Mastermind Revisits The MS261CM Type II

[nohoff]

Some of the terminology in the patent was cracking me up, The ‘rotatably supported’ crank and ‘pivotably supported’ throttle plate… Is that stuff standard patent lingo or a bit of creative translation from German?
Some of it sounded like a lawyer rewriting the bible. Lol

I read the german Version and its the normal patent lingo...
It hurts to read this thing as a german.

 

[retro]

I have been reading all the documentation I can find on this including the patent info.
From what I see, there must be some type of ECM / Chip within the casting of the coil.
I would like the part # and possible costs for this coil.
Being a long time hacker, I would love to Dig into this coil and see what is going on.

From the patent info, this is all the hardware locations associated to this and its notable that there are more than 2 Possible Solenoid locations.
View attachment 90047

There is a simple power supply (AC voltage and current being generated by the rotating magnets) supplying a processor chip inside the M-tronic coil. I assume that the alternator voltage and current supply is being converted to a DC voltage (and fully regulated) to power the processor though, because most processors require regulated DC power supply for stability reasons.

There are instructions provided for that processor, as well as a memory area providing for a history queue. I don't know how much one of those coils cost, but I'd guess they are priced quite high?

If I really intended to hack into one of the M-tronic systems, I'd be focusing more on what I could do as far as mods go... on the outputs of the system, rather than monkey around with a proprietary hard-coded processor chip having no known access hardware/software interface. Altering gross fuel supply potential and dwell time characteristics should be very easy to pull off after a few hours of study, measuring and testing... the only hurdle I'd feel like I'd have to overcome and master control of is the ignition timing range of capabilities. I'd begin my testing right there, because once I gain control of the ignition timing I'll have won all the money that is on the table! No need for me to waste my time complicating things more than they are... and for crying out loud, this system is ingeniously simple! Thats my 2 cents.

 

[retro]

Don't be skeered

Show me an improved mouse trap design and I'll buy into it. We've all been there and done all of that conventional porting stuff over and over for decades now.... I'm an old man, I'm bored, I'm tired and I'm disgusted working with the same-ole, same-ole. I'm interested in discovery... refining new ideas, integrating new tech and moving forward with them. These new strato mouse trap motors will probably smoke the tried and true old tech once a few more sharp eyeballs and creative minds have become focused on them. Some of those same sharp minds will discover and engineer something even greater.

I like your work and I admire all your accomplishments, please don't take these comments personally or negatively..? I just hope to see more folks interested in creating a better mouse trap.

 

[breese]

There are instructions provided for that processor, as well as a memory area providing for a history queue.

This is one of the questions I would be looking into. So far I have not found any info on-line for the processor... (In my past life, I hacked more than a few Sealed CPU / Chips).

If I really intended to hack into one of the M-tronic systems, I'd be focusing more on what I could do as far as mods go... on the outputs of the system, rather than monkey around with a proprietary hard-coded processor chip having no known access hardware/software interface.

The thing is, a lot of CPU / ECM chips have a method of reading and writing to them thru a "Port". A cable would have to be built.....
The up side would be the ability to Monitor it live, and possibly change the timing advancements.... for one..
Who knows, it might even be possible to write some documentation on Where to Cut, How to hook up cables, and how to hook it up to your portable computer.

Without having one of these in my hands... IDK.... But I am shopping for one.... lol

 

[nohoff]

maybe i should open an old M-Tronic ECU.
In Germany the M-Tronic ECU ist priced 10-15 Euros higher than a normal ignition coil.
In case of the MS 261 its a 2 Euro difference.

Shipping from Germany to US would be too expensive.

 

[breese]

There is a lot of on-line info on methods of removing the "plastic" casings without killing the CPU and or Print (if any) on the CPU....
Personally, I want the print....

 

[MustangMike]

Skipped tldr

???

 

[retro]

This is one of the questions I would be looking into. So far I have not found any info on-line for the processor... (In my past life, I hacked more than a few Sealed CPU / Chips).


The thing is, a lot of CPU / ECM chips have a method of reading and writing to them thru a "Port". A cable would have to be built.....
The up side would be the ability to Monitor it live, and possibly change the timing advancements.... for one..
Who knows, it might even be possible to write some documentation on Where to Cut, How to hook up cables, and how to hook it up to your portable computer.

Without having one of these in my hands... IDK.... But I am shopping for one.... lol

That would be very cool for sure! Probably be a major challenge and have lot of fun too!

But could it ever become cost/time/effective enough to become a justified sink for one's spare thought calories? After all, its just a simple electronic control gadget... it is NOT the power source for the tool. How much more useful could that gadget become to us, seriously? Hasn't it already accomplished what it was designed for and intended to do?

We can build and adapt larger and more sophisticated Mtronic carbs to existing motors ourselves. We can carve out larger, more effective (and specialized) strato tracts as well. We could spend a gazillion more on complex and creative gadget tricks too...

But in every real world work-sawing experience, gross power output potentials from every normally aspirated, pump-gas 2-stroke chain saw motor is defined and limited by its displacement. We gotta deal directly with that reality... its the source of power for the tool. These new Stihl strato motors provide some additional (and complex appearing) plumbing that we are not yet fully understanding and taking advantage of. Thar' be multi-headed dragons to be slayed in there I tells ya...!!!

Sorry for derailing... <returned to lurk bucket>

 

[breese]

That would be very cool for sure! Probably be a major challenge and have lot of fun too!

This is one of the things I really like to do.... I am new to the Chainsaw world outside of just using one, so digging into the technology (mechanically or electronically) is fun for me...

How much more useful could that gadget become to us, seriously? Hasn't it already accomplished what it was designed for and intended to do?

That is the question... Just like going to the Big Box store and buying a chainsaw.. Does it already accomplish what it was designed for?
After being on This Site, I would say No....
Not being on this site, I would have never known that.

