The Moody 362 C-M

[chadihman]

OK, no one get upset with me, remain calm, but this is what I am talking about, and I had a similar experience when I tried to "improve" a duel port muffler cover on my 044.

If you are loosing throttle response with a 180% opening, it is because you are loosing low end torque because you opened it up too much.

If you open it further, you will loose even more low and mid range torque.

While the motor may still be fine running flat out, it will be easier to slow it if you are running a large bar in tough wood. What percentage opening will result in the saw not performing well in the cut I don't know, but I believe it will happen at some point in time. Just because someone was able to cut cookies without noticing a loss of torque does not mean it did not occur.

Perhaps a saw on a dyno is the only way to resolve this issue.

I am not trying to twist facts to support my point of view. I am looking for hard evidence that will support one opinion or the other, and to date I have not seen it.

I got my supplies today to make my variable size exhaust outlet. I will test this soon. I'll test from 3/8" to 1" opening on the dyno. I'm very interested in seeing these results. I tested my 461 awhile ago and found a dual port muffler did nothing for it. I put the stock muffler back on to save fuel. I'm thinking to big is bad but I'll have to find that out.
Wife's away so I'm busy with my kids. Maybe Friday I'll have some #'s

 

[chadihman]

No muffler at all........just a straight shot right out of the jug. You can see the piston......



Looks pretty torquey.

That looks like a lunch box not a chainsaw

 

[blsnelling]

I got my supplies today to make my variable size exhaust outlet. I will test this soon. I'll test from 3/8" to 1" opening on the dyno. I'm very interested in seeing these results. I tested my 461 awhile ago and found a dual port muffler did nothing for it. I put the stock muffler back on to save fuel. I'm thinking to big is bad but I'll have to find that out.
Wife's away so I'm busy with my kids. Maybe Friday I'll have some #'s

How do you plan to compensate for tune changes between opening sizes? A slightly different tune will likely make more difference than a change in the muffler opening. Just curious how you control that.

 

[chadihman]

How do you plan to compensate for tune changes between opening sizes? A slightly different tune will likely make more difference than a change in the muffler opening. Just curious how you control that.

I have a oxygen sensor I used before maybe I'll thread that in my muffler. I'm thinking I'll just tune them by ear. Ideas?

 

[Derrick Sawyer]

Can you hookup a pressure sensor to monitor backpressure? Location of muffler port may make difference if in front or on side in rear, not just shear are, and then affect escape of exhaust and escape and reflection back of charge, of course depends on port angles/size/engine design that the 461 may be optimized for. I would trust the builders gut feelings here, you could read Gordon Jennings tuning 2cycle book 20 times but theory will only go so far with so many factors involved.

 

[Mastermind]

These last few months I've begun to think about the noise that a high compression, ported saw makes. In turn I started doing a few things different on my mufflers, at least on certain saws. What I've found is that the muffler opening isn't nearly as important as some may think. Adding compression, and getting the port timing numbers just so will make much more difference than knocking holes in a muffler.

 

[Jacob J.]

These last few months I've begun to think about the noise that a high compression, ported saw makes. In turn I started doing a few things different on my mufflers, at least on certain saws. What I've found is that the muffler opening isn't nearly as important as some may think. Adding compression, and getting the port timing numbers just so will make much more difference than knocking holes in a muffler.

Hmmm...I been trying to tell people that for years.

 

[angelo c]

Hmmm...I been trying to tell people that for years.

What ????
I can't hear you...im almost done modding my muffler enough to hear you over the noise...

Oh and BTW how cool is a quiet saw ???? Man that sure sounds girlie to me... My manly saw is loud as all he11 !!!!!

 

[dl5205]

These last few months I've begun to think about the noise that a high compression, ported saw makes. In turn I started doing a few things different on my mufflers, at least on certain saws. What I've found is that the muffler opening isn't nearly as important as some may think. Adding compression, and getting the port timing numbers just so will make much more difference than knocking holes in a muffler.

Seems like you put a lot of time and effort into something that's just a fad....

 

[Mastermind]

JJ, remember a few years ago when everyone said that you had to raise the exhaust to get gains?

Between Wigglesworth and Andyshine those myths were busted all to hell.

Hopefully in the future we can use dyno testing to dispel a few more myths.

I'm really looking forward to getting Chad's dyno and taking his design a little further.

 

[Mastermind]

Seems like you put a lot of time and effort into something that's just a fad....

I just wanna be the best fad in town.

 

[windthrown]

These last few months I've begun to think about the noise that a high compression, ported saw makes. In turn I started doing a few things different on my mufflers, at least on certain saws. What I've found is that the muffler opening isn't nearly as important as some may think. Adding compression, and getting the port timing numbers just so will make much more difference than knocking holes in a muffler.

Agreed... but some stock saws are begging for moderately larger exhaust ports (for example, the 026, 046, 361, and 310/390). I had a series of 026 saws, and the ones with the early factory mufflers with larger holes ran better, stock. Similar to the Euro 310 mufflers compared to the US models, and the CDN 046 Magnum DP covers.

Strato saws like the 362 are a completely different can of worms though.

 

[chadihman]

JJ, remember a few years ago when everyone said that you had to raise the exhaust to get gains?

Between Wigglesworth and Andyshine those myths were busted all to hell.

Hopefully in the future we can use dyno testing to dispel a few more myths.

I'm really looking forward to getting Chad's dyno and taking his design a little further.

How so?

 

[Mastermind]

Agreed... but some stock saws are begging for moderately larger exhaust ports (for example, the 026, 046, 361, and 310/390). I had a series of 026 saws, and the ones with the early factory mufflers with larger holes ran better, stock. Similar to the Euro 310 mufflers compared to the US models, and the CDN 046 Magnum DP covers.

Strato saws like the 362 are a completely different can of worms though.

That's exactly what I'm seeing. The Dolmar 6100 gained nothing with a muffler mod, nor did the MS661......

They no longer need to restrict the exhaust in an attempt to use the can as a afterburner to pass EPA guidelines. Now with the new strato technology, the muffler outlet can be correctly sized, and emissions are still low.

 

[Mastermind]

How so?

On what part of my post?

 

[Guido Salvage]

I just wanna be the best fag in town.

We never knew... I think this post contributed more than half of the others did.

 

[chadihman]

I have plans for dyno 2

 

[chadihman]

On what part of my post?

Taking my design a little further

 

[Mastermind]

Wiggs planted a seed in my mind of using an electric motor for a load cell. Your drive system may be able to be used to drive that motor......

 

[richard t]

I'm gonna to whoever posts the most on this thread or maybe send them 10 mini macs COD.