EPA specs

[Tony Snyder]

Does anyone understand how the EPA thing works and where it is going. Let me give you a couple of questions in my mind?

I read on here that the Jonsered 2083II got the 77cc jug for EPA reasons. Why would it be more acceptable at 77cc than 83cc?

I was told by a distributor rep that the Jonsered 2149 was first made at 49cc "because of the 50cc EPA size break". Now it is going to 52cc. Has that got an EPA advantage?

How does this size break thing play in all of this? Carrying that logic on, why would not every manufacturer want sizes right at the top, or just under the next break, if there are in fact breaks?

Or, is it all done on the fleet average basis?

What does this tier 4 and CARB II stuff mean?

 

[AJLOGGER]

That is a good question I have wondered all that myself, I have another question to add to that. It seems to me that Stihl mufflers are more resticted than husky and jonny red for EPA reasons, why is that, don't they all fall under the same guidlines as far as engine size etc? Or is Stihl just bowing to the epa more to get on their good side? Or am I just full of crap and they are all resticted the same?:Monkey:

 

[bwalker]

AJ I bet stihl and husky mufflers are just as restrictive cfm wise.

Tony, The epa in the past has segmented engines by cc's and regulated them accordingly. A example of this would be a 50cc and under saw would be less regulated than a 85cc saw. This is done for because as cc increases fuel consumption increases and and as a reuslt pollution goes up also. You can check the carb website for there standards and the epa site for tier 2 standards.

 

[Tony Snyder]

Thank you guys, but there is still a lot to be understood.

I'm waiting to hear from galer, dagger, eylof, and some rude stuff from Otto. All good guys.

 

[eyolf]

I imagine that Stihl and everybody else arrive at muffler specs through testing...they have a number to "hit" and play with various things, including muffler design, until they get it right. If the Stihl mufflers are more constrictive, its probably because that's what seemed to work out in combo with everything else. I doubt if the EPA has any magic numbers for anything but emmissions.

Who knows what the EPA is thinking when they publish their rules. 50cc is a popular saw size; not many "consumer" saws above this, and about the bottom for pro-level saws (Arborists, please- no brickbats), so that may be why there's a break there.

I'm going to say that the 77cc Jonsered jug just burned marginally cleaner than the big one. It could be something as simple as surface to volume ratio inside the combustion chamber, or as complex as adding in cooling variability and gas flow characteristics. I'm sure they could have fiddled around with it and got it to work, but at what cost...against how many sold?

I've spent a little time at the EPA site...it would be easy to get lost there, without ever finding the document you wanted. I know I haven't ever found what I wanted right away at any government site...