 

[CR888]

Mike if you like dual dawgs/roller catcher, the MS261 clutch cover has provisions to accept a 362 dawg kit. The 362 kit is bigger and not that pressed out thin style you get with the 261. Just remove (or leave) regular chain catcher and install 362 kit. Just need to drill two holes in the hex shapes in clutch cover. Cool you got a nice 50cc saw, I bet you use it a bunch more than you thought you would. I run a 16" solid Tsumura in our hardwoods it balances well but with softer timber you could run a Stihl Light 20".

 

[MustangMike]

This 261 will have 18" 3/8.

 

[tree monkey]

This is one of the questions I would be looking into. So far I have not found any info on-line for the processor... (In my past life, I hacked more than a few Sealed CPU / Chips).


The thing is, a lot of CPU / ECM chips have a method of reading and writing to them thru a "Port". A cable would have to be built.....
The up side would be the ability to Monitor it live, and possibly change the timing advancements.... for one..
Who knows, it might even be possible to write some documentation on Where to Cut, How to hook up cables, and how to hook it up to your portable computer.

Without having one of these in my hands... IDK.... But I am shopping for one.... lol

I might have one I can send you.

 

[JMoney]

No question is ever amateurish.

If a person manually adjusts the ignition timing by filing the key on the flywheel, the system will still seek to adjust (it will remain on the appropriate branch condition in the algorithm until it finds/overshoots optimum) the timing for optimum idle RPM and WOT RPM. And it will find optimum timing very quickly once it completes a relearning cycle. In other words, as long as the timing is not altered beyond the range that the coil legs spacing and flywheels magnets spacing provides, the system will correct for what that person has attempted to do.

Maximum RPM can not ever occur on an M-Tronic controlled engine while it is running lean. Can't happen while its running too rich either. Max RPMs occur in an engine only while the fuel mixture is stoichiometric AND while the ignition timing is optimal to attain max RPM.

If something happens to the motor causing it to lean out (monkey snot/banana peel patch falls off from a chewed carb boot?) suddenly, the system immediately retards the timing and keeps adjusting toward a corrected fuel/air ratio until it runs out of adjustment range. It either corrects the lean (or rich if its flooding with fuel) problem immediately or the motor slows and barely runs... or has stopped already due to retarded timing.

Only my answers are amateurish, no worries.

Thanks, that makes perfect sense. It is tempting to have just because I normally tune way richer than needed.

There is a simple power supply (AC voltage and current being generated by the rotating magnets) supplying a processor chip inside the M-tronic coil. I assume that the alternator voltage and current supply is being converted to a DC voltage (and fully regulated) to power the processor though, because most processors require regulated DC power supply for stability reasons.

There are instructions provided for that processor, as well as a memory area providing for a history queue. I don't know how much one of those coils cost, but I'd guess they are priced quite high?

If I really intended to hack into one of the M-tronic systems, I'd be focusing more on what I could do as far as mods go... on the outputs of the system, rather than monkey around with a proprietary hard-coded processor chip having no known access hardware/software interface. Altering gross fuel supply potential and dwell time characteristics should be very easy to pull off after a few hours of study, measuring and testing... the only hurdle I'd feel like I'd have to overcome and master control of is the ignition timing range of capabilities. I'd begin my testing right there, because once I gain control of the ignition timing I'll have won all the money that is on the table! No need for me to waste my time complicating things more than they are... and for crying out loud, this system is ingeniously simple! Thats my 2 cents.

Yeah it would be pretty cool to be able to change the way timing is controlled, so that it advances faster and/or further. It would be interesting to test out of giving a certain amount of advance along with an increase in fuel would improve performance (RPM or torque) vs the max RPM stoic ratio that the computer shoots for by default (just guessing that advancing much more than stock with a stoic ratio could be dangerous).

 

[tree monkey]

ran the 241 today that is still strato, I think it runs good. Julian did a vid of it and I/he will post it asap

 

[MustangMike]

Time for another Brad match up!

 

[tree monkey]

the 661 m-tronic works differently then the others. it gives optimal timing all the time at any rpm up to 13,800, it then retards to timing to slo the saw down.
other -tronics change the timing about 5 degrees at a time.

 

[retro]

the 661 m-tronic works differently then the others. it gives optimal timing all the time at any rpm up to 13,800, it then retards to timing to slo the saw down.
other -tronics change the timing about 5 degrees at a time.

Thats interesting. I already like the 661 module way more than the others! Would they be difficult (flywheel diameters the same?) to swap onto a 261?

 

[retro]

Yeah it would be pretty cool to be able to change the way timing is controlled, so that it advances faster and/or further. It would be interesting to test out of giving a certain amount of advance along with an increase in fuel would improve performance (RPM or torque) vs the max RPM stoic ratio that the computer shoots for by default (just guessing that advancing much more than stock with a stoic ratio could be dangerous).

The "optimum" RPM that the computer shoots for on each motor is unknown by me. I am also making an assumption, based on their choice of words describing the system, that "optimum RPM" may not necessarily = Max RPM. I'm guessing that many of these Mtronic modules might be RPM limited.

Advancing timing beyond the stock MAX can be very beneficial if you are running a good octane-stable fuel and have increased the compression and improved the air pump such that the torque curve has flattened, broadened and moved closer to your desired RPM ceiling. The motor will tell you when you dial in a bit too much timing.

 

[tree monkey]

you can advance the timing, cut key, a lot and the coil will the timing where it wants it. there are gains to be had by cutting the key because it lets the coil advance more at high rpm. I put a timing light on it with stock key and with cut key. timing at idle did not change.

 

[tree monkey]

my timing light only works up to 10,000 rpm. I need one to go to 15,000 or more to test in the wood changes