X-Torq vs 2-Mix?

[Haironyourchest]

Thanks Eddie I'll look into it

[spudulike]

Hi Stubby, the saws Im looking at are not Autotune or M-tronic. Im sure the intillicarbs are brill and all, but the idea just doesn't sit right with me. Im fascinated by the mechanical strato principle though, and would like to take advantage of it.

 

I have formed the opinion after researching around this topic for several months, that the "World Chainsaw Community" just might be the most superstitious group of manly men on the planet, after sailors....

 

And I mean that in a kindly way - and readily admit my own tendency to prejudice...If I dont shake and roll the mix can just so, each and every time I fill the saw, well...something terrible...will happen...

 

Not sure I share the Strato awe! Sure, it is a way forward for a greener two stroke but it severely limits the size of the inlet port and in some designs, the amount of fuel/oil that can flow through the carb.

 

It is a nice idea loading a slug of clean air at the top of the fuel/air vapour stack in the transfers but the restrictions are not so good.

 

The less fuel the saw uses, the less oil is distributed over the bottom and top end of the machine stressing bearings and top end components.

 

Personally I would use more oil in these type of machines, some say this will lean the mix down and whilst technically, it will, it is leaning it with OIL and NOT air and that means the saw will not get hot as a lean mix caused by AIR.

 

The autotune machines then take this to the next level and I also prefer a traditional carb despite the smart things the autotune does to mix and ignition timing!

 

Just my thoughts, give me a conventional 2T engine over a Strato any day!

 

Call me a dinosaur:lol:

[adw]

Just for your own information Husqvarna now produce most of there own cylinders in the factory, they are cast with open ports and a side plate is attached, Mahle piston are then fitted.

[spudulike]

Just for your own information Husqvarna now produce most of there own cylinders in the factory, they are cast with open ports and a side plate is attached, Mahle piston are then fitted.

 

Just for clarification, when you say "Open Ports" do you mean the outer part of the transfer is not solid but is covered with a plate as on the 560 for instance?

 

I usually call a cylinder with "Open Ports" as a cylinder with transfers that run as a channel up the inside of the cylinder and are.....well.....Open - like on the 345/350 as an example.

 

Not trying to be funny or clever:001_tongue:

[adw]

Yes you are correct, i am suffering from a curry and four pints of Kingfisher.

[Haironyourchest]

Spud, I have been following a s**t slinging fight on Arboristsite over the strato oiling issue this afternoon. There seems to be no definitive answer, but I would be using 40:1 HP Ultra as a matter of course. What bothers me is that there seems to be different designs of strato depending on the brand and also between saws of the same brand. The 461 appears to have a single intake carb and then splits the air from there? And then theres this "ramp" that targets the mix to the crank bearings. Then others seem to have duel carbs. Some appear to use clean air as a gaffer and others recirculate the exhaust??

 

Its all very vague. My fear is that I'll buy the saw and two years time there'll be a general consensus that the particular strato variant in my saw is the 'wrong' one....grrrrr

 

Why oh why is there no info anywhere, like a cutaway of each of these motors and a simple comparison of them? There must be tons of knackerd motors laying around in buckets in sheds around the world.

 

If anyone has one please cut it in half with a grinder and post to youtube. I will do the same should any come my way, If we all do it maybe we can all make more info red decisions....

[spudulike]

Spud, I have been following a s**t slinging fight on Arboristsite over the strato oiling issue this afternoon. There seems to be no definitive answer, but I would be using 40:1 HP Ultra as a matter of course. What bothers me is that there seems to be different designs of strato depending on the brand and also between saws of the same brand. The 461 appears to have a single intake carb and then splits the air from there? And then theres this "ramp" that targets the mix to the crank bearings. Then others seem to have duel carbs. Some appear to use clean air as a gaffer and others recirculate the exhaust??

 

Its all very vague. My fear is that I'll buy the saw and two years time there'll be a general consensus that the particular strato variant in my saw is the 'wrong' one....grrrrr

 

Why oh why is there no info anywhere, like a cutaway of each of these motors and a simple comparison of them? There must be tons of knackerd motors laying around in buckets in sheds around the world.

 

If anyone has one please cut it in half with a grinder and post to youtube. I will do the same should any come my way, If we all do it maybe we can all make more info red decisions....

 

 

OK, my logical thoughts here, others may differ but that is life:001_rolleyes:

 

If you use the typical single throat/choke carb for a strato engine, you are using valuable carb bore to just feed air in to the strato ports and therefore restricting the saw.

 

If you are using one of these carbs with an additional bore with a flap valve that opens in conjunction with the throttle, you now have a conventional carb doing it's thing and a separate mechanism controlling the air for the strato part and is therefore a better design IMO.

 

I guess the ultimate view would come from the factory engineers but the above are my views as I see them. I know the effect of resricting the air flow through the carb, even by a little amount and as much as an engineer may design the engine to work in this manner, just see it as a work around rather than a proper solution!

 

There is an excellent vid on youtube showing a typical Strato engine in operation -https://m.youtube.com/watch?v=IY7zQKw4qsQ

 

Note the way air is fed in to the transfers and is then used to scavenge the exhaust gasses from combustion out of the engine.

 

The 40:1 is a good idea as previously mentioned, a synthetic oil is also a very good idea.....again in my opinion.

[Haironyourchest]

Thanks for your thoughts Spud, Re. the duel intake vs single intake I had the same feeling, even not being a mechanical guy, as such.

 

I have watched the vid before, and just watched it again now. That x-torq appears to have duel intakes, it looks like a robust and proper design. Gives me a warm fuzzy feeling etc...Is that the same set up that is used in all Husq gear then? I will try to find out and report back, hopefully someone will beat me to it.

 

If Sthil has the rights to the patent then why do they put a single intake in their flagship saw and not just a regular x-torq? Just doesn't make sense to me....

 

Thanks again for your time and knowledge, wishing you a great Sunday afternoon Spud.

[spudulike]

Yes you are correct, i am suffering from a curry and four pints of Kingfisher.

 

It takes great skill to still operate correctly under this duress:thumbup:

[Eddy_t]

Thanks for your thoughts Spud, Re. the duel intake vs single intake I had the same feeling, even not being a mechanical guy, as such.

 

 

 

I have watched the vid before, and just watched it again now. That x-torq appears to have duel intakes, it looks like a robust and proper design. Gives me a warm fuzzy feeling etc...Is that the same set up that is used in all Husq gear then? I will try to find out and report back, hopefully someone will beat me to it.

 

 

 

If Sthil has the rights to the patent then why do they put a single intake in their flagship saw and not just a regular x-torq? Just doesn't make sense to me....

 

 

 

Thanks again for your time and knowledge, wishing you a great Sunday afternoon Spud.

 

 

Husky originally used the carb-separated system, prime example being the 372 and 365 x-torq models, this was later sold to Stihl. That system uses an extremely large Venturi on the carb to compensate, leading to modders using the 372 carb on the 390 to pull larger bars after porting.

 

The main reason behind the change-over is that it rapidly became apparent that the 2-mix strato system can be bypassed with a knife.

 

In regards to autotune or m-tronic, the computer chip runs a very simple program. At idle it tunes the saw for idle by closing a circuit that powers a magnetic valve (higher speed -> more power to the magnetic coil -> open the valve more, allowing more fuel through, which lowers speed. Lower speed -> less power to the magnet -> valve closes), at high rpm, it repeats the same system, but at a higher power need. Not sure how the limited coils work with this though, as that would lower the 'pull'.