Ms461 saw design

[KG441c]

I appreciate everyones input to the thread and learned alot about technology, combustion systems, porting, marketing, pride , ego, etc. When all said and done I still appreciate Randy and Brad taking their time away from their life , family, and homes to study the saw systems and put the time in on manipulating these systems and making them peform the best they can and still take the time to try and teach us new guys alil something. Im intrigued and interested in the mechanical and performance side of theses saws. Thoso guys could be porting and making money but they both
have always been willing to take time from family, jobs and personal time and help us guys out with the understanding of what they have put the time in to learn and what really makes the saw work regardless of what technology or Stihl marketing says about their product. I for one have no interest in trying to disprove what either one of them understand or dont understand but that they are willing to sacrifice their time to share what they know works and what dont. Ive built a few saws with advice from both of them and both saws have been strong runners. Appreciate u guys

 

[old-cat]

I have spent MANY hours in the Engineering Library at University of Washington, studying SAE tech papers on automotive engines. I know what sort of info is published about engine developements. So I would very much appreciate if one of you engineer people would show me an engineering tech paper about the MS 461. Otherwise, I'm not buying any of your fancy talk about it being a stratocharge design.

 

[KG441c]

I have spent MANY hours in the Engineering Library at University of Washington, studying SAE tech papers on automotive engines. I know what sort of info is published about engine developements. So I would very much appreciate if one of you engineer people would show me an engineering tech paper about the MS 461. Otherwise, I'm not buying any of your fancy talk about it being a stratocharge design.

I already posted it earlier in this thread

 

[nmurph]

That is marketing material.

 

[KG441c]

That is marketing material.

agreed but it stihls claim to deal with epa i think but it is from Stihls technical information manual.

 

[KG441c]

My original post was to try and understand their claim to this term they used and if its anything to it or just hype. Ill take randy and brads knowledge of the port timing and flow are the same as any other saw as they have dug into these machines and brought out another level of peformace in them

 

[old-cat]

I already posted it earlier in this thread

I looked at your post and all I saw was pages of the parts manual

 

[old-cat]

I just went back through the thread and saw your "tech" paper. That's not engineering development info, like what I asked for.

 

[KG441c]

I looked at your post and all I saw was pages of the parts manual

I just went back through the thread and saw your "tech" paper. That's not engineering development info, like what I asked for.

Thats all I have for u from this dumbass ole country boy from Louisiana who cant figure out how to load the manual on here im no engineer

 

[hseII]

Thats all I have for u from this dumbass ole country boy from Louisiana who cant figure out how to load the manual on here im no engineer

You are from Louisiana?

 

[KG441c]

You are from Louisiana?[/QUOTE
Natchitoches , La.

 

[hseII]

Cool.

I worked in Masfield for a while in 2011.

Good People down there

 

[Chris-PA]

Well, as for what saws have to meet what EPA emissions levels, that depends on the size of the engine and the number of units sold by a company. The 461 passes the more stringent CARB requirements and is sold in California. EPA/CARB numbers are likely met along with lower fuel use by not pushing raw fuel out the exhaust (like the earlier strato saws). That is their claim anyway.

My read on delayed/exhaust scavenging is that this is Stihls latest/new direction in technology along with Mtronic. The last two saws to be released have it. It is likely cheaper to produce than earlier strato designs, it is less complex, and seemingly has similar results on fuel saving and lower emissions. This and direct injection on their cut-off saws are the latest and greatest stuff from Stihl. I mean, its all just marketing hype, right?

Marketing.. two drink minimum!

Stihl's FI is not direct, they just squirt fuel into the case.

Assuming this system works as described, let's compare it to a piston ported strato. The Stihl delayed scavenging:

1. Uses exhaust backpressure and long transfer timing (although the porters say the timing is not unusual) to delay the fresh fuel charge.
2. The arrival of the entire fresh fuel charge, air and fuel, to the cylinder is delayed so that it does not have time to get across the combustion chamber and out the port before it closes.
3. Using exhaust gases to create the delay means the cylinder and transfers spend a lot of time filled with hot exhaust gas, and a deflector is added to help cool the piston.

