What are specs really telling us? If anything!

[Johnmn]

I have been thing about this for a long time wondering how to word it and discuss it. So I'll just start rambling.
Without a dino sheet, shoot even with one what are hp specs from manufacturers really telling us?
Is there a chance that there are better clutch designs that are giving us more power to the bar???? Think about that!

The reason I bring all this up is I have tried and tested a lot of saws from new stuff to old stuff. But most of my saws have been late eighties and newer.
And what I have found is regardless of what the specs say we really haven't made any gains in power since the late eighties. If I had a YouTube account and better internet I would post some videos. I have shared some via text with @Dub11 . But I have 2 saws here that I'm quite fond of that are 20+ years old and keep up or beat most if not all modern saws on their class.
Saw 1 jonsered 630 super, I have had a 2159, several 6100's, 562's, 036's, 262's and others. And quite honestly it takes all of there lunch money and laugh's.
It's rated at 4.3 hp nothing low nothing high.
Saw 2 Jonsered 670 champ - I have had a 2172, 440 and 7300. Now in this class the 670 doesn't always win but it always right there! Rated at 4.9 hp it should be a bit behind but it's not!

Now I'm not looking to start any arguments just looking and wondering mostly about power delivery. Maybe we should be concerned more bout torque or something else? Not sure?
Now this whole topic would probably change once saws become ported. But I'm talking stock, well not completely.
All my saws get a muffler mod and timing advance!

 

[huskyboy]

What size bar are you using to compare? There will hardly be a difference between them all with a 20” bar.

 

[Loanstar]

It's kinda like fishing lures. 99% are made to catch people and maybe a few fish. It's all in the marketing. Peak #s sell. Real world use is always different.

 

[Johnmn]

20 inch bar in 24+ inch hardwood. But who runs a 28 inch bar on a 60cc saw?

 

[Al Smith]

If you look at old specs they are just like electric motors in the fact they "embellish" the rating regarding HP .For example an 80 CC Mac model super 44 at 6.5 Hp or a Sachs Dolmar 166 at 12 HP .Generally speaking on a two cycle it's a tad over 1 HP per cubic inch .
If you cut to the chase as a general rule saws within the same displacement unless they are old as the hills have about the same power output .Then it boils down to personal preferences not that one will cut an 8 inch cant one second faster than the other .

 

[RIDE-RED 350r]

And then there are saws of very similar displacement yet have a different bore and stroke arrangement for the given displacement which can and often does alter the power curve for better or worse.

 

[XP_Slinger]

Another variable is the rpm at which peak power is achieved. An old Mac is a much lower rpm saw than say a 288 or an even newer 372. I think the rpm where peak power resides makes all the difference even when the peak power number is the same.

 

[Johnmn]

Another variable is the rpm at which peak power is achieved. An old Mac is a much lower rpm saw than say a 288 or an even newer 372. I think the rpm where peak power resides makes all the difference even when the peak power number is the same.

That's one thing about my 630 it doesn't rev as quite as high as the new saws but it seems to hold more RPM in the wood!

 

[XP_Slinger]

That's one thing about my 630 it doesn't rev as quite as high as the new saws but it seems to hold more RPM in the wood!

Bingo. That’s exactly what I’m talking about. It’s not about piss rev rpm, it’s about where the engine holds its power under load. Now throw in the gearing and what not and you start to understand why some “underdogs” shine, even with an equal or lower “max power rating”.

 

[Dub11]

Thinking about that 630 vs everyone else, it probably the "biggest" out of the ones you listed. I have a crank for one of these on the bench. I'd like to know how much heavy it is compared to other 60cc saws.

 

[XP_Slinger]

All in all my opinion is that the extra hp of the bigger saws gives you the option to run longer bars on bigger wood. That’s it. All the saws have different optimum wood diameter that show off their hp. Take for instance a 346xp rated at 3.7hp and a 372 rated at 5.2. Put them both in 6” wood and the 346 will either beat or be neck and neck with the bigger saw. Now take the same two saws and cut 20” wood, the bigger saw will obviously stomp the little one even though they would be very close in small wood. Given this fact these two saws can’t be compared imo. Built for different work.

 

[Simondo]

I have been thing about this for a long time wondering how to word it and discuss it. So I'll just start rambling.
Without a dino sheet, shoot even with one what are hp specs from manufacturers really telling us?
Is there a chance that there are better clutch designs that are giving us more power to the bar???? Think about that!

The reason I bring all this up is I have tried and tested a lot of saws from new stuff to old stuff. But most of my saws have been late eighties and newer.
And what I have found is regardless of what the specs say we really haven't made any gains in power since the late eighties. If I had a YouTube account and better internet I would post some videos. I have shared some via text with @Dub11 . But I have 2 saws here that I'm quite fond of that are 20+ years old and keep up or beat most if not all modern saws on their class.
Saw 1 jonsered 630 super, I have had a 2159, several 6100's, 562's, 036's, 262's and others. And quite honestly it takes all of there lunch money and laugh's.
It's rated at 4.3 hp nothing low nothing high.
Saw 2 Jonsered 670 champ - I have had a 2172, 440 and 7300. Now in this class the 670 doesn't always win but it always right there! Rated at 4.9 hp it should be a bit behind but it's not!

