Stihl MS 461 has me confused on dyno test.

[blsnelling]

I gotta disagree. The variables may be so significant that they negate the benefits of measuring at all. False data is worse than no data. If the oil temp/dyno temp/humidity/whatever change the data enough, then it may tell you that the mods you made gained you power when in fact you lost power. There's something to be said for timing cuts in the same log.

As already pointed out, oil and dyno temp have no effect on how this dyno works. It's simply putting a consistent load on the engine at varied RPMs. That's something you can't do with a log. There are so many variables in timed cuts it's not even funny. Just sayin

 

[chadihman]

Really? Every time you start?

That sure sounds tedious

Yep it sure is. Very time consuming. Trust me I would love to have the $1400 system that would make things much faster but what I have works for now

 

[chadihman]

As already pointed out, oil and dyno temp have no effect on how this dyno works. It's simply putting a consistent load on the engine at varied RPMs. That's something you can't do with a log. There are so many variables in timed cuts it's not even funny. Just sayin

Yeah man! You got it. Preach it brother so I don't have to.

 

[blsnelling]

I'd love to see the dyno results of a stock 550XP, muffler modded, and then portedotstir::jester: I'd also love to see the dyno results of the mods I do on a 201T. The last timed cuts I did showed a 40% improvement! It would bre interesting to see the HP and Tq improvements.

 

[MarkEagleUSA]

I could have had a Cadillac but settled for a Chevy.

Settled for?... I'd much rather have a Chevy than a Caddy.

 

[MarkEagleUSA]

I'd love to see the dyno results of a stock 550XP, muffler modded, and then ported

I could be persuaded to forego the warranty on my 550 for the right offer! :msp_w00t:

 

[blsnelling]

I could be persuaded to forego the warranty on my 550 for the right offer! :msp_w00t:

I don't know how to port a 550, lol. I'll mod you're muffler for you In my experience, most of the gains on the 550 was from the MM. The porting didn't do a whole lot on mine. Others seem to have had better luck. All the same, the dyno results would be interesting:jester:

 

[chadihman]

Settled for?... I'd much rather have a Chevy than a Caddy.

Alright smarty pants you get my point:msp_biggrin:

 

[Justsaws]

I gotta disagree. The variables may be so significant that they negate the benefits of measuring at all. False data is worse than no data. If the oil temp/dyno temp/humidity/whatever change the data enough, then it may tell you that the mods you made gained you power when in fact you lost power. There's something to be said for timing cuts in the same log.

Chasing gremlins is best billed hourly. There will always be a variable to eliminate, before you know it a building has to be constructed so air conditions can be controlled, then a controlled fuel tank has to be installed, then a service contract for the CP fuel, good lord do not forget the random occurring harmonics now we need a new building, and so on and so on.

This person built himself a log that is more equal than any found in nature and removed the huge variables of human cutting technique and the cutting chain.

I would suspect that as things progress additional variables will get sorted but they will never be eliminated, until then I will enjoy reading the findings.

 

[LegDeLimber]

shoot fellers, i didn't meant sound like I flounced off.
The rain's been crazy here for bout 2 months now and it was time get out for that one clear afternoon.
Was back to the rain again on Sat. that pan and stitched pic is from my front yard
There's a row of field stone (under the water) I layed out to slow/deflect things a bit in that area.

 

[chadihman]

shoot fellers, i didn't meant sound like I flounced off.
The rain's been crazy here for bout 2 months now and it was time get out for that one clear afternoon.
Was back to the rain again on Sat. that pan and stitched pic is from my front yard
There's a row of field stone (under the water) I layed out to slow/deflect things a bit in that area.

Hope ya get some drier weather

 

[ernurse]

Sh#t I better throw this thing in the scrap pile. Could everyone please remember that I stated I could have had a Cadillac but settled for a Chevy. Also rember that I do all my tests against a base saw witch is my OEM 460. This gives me a baseline every time I start. The 460 changes some in power from day to day with weather changes but the 460 gives me the same #'s every time in a few hour test time. Sorry if that came out wrong. I just ask that you quit bashing my Chevy cause its not a Cadillac.

