it will always be a robbing peter to pay paul situation.
a perfectly running optimized engine will have higher emissions of some things then one not. then there is optimization for horsepower or torque again nothing overlaps, it is either/or.
you go back to that time pre cats and other emissions devices that catch exhaust gases and computers had yet to even be known by most people.
think about the smog issues, and leaded gas... so they(gov) wanted to optimize being able to breath air with cars in heavy traffic and stop and go under 20 mph where most cars live in cities.
so the government says to the car manufacturers we need you to to produce a product that makes the air cleaner and we don't care how or you cannot sell it because people in cities are dying. this was actually pretty true, if you lived in los angles or new york city in the late 1960s you would be hacking up a lung during rush hour in the morning and night. it was so bad the carbon buildup was actually eating the mortar out of buildings and dissolving brick when it rained(acid rain in the city was no joke even into the mid 1980s)
basically car density reached a level were they needed to do something to slam the hammer down knowing it would take 20 years to really kick in.
thus the cars had to be detuned. they knew some people would get around it but the idea was throw enough at the wall that some would stick and make a change over time.
the auto industry did not recover Horsepower until the 1990s (20 years) based on new technological improvements, the change from carbs to fuel injection was arguably emissions control based.
with a carb we all know it gives the incorrect amount of air and fuel at all times, it just gets you close and it is easy to tune either way lean or rich to do what you kind of want.
so basically at the start I'm guessing they felt nitric oxide and nitrogen dioxide was more of a danger then co2 and other gases. they knew they needed time to come up with egrs and catylitic convertors to patch over the other gases.
well if you look back you can see the divide. you had people outside of cities wondering what the hell was going on why the cars lost so much horsepower. people inside cities getting less emissions over time but also not understanding what was going on and everyone complaining that cars got smaller and had less power, and it was the governments fault which was true. the problem was just like government over time they went outside their own power and just slammed the thumb down mandating impossible standards that people would have to pay for. this included safety regulations.
at the same time they did save lives but it took a long learning curve.
if you want a car that is clean to the environment, then it must run, lean and hot and be detuned. and it will smell sour but have less junk floating out the tailpipe.
if you want a car that maximized power then it must run rich, cold, and have lots of timing, and it will be sweet smelling with soot and other crap you don't want to breath in.
course this applies to engine design as a 1:1 ratio in the valves increased MPG and decreased emissions where before they optimized power and the intake and exhaust valves were sized 1:3 sometimes.
today since there are few classic cars compared to new cars on the road we can get away with making them run like the old days. but if you go to a REALLY big classic car show on a day with no wind you will feel like you smoked a pack of cigarettes, and taste everything in the back of your throat when you go to leave in your new car.
some even basic emissions controls are actually a good thing, pcvs are good at removing water from fuel and reducing varnish inside the engine.
a vapor can catches evaporating fuel. DVCV is an emergency safety if the engine starts to overheat. a vacuum advance increases mpg.
even the stock air cleaner acts as a emissions device but actually helps with cold starts and double dip fuel from a carb and back pressure which can be used for good things. this is the difference between a street car that you want running as well as possible all year round and a track car where you just want to gogogo and hope it doesn't rain or the temperature drops.
I guess they never calculated total emissions. The things that EPA required resulted in great reductions in gas mileage and therefore increased emissions. A 1968 302 would get 23 mpg. By 1977 that number was more like 17. Another fine example of what happens when the government says they know best are going to save us from ourselves. Chuck
