"New" 70cc class saws... Dyno day

[Red97]

Ran all the saws today...

In this order
572xp
7310p
7900
500i
462


Some showed up, some were lacking.

This is a comparison..... Hp/tq are what were measured today. Every saw had 6 pulls made, and the avg run was selected for display.

All runs were corrected to the same temperature/humidity.

If someone wants to enlarge the pics/legend feel free.

The pic's with the table of numbers show peak hp/tq with the "PK" next to them. Saw model is at the top of the column.

All saws had less than 3 tanks through to begin with

 

[farmguywithasaw]

The 500i sure has it down low. I wonder if the computer is the reason it drops off so steep like that in the higher rpms

 

[toadman]

I would have put the 7900 much lower on both number vs. 462, having both, but it's good to see actual numbers!

 

[Andyshine77]

I would have put the 7900 much lower on both number vs. 462, having both, but it's good to see actual numbers!

The power of the 7900 was always deceving, and the older ones were stronger and smoother. Red setup the saw as close to an old 7900 as it could be. My old school 7900 is just a hair behind my 500i. And even than each saw will always run different than the next. Too bad the EPA killed the 7900, and now Makita is killing it for real come 2022.

 

[mountainlake]

For all you (my saw runs 12000 rpm in the cut bs guys) look what happens to the HP at 12000 RPM and torque is even worse. Nice job Red. Steve

 

[toadman]

The power of the 7900 was always deceving, and the older ones were stronger and smoother. Red setup the saw as close to an old 7900 as it could be. My old school 7900 is just a hair behind my 500i. And even than each saw will always run different than the next. Too bad the EPA killed the 7900, and now Makita is killing it for real come 2022.

I do appreciate the oiler on the 7900, it oils a 32" just fine, and also the very solid feel in hand.
Feels Strong & robust, and what little I have taken it apart I have been favorably impressed with the build quality.
whereas the 462 is light enough I catch myself treating it much more gently than my other heavier saws.
I am not rough on my stuff, or try not to be.
**** happens though, and my help often don't give a crap about the tools.
the 462 is deceptively light for the power.
It actually is lighter, and handles lighter with a 25" es light than my 291 with a standard 20".
the 500i I hefted in a store made the same impression, lighter than most of my older 50-60cc saws.
If it holds up well, I will buy one in a couple years just for novelty

Interesting where the new echo fell.
I have not seen it in person, but I know a friend who has one brand new for his farm & he Is extremely happy with the power & handling!

My echos have all taken a very long period to break in.

more so than any other besides my 661, which still feels like it's gaining 80+ gallons of fuel later, but slowly enough I would not have noticed it without a comparison to my 394.
The 394 used to smoke the 661 for torque, and I don't know what's changed but I can dog the 661 far harder now with the 8 pin than I could when it was new & it pulls the same chain harder low end than the 394 did when I drug it out as of yesterday.
so that's a small factor here as well

 

[mountainlake]

My Echo CS500P took a long time to break in also , as it came with a clogged up muffler, tuning was good and not broke in it was a dog. Now it cuts good. How clogged up s the muff on the 7310. Steve

 

[cuinrearview]

For all you (my saw runs 12000 rpm in the cut bs guys) look what happens to the HP at 12000 RPM and torque is even worse. Nice job Red. Steve

I don't think the guys saying that are running box stock saws, and the chain setup to achieve this is a whole other box of variables that a dyno takes out.

 

[Red97]

The 500i sure has it down low. I wonder if the computer is the reason it drops off so steep like that in the higher rpms

That drop off is where the saw was 4 stroking and not cleaned up. I'm sure with some more time it will be 13k range like it should be.

My Echo CS500P took a long time to break in also , as it came with a clogged up muffler, tuning was good and not broke in it was a dog. Now it cuts good. How clogged up s the muff on the 7310. Steve

7310 is an open can.

Was rather disappointed with its showing. But tis the way it goes sometimes.

 

[holeycow]

Well, too bad that the Echo isn't really in the mix. Huh. It's not even close by the numbers.

 

[Red97]

Well, too bad that the Echo isn't really in the mix. Huh. It's not even close by the numbers.

It is 25% ish behind in hp tq is close. But nothing to wow.

I'm going to guess it gains better than the rest with porting and all will be very close once ported.

 

[Red97]

Here is a pic of my dyno setup.

 

[holeycow]

the Echo's curves look like it has very good power characteristics ie, the torque hangs in there as the power builds. It just needs a little more. Echo needs to apply themselves. Why would they go through all the trouble to arrive at the bottom? It makes no sense.

Anyway, that is an awesome test!!

 

[Red97]

the Echo's curves look like it has very good power characteristics ie, the torque hangs in there as the power builds. It just needs a little more. Echo needs to apply themselves. Why would they go through all the trouble to arrive at the bottom? It makes no sense.

Anyway, that is an awesome test!!

Well it is lighter and more power than the old sc800 they offered...

 

[sean donato]

Id really like to see this line up after the saws have about 10 tanks through them. From what I've been seeing the 572xp doesnt come Into it's own before that mark, I'd imagine its much the same on the other saws. I know that can be a tough metric to go buy, but I think it would correlate well to your testing. Very nice to see the numbers side by side. Thanks for posting them up!

 

[cuinrearview]

Id really like to see this line up after the saws have about 10 tanks through them. From what I've been seeing the 572xp doesnt come Into it's own before that mark, I'd imagine its much the same on the other saws. I know that can be a tough metric to go buy, but I think it would correlate well to your testing. Very nice to see the numbers side by side. Thanks for posting them up!

Joe offers dyno services for anyone wanting to have their saw ran. You can break it in any way you want.

 

[mountainlake]

That drop off is where the saw was 4 stroking and not cleaned up. I'm sure with some more time it will be 13k range like it should be.



7310 is an open can.

Was rather disappointed with its showing. But tis the way it goes sometimes.

Is the outlet clogged up like the 590 600 620 and 500p. Seems like lately Echo been making the muffs to open up easy. Steve

 

[PV Hiker]

@Red97 Help me understand your setup... Is the dyno putting a load on the sprocket like loading it in a cut? Or are you just testing no load? Are you able to put a resistance to measure how a saw does with a load on it?

 

[Andyshine77]

the Echo's curves look like it has very good power characteristics ie, the torque hangs in there as the power builds. It just needs a little more. Echo needs to apply themselves. Why would they go through all the trouble to arrive at the bottom? It makes no sense.

Anyway, that is an awesome test!!

They simply don't have the technology in the saw to meet emissions, so sacrifices are going to be made.

 

[Red97]

@Red97 Help me understand your setup... Is the dyno putting a load on the sprocket like loading it in a cut? Or are you just testing no load? Are you able to put a resistance to measure how a saw does with a load on it?

High rpm no load, slowly add load. Pull each saw down to 5k rpm. Could stall the chain if I wanted.