Fantasy to reality, hot saws... Spud? and others

[Mick Dempsey]

1 minute ago, Stubby said:

Precisely my dear Watson . ?

Elementary, but ok?

[Rob D]

31 minutes ago, Stubby said:

The manufactures true intention is to make money ...

 

Maybe but not all the time. Egos come into it, politics come into it. I don't think it is all about the money. There are some weird power games played at the top and there is a lot more placed on the ability to 'control' rather than simply making money.

[Stubby]

4 minutes ago, Rob D said:

 

Maybe but not all the time. Egos come into it, politics come into it. I don't think it is all about the money. There are some weird power games played at the top and there is a lot more placed on the ability to 'control' rather than simply making money.

OK Rob . I am not a big player . I accept what you say . With money comes power though . ?

[MattyF]

In a similar discussion elsewhere on the internet an experienced logger is asked why he doesn’t use ported saws.
 
He says it’s because he values what he has left of his hearing.
 
Something that hasn’t been mentioned so far on this thread.

True that Mick , I do try and ask spud not to completely gut the mufflers on saws ...

[SbTVF]

In a similar discussion elsewhere on the internet an experienced logger is asked why he doesn’t use ported saws.
 
He says it’s because he values what he has left of his hearing.
 
Something that hasn’t been mentioned so far on this thread.

Perhaps he should wear ear defenders then?

[Stubby]

I will conceded that noise pollution does go up with most ported saws . My 372  was mentioned once or twice .  

[Mick Dempsey]

27 minutes ago, SbTVF said:

 

Perhaps he should wear ear defenders then?

 

He does, a ported saw will exceed noise limits put in place by research into hearing  by experts etc. (Blah blah) Even with protection in place damage could happen. 

Don't get me wrong, I’m no safety nazi, but noise is as big an issue as emissions with these modifications, both to the user and the public.

Edited December 3, 2018 by Mick Dempsey

[Rich Rule]

2 hours ago, Stubby said:

I will conceded that noise pollution does go up with most ported saws . My 372  was mentioned once or twice .  

When Steve rebuilt my 660, fettled with the ports and fitted a dual port muffler...  he said Mrs Spud could hear him running the saw up from home.  He was at his log site as to not piss the neighbours off.

 

I have a couple of 200t's done by Spud, a 150 and a 660.  All cracking saws and really bring a smile to my face when I use them.

[stihlmadasever]

I get looks when i start my spuded 346xp.Its pretty vocal!

I been offered silly money for that saw.

How much do you guys think its worth?

Most ive been offered is 400 notes!

[wyk]

2 hours ago, Mick Dempsey said:

He does, a ported saw will exceed noise limits put in place by research into hearing  by experts etc. (Blah blah) Even with protection in place damage could happen. 

Don't get me wrong, I’m no safety nazi, but noise is as big an issue as emissions with these modifications, both to the user and the public.

If you'll pardon my rambling diatribe:

 

It's difficult to debate the emissions effectively on a ported vs OEM small engine.

 

Many porters with take the combustion chamber and reshape it, whether through using different gaskets, or none at all, or by machining the cylinder base and combustion chamber. This promotes a better, cleaner burn, which begets more power. This is a step manufacturers can not themselves do because it is basically building to tolerances that they can not accept in assembly line manufacture without adding much higher costs(and risks) as every chamber will have to be measured and tested before leaving the factory VS a sample QC control test earlier on in the factory after forging/production. I have a ported 241 with a squish measurement that varies between .0199 and .018 depending on where the measurement is taken. The manufacturers measurement was closer to .037, a nice, safe assembly line part unlikely to cause production or customer issues.

 

Noise is always an issue with ported saws, as part of what the manufacturer must take in to consideration is the noise output. This almost never goes hand in hand with performance - whether saw or bike or car or jet. Removing baffles or opening exhausts up more has always been a cheap way to gain more power. There are some saws I have tuned that have gained a 30% improvement in cut times with a muffler modification. Did this saw also produce 30% more emissions? I don't know, because I have no means to measure it. But it is often the case with two strokes that improving the power, improves the amount of hydrocarbons are burnt per HP.

 

Porting itself changes the timing of the port openings and, or, their shape(in the most strictest sense). You certainly can argue the saw will take more fuel, because it's been specifically designed to do so. But whether in the over all scheme of things it puts out more carbon emissions vs the production output is difficult to debate without proper testing. Porting usually goes hand in hand with exhaust tuning and combustion chamber modification to make an over all package more powerful. The goal isn't really just to burn more fuel, but to make more power. Often times these can go hand in hand.

 

Now let's reverse engineer a few things to get a better handle on why porting makes a difference:

 

A manufacturer has to meet guidelines. The most recently applicable are the Phase II US EPA emissions that were phased in between 2001 and 2007 - the most pertinent designs of which measure carbon emissions per KwH. And we can easily argue the vibration and noise regulations from 2009 by the EU also apply(https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:32009R0219 for the noise regulations).

 

This is why we've seen several new developments in chainsaw design the last decade; more restrictive exhaust designs, different port timing, strato ports, catalytic converters(though these came on the scene in the late 90's in Europe, they are more common in saws made for other markets that have moved to our own in recent times - Japan, for example, does not require emissions testing on many small engines so long as the front of the machine meets EPA stage IIIa guidelines), newer electronic coils and timing, electronically controlled carbs, air injection systems, and fuel injection systems.

 

Basically, with the exception of electronic ignition and carburetion, most of the technologies designed to reduce carbon emissions and to reduce noise emissions will reduce power, or reduced the RPM where the power would be delivered to reduce KwH emissions. Since all manufacturers had to play by these rules, they all redesigned their saws, but appeared to keep their HP ratings and saw weights in place due to marketing, even though they all most definitely changed for the worse. Some 10mm 044's in the EU had a single port muffler with a baffle and a catalytic converter, and yet STIHL rated these the same HP as their previous version without a duel ported muffler and no cat. Same weight, too. This is why your dual ported exhaust STIHL046 from the 90's will easily out cut a STIHLMS460 from the 2000's. And why the 044/440 disappeared for a while(to meet emissions).

 

You can take any of these EPA conformist saws, measure their port timing and designs, and take many of them back to before they were modified whether for emissions, or noise, or both. That is porting.

 

In other words, efficiency, performance, noise, and emissions are not necessarily bed pals, but are effected by regulations. Everyone had to play by the same rules, so no one player(besides maybe McCulloch before they sold out) suffered more than the others. One could easily argue this isn't necessarily an efficient engineered design - that this is engineering to meet regulations.

 

Again, will this increase the KwH emissions to modify? Most surely, it will. But will it increase or descrese the KwH/W - the amount of emissions per out put of work done - who knows. This has likely never been tested because the manufacturers only need to conform to government rules. It's really up to us to decide whether it's something we want to do. I personally have very few saws that I haven't modified or ported myself. I like to spend as little time, with as little saw as possible when in the field. That's my priority.