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

[chadihman]

I build saws that make torque. I don't look for additional unloaded RPM at all.

My reasoning is that by making more power.....the engine will hold more RPM in the cut. At about 10,500 - 11,000 RPM.

Now, here's the thing. My engines don't do well in cant races....even with taller gearing. Discuss

I made a quick graph to show my opinion of a kick azz saw. Saw 1 will have its max hp at 14000 rpms and it it gains torque slowly but the torque doesn't drop off till its at 7000 rpms. Saw 2 has more torque at 8000 rpms and below but its not a good useable rpm. Saw 1 wins. Make the torque up at high rpms and make it hold onto the torque in useable rpms and it will kick azz.

Just my .02
Discuss.

 

[redfin]

Its all fluff but show me a strait line across that graph. That's the saw I want.

Oh wait they make those but then you get all tangled in cords and stuffs.

 

[Haywire Haywood]

Its all fluff but show me a strait line across that graph. That's the saw I want.

Oh wait they make those but then you get all tangled in cords and stuffs.

Go solar... just need a 10 gallon hat with solar panels on the brim.

 

[Haywire Haywood]

Sure, I can at least try to help you.

First, torque by itself means NOTHING! For example, consider a torque wrench 1 foot long mounted horizontally where you hang a 10# weight at the end of the bar. The other end of the bar is fixed and cannot move! At the point where the bar is fixed, there will be a force (TORQUE) of 10 pound foot.

Increase the bar length to 5 feet with the same 10# pounds mounted on the extended end and there will be 50 pound foot of force at the secured end or a TORQUE of 50 pound foot. Notice that TORQUE by itself means NOTHING!

Now consider HP which whose name was adopted by James Watt when he attempted to show how powerful his steam engine was by relating it to horses. He said 1 horse can raise 33000 pounds 1 foot in 1 minute or 550 pounds foot in 1 second. Now people could understand how horsepower could related to doing work.

Foggy

In your first scenario, the power was being expended, but was not enough to overcome the load and the energy expended was absorbed by the bar. In the second example, the power applied was sufficient to overcome the load, so it moved. The only difference between the two is the power to load ratio.

 

[hseII]

You didn't read my first post in thus thread did you?. Its OK I do the same thing all the time.
I'll fill you in. The 660 is supposed to be 1 HP stronger than the 461. I broke the brand new 660 in on the dyno with a little over two tanks then tested both stock saws back to back twice on the dyno from 10,000 all the way down to 6500 rpms. I recorded #s every 500 rpms. The 461 was 2-3% stronger at 10,000, 9500, 9000, 8500, and 8000 rpms. Then at 7500 they were tied. Then the 660 was 3% stronger from 7000-6500 rpms.

I don't have no horse in this race, however, a 660 is not "broke in" until 10-15 tanks of fuel.
I did not just read this in a book or on the intertube; I know this first hand.

I would hope by now Everyone here agrees the 660 is a dog in new, not broken in, stock muffler form. That is a fact of life. Just like many other new saws from a lot of manufacturers.

However, a 660 is indeed a "stronger" saw when broken in and muffler modded;
I will personally know sometime mid August just how much "Stronger" a Monkey can make my low hour 660;

Both Saws are good Options within their respected purposes.
Will a 461 or 660 pull a 32-36" bar? Of Course.
The 660 will just do it better and longer because that is the intended purpose of a 90cc class saw.

Will the 461 or 660 pull a 25-28" bar? Of Course.
The 461 will do it better as it weighs less, and burns less fuel, as most 70cc class saws would.

the numbers are nice, but the story is told when the longer bar is buried to the dawgs.

That's where a 660 will continue to out perform day in and day out.

Thank You OP and Good Day.

 

[chadihman]

No testing today but tomorrow is going to be the last stock testing of the 660 along with a dual port test then this 660 is getting torn down. I'll have a line graph up by this time tomorrow. I'll run two or three more tanks through the 660 to be sure it's broken in. I'm rooting for the 660. It might just beat the 461 this time as the last test was close.

