Chainsaw Muffler Modifications - Internet Sales World Wide

Eric Frei

No, not much louder, certainly nothing to worry about unless your some shiny ass with a decibel meter trying to take us back to the stone age!

Here you go, look out, check out this GOVT BS.
sfmc_fmplans_7 and that's from the State that felled the worlds tallest tree to measure it then burned another big bastid being idiots.

.... Goes hard mate, and after spending some time editing the video I could clearly see the difference. You know, like many of you that has leaned on a saw ... when you have enough power to push on through the cut you do.

When it's a little "time consuming" you tend to bite the dogs in and use leverage, not because you need leverage but because you need some rest from the extra time it's going to take in addition to some regulated/metered pressure on the saw chain. I didn't find myself using the dogs (bumper spikes for the nerds) too often with the modded muffler as I felt confident just pressing through the cut I wouldn't be stalling the saw or nancying it.

Anyway, the YouTube video is out, the quality should be pretty good and ole Wojo should be proud.

YouTube - Wojo modified chainsaw muffler trialled by Ekka

Image from above Tas govt link.

Attached Thumbnails

 

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ScottWojo

Awesome! Awesome! AWESOME!!

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ScottWojo HP Modified Chainsaw Mufflers| GB Bar and Chain Distributor.

jokers

Ekka,

Let me offer some constructive criticism about your video. The way that you rocked through the cut with the stock saw is fairly inefficient, you`re double cutting in some places and not fully loading the chain in others, it`s reminiscengly hucksterish ala the NWCS before and after videos. It would be more interesting to see the same technique employed in both cuts and then if it shows the Wojo mufflered saw to be, let`s say, 3 seconds quicker, then you`ve clearly illustrated something that is very hard to dispute.

Another point, you mentioned that you had to back the idle screw out quite a bit after installing the modded muffler, we all understand that was because the saw is now running leaner, right? A more appropriate approach would probably have been to adjust the lo speed screw counter-clockwise to enrich lo speed operation and have the effect of slowing the engine while optimizing the fuel/air ratio, then make a fine adjustment via the idle screw to to get idle speed where you want it. This would also be beneficial on the top end speed and power because about 1/3 of the hi speed fuel comes through the lo speed circuit. The fact that you couldn`t get quite as much adjustment out of the hi speed screw as you wanted supports what I`m saying. It`s quite possible that if you went back through the carb adjustments from the ground up that the improvement shown with the Wojo muffler might be even greater.

ScottWojo

Erik,

Does that saw have limiter caps? You need to remove them to fully adjust the carb. Special Stihl tool, of course.

That is an awesome video, you could actually sell that stuff as advertising. Great Job.

With Great Esteem,
Scott.

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ScottWojo HP Modified Chainsaw Mufflers| GB Bar and Chain Distributor.

jokers

Actually the special tool is not necessary, just run a coarse thread deck screw into the limiter cap, line up the tab with the slot, and yank it out. Cut the ears off before replacing.

Eric Frei

The upper cut is fairly evenly done in comparison, also I did not change or sharpen the chain so the benefit of the doubt goes to the stock muffler which clearly did not win.

The true test is a bench dyno, but this gives an indication that clearly the saw performs better.

I'll have a look at the carby today, I think the L screw was on limit too as I tried adjusting that and it wouldn't budge.

I went through all the cuts I did and these two are close in technique. Click the link below, it's a quick wmv.

Attached Files

wojo2.wmv (622.6 KB, 690 views)

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jokers

Ekka,

I like your second video much better, it was a very clear comparison.

BTW, I still take the perspective that dynos are interesting but not necessarily useful or reliable. Walkers have one and on the 346 that I bought from them, the before and after dyno runs showed both a widening of the power band as well as a greater peak horsepower. All very interesting and probably useful to justify the price of their mods, but on the other hand, a dyno is only as good as and as honest as the person operating it.

Videos with sound can tell you if the saw is being tuned and operated properly, and wasn`t it you who said that a 25% increase or something to that effect might only yield a 5% reduction in cut times? Doesn`t that then make dyno numbers somewhat abstract versus an actual demonstration of how much more quickly you might make an actual cut? I say don`t get hung up on dynos for more than trending.

Eric Frei

Jokers,

Dynos I suppose are a little more controlled and scientific. It's the common and accepted way of measuring engines output.

Now in a similar way years ago when I was young and into music I had custom built some speakers/amp etc. The tech told me that you roughly have to 10x the watts to double the decibels output.

Saws are similar, is a 100cc saw twice as fast as a 50cc saw when cutting say a 16" dia log?

If outputs can be shown by dyno then comparison sawing tests done we might be able to get some rules of thumb. Wouldn't that be great.

Could be an equation like a 10% faster cut shows 20% more HP. Who knows, but I do know it cuts faster and you can press harder on it.

