Inside the MS362

[Tzed250]

I always run a 7-pin on a 60cc saw. They'll pull an 8-pin but not as well. Perhaps Andy was right, and I should have left the 361 out of this. This is ultimately about how the 362 responds to mods. I was just trying to answer to question in everyone's mind.

Your first intent was the right one. No saw runs in a vacuum. All facts are related. The 441 and 576 will be directly compared to the 440 and 372.

Of course it matters what the gains are, but across the field comparisons are inevitable.


.

 

[stihlboy]

I see where you're going with this but it's a bit of a moot point. A 346 would hand both of those saws there ass in 6" wood. Most of the cutting the 60 cc saws will do will be in the 10"-18" range.

true because at that point it is not loading the engine its all about chain speed and top end holding rpm..........

so if you slapped a 20+inch bar on these 362's the ported saw would have an even greater percentage in improvement right???

 

[FATGUY]

true because at that point it is not loading the engine its all about chain speed and top end holding rpm..........

so if you slapped a 20+inch bar on these 362's the ported saw would have an even greater percentage in improvement right???

I would have to agree 100%. The more load you put on the saws, the greater the difference will be between the stock and the ported one. That being said, if you push them so far that their rpms drop dramaticaly then all bets are off.

 

[bitzer]

I sat and stared at this P&C for a good long while trying to decide what I wanted to do with it. In the end, I basically treated it like any other saw. The only thing the strato really does is add that extra puff of fresh air to help push out the exhaust. I also believe I can explain why WOT tuning RPMs are not that high, and why it can't be pushed as far/hard as a 361.

Look at the intake port. It's only about half the width of a normal intake. It's limited by the pockets in the piston that carry the strato charge. All fuel comes through that one small intake port. So it only stands to reason that it can't flow what a traditionally ported engine can. I was able to widen it a little, but not much. I did lower it 4°, but it would need a lot more width to do more. The intake and carb are matched accordingly. So those are bottle necks as well.

Here are the beginning and final port timing numbers.

Exhaust 103° - 100°
Transfers 131° - 124°
Intake 73° - 77°

As you can see, I raised the transfers a lot. I also widened the rear ones. Transfer flow is needed to maintain RPMs in the cut, so they had to come up considerably.

The exhaust was a little low stock, but I don't like to raise it much. I build for torque and compression is your friend.

Now for the pics.

Here's the tiny intake. You can see where the edge of the skirt rides. I went as wide as I could.

I widened the exhaust a TON. I went a full 70%, as measured along the curve. I wouldn't doubt that I widened it at least 3/8"!

I widen it at the flange as well and taper it all the way in.

I raised the tranfers a lot as well. They were really low to begin with at 131°.

On the strato ports, I only slightly widened them. I did very little to them.

Thats pretty much what I did on my 455. The intake was actually a perfect circle and very small. I widened as much as I could and lowered it. The exhaust was also tiny and I widened a lot and raised some. The bottom of the transfers I rasied and the top I raised and pointed up and back. I still believe the strato air is needed for combustion. When that port was closed off the saw was WAY rich all the way to the needle 1/2 turn out (from max out 2.5 turns). I don't buy the sweeping of the piston with strato air. I just don't think it would do anything to control unburnt hydrocarbons (trying to think of it from the EPA point of view). I bet all that transfer work was a mother tho. As always very cool pics and work Brad!

 

[Maldeney]

Very interesting design....... Not seeing it in person myself, I would think that the "strato" port and extra air would be for assitance with complete combustion. It is one of those things that I would have to hold in my hands and stare at for hours to try and get inside "it's" head.

+1

 

[blsnelling]

It is one of those things that I would have to hold in my hands and stare at for hours to try and get inside "it's" head.

+1

I'm with you on that!!!

 

[Curlycherry1]

Very interesting design....... Not seeing it in person myself, I would think that the "strato" port and extra air would be for assitance with complete combustion. It is one of those things that I would have to hold in my hands and stare at for hours to try and get inside "it's" head.

Does anyone know who came up with the strato design, specifically who might own the patents? The patents will have background information about what it is supposed to do and why. It may not be detailed but it could end a lot of speculation. Then again, no speculation = no fun.

 

[Maldeney]

Does anyone know who came up with the strato design, specifically who might own the patents? The patents will have background information about what it is supposed to do and why. It may not be detailed but it could end a lot of speculation. Then again, no speculation = no fun.

A guy named Strato! :greenchainsaw:

Did I get the Million dollar question right?

 

[blsnelling]

Does anyone know who came up with the strato design, specifically who might own the patents?

Wasn't it Redmax, and that's why Husky bought them? I may have that all wrong though, lol.

 

[kevlar]

I believe Red Max first came up with the technology.

 

[Curlycherry1]

I believe Red Max first came up with the technology.

I searched Red Max, Redmax, and husqvarna and all I am seeing is a lot of sewing machine patents under husqvarna. I see a design patent for an inlet manifold but design patents are nothing more than pretty pictures.

 

[Philbert]

A guy named Strato!

I don't know. But the 'guys' (I'm assuming a variety of different engineers have worked on this) could be termed 'Stato-various virtuosos!"

Philbert

 

[blsnelling]

I don't know. But the 'guys' (I'm assuming a variety of different engineers have worked on this) could be termed 'Stato-various virtuosos!"

Philbert

I think Bach worked with them as well.

 

[Maldeney]

Thought for sure I won the Million dollars!

 

[stihlboy]

http://www.poweruplawncare.com.au/zenoah/strato_charged.html


you are welcome

 

[Philbert]

I think Bach worked with them as well.

Well of course, you like Bach, because you are always trying to get your engines in tune . . .

(sorry - I'll stop with that one)

Philbert

 

[stihlboy]

Thought for sure I won the Million dollars!

maybe you aren't such a bad guy after all ill rep ya positive when i can

 

[Curlycherry1]

Yuk, yuk, yuk, you guys crack me up! Anyway, while you were playing 3 Stooges I found some patents by Stihl.

These two seem to be pretty key and explain a lot of what is going on.

US 6,571,756 and this one is more of the same but easier to make 6,598,568.

Bottom line it is all about the cleaner combustion baby, combustion!

 

[stihlboy]

Yuk, yuk, yuk, you guys crack me up! Anyway, while you were playing 3 Stooges I found some patents by Stihl.

These two seem to be pretty key and explain a lot of what is going on.

US 6,571,756 and this one is more of the same but easier to make 6,598,568.

Bottom line it is all about the cleaner combustion baby, combustion!

hey genious! click on the link i posted

 

[blsnelling]

hey genious! click on the link i posted

Back off Fred.