Echo CS-400 Chainsaw Muffler Mods

[Team FAST]

I modified the muffler on my Echo CS-400 Chainsaw, mostly based on recent recommendations provided by many individuals posting in other threads on this forum.

However, I thought it might be interesting to quantify the airflow differences of the mods using a Superflow SF-110 flowbench. You can see how the various pieces of the muffler contribute to the airflow results, as well as a direct before/after comparison. The attachments tell the story.

I have a powerpoint file of all these attachements if anyone wants a copy.

Enjoy! Comments welcomed/appreciated.

-erik

 

[Team FAST]

Echo CS-400 Muffler Mods

Here's the next five slides in my presentation.

 

[Team FAST]

Echo CS-400 Muffler Mods

Here's the last slide!

 

[keith811]

nice work,

I just drilled a 1/2" hole in the front of my muffler. doesn't look the best but works great. I thought I was going to have to cut out a bunch of stuff from inside the muffler but the only thing in it was one little deflector right under the stock outlet so now the exhaust has a direct outlet square in front of the port..

 

[caotropheus]

Team Fast

Very nice indeed. I like the equipment you used to make the silencer transformations. It is much more exact than using empirical measurements.

 

[Hddnis]

Thanks for sharing that with us. Rep sent.



Mr. HE

 

[Terry Syd]

Deflector

Thanks for doing that in depth analysis of the muffler mod and showing us the results. Rep sent.

I note that the flow continued to increase when the deflector was taken off. Perhaps you may want to look at the area of the deflector opening.

When I was doing the calculations on my new 450 Husky, I found that the opening of the deflector was the limiting factor. After I opened up the deflector outlet, the outlet inside the deflector then became the limiting orifice (which was then modified so that the deflector outlet again became the limiting factor).

When I opened up the area inside the deflector I drilled three holes that would direct the flow towards the outlet of the deflector. That was done in an attempt to prevent turbulence inside the deflector which could increase resistance to flow. - Thanks again for the PP presentation.

 

[caotropheus]

After Terry's post, I would like to emphasize that the spark arrest net clogs very easily in Echo saws. Usually fellows around here open it up and let the exhaust gases flow out freely. Take a look at my Echo 341.


http://www.arboristsite.com/showthread.php?t=129486

 

[Hddnis]

The spark screen can clog up, but some of us don't have the option of removing it.




Mr. HE

 

[XJPete87]

Nice job.. Love the actual flow bench numbers. How do you guys enlarge the holes internal to the muffler? Do you split the cases? mine are brazed together and seemed like a real PITA to seperate..

 

[Team FAST]

I did split the cases and it was a real PITA. The two halves are furnace brazed together and the factory and there is a spot braze on center of the intenal baffle holding it to the outside can as well. I ended up using a disc sander and sanding off the outer lap seam. Then I had to carefully braze the assembly back together as a butt joint.

I think the mods could be accomplished without disturbing the outer case assembly. However, enlarging the internal baffle holes like I did might prove difficult.

I chose to provide flow data for each component in the muffler assembly so you can see the redecution from each indivudal piece. I am running it with the screen on, to keep things reasonably safe and forestry compliant.

 

[Team FAST]

After Terry's post, I would like to emphasize that the spark arrest net clogs very easily in Echo saws. Usually fellows around here open it up and let the exhaust gases flow out freely. Take a look at my Echo 341.


http://www.arboristsite.com/showthread.php?t=129486

I happen to have a CS-341 saw as well (really love it) and I noticed that mine also has a CAT muffler. I also noticed that the Echo CS-3400 has an earlier non-cat muffler which is a bolt on swap. Looks like I'll be doing another flowbench comparison soon

 

[malador]

I subscribed to this forum just so I could see your slides. Nice job! I copied everything you did, plus enlarged the deflector holes. Before the 18” bar was almost more than the motor could handle, not anymore!

 

[HLC03]

Thats hilarious. I subscribed to arboristsite just to see the slides of this mod as well. Team FAST, NICE JOB! The Echo CS-400 is my first and only chainsaw so far. I love it. I really want to do some mods to the muffler, but all the brazing and welding of stuff is way out of my mechanical reach. What can I do to my CS-400 saw with basic tools and maybe a drill and dremel tool? Can you help me?
Thanks A LOT in advance.
Adam

 

[mweba]

Wish I had toys like that. Would be interesting to see how a competeing manufacturers muffler stacks up against the cat echo.
On my cs-450p the cat sits to one side so bypassing it was easy. Unlike your model which sits in the center. These saws respond well to this mod.

 

[malador]

Thats hilarious. I subscribed to arboristsite just to see the slides of this mod as well. Team FAST, NICE JOB! The Echo CS-400 is my first and only chainsaw so far. I love it. I really want to do some mods to the muffler, but all the brazing and welding of stuff is way out of my mechanical reach. What can I do to my CS-400 saw with basic tools and maybe a drill and dremel tool? Can you help me?
Thanks A LOT in advance.
Adam

I didn't split the muffler at first either. Even with doing everything but the split ,I still got a big power increase. You will have to remove the limiter caps aswell. Otherwise the motor is going to run to lean.

*edit* you will need the dremel tool. I mostly used the cutting will and sanding drum.

 

[Team FAST]

I split the muffler as part of the original investigation to see the entire guts in detail. In hindsight, it is not required to spilt the muffler open to remove the Catalytic converter, or open up the outlet at the screen.

I would like to see a CS450 muffler stock to see what Echo did differently. I'd be willing to repeat the experiment if someone could provide the donor. They would get a "Team FAST tuned" muffler in return.

The purpose of the flowbench measurements was an attempt to quantify the amount of backpressure present in a stock muffler and show the relative gains accomplished by modifying the muffler. Obviously carb tuning was required. It definately wanted more fuel. I think there is more horspower available if the ignition timing curves could be adjusted.

-erik

 

[HLC03]

erik,

i'd be more than happy to mail you my cs-400 muffler. the only thing is I need the saw for a job this week. if I sent you the muffler and the funds for quick shipping how fast could you turn it around to me? i'd be willing to add some money in there for your time. let me know. I just need some detailed help after you send it back to me so i can tune the saw, and adjust the air fuel ratio.

on the other hand I would be also willing to tackle this mod by myself if you could offer detailed info of each step. I can also post pics of the process. thanks for everything,
adam

 

[mweba]

CS-450p muffler. I didn't get the greatest pics at the time. As you can see, the cat looks the same. Just the placement is different.

I have a 346xp cat muffler floating around. If I find it, I will send it out with all the other stuff I need to get out for other members.

 

[Zombiechopper]

the last slide where it says, "40cc Echo now hangs with 55cc saws!"

You haven't run too many 50cc saws have you? Let me just suggest you change that slide.