Got Duals?!?!

[JimL]

Cause I do!

 

[JimL]

I cut too biga hole so I had to fill it with weld. ugly but worked.

 

[JimL]

.

 

[tundraotto]

sure do

 

[woodsjunkie]

Me too on every saw i own

 

[woodsjunkie]

and one with just one

 

[woodsjunkie]

last pair

2165 & 2149 both by Dennis

 

[John in MA]

Most of my saws are too old to need it.

Then there's the Mac with the open stack. Those were the days--when men were men and couldn't hear the women.

 

[tundraotto]

hey JimL - I recreated your photo with bigger ports, the lighting was not great but I figured I had to do it anyway sorry for the picture quality...

 

[JimL]

Originally posted by tundraotto
hey JimL - I recreated your photo with bigger ports, the lighting was not great but I figured I had to do it anyway sorry for the picture quality...

That a ford?

 

[Marky Mark]

Here's mine

Here we have my only Stihl saw. It was going to be a boat anchor until Dozer Dan put some guts in her.
I couldn't believe the power he gave this saw it was a true piece of crap before the face lift. I had run about 3 tanks of gas thru this saw and was about to sell it.

 

[HUSKYMAN]

Here's a nice pair

 

[HUSKYMAN]

Whoops 2nd attempt

 

[HUSKYMAN]

Or this one

 

[woodsjunkie]

I sure do like them Duals, I just put them on my 2002 2500HD chevy wow whata differance

 

[Jacob J.]

Howdy-

I notice a lot of these pipes in the mufflers are welded into the casing. I recently bought a "Walkerized" 066 from a dealer in Canada. When I got the saw, it was noisy and fast. With a 25" bar and new Stihl 36RSK chain it cut very fast. However, I didn't notice a whole lot of different over a stock saw with a 42" bar and the same chain buried into a big fir ( 6' ).

The muffler mod on this Walkerized saw was basically two big pipes welded into either side of the casing. One went through the stock exhaust port. It was basically like someone just drilled two giant holes in the muffler. I know the horsepower gains from drilling holes in the muffler casing are minimal ( <1 horse ). So my question to the saw builders is this:

Would it be prudent to bring the pipes back inside the muffler, stopping them a certain distance from the wall of the casing? Perhaps that way you could use the wall of the muffler ( back or side ) as a venue to bounce the exhaust wave off of and hold it for a millisecond thereby maintaing the proper back pressure ( for whatever you have the exhaust port tuned for ).

Perhaps a person could lengthen the piping and give it shape to delay the scavenging of the exhaust? I recently bought a Tecomec muffler and mounted it on an 064. The Tecomec muffler had one pipe out the side, in the same position as a Stihl stock exhaust port, but the Tecomec engineer had run the pipe a distance inside the box of the muffler and pointed the opening of the pipe toward the front casing of the muffler. The saw sounds like a stock Honda trail 90 engine with a straight pipe.

 

[rupedoggy]

Exhaust modification is not simple. If you get less back pressure you get more performance, but only to a certain point. Kart builders built a slipper pipe to change length of the total pipe. Out of the corner one length was desireable, and on the straight another was better. Now your assignment is to build a slipper piped muffler saw and report back to all of us with the result. Babcock will help with dynamometer calculations and KD will time you in your cuts. Mike

 

[dbabcock]

Careful Mike, you start assigning homework projects to people and they might start thinking that you were actually Dagger.

 

[bwalker]

Would it be prudent to bring the pipes back inside the muffler, stopping them a certain distance from the wall of the casing? Perhaps that way you could use the wall of the muffler ( back or side ) as a venue to bounce the exhaust wave off of and hold it for a millisecond thereby maintaing the proper back pressure ( for whatever you have the exhaust port tuned for ).

Jacob, The mufflers on saws are pretty crude in that they are not tuned in the traditional sense. In a untuned sytem restriction is very detrimental. Adding additional outlet area frees up some power and more importantly reduces the pistons ring belt temp. That being said performance can be hurt by just hogging out the outlets hole. As Mr. Rupley alluded to some back pressure is needed for the system to function at peak output. Saw mufflers have more in common with fourstroke mufflers designs in this regard.

 

[Dennis]

muffler test

Been there, done that...I took different lengths of pipes, and welded them in...the problem with the longer pipes inside the muffler, is the vibration it causes inside the muffler...couldnt keep bolts in them, even with loctite, until we got the pipes pretty much flush with the inside of the muffler...