How can one make a car's engine heavier without certeris paribus making those two things worse?
High bulk-- irrelevant; the car is normal sized.
Engineers have to shoehorn engines into engine bays. The larger the engine, the more expensive the shoehorning. Their are myriad examples in the automotive press of automakers running into the engine-bay-size obstacle when trying to fit larger, more-powerful engines into existing car models.
High smog pollution-- not since the introduction of ultra-low sulfur diesel in the US in 2007.
NOx emissions are not affected by fuel sulfur level. Cleaning up the smog emissions of diesels still requires expensive bandaids that gasoline engines (as long as they operate at low-enough temperatures) do not require. If diesel-level NOx emissions were allowed for gasoline engines, then ceteris paribus gasoline engines would be more powerful and efficient and less costly.
The same emission limits apply to all vehicles regardless of the fuel they use. That is, vehicles fueled by gasoline, diesel, or alternative fuels all must meet the same standards. Since light-duty emission standards are expressed in grams of pollutants per mile, vehicles with large engines (such light trucks or SUVs) have to use more advanced emission control technologies than vehicles with smaller engines in order to meet the standards.
What about the increased tire-wear and decreased handling that I mentioned? http://news.ycombinator.com/item?id=458104
How can one make a car's engine heavier without certeris paribus making those two things worse?
High bulk-- irrelevant; the car is normal sized.
Engineers have to shoehorn engines into engine bays. The larger the engine, the more expensive the shoehorning. Their are myriad examples in the automotive press of automakers running into the engine-bay-size obstacle when trying to fit larger, more-powerful engines into existing car models.
High smog pollution-- not since the introduction of ultra-low sulfur diesel in the US in 2007.
NOx emissions are not affected by fuel sulfur level. Cleaning up the smog emissions of diesels still requires expensive bandaids that gasoline engines (as long as they operate at low-enough temperatures) do not require. If diesel-level NOx emissions were allowed for gasoline engines, then ceteris paribus gasoline engines would be more powerful and efficient and less costly.
Originally (under the EPA's Tier 1 regulation), there was a dual standard (gasoline and diesel) for light-vehicle smog emissions. http://www.dieselnet.com/standards/us/ld.php
Now, there is a single standard (Tier 2 regulation). http://www.dieselnet.com/standards/us/ld_t2.php
The same emission limits apply to all vehicles regardless of the fuel they use. That is, vehicles fueled by gasoline, diesel, or alternative fuels all must meet the same standards. Since light-duty emission standards are expressed in grams of pollutants per mile, vehicles with large engines (such light trucks or SUVs) have to use more advanced emission control technologies than vehicles with smaller engines in order to meet the standards.