Alternatively, for the piston ported strato:

1. No excessive backpressure is needed.
2. The only portion of the fresh charge that is delayed is the small volume of air that carries the fuel - most of the air for the fresh charge has lots of time to get to the combustion chamber and is already there when the fuel arrives.
   
3. The delay of the fuel is caused by cool fresh air drawn through the strato intake and across the piston.

Interesting that Stihl has used this on two designs, one of which has been recalled, apparently for piston problems.......

 

[old-cat]

Thats all I have for u from this dumbass ole country boy from Louisiana who cant figure out how to load the manual on here im no engineer

I realize you are very much in the same playground as me. It's the engineer people who I am directing my request for info.

I did a little searching in the SAE site but they want $$$$ to read their stuff.

 

[KG441c]

Cool.

I worked in Masfield for a while in 2011.

Good People down there

I work at a linerboard mill in Campti La. about 30 minutes southeast of our other mill in Mansfield La

 

[KG441c]

Stihl's FI is not direct, they just squirt fuel into the case.

Assuming this system works as described, let's compare it to a piston ported strato. The Stihl delayed scavenging:

1. Uses exhaust backpressure and long transfer timing (although the porters say the timing is not unusual) to delay the fresh fuel charge.
2. The arrival of the entire fresh fuel charge, air and fuel, to the cylinder is delayed so that it does not have time to get across the combustion chamber and out the port before it closes.
3. Using exhaust gases to create the delay means the cylinder and transfers spend a lot of time filled with hot exhaust gas, and a deflector is added to help cool the piston.

Alternatively, for the piston ported strato:

1. No excessive backpressure is needed.
2. The only portion of the fresh charge that is delayed is the small volume of air that carries the fuel - most of the air for the fresh charge has lots of time to get to the combustion chamber and is already there when the fuel arrives.
   
3. The delay of the fuel is caused by cool fresh air drawn through the strato intake and across the piston.

Interesting that Stihl has used this on two designs, one of which has been recalled, apparently for piston problems.......

Has anyone heard of a 461 being recalled with this problem like the 661?

 

[Chris-PA]

Has anyone heard of a 461 being recalled with this problem like the 661?

I sure wouldn't know - and I was also just speculating and stirring up trouble. I have no way to know if the recall is in any way connected to this system.

 

[KG441c]

I sure wouldn't know - and I was also just speculating and stirring up trouble. I have no way to know if the recall is in any way connected to this system.

Lol!! Thats a question Id like anwsered whether the 461 quad port and so called delayed scavenging is the exact same design as the 661 and if so why havent any oof the 461s failed?

 

[Mastermind]

You port saws and you do not care how they are designed? Sad... and worrisome.

Well once you explained to us that since you were a successful engineer, this must be a stratified engine, what else is there to say? That sort of reasoning is impossible to refute.

No matter that I've had dozens of these saws apart.....and see nothing different in their design that would make them regurgitate exhaust gases, you being a retired engineer makes what I see wrong.

Even attempting to explain how one of these carbs work is a waste of time here.......

Strato, non-strato, puking hydrocarbons or not.......I don't really care at this point.

 

[Trx250r180]

Well, as for what saws have to meet what EPA emissions levels, that depends on the size of the engine and the number of units sold by a company. The 461 passes the more stringent CARB requirements and is sold in California. EPA/CARB numbers are likely met along with lower fuel use by not pushing raw fuel out the exhaust (like the earlier strato saws). That is their claim anyway.

My read on delayed/exhaust scavenging is that this is Stihls latest/new direction in technology along with Mtronic. The last two saws to be released have it. It is likely cheaper to produce than earlier strato designs, it is less complex, and seemingly has similar results on fuel saving and lower emissions. This and direct injection on their cut-off saws are the latest and greatest stuff from Stihl. I mean, its all just marketing hype, right?

Marketing.. two drink minimum!

Have you put any time on a 461 yet ? I do not know how they run stock ,but my modded one drinks fuel ,i think the epa stuff is broked or something