 

[treeslayer2003]

i have no doubt.........however, it does show how good the 461 is for its size. i stiil say the 660 should have been much better, after all it is a 90 cc saw.

 

[foggysail]

In your first scenario, the power was being expended, but was not enough to overcome the load and the energy expended was absorbed by the bar. In the second example, the power applied was sufficient to overcome the load, so it moved. The only difference between the two is the power to load ratio.

OH really??? Torque is a force and thats it! By itself no work is done period! Believe whatever you want, nobody is telling you to "get smart!"

 

[Hedgerow]

OH really??? Torque is a force and thats it! By itself no work is done period! Believe whatever you want, nobody is telling you to "get smart!"

Get over yourself ...

Carry on...

 

[Haywire Haywood]

His definition of 'work' is correct though. I remembered the phrase 'force over distance' from high school science class and googled it.

Doesn't help me understand my original question though.

Why does the rpm the engine turns when it makes peak torque affect anything?

Momentum of the spinning mass maybe?

 

[weedkilla]

Why does the rpm the engine turns when it makes peak torque affect anything?

Momentum of the spinning mass maybe?

It's a common and simplified way of showing the effective power band.
If max torque is at 7500rpm, and max power is at 9000rpm then you can consider the saw has an effective power band of 1500rpm.
It's often less important exactly what revs the saw turns at max torque - but more important what the gap is between max torque and max power.

There is more, but that's a pretty good start.

 

[chadihman]

Why does the rpm the engine turns when it makes peak torque affect anything?

Momentum of the spinning mass maybe?

Look at it this way. Let's say you're cranking a winch with a one foot handle. If your pushing five pounds your torque is five ft-lb. It takes more energy to crank the weight in at twenty five cranks per min than it does at five cranks per min. The work done shows. Twenty five cranks a min moved the load five times further than the five cranks per min job did.

 

[foggysail]

Look at it this way. Let's say you're cranking a winch with a one foot handle. If your pushing five pounds your torque is five ft-lb. It takes more energy to crank the weight in at twenty five cranks per min than it does at five cranks per min. The work done shows. Twenty five cranks a min moved the load five times further than the five cranks per min job did.

Yes, and in both cases the torque remains 5ft-lb or 5 lb-ft. The HP can be calculated for these both conditions as HP= torque*RPM/5252. The second case...25 cranks per minute requires 25 times the HP of the first case. In both cases work is being done.

 

[Mastermind]

Y'all make my head hurt.

I'll just hog everything out and hope for the best.

 

[chadihman]

Yes, and in both cases the torque remains 5ft-lb or 5 lb-ft. The HP can be calculated for these both conditions as HP= torque*RPM/5252. The second case...25 cranks per minute requires 25 times the HP of the first case. In both cases work is being done.

Exactly

 

[MustangMike]

Expanding on what Chad said ... RPM is speed ...

Pretend you can move 10 lbs at 10 MPH, the 10 lbs is like torque and the MHP is like RPM.

If someone else can only move 8 lbs, but can move it a to 30 MPH, they can move 24 lbs in the same amount of time you can move 10 lbs, so they generate more HP even though the torque is lower. HP represents a level of torque at a level of speed.

Hope this helps.

 

[redfin]

Exactly

Shouldn't you be dynoing and stuff? Class is over for the book nerds bring on da videos!

 

[chadihman]

Shouldn't you be dynoing and stuff? Class is over for the book nerds bring on da videos!

Hold your britches on! Gotta mow grass and help my bro fix his tiller then dyno time

 

[MustangMike]

Work comes first, but we so love the Fun!!!

Don't feel bad, I'm staining the Deck today, I'll trade ya!

 

[redfin]

Hold your britches on! Gotta mow grass and help my bro fix his tiller then dyno time

Sorry, ill go back to splitting wood now.