Man don't sweat it. You have something here that to my knowledge no one else on this forum has. Im thinking you're going to get plenty of "envy criticism" and people that don't want to hear that they just "tore up" their $1000 saw for no good reason. I might be a nobody on this forum but what you're doing is very interesting to me. I'm all about factual info and that's what you're giving us so thanks and keep on keepin on.

 

[chadihman]

I brought back the first video I made of this. It's had some changes so I'll try and make a new one. A laboring mm chainsaw is music to my ears. I took this with my phone so the sound isn't the best. Some day I'll have the dyno at a gtg and some of you fellas will get the thrill of there saw begging for mercy. I love cutting wood but this is just as fun. I had a crank bearing blow on my 460 on the dyno but no other problems so far. I'm pretty sure a lean running saw would be toast quickly.[video=youtube_share;VGpxVzkYU70]http://youtu.be/VGpxVzkYU70[/video]

 

[ernurse]

What is giving you numerical data. And what is the digital scale for? Torque?

 

[maico490]

What is giving you numerical data. And what is the digital scale for? Torque?

The scale measures the weight of the air resting on it just before the saw burns it. From this the power is calculated.:hmm3grin2orange:

It can also be recalibrated to measure how much the oil has heated up which is useful to people who don't understand how this dyno works

 

[jimrb]

What does the scale read? I mean units of measure as in grams or ounces? Is the scale know to be repeatable? I have a digital hanging scale and I swear that if I weigh something in the middle of the scales range, turn off the scale then back on and measure again the weight is not exactly the same using grams. I know some scales have a plus/minus 3% or other accuracy value. My digital people scale can flip flop between 165 and 165.5 which I guess can just be how much on the cusp I am between the two weights. Of course resolution not being very high on a cheap meat scale, I mean people floor scale.

 

[chadihman]

What is giving you numerical data. And what is the digital scale for? Torque?

Torque × rpm ÷ 5252 = HP. The digital scale reads the rotational torque from the hyd pump. My torque arm is 1.5ft so the pounds on the scale is multiplied by 1.5 and that's my torque. I have an rpm sensor picking up rpms from a magnet on the driven sprocket shaft. I place a load on the saw by turning the hyd flow valve closed. The further the flow valve is closed the harder it is for the saw to turn the pump. I record the rpm and scale reading from 11000-6500 rpms in 500 rpm increments. Then I use a calculator to figure out torque and HP.

 

[ernurse]

Thanks I get it now.

 

[chadihman]

What does the scale read? I mean units of measure as in grams or ounces? Is the scale know to be repeatable? I have a digital hanging scale and I swear that if I weigh something in the middle of the scales range, turn off the scale then back on and measure again the weight is not exactly the same using grams. I know some scales have a plus/minus 3% or other accuracy value. My digital people scale can flip flop between 165 and 165.5 which I guess can just be how much on the cusp I am between the two weights. Of course resolution not being very high on a cheap meat scale, I mean people floor scale.

Its a postal scale. Its resolution is .005. I zero the scale then pull the saw down through all the rpms and then release the load and the scale returns to near zero .05 is the worst.

 

[Jacob J.]

Does the dyno temp really matter? I do see the load decrease a little as the oil warms and flows easier through the flow valve but that doesn't matter because I just adjust the flow closed a little more to hold the saw at a steady loaded rpm.
I let the saws idle for a minute then pull them down to 8000 rpms for 30 seconds before testing. I really think I'm going to get the performance trends system as you suggested. An rpm sweep could be done in 10 seconds.

As long you're testing both saws under the same or similar conditions then the dyno temp shouldn't really matter. Just establish a baseline for your testing conditions and go from there.

Timber cutters here have noticed the same thing about the 461 that you have- the addition of a dual-port muffler or different air filter system doesn't really change the saw's median operating RPM or torque band. It's a bulldozer no matter how you set it up. Most are keeping the saw completely stock here. Porting is the one factor that really makes the operating characteristics of the 461 change.