creating more drag.
i think the best way to release the exhaust gasses would be to imagine 2 long, flat header collectors 1/8 to 1/4 inch tall but 36inch in width surounding the body about its circumferance, releasing the hot exhaust gases into the air strem smoothly around the entire body diameter.
the ideal placement would be as close to the nose as possiable so the hot gasses could cover as much of the body over the longest distance, if you have a bullet shaped nose, which a LOT of the tanks and streemliners fall under this, you can imagine a bell shape being placed over the nose and it having a small air gap between it and the body for the exhaust to escape and the outlet device would have minimal effect on the vehicles aero. the bell shape with a circuler exhaust inside would distribute the exhaust evenly, if you only had a straight pipe sticking out the front, the gas distribution would be all over the place, the aero impeded, plus the on coming air would be working against the exhaust flow, trying to push back down the pipe.