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relatively, i can't see someone a 50cc 2-stroke moped putting out more emissions than a huge 3-ton BMW X5 with a massive diesel engine, awd etc. which is carryi

• jjeaff 4y ago
  I don't know, run a full size modern diesel car in a garage for a few seconds then compare it to a 2 stroke running for the same amount of time. The 2 stroke will certainly smog up the place quicker.
  • canbus 4y ago
    those are just the visible gases - you can't see carbon monoxide etc.
  • camtarn 4y ago
    Yep. The scooter might output less CO2, but due to the primitive nature of the 2-stroke engine, it's basically chucking a rich aerosol of unburned fuel and lubricating oil out the exhaust. The X5, by comparison, has a catalytic converter to get rid of carbon monoxide, nitrogen oxides and unburned fuel, plus a particulate filter to get rid of soot; it will also have secondary emission control systems to stop fuel vapours escaping from the fuel tank and crankcase. 2-strokes have remarkable power-to-weight ratios and are pleasingly mechanically simple, but goodness me they're dirty.
• mschuster91 4y ago
  > relatively, i can't see someone a 50cc 2-stroke moped putting out more emissions than a huge 3-ton BMW X5 with a massive diesel engine, awd etc. which is carrying one person at any given time. Different kinds of emissions. CO2-wise, yes indeed the moped is less harmful. But the other emissions... a modern car is essentially a chemical lab on wheels. At least one actively managed catalytic converter to remove NOx, another one for diesel engines to burn leftover carbon monoxide, and then a particulate matter filter to trap and burn-off soot and other micro particles. A two-stroke engine usually only has a passive catalytic converter and that's it. It emits by design unburned fuel-oil mixture into the exhaust because the mixture is used as a lubricant, and beyond a muffler it has absolutely zero noise emission control.
  • canbus 4y ago
    i agree, and im not trying to undermine modern research and development on emissions, but my point is that perhaps larger cars should be discouraged as they are hugely overkill for most people's needs and exist as status symbols - if coming purely from an emissions standpoint they are terrible compared to an equivalent small car or motorbike etc yet people seem to blame 2 strokes and old cars when in reality they are not the sole cause of the problem
    • camtarn 4y ago
      Ah, yeah, that's fair. Each individual vintage vehicle is terrible, but there really aren't that many of them, whereas there are millions of large cars/pickups being sold per year. I'd certainly support some sort of measure aimed at large vehicles which aren't used for some sort of large-vehicle-appropriate task.
      • dsfyu404ed 4y ago
        Slap up some rolling truck scales on your existing toll roads and pro-rate tolls with the discount maxing out right at GVWR (which you got by looking up their vehicle with your existing ALPRs) and then spend a decade hammering out edge cases. It will never fly because the demographics that are usually supportive of that kind of legislative action are almost exactly the same demographics who buy 3-row SUVs for 2-kid households and hand wring like it's the end of the world if you put four adults in a compact car or throw plywood on a roof (but a kayak is fine).
    • andrepd 4y ago
      Yes I mean classic cars are dirty but there are very few of them, most being used only seldom. However there are 10s of millions of >2 ton hunks of metal being used to haul mostly 1 person around, with all the consequences that implies: pollution, noise, space for roads, space for parking, traffic fatalities, etc. That's a real problem.