Stihl 461 vs 660 videos - 20" 24" 28" 32"

Arborist Forum

Help Support Arborist Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

redbull660

Addicted to ArboristSite
Joined
Oct 9, 2013
Messages
1,393
Reaction score
3,631
Location
Wisconsin
here are some detailed tests I did between the 461 and 660.

461 - ended up with a 3x ported muffler. I actually tested this out against other setups and it was the fastest. I also took out the limiter tabs and was able to extract some more power going richer. I have it as good as I think I can get it with out other mods like porting etc.

660 - during the tests I switched muff mod combos. But I still haven't settled on one particular muffler mod yet. Limit tabs were not removed as I still had room. So I guess I feel like the saw might have more to go yet on the muff mods.

Both saws are R version with HO oiler.

24 28 32 vids will be a few posts down after this 20" post.
--------------------------------------------------------------------

20" bar - both saws share a slightly used (2 test cuts) Stihl RS chain & also a slightly used (2 test cuts) Stihl RSLH (sq. grd half skip) chain. 461 did cuts first then

1st 461 with RS chain
cut 1 oak log#1 - 10.7
cut 2 oak log#2-10.5
cut 3 cherry - 18.6

then 660 with same RS chain
cut 1 oak log #1 - 8.7 sec
cut 2 oak log#2 - 10.4 sec
cut 3 cherry - 16.7 sec

I did the cuts this way so the first cut would make sure the saw was warmed up (although I already warmed up the saw prior to cut 1) and also so the wood didn't change to skew results.

Next 461 with RSLH chain
cut 1 oak log #1 - 10.4
cut 2 oak log #2 - 11.6
cut 3 cherry - 18.3


then 660 with same RSLH chain
cut 1 oak log #1 - 9.6
cut 2 oak log #2 - 10.9
cut 3 cherry - 17.4





- 660 did beat 461 with both chains. Considering it went 2nd I give it a little extra applause.
- RSLH was about the same as RS with the 461.
- RSLH was slower than RS with the 660.

Over all I would say the 660 had a little more speed, but a lot more torque than the 461 with the 20" bar.
 
24" - 2 new rs chains and 2 new rslh chains for 461 and 660. 3 pieces of wood.

small oak
461 new rs - 9.8
660 new rs - 9.5

says "small oak" but it should read "bigger oak"
461 new rs - 13.9
660 new rs - 12.6

cherry
461 new rs - 36.4 sec
660 new rs - 32.4 sec

next, RSLH chains

small oak
461 new rslh - 12.1
660 new rslh - 9.6

bigger oak
461 new rslh - 15.8
660 new rslh - 13.2

cherry
461 new rslh - 38.6
660 new rslh - 33.7



- 660 was faster again then 461. Even when using the slower RSLH chain, 660 was still faster than 461 with RS chain.

- RSLH was a little slower than RS on the 461.
- RSLH was slower than RS with the 660.

Over all I would say the 660 had more speed, but a lot more torque than the 461 with the 24" bar. It also didn't get stuck nearly as bad as the 461 in the cherry.
 
28" - 2 new rs chains and 2 new rslh chains for 461 and 660. 1 piece of oak and 1 piece of cherry

oak
461 new rs - 17.5
660 new rs - 15.7

cherry
461 new rs - 25.8
660 new rs - 23.8

Jug/Cyl Temp Check


tip - same at 90 degrees
bar - same at 120 degrees

Jug 461 - 287 F degrees avg.
Jug 660 - 260 F degrees avg.


next, RSLH chains

oak
461 new rslh - 17.4
660 new rslh - 16.9

cherry
461 new rslh - 27.0
660 new rslh - 25.5





- 660 faster than 461. Not by much. This is my favorite length bar for both saws. Seems to be the sweet spot for both. Although I could argue for the 24" on the 461 as well.

- RSLH again slower than RS.

- again I would say the 660 has a bit more speed but still quite a bit more torque at 28".

- very interesting the 660 jug/cyl temp was 27 degrees cooler after the same cuts as the 461. wish I would have done this in the other vids. :(
 
32" - 2 new RSLH chains and they share a slightly used RS chain with 461 going first and 660 using RS chain 2nd.

oak
461 rslh - 11.5
660 rslh - 9.7


Bigger oak
461 rslh - 20.5
660 rslh - 18.1

Cherry
461 rslh - 45.1
660 rslh - 40.4


RS chain up next 461 first

oak
461 rs - 11.1
660 rs - 9.6

Bigger Oak
461 rs - 21.0
660 rs - 19.1




again 660 faster than 461.

660 bit more speed and for sure more torque

Seems to be more advantage to using the half skip on the longer bar.
 
More thoughts between the two saws -

- I almost want to say that the 461 seemed to have more trouble with RSLH chains as the stihl square ground has a more blunt edge at 20 degrees vs RS at 30 degrees. I would think this would require more torque to pull the chain through this hard wood.

- fuel mileage - 461 was probably a little better, but the tank is smaller so you still have to fill up just as often as the 660.

