My Grandfather (RIP) contention was that the smog equipment cut out 1/2 the pollutants per gallon of gas, but reduced the MPG by half. As the distance to work was the same the pollution was unchanged.
My Grandfather (RIP) contention was that the smog equipment cut out 1/2 the pollutants per gallon of gas, but reduced the MPG by half. As the distance to work was the same the pollution was unchanged
Today the main improvement is the electronic ignition system and computer timing that reduce pollution.