Husky 359 Muffler Mod!!!

[rahtreelimbs]

This is the latest muffler mod that I have done. The muffler on a Husky 359 is very restictive. It is a wonder the saw wants to run at all. There is a plate/baffle that runs across the inside of the muffler with a smallish 1/2" or so hole in it. From there a tube of about 3/8" lets the whole works out.

The front bracket that holds the muffler to the case is about an 1/8" from sitting flush on the muffler. This ruled out the ingenious way that Ken Dunn had used the bracket to hold the screen in place. I put a 7/8" hole above the bracket in the mufller and also straight through the inner wall too. This gives a straight shot from the exhaust port out. I then did my usual, weld a plate with a screen. The outlet is 5/8". In my experience that along with the stock opening works pretty well.

I didn't cut with the saw stock. From the sounds of the saw and the fact that it was so restictive is should have a good increase.

 

[rahtreelimbs]

Second pic!

 

[Mange]

Please let me learn some more.
Do fuel consumtion encrease, How much more power do you get, and Is there any reason why they diddn`t construct the muffler like this when they spent a lot of mony develop the saw.
I beleave you, and aggre, but don`t understand..

Mange

 

[Crofter]

Mange; Expect cutting times to decrease about 20%. Fuel consumption increases, but you can get more work done in the same time. Biggest drawback in my mind is much louder exhaust noise. This, along with probably certain exhaust emissions is why the manufacturers equip the saws with the restrictive exhaust systems.

Frank

 

[bwalker]

Rocky, The trucking industry is no longer exempt. The new trucks on the road today are actually burning very clean,

 

[Crofter]

Brian, I agree that chainsaws are pretty minimal contributers to overall pollution. The trucking industry hasn't escaped pollution abatement regs though, but they do have the clout to hold back implementation as long as possible. Yah, you dont see too many tiny exhaust holes on the airlines!
I think there may be something in the way of practical fuel injection for 2 strokes just around the corner. I think if manufacturers could get more power (with acceptable emisssions) they would jump on it quick. The restricted exhaust is a temporary fix. (which we know how to fix!)


Frank

 

[YUKON 659]

Rich, nice job on the muffler. Here's a picture of a 357 muffler I did for my son a while back....I think it is similsr to the 359.

Jeff

 

[rahtreelimbs]

Originally posted by YUKON 659
Rich, nice job on the muffler. Here's a picture of a 357 muffler I did for my son a while back....I think it is similsr to the 359.

Jeff

I like how you went out the side......real nice!!!

 

[sedanman]

Rocky, Do you know what the stoichiometric ratio for gasoline is? It's about 14.7:1. Do you know the actual a/f ratio of most 2 cycle power equipment? Between 6 and 8:1. I can commute to work and back on 2 gallons a day and because my car runs close to 14:1 a/f ratio and has a catalytic converter and other "emissions" equipment it emits LESS than a chainsaw whos operator uses 1 gallon a day. Here's the definition of stoichiometric in case anyone thinks I'm making words up. BTW, you have lighten up, the world is not a machine whos single purpose is to screw you into the ground.

http://www.taftan.com/thermodynamics/COMBUST.HTM

 

[rahtreelimbs]

Originally posted by Mange
Please let me learn some more.
Do fuel consumtion encrease, How much more power do you get, and Is there any reason why they diddn`t construct the muffler like this when they spent a lot of mony develop the saw.
I beleave you, and aggre, but don`t understand..

Mange

If you have the tools, time and talent or know someone who does, you are really missing out if you don't open up a muffler!!!


This is free power just begging to be let out, and with todays restrictive mufflers the gains are very high and well worth it!!!

 

[bwalker]

FWIW the EPA claims that 1/10th of all emmisions is caused by non road engines.

 

[Kenskip1]

359 Mufflermod

It looks like a first class job.My question for you is what will happen if this modification is performed on a new 359, that has the restrictor caps on the carb? I have my mind set on the 359 and I would like to help this thing breath.My local dealer told me that the carb is not adjustable on the high speed side. (Husky)
Thanks for th information, Ken

 

[Kneejerk Bombas]

That saw has an adjustable high speed jet.
Look here: http://weborder.husqvarna.com/order/webec/search.jsp?languageid=US&brandid=HQ&docTypeO=on&docLangO=US&noFoundTxt=No+operators+manuals+found%2E&title=359&format=HTML
Figure out which saw you have, then look under maintenance or carburator.
Your saw has limiter caps which may need to be pulled off the jets to get the adjustment you need.

 

[rahtreelimbs]

Re: 359 Mufflermod

Originally posted by Kenskip1
My question for you is what will happen if this modification is performed on a new 359, that has the restrictor caps on the carb? I have my mind set on the 359 and I would like to help this thing breath. Ken

This 359 has the limiter caps on the low and hi side. Like all the saws that I have a modded muffler on these caps will be gone. The Shindaiwa 360 that I have has a fixed Hi side jet, non-adjustable. With the muffler opened up this saw will rev to over 15,000 rpm, but it has more power. I know it is running a tad lean because it doesn't 4 stroke too much, but it never 4 stroked that much be fore the muffler mod.

 

[glens]

Originally posted by dayman
Since it's legal to mod mufflers, why are you whimpering so much?

Not exactly true.  You won't do time, yet, for modifying them, but in certain situations you can be fined.  Certain other situations (such as Federal land, &c.) require stock running gear as well.

Glen

 

[Mange]

Well Rich, I will test open up, and I have 2saws in mind: Hva 444, 254. Thease I must try.

Mange