Yet Another Chainsaw Dyno

[bikemike]

Does piltz build these saws it wont idle. Then il send it to get dyno run. Pics wont post remington limb n trim

 

[Mastermind]

Does piltz build these saws it wont idle. Then il send it to get dyno run. Pics wont post remington limb n trim

English Mike. We need English.

 

[olyman]

English Mike. We need English.

yeah!!

 

[dieseldave]

I had a '82 490 but sold it about 10yrs back to buy a modern bike. Still kicking myself now. A 495 KTM was one of the few bikes the Maico wouldn't outrun to the first corner but was a lot easier to ride for the rest of the race. As Dirt Bike said back in the day "the 495 has more power than anything else on the market. Sometimes it has more power than two of anything else!"
I wouldn't think the hub should be a problem as it has no spoke tension on it or any of the forces from a spinning rim. However the forces go up as the square of the speed so a guard would possibly be a good idea. Also if the chain did break they tend to go forwards where you could be taking measurements.
As you say electronic gathering of the data is the way forward but none of that stuff is on my list of specialist subjects.

An '82- that was the one that snapped shocks, right? I rode one once, and my impression from the ten minutes or so I spent on was very positive, it was a sweet bike. Another friend had an '83 Sand Spider and I could never get along with that one, just too damned tall. Another guy I knew also had an '81 495 and we used to run enduros with them. The reason for taking a 53hp bike into tight woods escapes me now, but we did and had fun at it. Well, we told ourselves it was fun- looking back on it now, all I can remember is ricocheting off of trees while being passed by KDX200's lol

 

[AKDoug]

Would you like a "cutterless" chain for that contraption? I can get them from Stihl. How many drivers?

 

[dieseldave]

I guess it would be a good idea to make this thing safer, although it might take some of the sense of adventure out of running it lol. Some cutterless chain and a set of guards over the hub and chain would make it much more survivable in the event of a spontaneous unplanned disassembly. It is .050 3/8" 72DL, let me know how much they are before ordering it up.

 

[AKDoug]

I guess it would be a good idea to make this thing safer, although it might take some of the sense of adventure out of running it lol. Some cutterless chain and a set of guards over the hub and chain would make it much more survivable in the event of a spontaneous unplanned disassembly. It is .050 3/8" 72DL, let me know how much they are before ordering it up.

PM me your address. I'll get you one on the way in the interest of science

 

[ChoppyChoppy]

Nice... I know it's kinda of hard to find. Do you guys have a big roll? Might be interested in buying 25 or 50ft.

 

[Rudolf73]

Nice setup Dave, looking forward to some saw tests.

Also there is dyno software available which uses load cell data, etc to draw graphs and such, but they were a few hundred $$ from memory. Hopefully someone has come up with a more affordable option by now.

 

[B-N]

Have you ever looked into using an arduino for data acquisition/management?

I know very little about them but the best I can gather you would need:

$40 arduino
$20 load cell
$10 hall effect sensor
$20 ish for various wirey bits

I'm right in the middle of a large home improvement project that seems to be taking far longer than it should. Once I free up some time I will try to look into the details of this and become a keyboard expert!

Unfortunately it won't be any time soon.

 

[dieseldave]

Here are a few pics of the nearly completed project. I had to move some things around, got the scale and tach readout closer together so that they can be read (or videoed) at the same time, and bolted some shielding on. Also added the wheels and removable handles to make it easier to move around, and if I'm not using it as a dyno I can use it to bring a few loads of mulch to the garden lol. I realized tonight that I have to make the bar adjustable to accommodate different saws, might be able to get to that tomorrow. Videoing the tach and scale does work (sort of), better than trying to run the saw and read everything at once. Getting very close to being able to get some actual numbers from this thing.

 

[dieseldave]

I tested my Dad's 51 tonight, it is a 51 that I put a closed port 44mm jug on, mildly ported with the squish set at .020". I think the port timing is 105ex, 118tr, and 108in but I'd have to look in my book to be sure. I read a peak hp of 3.3 at 8200 and the torque maxed at 2.25 at 7200. Husky says a stock 55 is good for 3.3 hp, but as with all hp numbers measured "at the brochure" you can be sure that is on the high side of optimistic lol. My plan is to gather up some stock saws and get the data from them to compare to the claimed factory numbers so that I can make a "correction factor" when testing modded saws vs stock.

