[Don]

Restrictors, for a variety of purposes, are not unique to NASCAR, a Lotus example below.

"The Exige R-GT is powered by a 3.5-liter supercharged V6 engine, which produces 302 horsepower. That energy is routed to the wheels through a six-speed sequential transmission. The engine is the same as the one found in the standard Exige, however 34-millimeter air restrictors have been put in place to control the power, as is required by the FIA rulebook for R-GT racing."

ALMS also uses restrictors, with different size openings to " equalize performance " and " maintain a level playing field " With the C5.R Corvette, the restrictor opening was decreased for their engines during the racing season.

" The ALMS rules mandate the use of air restrictors to equalize the performance potential of the wide variety of cars that compete in the series. The size of the restrictor is determined by the vehicle's weight, engine displacement, induction system (naturally aspirated or turbocharged) and other factors. The C6.R Corvette, for example, is required to breathe through two 31.8-mm restrictors. These orifices are about the size of a 50-cent coin."

" Much like the carburetor restrictor plates used by NASCAR on superspeedways, the ALMS air restrictors limit airflow through the engine, thereby controlling the horsepower produced. Moreover, ALMS officials can change the size of the restrictor orifice to maintain a level playing field "

Seems too simple, but had wondered if controlling speed could be achieved by reducing the CI, currently 358, and resulting HP, then eliminating the restrictor plate, or would there still be pack racing at a lower speed due to the high banking and tire technology. But, the offset would be different engines, more so than the unique restrictor plate engines, for a few tracks and driving up the cost.

At the 2012 speeds and aggressive driving in both the corners and straights, has the human reaction time, to either an incident or just racing, too slow to avoid the consequences........, while traveling the length of a football field in one second, 140 vs 195 mph