I call B.S. on Stihl. My dyno doesn't lie. MS 461 is king over MS 660

[chadihman]

I did a bunch of dyno testing lately using my stock 461 as a base saw for 660 testing. I'm testing some modifications on a brand new 660. My 461 is broken in and the 660 was broken in on the dyno with two tanks run through it. Both saws are running 91 octane ethanol free gas mixed 40:1 out of the same can. the first test I had a 7 pin on the 461 and the 660 had an 8pin sprocket. I tested both saws and did the calculations for the ratio difference. I was amazed that the 461 was putting the 660 to shame. I got to thinking that maybe the 8 pin on the 660 was a disadvantage as the chain speed and shaft speed may have caused more drag.

The next test I ran an 8 pin sprocket on both saws and carefully checked the chain tension was slightly sagging on both saws when I attached them to the dyno. Again the 461 spanked the 660 through most of the rpms. The 461 max hp was at 9000 rpms and the 660 at 8500 rpms. The 461 had max torque at 6500 rpms and the 660 at 7000 rpms.

The 461 was 3.3% stronger at 10000 rpms, 3.3% stronger at 9500 rpms, 3.6% stronger at 9000 rpms, 2% stronger at 8500 rpms and 1.8% stronger at 8000 rpms. The 461 and the 660 were dead even at 7500 rpms then finally the 660 had a 3.7% gain at 7000 rpms and a 2% gain at 6500 rpms.

I now know why I sold my 660. My 461 runs a 36" bar well. How is Stihl getting there Hp #'s. I'm going to get the stock port timing #'s, squish and compression before I tear it down to see if there's something ailing this 660. Lets hope the 661 is much stronger than the 660 cause I dont see need for the 660 with the 461 over powering it through all the useable rpms.

 

[bryanr2]

opcorn:

 

[bryanr2]

In the opening sentences you said "your 461 is broken in and the 660 was broken in on the dyno with 2 tanks thru it" How many tanks do you have thru the 461? I wouldnt think a saw would be broken in with 2 tanks. Maybe 10-15.

 

[chadihman]

In the opening sentences you said "your 461 is broken in and the 660 was broken in on the dyno with 2 tanks thru it" How many tanks do you have thru the 461? I wouldnt think a saw would be broken in with 2 tanks. Maybe 10-15.

Yeah My 461 might have 20 tanks through it. I ran the 660 hard through two tanks. I pulled it down hard through a range of rpms and then letting it cool down before giving it a workout again. I'm no master at breaking a saw in but my guessing is that the hard workout on the dyno on two tanks is worth more than 5 tanks in wood.

 

[cutforfun]

Go cut some wood!! 30" or larger and see what saw has more power?

 

[weedkilla]

So glad to hear the dyno is running again. Hope to see you inundated with saws shortly!
I'm sure this thread will disintegrate as quickly as the previous ones as your data disagrees with what people would like to believe. The rest of us commend what you have done and eagerly await more tests.

 

[treesmith]

I never thought I'd give a dislike but you just made my 660 cry...

 

[cgraham1]

I'm sure this thread will disintegrate as quickly as the previous ones as your data disagrees with what [most] people would like to believe.

Let's hope that people will keep an open mind this time.

opcorn:

 

[MustangMike]

I won't say it was fair comparison, but my 044 recently out cut a 066, both with 24" bars. My 044 has a dual port muffler (the 066 just had 2 small holes added), a K&N air filter, and square file chain, so it was not a even comparison. I was still surprised that the 044 was cutting noticeably faster. Not sure how sharp the chain was on the 066, but the owner is a pro.

 

[KenJax Tree]

i bought a 660 a few years ago and ran 2 tanks through it and hated it so i sold it and bought a 390xp and never looked back.

 

[KenJax Tree]

I won't say it was fair comparison, but my 044 recently out cut a 066, both with 24" bars. My 044 has a dual port muffler (the 066 just had 2 small holes added), a K&N air filter, and square file chain, so it was not a even comparison. I was still surprised that the 044 was cutting noticeably faster. Not sure how sharp the chain was on the 066, but the owner is a pro.

Mike were both bars buried in 24"+ wood? My 562xp will cut faster than my 372xp with 20" bars until they're buried then the 372's torque wins.

 

[treesmith]

I'm quite partial to my mate's 390xp, it's completely stock and runs a 36" pretty well in dead Aussie hardwood

 

[wyk]

So the next step is to put 36" bars on both and put them in 3'+ wood...?

 

[Streblerm]

I know it isn't a 660 but I was initially unimpressed when I got my 394. I was running against a 70cc saw and sharing a 24" bar and chain. I was thinking why would I want to lug around all this weight for a saw that cuts the same or maybe a touch slower? When I finally got a 34" bar and buried it in some hardwood I began to understand what the 394 was all about.

 

[weedkilla]

So the next step is to put 36" bars on both and put them in 3'+ wood...?

Kind of - but only to show what revs each saw is happiest pulling in the cut, so we have a better idea what part of the power curve is relevant. Probably 8500-9500 is my guess. If they bog down to below 7000 then the advantages of the 660 will be evident. In a cookie cut situation I don't see why they would, in the real world it will happen. Cutting won't show anything that the dyno won't - but the two are required together to get the full picture.

Then it just comes down to reading the data that is produced by a dyno and having a good knowledge of the revs your saw actually works at in a cut. Tachos and dynos go together as tuning tools - irrespective of the engine type.

 

[chadihman]

So the next step is to put 36" bars on both and put them in 3'+ wood...?

I'll do that test if I can find a 3 ft log. I'd bet my paycheck that the 461 would still win. This to me this is a clear win for the 461. The 461 had more torque from 10,000 all the way down to 7500 rpms. The 660 has a little more torque below 7500 rpms so it would be a little more resistant to stalling out if it grabbed or was pushed to hard in the wood. How often is a saw bogged down to 7000 rpms or below? I'm still in shock that the 660 fell short from 10,000 to 8,000 rpms. There even at 7500 rpms but the 660 was only 3% stronger from 7000-6500 rpms.

 

[weedkilla]

Chadihman, have you seen the kwf/dlg tests for these saws? Do you know if the us versions of these saws are the same as the euro ones?

Does anyone know how those tests are conducted? Ie- multiple saws sampled, one saw supplied by the manufacturer that may be a little more carefully prepped than normal, random pick from the warehouse.......?

 

[Duane(Pa)]

I'm in. I like a good showdown........ and fumes

 

[chadihman]

Kind of - but only to show what revs each saw is happiest pulling in the cut, so we have a better idea what part of the power curve is relevant. Probably 8500-9500 is my guess. If they bog down to below 7000 then the advantages of the 660 will be evident. In a cookie cut situation I don't see why they would, in the real world it will happen. Cutting won't show anything that the dyno won't - but the two are required together to get the full picture.

Then it just comes down to reading the data that is produced by a dyno and having a good knowledge of the revs your saw actually works at in a cut. Tachos and dynos go together as tuning tools - irrespective of the engine type.

You beat me to it. Yep most saws run 8500-9500 rpms in the wood so the 461 will win if the saws never drop below 7500 rpms. The 660 is only 3% stronger at 7000 rpms and 6500 is getting really close to clutch slippage.

 

[chadihman]

I have to do a wood test soon as this 660 is getting a mod soon then it's onto more testing. I have some 30-36" english walnut rounds I could cut some cookies out of. I have a 36" bar and a bunch of loops of new loops of RSC and A bunch of square ground chain. I'll place a tach in view of the video camera so you guys can see the rpm in the cut. Tomorrow I'll have a couple hours free to do some wood tests.