Another chainsaw dyno...

[MustangMike]

The whole point of building a hybrid is to increase velocity. Why increase volume to match a 460? If that was the case, just port a 460.

Actually, initially, I believe it was to have addl displacement with less weight, but most of the early ones did not match the performance of ported 460s (especially for torque).

Your saw, and CFB's, are obviously glowing exceptions to that. Many of the earlier ones had high RPMs (due to the reduced case volume) but often were peaky and lacked the grunt in the mid range.

Your saw reflects a different way of "skinning the cat"! I'm intrigued! I would not have thought that would work.

 

[Nutball]

For me the big echo 1200/1201 has already won without the need of test or dyno, I've run the common big saws everyone runs mostly. 088/084, 070/090, 076, 395xp ported and so on.

Nothing comes close to 1200/1201 in big hardwood running long bars. The torque is 2nd to none and i prefer the slower rpm, you guys will probably laugh at me. The reason why it owns big hard wood is simply because the chain needs time to grab on the hardwood and scoop it out, something the dyno cant mimick and applies in environment.

Imagine you're shoveling snow in your driveway, you can dig a little and throw quicker or you can dig alot and throw alot slower. Now imagine its earth, you cannot dig a little because its lump. Even if you did its counter productive and you're doing less work, if you take your time stomping your feet on the shovel and move more material even slowly you're doing more work.

In big hardwood 1200 will win everytime, this hardwood is rock hard and dense. 395xp .404 ported barely got through, i cant imagine a stock saw. 1200 was smiling all the way and was asking for more lol

So, where's the picture of the 1201 posing after that big cut?

As the dyno shows, the 1201 easily achieves 6-6.5ftlbs of torque. Only the best of the ported or stroke lengthened 90cc saws went much over 6ftlb, but at higher rpm. So, in theory we have some saws like a 7900, 661, and 395 that should cut that big log way faster, but then comes the variables: does that wood cut best with a slower chain? Did you use 404 on the 1201 which has better chip clearance than 3/8 on the 395? Can the 1201 put out more oil to run a long bar with less friction than 90cc saws?

Thanks for sharing your experience running a 1201. I wish I had one.

 

[NightRogue]

I was covered with chips working on that wood lol, anyway here's another picture of me with my precious 1200 42" and my ground guy with 084 30" because its a cry baby in hardwood and wont pull low raker chain [emoji23]
Here's the link 1200 running on moderately hardwood, rosewood tree

Yes you're right, 084 are rated at 5.8ftlbs. 1200 at 6.7ftlbs, the big difference in cutting power comes due to the lower rpm im guessing. Ported 395xp is my favourite in medium hard to soft wood, if thats what i deal with everyday I'll get rid of every other big saws in my stable no question. They're a joy to run, so smooth and fast. My 395 is ported in torquey way, 102,122,78. On a silky oak which is pretty soft for our standards lol, 395 ported handed 084 ass everyway and everytime. 1200 is useless in this environment because they lack the chain speed the other 2 has.

1200 has the best oiling capacity I've seen, they over oil 42" in lowest setting. Crank driven oiler which dumps alot oil in lowest setting, auto oiler can probably feed 60" with max setting easily. Manual oiler is overkill in any application, it will literally gush out oil through the clutch cover gap when pressed running 42". I had to cut a slot on my 42 bar oil hole to let it stay in the bar, the only reason im using the manual oiler is with use it or lose it mentality. To prevent rust and crud jamming up, otherwise they'll oil double power head mill setup single handedly

Yes 3/8 gets stretched out and thrashed too soon, they suit 395 and 084 alot but unfortunately the wood i deal with dont allow it. 404 are nice, they hold the edge and dont dull that quick, they hit a knot or grit and just dull 1 cutter and move on like nothing happened lol. On the other hand 3/8ths, if you hit something in our wood it'll be a long day [emoji28]

Sent from my INE-LX2r using Tapatalk

 

[Bigmac]

I believe we will find torque per CC to be the limiting factor common to most saws, then it just becomes a matter of who can keep that torque going to the maximum rpms.

A very good naturally aspirated 4 stroke will be round 80-90ftlb per litre of displacement, there are 90s/2000 era everyday factory street cars (Honda S2000, BMW M3) that made near formula 1 specific torque outputs, as in their breathing efficiency/Volumetric efficiency was optimised to a very high level, they just didn't make the HP because they span under half the RPM of F1, though the real limiting factor, piston speeds, not wildly different.

Specific torque per displacement is kind of a hard limit, in 4 stroke world at least, torque and volumetric efficiency correlate very well, naturally aspirated volumetric efficiency peaks around 125%, achieving that at 8000 rpm is one thing, achieving it 16-20,000rpm is another, and that is how small NA F1 engines made power, RPM.

If you can maintain your torque at 11000 rpm as opposed to 8500 rpm, well there is your 30% HP gain.

That all good points, maintaining torque at high rpm makes big hp! My banshee makes 60 lbs of torque at 440 cc that equates to 130lbs per liter n/a

 

[Bigmac]

"in most forms of motor sports torque under peak is the winner in the real world" - but don't forget the other part of the formula - 'power to the ground!'

Yep, that’s all in the setup! A more forgiving powerband is easier for most to control. I am an rpm nut, but love torque! I d-stoked my car motor to make it easier to hookup, and rpm better, so I get what your saying

 

[Bjorn]

Hallo. To maintaining torque at high rpm on a 2- stroke engine, the best way is to build a calculated expensioncamber/ pipe. I Will build a pipe for my CFB hybrid, this year. And When its finnished I Will put it on my youtube Chanel.