- weight w/ light bars - 20" 461 not as ass end heavy, 24" both pretty close, 28" again pretty close, 32" 461 a bit more front heavy.

- cutting with the two... I would have to say that the 660 made what felt like a dull chain on the 461, feel sharp again. It just does better with a duller chain, I am guessing because it has the torque to pull it through where the 461 seems to rely more on chain speed. cont...

So the sharper the chain, the closer the 461 gets to the 660. And as the chain dulls the 660 pulls away from the 461.

Overall I would say this -

In ideal conditions (like cutting cookies with sharp chains) the two saws are very close in speed.
In less than ideal conditions, the torque of the 660 makes it really shine over the 461.


as far as RSLH vs RS. I've worked with RSLF (square full skip) and it's really fast but it seems to dull quite a bit faster than RS, at least in the wood I was using it on. I found this to be the case with RSLH (square half skip) as well. I would have to say the 20 & 90 degree angles work against it (more blunt than RS at 30 degrees). I'm sure it has it's place in some type of wood. But I have yet to figure out what it is.

That said, I'd have to say an RS half skip (not currently made by stihl) would be awesome! note: I have since started experimenting with grinding off every 3rd cutter and took a chain apart and put it back together as half skip RS....tests to come.

Probably forgetting something so if you have questions just let me know!
 
Nice videos, makes me wonder how well a stock MS460 would keep up with an 066 Magnum with 28-32" bars...
 
I cant even see the videos, just a grey circle with an exclamation point on the post:cry:
 
More thoughts between the two saws
That said, I'd have to say an RS half skip (not currently made by stihl) would be awesome! note: I have since started experimenting with grinding off every 3rd cutter and took a chain apart and put it back together as half skip RS....tests to come.

Probably forgetting something so if you have questions just let me know!

If I were you I would just grind the half skip Square on a regular round grinder and make your own RS half skip. It's easy enough to do. I do this with .404 stihl chain as you cannot get the sequence I want in round ground, only square. I usually run it till it's dull and then regrind it round. It seems sacrilegious to grind a new chain so that's why I run them once first.

-AJ

Awesome thread btw!
 
If I were you I would just grind the half skip Square on a regular round grinder and make your own RS half skip. It's easy enough to do. I do this with .404 stihl chain as you cannot get the sequence I want in round ground, only square. I usually run it till it's dull and then regrind it round. It seems sacrilegious to grind a new chain so that's why I run them once first.

-AJ

Awesome thread btw!


thanks.

yep, done that as well. resharpened just isn't quite the same as factory. I want apples to apples sharp chain.

My next test is going to be 660 w/ 28" tsumura 3/8 .063 bar vs 28" tsumura 404 .063 bar. (i have both bars ready to go) Using RS and half skip RS in oak and cherry. So...

3/8 91dl RS
vs
404 83dl RS
vs
3/8 91dl RS "H" half skip - every 3rd tooth ground off - chain is done
vs
404 83dl RS "H" half skip - every 3rd tooth ground off - not quite done yet.
 
Thanks for providing the excellent information. Been missing not seeing any dyno results for a while.

For bars 24" & under I think the skip chain is a handicap. RSLK/RSL w/o any skip out cuts RS on my 20 & 24" bars. I use it on all my saws. (I got one roll that says RSLK and one that just says RSL and I can't see any difference).

What muffler mods did U make to the 660? Did U remove the baffle? The dyno tests showed a big improvement from removing the baffle and adding the dp cover.
 
The 660 had about 3/4 of the baffle face plate removed so exhaust could more easily flow out. I actually angled/bent the other 1/4 of it to direct the airflow at the hole/opening in the dp cover. Along with the stock port. I made a .375 x .6 hole on the opposite side to create a 3x port. That is my 3x port for the 660.

I think I also used in a couple of the above vids a 066 mag copy - which would be a stock rear half with full baffle intact (NOT cut out in any way) + .65" dia hole (I opened up the .375 stock port) + dp cover. This is how the 066 mag was.

After seeing how the 461 performed with baffle intact, and then learning the 066 mag specs I have just recently decided that it may be more beneficial to just leave the baffle alone in the 660.

Apparently with these two saws (could be different with other stihls or other saws) back pressure is needed. My experience doing all this has lead me to the following...

you can get back pressure from either
1. the baffle
2. exit port restriction

So if you leave the baffle alone you can open up the exit ports larger.
OR
if you take the baffle out you have to leave the exit ports smaller. ie. restriction.


Personally, I believe that stihl with the old 066 Mag had things pretty well maxed out and this was prior to the epa bs. Copying those specs seems to be the most sensible thing to do.

The only way to truly find out is to do some tests.

my idea for a tests would be the following

stock - set a baseline
vs
stock rear + dp cover
vs
stock rear with .65" port + dp cover
vs
rear half no baffle with .65" port + dp cover
vs
a modified idea i have lol - stock rear half with .75" port on one side and .75" port on the other + stock cover. my theory is that you might get better directional flow. But to equal the square surface area of a 066 mag copy ie. .65 port + dp cover you need 2 .80" dia holes on each side.

here is the math..