 

[dieseldave]

I've had a chance to run a few more saws on the dyno. I borrowed my neighbor's minty fresh 562 when he wasn't looking and it managed 4.4hp at 9600 and 2.6ft/lbs at 8600. My 288 went 5.8hp at 8900 and 3.8 ft/lbs at 7700- I think it could have managed a higher torque number if I had pulled it down lower. My experience so far is that it is easier to get a reading from the bigger saws, the numbers don't jump around as much. I ran 3 back to back pulls with the 288 with no issues with the dyno overheating so I think it's ok in that respect.
I spoke to Kevin at Performance Trends today about data acquisition. Looks like it's going to be over a grand, but I think it's going to be a necessity to get good repeatable results. Might have to sell a saw or two to do it, though

 

[B-N]

DD

How many tanks through the 562?

Would you be able to post the video on youtube?

$1000? Wow! That would make me think long and hard about going analog! However it would be tough to beat having a professional take care of it and know it's done right.

 

[dieseldave]

I'm not sure, but I'll guess at 10 or so, enough to be broken in I think. Here's a vid of the readout
I ran the "Dolmar/Makita 6401 converted to 8401" tonight. It was just slightly behind the 288, peaking at 5.62hp at 8200.
I ordered a new tach with a faster refresh rate to tide me over until I can get the data acquisition package, but even with that you can see from the video what a challenge it is to get good numbers

 

[gomoto69]

Nice job on your project, but maybe you could explain a few details i can't make out from your pics, first, the arm that pushes down on the scale, is it attached to the brake caliper? Is the caliper a radial design, ie mounted to the axle of the hub? Do you use the scale readout in pounds directly or do you have to divide it by the gear ratio from drive to driven sprockets? Also, you mentioned you would prefer to measure rpm off the hub instead of the saw, maybe you could adapt a crankshaft position sensor from a modern car to accomplish this, i believe a notch in a solid steel ring is all the sensor needs to pick up a signal for rpm, and there's probly some simple automotive software that would allow u to moniter cp sensor signal for accurate digital rpm readout. Just some thoughts, again, nice job!

 

[drf255]

Great job Dave.

Will you be doing Dyno testing for a fee?

How far are ya from Long Island?

 

[Mastermind]

Gotta be a way to make this work......

http://www.arduino.cc/

Someone else posted it before I thought.

 

[dieseldave]

Nice job on your project, but maybe you could explain a few details i can't make out from your pics, first, the arm that pushes down on the scale, is it attached to the brake caliper? Is the caliper a radial design, ie mounted to the axle of the hub? Do you use the scale readout in pounds directly or do you have to divide it by the gear ratio from drive to driven sprockets? Also, you mentioned you would prefer to measure rpm off the hub instead of the saw, maybe you could adapt a crankshaft position sensor from a modern car to accomplish this, i believe a notch in a solid steel ring is all the sensor needs to pick up a signal for rpm, and there's probly some simple automotive software that would allow u to moniter cp sensor signal for accurate digital rpm readout. Just some thoughts, again, nice job!

The arm is attached to the caliper which is attached to the axle but free to rotate. The scale readout and the rpm readout are both from the hub so hp can be measured directly from those numbers. To get the rpm of the saw or the torque of the saw you have to figure in the reduction which is 24 to 7. I thought about a crank or cam sensor but I just got a tach that uses a hall effect sending unit so I'll try that out first.

Great job Dave.

Will you be doing Dyno testing for a fee?

How far are ya from Long Island?

I'm pretty near Atlantic City if that's any help. I would consider testing saws for others once I get a good data acquisition setup, it's just too much guesswork right now.

Gotta be a way to make this work......

http://www.arduino.cc/

Someone else posted it before I thought.

I looked at that site but I don't really know what I'm looking at lol. I'm sure that someone who knew what they were doing could make up a system that would work. Kevin from Performance Trends spent a good bit of time with me on the phone the other day trying to explain it all. The gist of what I got was that the expensive part was going to be the load cell and amplifier. Apparently single cylinder engines are tough on load cells and only a good one will do the job and provide a reasonable service life. He went into great detail which I remember little of now but it all sounded very convincing lol. I believe that this is one of those cases where the cost will be worth it in the long run. The system he described to me is also expandable, and has the capability to compensate for weather and temperature plus the ability to accommodate a/f and temp sensors. It's pretty sexy. http://performancetrends.com/dtm-dyno.htm

 

[gomoto69]

Thanks for the clarification. You would think there must be a simple interface to record and plot info input from an accurate digital scale and your tach, but then there's really no substitute for having the proper equipment either, especially if you can add other inputs in the future as you mentioned, 02 sensor and pyrometer would be invaluable for accurate tuning rather than just a measurement of engine output, I think you're project is just getting revved up here! Gets me thinking, maybe i should add a pyrometer to my 298 when i get it set up on my mill, see what's actually going on when you just tune out the 'burbble'! Food for thought!