Philip Wheelock
Finis Origine Pendet
Of course.I doubt I have a warranty on a pawnshop saw that's been run a bit?...
Of course.I doubt I have a warranty on a pawnshop saw that's been run a bit?...
There are two main sources of emissions on chainsaws, which are primarily unburned fuel going out the exhaust. The first is scavenging losses due to the exhaust port being open while the fresh charge is entering the cylinder, and the second is the poor fuel control of conventional all position carbs. A cat does absolutely nothing to address the cause of these emissions, rather it just burns up some of the wasted fuel in the muffler, turning it into heat not mechanical energy. It's a poor band aid at best, and it also is restrictive and gets very hot (especially if you enrich the mixture).
I look at strato as a performance improvement. Because it's mostly air going into the cylinder during much of the time the exhaust is open, you are free to adjust port timing for better performance. I don't know how this test was done, but the only real way to do such tests is to run the engines on a dyno and measure power, efficiency and fuel used. I don't have much doubt that the major manufacturers have all done just that, and I would bet that there's a reason Stihl and Huqvarna have spent so much on strato and feedback carbs (either developing it or licensing it). Heck, even Dolmar is developing their own strato system, and Echo has a strato saw.there is a tests that has shown the dolmar 421 (conventional 2 stroke) to require LESS fuel than the Husqvarna 445 (modern strato design engine) and only slightly more than a Stihl 251.
I think it is essentially the same here - so they put the tighter emission controls on the high volume consumer stuff so they can have a freer hand on high performance models.Don't know how it is in the US, but here all companies have a certain amount of "environment points" that they can use on the saws they sell. They produce environmentally friendly models so that other models can still be produced convetinally.
I'm not sure what material these catalysts are, but they are simple one stage units. Not at all like what would be found on an automobile. Then they are downstream of a fuel system that is dreadfully inaccurate, creating very rich mixtures much of the time (even if set correctly under load). I suspect they're just trying to burn up some extra HC to stay under the limit.I see it a little different. The cat fullfill's for me a slightly different role. It not only burns "unburnt" hydrocarbons but also carbon monoxides and nitrogen oxides. How far I can not say. But in this area the glorified strato design still pumps out the carbon monoxides and nitrogen oxides without any effect on them at all while the decated conventional engine would only be pumping out more unburnt fuel. How much that really is I cannot say. I will add although that the main reason for headaches in the two stroke engine area is certainly carbon monoxide.
That saw you just bought is an impressive little machine and has all the latest stuff (none of it developed by Stihl, but at least they paid to use it). All of it was originally designed to meet emissions requirements, but it improves performance and efficiency as well. Just like the V8 on your F150.As a non Prius guy(they look like crap) my new Ford F-150 V8 does in fact appreciate what they do for it's spot in the CAFE scheme of things.
Looks like I could get some carbon credits from my tree farm acres of timberland and use them to hotrod my new saw?
I see not so much difference in the Euro approach than CAFE here in USA. I do see a lot of diesels in Europe that smoke more than my orange tractor. In Mexico they'll actually fog you off the road when following on a MC.
Now, back to saving the earth...one chainsaw at a time![]()
Bigger carbs and run alcohol sure it's tough on cold starts, uses more haul, but burns very clean and waisted fuel is environmentally friendly than today's fuel. Moonshine can be made in very big batches.There are two main sources of emissions on chainsaws, which are primarily unburned fuel going out the exhaust. The first is scavenging losses due to the exhaust port being open while the fresh charge is entering the cylinder, and the second is the poor fuel control of conventional all position carbs. A cat does absolutely nothing to address the cause of these emissions, rather it just burns up some of the wasted fuel in the muffler, turning it into heat not mechanical energy. It's a poor band aid at best, and it also is restrictive and gets very hot (especially if you enrich the mixture).
Of course you are right that often conventional 2 stroke technology is less fuel efficient compared to strato design(companies speak of 20% less, realistically I assume 15%). Although that of course is not always true. F.e. there is a tests that has shown the dolmar 421 (conventional 2 stroke) to require LESS fuel than the Husqvarna 445 (modern strato design engine) and only slightly more than a Stihl 251.
Why is this the case? I donot know, but the test (done btw. by a review magazine in the Stihl labarotories) does seem valid, as many have reported similar experiences. So I see engineering in conventional 2 stroke technology still not as obsolet. And it only reflects how sloppy some companies work although they have "advanced" technology.
I do not believe there are any Stihl or Husqvarna (or Poulan) saws that still have cats. Instead they use strato and often feedback carbs on the high volume models, and often they can get away without either on the bigger, lower volume units.
Don't know how it is in the US, but here all companies have a certain amount of "environment points" that they can use on the saws they sell. They produce environmentally friendly models so that other models can still be produced convetinally.
Why do they do it? I cannot say, but only assume, although they posses the patent rights, it simply is not worth it for them! And what is really funny about it is that it is typically on those models(large cc saws) where strato would REALLY benefit the environment and lead to substancial fuel savings!!!
Further low volume producers (the reason the chinese copies come with a million different names for the same saw) are still excluded from the environment checks.
Manufacturers that cannot or will not pay to develop or license the technologies that actually reduce wasted fuel are left with trying to reduce scavenging losses through modified conventional porting, setting the carbs as lean as they can, and stuffing a cat on the exhaust to burn up what still comes out.
I see it a little different. The cat fullfill's for me a slightly different role. It not only burns "unburnt" hydrocarbons but also carbon monoxides and nitrogen oxides. How far I can not say. But in this area the glorified strato design still pumps out the carbon monoxides and nitrogen oxides without any effect on them at all while the decated conventional engine would only be pumping out more unburnt fuel. How much that really is I cannot say. I will add although that the main reason for headaches in the two stroke engine area is certainly carbon monoxide.
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That saw you just bought is an impressive little machine and has all the latest stuff (none of it developed by Stihl, but at least they paid to use it). All of it was originally designed to meet emissions requirements, but it improves performance and efficiency as well. Just like the V8 on your F150.
The strato engine and the feedback carbs are mechanically very simple, but effective. They are elegant and clever engineering, which is why I appreciate the designs.
The twin path strato carbs are probably the way things will go, as they are simpler (=cheaper) and smaller. They eliminate the one extra moving part required for strato. What you don't get is the ability to have the strato air valve open separately, which effectively allows different port timing at idle and WOT. Also, with a separate air valve there is never fuel mixed into the strato air path.I thought you have posted on here how that ms241 is not as advanced as some strato Poulans. (at least in the porting aspect) The carburetor is of the type with an upper and lower single opening instead of the more advanced one carb and one air only opening. Stihl gets more power per cc out of the 261.
Oh yeah I had some good shine in the hills of East Tennessee.Bikemike(that should be my handle? as I'm a mike that bikes?)
Anyway, since you have yer mind fixed on moonshine for fuel I'll share this tidbit: My FIL and everyone in his family were in the oil/gas business in E KY , also WV,OH & TN. He said during the depression they used to distill/cook off crude oil into a rough version of gasoline that would run prewar engines. In my short time in KY since coming here at age 30 in 1973 I've known several shiners, not all of whom did it as their day job/profession. I know not one these days, they either quit or died.
Guy commenting on e85 fuel above-the economy it offers is horrible thus it really has little to offer. Plus in todays oil market it's actually higher than 87 near me. Only an idiot would buy the stuff much less drive to get it?![]()
I make maple syrup which isn't exactly a get rich quick scheme-maybe a bit like like shine in that respect. Old saying in KY that if you "go to the woods to make make a living", yer earning your money! Texas is my pass through spot when I ride Mexico in the winter. Where's the "abyss"?
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