 

[Red97]

I was covered with chips working on that wood lol, anyway here's another picture of me with my precious 1200 42" and my ground guy with 084 30" because its a cry baby in hardwood and wont pull low raker chain [emoji23]
Here's the link 1200 running on moderately hardwood, rosewood tree

Yes you're right, 084 are rated at 5.8ftlbs. 1200 at 6.7ftlbs, the big difference in cutting power comes due to the lower rpm im guessing. Ported 395xp is my favourite in medium hard to soft wood, if thats what i deal with everyday I'll get rid of every other big saws in my stable no question. They're a joy to run, so smooth and fast. My 395 is ported in torquey way, 102,122,78. On a silky oak which is pretty soft for our standards lol, 395 ported handed 084 ass everyway and everytime. 1200 is useless in this environment because they lack the chain speed the other 2 has.

1200 has the best oiling capacity I've seen, they over oil 42" in lowest setting. Crank driven oiler which dumps alot oil in lowest setting, auto oiler can probably feed 60" with max setting easily. Manual oiler is overkill in any application, it will literally gush out oil through the clutch cover gap when pressed running 42". I had to cut a slot on my 42 bar oil hole to let it stay in the bar, the only reason im using the manual oiler is with use it or lose it mentality. To prevent rust and crud jamming up, otherwise they'll oil double power head mill setup single handedly

Yes 3/8 gets stretched out and thrashed too soon, they suit 395 and 084 alot but unfortunately the wood i deal with dont allow it. 404 are nice, they hold the edge and dont dull that quick, they hit a knot or grit and just dull 1 cutter and move on like nothing happened lol. On the other 3/8ths, if you hit something in our wood it'll be a long day [emoji28]

Sent from my INE-LX2r using Tapatalk

Sweet saw!

Have one that looks just like it, green and all....



I'm thinking you should just start growing softer wood.

Then the fast saws can play too.

I would be curious to know where most of the modern chain designs are from?

Seems the design is just not the greatest for what you, and others abroad cut.

I'm going to have to try and "turtle " port one someday

See if you really can make the tq at low rpm...

Interesting stuff to ponder

 

[00wyk]

Sweet saw!

Have one that looks just like it, green and all....



I'm thinking you should just start growing softer wood.

Then the fast saws can play too.

I would be curious to know where most of the modern chain designs are from?

Seems the design is just not the greatest for what you, and others abroad cut.

I'm going to have to try and "turtle " port one someday

See if you really can make the tq at low rpm...

Interesting stuff to ponder

We have wiring and nails etc in our wood on an estate that is hundreds of years old. I use semi chisel chain almost exclusively.
If I ask for it at the local shops, I get a blank stare most of the time. I order mine in bulk from:
https://www.chainsawbars.co.uk/

 

[00wyk]

Yep, that’s all in the setup! A more forgiving powerband is easier for most to control. I am an rpm nut, but love torque! I d-stoked my car motor to make it easier to hookup, and rpm better, so I get what your saying

A 'daily driver' in other words.

 

[Stump Shot]

Turtle Power!

 

[00wyk]

I agree with you, Deets, and Terry. Stock timing is meant to take advantage up to maybe 10.5k, maybe 11.5? I see a lot of dyno dipping in that region in the dyno numbers thread - check them out. I doubt much of it is resonance. I would wager timing(and fuel and air in some cases). The higher the RPM, the more timing, air, and fuel you need. The engineers likely assumed no one is going to be cutting with a stock saw at 12K RPM, and you sort of want the saw to four stroke fairly shortly after that for tuning whether MTronic or not, so may as well be conservative with the curve for safety reasons and let her load up there.

I am going to guess it’s timing, that’s how my banshee reacts on the dyno when I pull timing after peak hp

 

[MustangMike]

If your saw does not eat wood at higher RPMs, then change your chain set up.

 

[NightRogue]

If you saw does not eat wood at higher RPMs, then change your chain set up.

Agree completely but we're limited with sprocket/rim gearing option, you cant make 6 pin 404. That size wont fit the crank, 1200 pulls 404 like a diesel on power stroke. Gotta love the high torque low rpm in heavy duty applications

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[mgr1]

Echo cs 1200 is a 44mm stroke.
Want to see a solo rex or super rex with 54mm stroke on the dyno.

 

[RI Chevy]

Someone had a SOLO stroker that ran strong!

 

[00wyk]

Someone mentioned something about the difference timing can make on power. I couldn't find any easy charts, but from my background as a kid modifying old Fords and Chevy V8's, I knew what a difference timing can make. So I dragged up a power nation small block Chevy dyno run. They advance the timing from 28* to 37* and find another 53HP or so in timing alone:

That's supposed to start at 8:42 ish

And a simple video to explain to the newly initiated why the timing has to change:

 

[mgr1]

There is a project on a German site. A guy made a full adjustable Electronic ignition on a Stihl 4 stroke.

 

[Backtroller]

I was wondering where you could mount a MSD box on a saw or a FiTech on a 500i lol

 

[mgr1]

Stihl km130

 

[MustangMike]

I have another relevant Hybrid question for both CFB and DEETS (since our dyno is down and we need to keep this thread alive).

Are you guys running Stihl style double ring pistons, or Husky style single ring pistons that allow you to further open the Exhaust?