One man's snow machine emissions

Discussion in 'Emissions' started by SentraSE-R, Feb 10, 2009.

  1. SentraSE-R

    SentraSE-R Pishtaco

    I just read an article claiming that a single two-stroke snow machine in a race emits 150 times the hydrocarbons as a car driving roughly the same distance from San Francisco to Chicago. The same article says that one snow machine emits as many cancer-causing and smog-forming pollutants as a Chevy Malibu driven around the Earth at its equator 28 times.

    The article drips with political poison, but the facts are probably correct. A lifetime of driving a responsible car will be erased as soon as a few snowmobilers crank up their engines tomorrow.
  2. warthog1984

    warthog1984 Well-Known Member

    This is false. A 2 stroke engine w/o a catalytic converter Will emit noticeably more pollutants than a cat-equipped 4 stroke.

    However, the difference is more on the order of 4-5x, and Not 4000-5000x.
  3. Taliesin

    Taliesin Well-Known Member

    The newer 2 stroke engines do much better as well.

    The '06 motor on my boat is a 2 stroke that meets the California requirements for a 4 stroke.
  4. Mendel Leisk

    Mendel Leisk 2010 Prius (CAN Touring) Staff Member

    "A lifetime of driving a responsible car will be erased as soon as a few snowmobilers crank up their engines tomorrow"

    I've had similar thoughts walking past a couple of warming up diesel flatbed trucks, morning after morning. You pretty much held your breath 100 feet either side of these stink pots, and still got fumigated.
  5. PILL

    PILL Well-Known Member

    I can't help but notice the negative and condescending tone of your post.

    Do you have a better option to warmup these trucks? Diesel engines need to be warmed up...
  6. jkp1187

    jkp1187 Well-Known Member

    The whole article is just an attack on a political has-been from some hack writer. I am not buying unless you get a much better source.

    @PILL: Sure. Use railroads. Save the highways for cars. ;)
  7. daisy

    daisy Member

    Well, this is discoverable.

    According to the EPA, a 2009 Chevrolet Malibu has an air pollution score of 9.5. This chart (PDF warning) says that that means it emits less than 0.01 g/mi of unburnt hydrocarbons.

    This lab report from the Southwest Research Institute gives emissions for a 4-stroke snowmobile as 3.28 g/mi at WOT (this is a race, after all). They say on page 13 that "a conventional 2-stroke powered snowmobile was tested … using the same test procedure." The two-stroke emitted 20x as much unburnt hydrocarbons as the compared 4-stroke, so the "conventional" 2-stroke should emit 65.6 g/mi. That's 6560 times as much.

    Now, who knows how much cleaner Todd's snowmobile is compared to this "conventional" 2-stroke. However, even the 4-stroke started out being 328 times as bad as the Malibu, so it wouldn't surprise me if Todd's snowmobile was 150 times as bad.

    I think this may be more a statement about how good modern emissions controls are, rather than how bad two-strokes are. Also, note that this is only local smog-forming pollutants, not greenhouse gas emissions.
    Last edited: Feb 16, 2009
  8. PILL

    PILL Well-Known Member

    Trains are great, but like buses and trains for people, they aren't always practical.
  9. TimRogers

    TimRogers Member

    This is a bit of an apples to oranges comparison, given that the EPA testing on any car never gets into the larger throttle openings and therefore the fuel mixture required by the engine is always at a stoichiometric 14.7:1. If they ran the same test at WOT with the Malibu (or any gasoline engine for that matter), the fuel mixture would be in the 13 to 12:1 range, which a catalytic converter can't cope with as there is not enough free oxygen for the hydrocarbons to combine with.
    The snow machine should be running at a similar stoichiometric ratio as the Malibu at "cruise", of course without the benefit of a cat. to clean the emissions.
  10. Tochatihu

    Tochatihu Well-Known Member

    This web site seems to tell us where these engines fit in emissions wise.

    More math is needed to compare to cars, but qualitatively I'd suggest that they aren't quite 'clean' yet.

    If they are primarily operated outside urban areas, then the smog forming potential is much lower. Reducing NOx and HC in cities is the big deal (according to me).

    Therefore I have more concern about diesels (OK, most diesels) and the old-car fleet.

  11. Pryme

    Pryme Active Member

    I enjoy to ride my honda cr250 mx bike, not sure of the polution but it is a 2 stroke and will knock on anything less then 100 octane. very high compression. to bring semis into the conversation is silly imo. without them, our life would be very different! I do feel they should have some sort of test for them but we need them none the less!
  12. Shiba3420

    Shiba3420 Well-Known Member

    If I remember my trip to Alaska (which was during summer), I pretty much saw 2 kinds of snow ones which seemed to be owned by either the state or visitors, and old beaters which were common amoung the locals. However, the locals may have just left the old beaters where they could be seen while the newer ones were stored out of site in a shed. I have to imagine that some of those were as bad as you could buy. But many are further modified for either speed (racing) or efficiency. In both cases, i suspect much of the emissions are pretty awful.

    On the other hand, it wasn't difficult to find some hard data on what these engines may do. This report was from 2002, but assuming that people in Alaska often keep and use what is already working (which is much cheaper than constantly bringing in new) then this should be pretty good.
  13. Taliesin

    Taliesin Well-Known Member

    One note on this,
    In the last 3 years or so they have released 2-stroke engines that meet the 4-stroke California requirements.

    That's what I have on my boat.
  14. oilburner

    oilburner Active Member

    We? Need? Some people want them a lot more than others, but it's never a need.
  15. diamondlarry

    diamondlarry Super MPG Man/god :D

    Not sure I would say never. I think he was referring to trucks/semis and trains. Unless there is another way of transporting goods on a large scale, there will always be a need for diesels.
  16. sidfreak

    sidfreak Well-Known Member

    Well, when you put the amount of snowmobiles against the amount of cars and trucks and the amount of run time of each, I'd say cars pollute more by somewhere in the 500,000 to 1 ratio. Not to say that cleaning up 2 strokes is not a good idea but lets be realistic here. I suppose that if u add all the weedeaters, chainsaws and any other small engines that are 2 strokes, it might drop it to 480,000 to 1, but then u'd have to add all the nascar/circle track and such race cars that are running wide open, 3 or 4 nights a week as well.
  17. 2RR2NV

    2RR2NV Ultimate Newbie

    i agree with shutting down those NASCRAP races. or maybe they need to bring out the ALL EV races, where they still go for max speed, but they have to swap batteries or some such thing. and/or make the race shorter. watching 3 hrs of racing goin left, just wait til the last 3 mins and you're gtg. :)

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