Stihl 260 muffler mod data, temp, sound level and preformance

[whatsnext]

Hey fellas, I think it's great that you guys are so into the nuances of your respective technical fields. Is it possible to stop arguing with each other. So I pose this challenge to you, gentlemen: Can you put your heads together long enough to define a degree of accuracy? 5%? 15%? I know it's hard to set aside ingrained technical learning, but try to keep in mind...this is NOT a definitive thesis on the matter at hand.

You must be new here.

 

[tony marks]

good work timberwolf. u went to a lotto trouble to get useful info. we appreciate u publishing it.

 

[Lobo]

Timberwolf, I echo what Tony has posted.

Most of us I guess realized off the bat that your testing was not perfect and it was to be used as a guideline and indicator primarily, more precise tooling would change the numbers slightly but the patterns would remain fairly consistent I am convinced.

Thanks again for all the work.

 

[DanMan1]

when was this marty? I belive by the description that timberwolf used a Raytek infrared thermometer that is the industry standard and record the temp with a .1 degree accuracy - approx between 50 -1300 degrees - is that what you used? tach is great to use, but where your test conducted in specified conditions like these were? ie. same saw, same beginning temp, same log, same sawyer, same chain, same day, etc.??? please post a link.

Timberwolf,

This was the post that really sparked my initial response. Then someone had to tell me what I wrote was wrong, and then we are off to the races.

Assuming you put the beam on the same area of the components each time, you should feel comfortable stating that your relative ( not absolute) meaurements are good within a couple of degrees. As long as you don't state things like ".1 degree accuracy", you can't get any guff from people.

 

[BigUglySquirrel]

Yeah...still pretty new to the site. Don't have a whole lot of time to sit on the computer...but this site is worth the time I squeeze in. Didn't mean to ruffle any feathers...it just seemed to be a a waste of obvious experience and expertise to quibble over things that mean little to nothing to most people. I'm not dogging anyone. I'm actually QUITE impressed with the amount of VERY informed and VERY well read contributors. It just kinda upset me to see guys get so caught up in technical comparisons that it kinda stole Timberman's thunder on a really good "homebrew" comparison. Sorry for any smashed toes....rock on!

 

[ErrolC]

I have to add my 2c worth ...I just love this site...better than any of the drama my family watch on the idiot box..I love it..good effort & results timberwolf...all in the quest for knowledge..no one knows it all...some might think so.

Q: Few people are capable of expressing with equanimity opinions which differ from the prejudices of their social environment. Most people are even incapable of forming such opinions... Albert Einstein

Q:Only two things are infinite, the universe and human stupidity, and I'm not sure about the former...Albert Einstein

Q: Imagination is more important than knowledge... Albert Einstein

 

[Al Smith]

Oh,what the heck,it's all good .As my grandaddy used to say"there is more than one way to skin a cat".

 

[klickitatsacket]

Timberwolf Thanks for the work you did and for posting it. When I first found it, I even printed out your results. I have a copy of them in my note books.This post is also why I do not post a lot of my testing data. Pi$$ on lazy nit pickers who do NOTHING but read or who have never tried to learn on their own with out the use of some one else's money. You could easily spend a half million dollars to prove exactly what you already proved. Muffler modification reduces heat and unrestricts flow. When it comes right down to it that's all you really need. If you really wanted to get picky just run the same tests 5 times each and take averages. The chances of NASA coming up with better data that is relatively meaningful would be about the same as congress doing something relatively meaningful.

 

[cbfarmall]

How then,may I ask,do they take measurements in the production of steel?

Hey, something I can answer. We use disposable thermocouples mounted on the end of a cardboard sleeve. In a basic oxygen furnace, the system is referred to as a sublance. The sleeve is meant to protect the sublance pole which transmits the reading from the thermocouple to the computer. When the steel is in a ladle, it is more or less the same equipment on a smaller scale. We call it an autosampler.

For liquid steel, infrared is useless because you would only be measuring the slag surface temperature which is considerably cooler than the steel. After all, anytime liquid steel is exposed to air it oxidizes and slag is formed. So you have to get the measuring device through the slag (which is not always easy) and into the 1600 degree steel. That means your gonna lose whatever you stick in the steel.

I think the sublance thermocouples are around $50 a pop, the ladle thermocouples around $12. And they are accurate to +/- 3 degrees, which is good for steelmaking.

But this has nothing to do with chainsaws, so I will diminish...

Chris B.

 

[klickitatsacket]

Do have a picture of this image by any chance that you could post? I would love to see it. Chowdozer is there any way you could do some stuff like this for me. Take some thermal images of the saw, maybe a before and after picture. I was thinking that your saw would be perfect for this. I would drive it up if you are interested.

 

[Jtheo]

Here is the data I measured during a muffler modification on my 260.

Saw is was new 3-4 tanks of gas, sharp .325 Stihl RS chain on a 16" bar.

Tempratures were measured with a digital lazer spot infared sensor. measuements were taken from the hottest area on the front of the muffler cover, and the hottest exposed area of the head which seemed to be just below the cooling fins on the bar side. Outside air temperature 5 degrees C.

Sound levels were measured using a calibrated digital sound meter, peak measurments were taken at 10 feet directly in front of the saw with both the saw and meter 3' above the ground (open field).

Cut times were 3 cut averages measured by stop watch on a 12" dry spruce.


The muffler modification entailed 5 steps.