066 mag -

.65" dia hole = .65 / 2 = radius or .325" surface area = pi r 2 so .325 x .325 = .105625 x pi or 3.14 = .3316" 2
dp cover = is a simpler calc it's approx 1.28 x .5 = .64"2

so total exit port surface area of the 066 mag = .64 + .3316 = ~.97"2


my double side port at .75" each = .75/2 = .375 .375x.375 = .10625x3.14 .441"2 soo .441 +.441 = .882"2 but if you make them .80" each then surface area grows to 1.00"2 So somewhere between .75" and .80" each.


that said - the way I had the baffle cut seemed to produce a lot of power. It's tough to say if the above would beat or not.


I think if I were to do it again I'd do the 3x port cuz it looks cool, sounds awesome, and is really fast. I'd just do the holes so my surface area came up to the same spec as the 066 mag.

So that would be stock port re-drilled with a 7/16 bit and then other side 7/16th bit used to make port. Then add DP cover.

dp cover = .64"2
7/16 = .4375 /2 = .21875 x .21875 = .04785 x 3.14 = .150"2 per side so...

.15 + .15 +.64 = .94 066 mag was. 97 soo if you gave the 7/16 holes a very slight angle you'd have it. :) how is that for splitting hairs!
 
The 660 had about 3/4 of the baffle face plate removed so exhaust could more easily flow out. I actually angled/bent the other 1/4 of it to direct the airflow at the hole/opening in the dp cover. Along with the stock port. I made a .375 x .6 hole on the opposite side to create a 3x port. That is my 3x port for the 660.

I think I also used in a couple of the above vids a 066 mag copy - which would be a stock rear half with full baffle intact (NOT cut out in any way) + .65" dia hole (I opened up the .375 stock port) + dp cover. This is how the 066 mag was.

After seeing how the 461 performed with baffle intact, and then learning the 066 mag specs I have just recently decided that it may be more beneficial to just leave the baffle alone in the 660.

Apparently with these two saws (could be different with other stihls or other saws) back pressure is needed. My experience doing all this has lead me to the following...

you can get back pressure from either
1. the baffle
2. exit port restriction

So if you leave the baffle alone you can open up the exit ports larger.
OR
if you take the baffle out you have to leave the exit ports smaller. ie. restriction.


Personally, I believe that stihl with the old 066 Mag had things pretty well maxed out and this was prior to the epa bs. Copying those specs seems to be the most sensible thing to do.

The only way to truly find out is to do some tests.

my idea for a tests would be the following

stock - set a baseline
vs
stock rear + dp cover
vs
stock rear with .65" port + dp cover
vs
rear half no baffle with .65" port + dp cover
vs
a modified idea i have lol - stock rear half with .75" port on one side and .75" port on the other + stock cover. my theory is that you might get better directional flow. But to equal the square surface area of a 066 mag copy ie. .65 port + dp cover you need 2 .80" dia holes on each side.

here is the math..

066 mag -

.65" dia hole = .65 / 2 = radius or .325" surface area = pi r 2 so .325 x .325 = .105625 x pi or 3.14 = .3316" 2
dp cover = is a simpler calc it's approx 1.28 x .5 = .64"2

so total exit port surface area of the 066 mag = .64 + .3316 = ~.97"2


my double side port at .75" each = .75/2 = .375 .375x.375 = .10625x3.14 .441"2 soo .441 +.441 = .882"2 but if you make them .80" each then surface area grows to 1.00"2 So somewhere between .75" and .80" each.


that said - the way I had the baffle cut seemed to produce a lot of power. It's tough to say if the above would beat or not.


I think if I were to do it again I'd do the 3x port cuz it looks cool, sounds awesome, and is really fast. I'd just do the holes so my surface area came up to the same spec as the 066 mag.

So that would be stock port re-drilled with a 7/16 bit and then other side 7/16th bit used to make port. Then add DP cover.

dp cover = .64"2
7/16 = .4375 /2 = .21875 x .21875 = .04785 x 3.14 = .150"2 per side so...

.15 + .15 +.64 = .94 066 mag was. 97 soo if you gave the 7/16 holes a very slight angle you'd have it. :) how is that for splitting hairs!
Good lord that hurt my head.
 
K is klassic. The biggest tell tale is the rakers.

I know, but I did not see any difference, and the website is not consistent with listing them both, sometimes I see one, then I see the other. I think they started making them both the same. Like RSC became RS, even though the old RS had a different raker.
 
Thanks for all the great info, I was doing all those calculations when I was trying to determine how much to port my saws.

I also came up with formulas to tell you how much to remove from the key to advance UR timing, as I don't have a degree wheel.

Now that U let the saw breath better, U may wish to play with the timing. Maybe with a timing advance, that baffle will not be as important.
 
that very well could be. I know Mastermind removes the baffles from the 461 & 660s and from what I can tell doesn't have the problems I faced when I removed the baffle...which is: erratic idle and sucks gas.
 
Back
Top