661 Muffler mod progression

[KenJax Tree]

now that is a good idea! so any ideas on how to attach my fast tach? Or should I get whatever tach Mopar is using?

Velcro?

 

[Moparmyway]

the variable becomes applying more load to the higher HP saw to get it down to the same RPM as the lower HP saw. By doing so the saw will pull bigger chips and mover more material but the chain is limited to how big of a chip it can make before you just start creating more friction

But there is a limit to how much bite you can take before the chain becomes overly grabby, whereas if you allow the higher RPM to give you more chainspeed, you reduce cut times without hammerin the cutters by taking larger bites.

Small chips are removed easier, and in timed cuts, high chainspeed rules. This means more RPM in the cut for a faster cut, no ?

 

[Time's Standing Stihl]

Having a tach attached to the saw is the only way to achieve this.
Its a great way to "test" all different things, like different angles on chain, muffler mods, port work, different air filters, etc .....

What tach are you using with your 661? I use works connection on all of mine, but for some reason it doesn't work worth a **** on the 661. My only guess is the rev limiter is messing with it????

 

[Moparmyway]

What tach are you using with your 661? I use works connection on all of mine, but for some reason it doesn't work worth a **** on the 661. My only guess is the rev limiter is messing with it????

I use a Hardline, never had an issue .............

 

[blsnelling]

The ideal RPM will vary by saw. A good operator knows how to listen to the saw and keep it in that sweet spot.

 

[blsnelling]

I use a Hardline, never had an issue .............

Even on a 661?

 

[KG441c]

What tach are you using with your 661? I use works connection on all of mine, but for some reason it doesn't work worth a **** on the 661. My only guess is the rev limiter is messing with it????

STIHL EDT 8 works with mtronics

 

[big t double]

I didn't think a fast tach could read the m-tronic flywheels...interesting.

 

[KG441c]

I didn't think a fast tach could read the m-tronic flywheels...interesting.

No. Something about a double reading that confuses a regular tach

 

[big t double]

No. Something about a double reading that confuses a regular tach

yea the double magnet flywheel messes em up...same as ms280i

 

[Moparmyway]

I can tell you that it works on my 661.
I wasnt sure it would, so I took one off another motor. When it did work, I just ordered a new one for the 661 and never had an issue.

The pick-up wire wraps around the plug wire, so it only reads when the plug fires.

 

[Marshy]

But there is a limit to how much bite you can take before the chain becomes overly grabby, whereas if you allow the higher RPM to give you more chainspeed, you reduce cut times without hammerin the cutters by taking larger bites.

Small chips are removed easier, and in timed cuts, high chainspeed rules. This means more RPM in the cut for a faster cut, no ?

I don't disagree that the chain has limits, I even mentioned that in my previous reply. Yes chain speed has a direct relation to the speed of the cut, I understand that also. However, were not talking about trying to slow the higher HP saw (rather the same saw but with a MM or different oil ratio) by several hundred RPM. Your only trying to match the same RPM as the stock saw RPM by adjusting more load to the mod saw. The chain should be able to handle the extra chip load. You set the baseline with the stock saw an RPM. I don't think it would be unreasonable for the saw to see that same RPM as each other in the field under normal use in some circumstances.

Again, the largest variable is applied load so its not a fair question to ask but it does have some bearing... have you measured the RPM of a stock vs MM saw in the cut with the same load? How many more RPMs did it hold? Have you tried this comparison?

 

[big t double]

I can tell you that it works on my 661.
I wasnt sure it would, so I took one off another motor. When it did work, I just ordered a new one for the 661 and never had an issue.

The pick-up wire wraps around the plug wire, so it only reads when the plug fires.

then I stand corrected...thanks for the info.

 

[Moparmyway]

Again, the largest variable is applied load so its not a fair question to ask but it does have some bearing... have you measured the RPM of a stock vs MM saw in the cut with the same load? How many more RPMs did it hold? Have you tried this comparison?

Yup, sure have. I gained 1500-2000 RPM when allowing the same chain to self feed by modding the muffler.

I made one cut with my 661, then I modded the muffler - so it was easy to see (with the tach) and feel the difference

 

[Moparmyway]

then I stand corrected...thanks for the info.

I have a few dudes wanting to see a video of mine working ............... I will try to put something together in the next few days and if I cant grab any wood, then it will just be a piss revvin show

 

[Marshy]

Yup, sure have. I gained 1500-2000 RPM when allowing the same chain to self feed by modding the muffler.

I made one cut with my 661, then I modded the muffler - so it was easy to see (with the tach) and feel the difference

I still think the chain is capable of the added chip load. I can't test this because I don't have a MM. I think it's worth exploring.
How many times have you ever leaned on a saw and changed the RPM 1500-2000?

 

[Moparmyway]

I still think the chain is capable of the added chip load. . I think it's worth exploring.

I agree 100%. The chain would probably be capable of handling the extra load.

How many times have you ever leaned on a saw and changed the RPM 1500-2000?

I can lean on a saw and watch the RPM go all the way down untill the clutch stalls, so trying your exploratory idea is pretty easy to do except I dont have any stock mufflers anymore .......... LOL

 

[Marshy]

I agree 100%. The chain would probably be capable of handling the extra load.



I can lean on a saw and watch the RPM go all the way down untill the clutch stalls, so trying your exploratory idea is pretty easy to do except I dont have any stock mufflers anymore .......... LOL

But you have oil ratios to test!

 

[Moparmyway]

But you have oil ratios to test!

Nope ............. not me !
I aint testing no oil ratios !
Now ........... different oils, thats a different story ................ I might be testing that in the close future

I will just stay dumb and stupid as I mix @ 32:1 for mostly everything.

Blasphemy that I am running 25:1 in my ported 066, but I want the extra oil for the sensetive main bearings.
I am sure it dont mind the extra oil, its pretty stout and spins well past 14,000 with all the extra oil hittin the piston

 

[blsnelling]

STIHL EDT 8 works with mtronics

I need to get me one of those.