1 stock
2 stock muffler redrill existing outlet to 7/16 and add one 7/16 hole
3 add one more 7/16 hole
4 join 3 holes and square opening to 7/16 x 1.5 inch plus file back and open deflector angle.
5 match exaust port to muffler

The test consisted of the folowing steps

1 measure temp with saw cold roughly 7 degrees C
2 start and idle saw for 2 min monitor temp until stable
3 measure idle sound level
4 cycle saw to full RPM 5 times and record max sound and rpm
5 cycle saw between idle and full rpm for 1 min and measure temp
6 cut 3 disks and measure temp
7 allow saw to cool befor next test

AND HERE IS WHAT I FOUND
-----------------------------------

Stock muffler opening 0.11 sqr inches
---------------------------

RPM 13450
Idle sound level 80.2 db
Max sound level 97.1 db
Idle temp muffler 64 C
Idle temp head 60 C
Cycle test temp muffler 119C
Cycle test temp head 68C
3 cut test temp muffler 183C
3 cut test temp head 105C
3 cut test time 8.5 sec


Muffler with two 7/16 openings total 0. 30 sqr inch
---------------------------------------

RPM 13650 +1.5%
Idle sound level 84.9 db +5.9%
Max sound level 99.5 db +2.8%
Idle temp muffler 62 C -3.2%
Idle temp head 58 C -3.4%
Cycle test temp muffler 89C -33.7%
Cycle test temp head 62C -9.7%
3 cut test temp muffler 164C -11.6%
3 cut test temp head 96C -9.4%
3 cut test time 8.0 sec -6.3%

Muffler with three 7/16 openings total 0.45 sqr inches
-----------------------------------------

RPM 13750 +2.2%
Idle sound level 87.1 db +8.7%
Max sound level 101.8 db +4.8%
Idle temp muffler 56 C -14.3%
Idle temp head 55 C -16.4%
Cycle test temp muffler 88C -35.2%
Cycle test temp head 62C -9.7%
3 cut test temp muffler 147C -24.5%
3 cut test temp head 105C -12.9%
3 cut test time 7.6 sec -11.8%

Muffler with one 7/16 x 1.5 inch opening total 0.66 sqr inches
--------------------------------------------------

RPM 14000* +4.1%
Idle sound level 89.9 db +12.1%
Max sound level 103.0 db +6.1%
Idle temp muffler 54 C -18.6%
Idle temp head 52 C -15.4%
Cycle test temp muffler 82C -45.2%
Cycle test temp head 61C -11.5%
3 cut test temp muffler 143C -28.0%
3 cut test temp head 85C -23.6%
3 cut test time 6.9 sec -24.6%

* mixture richer by a hair RPM = 14100 before adjustment

Exaust port matched and smoothed
---------------------------------------------

RPM 14050 +4.4%
Idle sound level 89.9 db +12.1% NC
Max sound level 103.0 db +6.1% NC
Idle temp muffler 54 C -18.6% NC
Idle temp head 51 C -17.6%
Cycle test temp muffler 82C -45.2% NC
Cycle test temp head 61C -11.5% NC
3 cut test temp muffler 143C -28.0% NC
3 cut test temp head 83C -26.5%
3 cut test time 6.7 sec -26.8%


Other Notes

My cutting tequnique may have improved over the tests, however I was cutting disks off towards the larger end of the log during the last few tests, so it probably equals out.

The air temprature was cool for the tests, the engine tempratue factors may well be more pronounced if the same tests were done during hot weather.

Even though the sound level data shows an increase of 12% idle and 6% maximum the real change in much greated due to the logarithimic nature of the db scale, the precieved change of a 10 db increase as in the saw idle measurments would be that the sound level has doubled.

Allthough the mixture seemed to be good at 14000 rpm I richened it to achieve 13800 when I was finished.

gains don't seem to be falling off too fast so I will likely open up the muffler a wee bit more in the future.

Data tables don't post well, I think I'l make it a text file and attach it next time.

Wife didn't think much of me spending most of the day making the chain saw louder! Just wait til I finish the 066. lol

Timberwolf

Thank you for this information. This is one of the reasons that I enjoy this forum so much.

 

[chopperfreak2k1]

for all the time, thought and work that went into this, THANK YOU Timberwolf

 

[Naked Arborist]

Timberwolf Thanks for the work you did and for posting it. When I first found it, I even printed out your results. I have a copy of them in my note books.This post is also why I do not post a lot of my testing data. Pi$$ on lazy nit pickers who do NOTHING but read or who have never tried to learn on their own with out the use of some one else's money. You could easily spend a half million dollars to prove exactly what you already proved. Muffler modification reduces heat and unrestricts flow. When it comes right down to it that's all you really need. If you really wanted to get picky just run the same tests 5 times each and take averages. The chances of NASA coming up with better data that is relatively meaningful would be about the same as congress doing something relatively meaningful.

Thanks Timberwolf!
Here it is for the masses (that's you and you) need to know about a muffler mod. I NOW SEE that the KNIT-PICKING started a LONG LONG TIME ago on here.

All these saw questions about mufflers GEZZZ. Like you never heard of a Flow Master muffler on a street vehicle? REEEEEEEEALLY?? I know for a fact you have all literally "hear'd" dem befour" WAA BAA LOL.

Grind it, fill it, juice it or drill it but always RUN IT HARD! It it fails there is much more to be learned by then.

Now back to our regularly scheduled program about port timing numbers and whose are best.

 

[hdbill]

Timberwolf

Great info and post, really helps and explains for a whole lot of folks reading. To bad there has to be a pi$$ing contest from other readers that dont really help nothing but thier egos

 

[thomas1]

Bump

 

[Iron Buffalo]

Awesome Muffler Mod Thread, Thanks Timberwolf !

I was wondering if your tests were performed with the Spark Arrestor Screen installed ?

Sorry for replying to such an old thread but this information it Timeless

Thanks

Iron Buffalo

 

[ncfarmboy]

He hasn't been on any site that I know of in years. Saw some of his muffler work before site crash no spark screen.
Shep