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jokers

I agree that using a dyno is more scientific and the standard way of measuring engine output, but controlled is the operative term here. The dyno needs to be set up properly for each run and a slight error or differential here or there can vastly skew the results, thus renderring results that may not be reliable. This is why I`m pretty well satisfied with the empirical results gleaned from cut times if factors are standardized(huh, sounds scientific...). A 100cc saw does not necessarily cut twice as fast as a 50cc saw regardless if the 50 cc saw is rated at 3.5 hp and the 100cc at 8 hp. Put a 50 cc saw in it`s element, 12 inches and under and the extra displacement of the big saw doesn`t help as much as it would in larger wood like 24" where most 50cc saws would be struggling. What is more important to me is how does 50cc saw A compare to 50cc saw B?........and so on....... A rock mechanic, as Gypo so endearingly refers to them, can make a 10hp saw look like a dog, what really matters(to me anyways) is how quick a saw does it`s job compared to another under similar circumstances.

I`m trying to convince you that you`re wrong, LOL. I`ll stop now and accept that we just don`t see eye to eye on this.

newguy18

Cool deal,you gonna buy one for all your saws now?just think you can slay twice as many palms in one day if you do.

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I ship USA saws out of the USA

old schooler

Eric Frei

Jokers,

You dont have to convince me of anything. I see the merits of both and like you it's all about cutting wood.

Now Echo make some large cc saws. Once I was given one of their largest ... I think Vovlo helped design them due to the "ergonomics and power/weight ratio"

Anyway, with all that text book hp and torque it cut like a rock! Give me a Husky or Stihl etc any day.

So I know what you mean.

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jokers

Now that`s funny because I can relate exactly to your Volvo analogy! I once had a boat with a Volvo Penta 290 outdrive, man that thing was beefy and durable and had several nifty features that might have been useful in a commercial environ but it was too much drive(drag) coupled to my puny little Chevy 5 liter engine.

newguy18

Poor guy,should have bought a ford.

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Eric Frei

I popped the rubber grommet of the side to have a look.

The H jet is on limit the other was just stiff to turn.

When you look in there you see a couple of red plastic things. There's a couple of small holes or marks near each one.

So how do you turn further when it's a limit? How are they held in? Need an IPL diagram of it.

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newguy18

Ekka they should just pop off with a screwdriver or a pair of needle nose pliers.

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jokers

The Ford was even more anemic than the Chevy.

jokers

Ekka, slowly turn the red limiter caps as you observe and you will see that at one point in it`s rotation, the slot next to the screw head will go red, this is the position where you can pull the limiter caps off. As you can see there is no way that you will get pliars on these caps, that`s why Stihl makes a dedicated tool or you can use a screw as I suggested earlier. Once you`ve got the first one off you`ll realize how simple it really is.

newguy18

I got 2 and i'm not complaining.

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Eric Frei

Thanks Jokers, I'll have a go of that this weekend, if I stuff it up I got spare carby's.

That's what lifes become, a bunch of limits imposed by nerds!

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jokers

Don`t worry Ekka, you can`t do any permanent damage to the carb, the red caps are simply plastic caps over the actual screws. I don`t know what it`s like over there at the Stihl shop but here the caps are required to be replaced when a saw comes in without them so they are plentiful.

ScottWojo

Eric,

Hows the saw going? Did you have a chance to mess with the limiter caps?

Thanks,
Scott.

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ScottWojo HP Modified Chainsaw Mufflers| GB Bar and Chain Distributor.

PTC

Modified muffler arrived at my front door yesterday. Fitted to the 460 last night. Saw seems to run and idle perfectly without any tuning.

Definately sounds and feels more powerful, but I havent tried it out properly yet. Am a bit reluctant to until ive had it tuned with a tacho, not sure when that will be

ScottWojo

On the first thread there is a link to tune your saw by ear. If its there and it sounds good, why be reluctant? Go cut wood.

Glad to hear you like it.

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PTC

just thought it seemed funny that my saw doesnt need any tunning after reading Ekka's posts.

Anyway it sounds fine, im sure its not running too lean. Will cut wood tomorrow

ScottWojo

Well, every saw is different, and every muffler is hand made. Plus the elevation may be different as well.

Pm me your address again and I will send you another spark screen that will let more exhaust through. You can experiment with different screens.

Thanks,
Scott,

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PTC

Will do,

PTC

By the way, have you got a muffler to suit a husky 375?

JayD

If your worried about your saw being to lean, Whip out the spark plug after 5 mins and check out the colour of the burn,It should be a nice browny colour,If its whitish or grey it's lean.
Hope this Helps

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PTC

Good Idea

ScottWojo

If I can get the muffler, from you it will be about $85.00. If I have to buy the muffler just add the cost of the muffler.


Thanks,
Scott.

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ScottWojo HP Modified Chainsaw Mufflers| GB Bar and Chain Distributor.