Now I'm not looking to start any arguments just looking and wondering mostly about power delivery. Maybe we should be concerned more bout torque or something else? Not sure?
Now this whole topic would probably change once saws become ported. But I'm talking stock, well not completely.
All my saws get a muffler mod and timing advance!

I think some consideration needs to be given to the regulations the saws back in the 1980's and the current crop of saws have to comply with.
2 stroke motors have to do much better on fuel than some in the past did and needed to , plus the emission standards are vastly different. The output of a modern saw could be looked at as having to do "well on less" than in the past.
50cc is 50cc back then and now, so given the basic constraints of the design for a production item and having to keep within much tighter controls , also, still try and keep a compact and competitive weight.
Its not as if you just can just follow some of the automotive methods to gain power pro rata of CC of a engine and really , approx 4.0 hp from 50 cc isn't so bad a average and was a little less on average back in the 1980's.
Saws have had many nice changes over the yrs to make them more user friendly , proper matching of chain and bar to the saw and using that saw for what its designed to be cutting , then there should be no real issue.

 

[redline4]

Thinking about that 630 vs everyone else, it probably the "biggest" out of the ones you listed. I have a crank for one of these on the bench. I'd like to know how much heavy it is compared to other 60cc saws.

Crappy old analog scale, J-red 630 super, 18" bar and chain. Not sure how much fuel/oil, but theres some. Shows about 17ish lbs.

 

[huskyboy]

“Specs” say about a 1/2 lb heavier dry pho than most 60cc saws. 630 is really a 70cc chassis with a smaller bore topend. Like a 365/372 or 6400/7900.

 

[longleaf]

I don’t pay any attention to hp. I may get some flack on this one but I think there are some people who will back me up. I have a ported 620p and my friend has a ported 562 same porter. If you run a out of the box 20” chain the 562 maybe faster? Can’t tell without a watch. More rpm and more hp according to specs. Start filing the rakers down or putting 24-28” bars on the the 620 is the clear winner. Not talking handling weight side ways balance, blah blah blah. Expose the torque and the 620 wins.

 

[Dub11]

I don’t pay any attention to hp. I may get some flack on this one but I think there are some people who will back me up. I have a ported 620p and my friend has a ported 562 same porter. If you run a out of the box 20” chain the 562 maybe faster? Can’t tell without a watch. More rpm and more hp according to specs. Start filing the rakers down or putting 24-28” bars on the the 620 is the clear winner. Not talking handling weight side ways balance, blah blah blah. Expose the torque and the 620 wins.

I believe that, the 562 has crank stuffers that's for higher revs,

 

[XP_Slinger]

I don’t pay any attention to hp. I may get some flack on this one but I think there are some people who will back me up. I have a ported 620p and my friend has a ported 562 same porter. If you run a out of the box 20” chain the 562 maybe faster? Can’t tell without a watch. More rpm and more hp according to specs. Start filing the rakers down or putting 24-28” bars on the the 620 is the clear winner. Not talking handling weight side ways balance, blah blah blah. Expose the torque and the 620 wins.

I’m with you on this. I file hp #’s away as “nice to know” but other than that dot dot dot

 

[drf256]

HP is a mathematically derived number. It’s torque x rpm / 5252. That’s why curves, if they aren’t BS, will always cross at 5252 on a Dyno curve chart.

That gives the OEM leeway to advertise things how they want to without it being false.

Case in point, the 1969 L88 427 Chevy. They rated it at something like 430HP at 5000 rpm. They rated the Tipower motor at 435HP at 6500 rpm to dissuade the public from buying the race motor and to trick the auto insurers. The L88 was making 550Hp at 7000 rpm, but it was “only” 430 @ 5000.

Torque is what matters to me in a firewood saw, which is all I build. HP is a byproduct. I want “lean on power”.

 

[XP_Slinger]

HP is a mathematically derived number. It’s torque x rpm / 5252. That’s why curves, if they aren’t BS, will always cross at 5252 on a Dyno curve chart.

That gives the OEM leeway to advertise things how they want to without it being false.

Case in point, the 1969 L88 427 Chevy. They rated it at something like 430HP at 5000 rpm. They rated the Tipower motor at 435HP at 6500 rpm to dissuade the public from buying the race motor and to trick the auto insurers. The L88 was making 550Hp at 7000 rpm, but it was “only” 430 @ 5000.

Torque is what matters to me in a firewood saw, which is all I build. HP is a byproduct. I want “lean on power”.

Same here Doc, I don’t want a peaky power curve that falls on its face if you push it a little.

Great example using the l88

 

[longleaf]

HP is a mathematically derived number. It’s torque x rpm / 5252. That’s why curves, if they aren’t BS, will always cross at 5252 on a Dyno curve chart.

That gives the OEM leeway to advertise things how they want to without it being false.

Case in point, the 1969 L88 427 Chevy. They rated it at something like 430HP at 5000 rpm. They rated the Tipower motor at 435HP at 6500 rpm to dissuade the public from buying the race motor and to trick the auto insurers. The L88 was making 550Hp at 7000 rpm, but it was “only” 430 @ 5000.

Torque is what matters to me in a firewood saw, which is all I build. HP is a byproduct. I want “lean on power”.

Thanks that’s a good explication. That explains why steam engines had very little hp and torque was in the holy chit range.