Rudolf73
Addicted to ArboristSite
Cheers Rick!
Chainsaw Dyno bring saws to there knees. Build from start to end with video
- Thread starter chadihman
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Cheers Rick!
deezlfan
Meadow River Lumber Co. 6
When I saw the unit in your pictures, the first thing I thought of is: I could modify it to run a wood splitter... Guess i just can't leave anything as intended. Cool build by the way!
Excellent work!
chadihman
Addicted to ArboristSite
No sir I'm not a rocket scientist. Even though some of the homemade bombs my brothers and I made as kids turned into rockets. It really is a miracle that I still have all my fingers. Being a curious farm boy never left me. My little girl calls me tinker as she learned the meaning of a tinker on the movie tinker bell.
sachsmo
Addicted to ArboristSite
Got the dyno done for the most part. I have lots of pictures of the build and a video of a MS 460 begging for mercy.
That is really kewl,
I have a not so scientific approach, strap a saw onto a Alaskan type mill and start ripping through an 18' 30" Oak.
Not much for bragging rights, but it WILL separate the men from the boyz!
parrisw
Tree Freak
How did you center the shafts on the box that the pump is in so it would run true?
nmurph
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Yep, if you don't add more fuel adding more air makes it leaner.
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If you can read this, thank a 346
I dis-agree. If the saw is sucking more air and has become leaner then if you richen it up with more air, will that not give more fuel air mixture and more horsepower. That is what this dyno will prove, no more speculation.
parrisw
Tree Freak
If the saw is pulling more air, it will also pull more fuel.
More air doesn't enrich an already lean air to fuel mixture. And while a saw may suck more fuel (to an extent) due to the removal of the air filter, it may not suck enough to compensate for the additional airflow into the system (depending on the tuning at the time), thereby most likely resulting in a lean condition....same as any additional source of air introduced to the system not compensated for by adjusting the mixture accordingly. And yeah, it may scream under those conditions...until the piston melts down.
Conversely, a completely funky air filter whose lack of airflow has been compensated for by leaner and leaner tuning over time will certainly create a severely lean condition if replaced by a new/clean air filter...and probably burn up the top end if the mix isn't re-enriched enough to compensate for all the "new" air.
Too much air is too much air if not compensated for regardless of the source.
But back to the dyno!!!
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I agree but how much of a gain, and we know there will be one, will no longer be speculated on.
RiverRocket
ArboristSite Guru
That's really Awesome...You should Patent that thing...:msp_thumbup:
Except if you have more air through the venturi of a carb it will pass over the jets and pull more fuel.
If there is an air leak after the carb it will not pull more fuel from the jets.
Couple of questions 1) Are you taking into account the gear reduction on your sprockets? 2) By what I can see some of your fluid heat is coming from the way that exhaust outlet is pointing or so it appears from here
chadihman
Addicted to ArboristSite
I know that the saw was not to lean because it had the four strokin still going on with no load. It probably made it a little more lean but not enough to hurt anything as I tend to tune em a little on the fat side now anyway. I'll get a video tommorow of the saw running with the air filtr on and off.
I was just stunned to see the results in front of me when the air filter was pulled off while the saw was held at 9000 rpms. I found that the highest readings for the 460 were at 9000 rpms. It seemed like the saw was still pulling hard at 8000 rpms but the gain on torque was not great enough to raise the Hp because the rpm went down. The torque will continue to rise as the saw is pulled down harder but torque and rpm make hp not torque alone.
I was just stunned to see the results in front of me when the air filter was pulled off while the saw was held at 9000 rpms. I found that the highest readings for the 460 were at 9000 rpms. It seemed like the saw was still pulling hard at 8000 rpms but the gain on torque was not great enough to raise the Hp because the rpm went down. The torque will continue to rise as the saw is pulled down harder but torque and rpm make hp not torque alone.
chadihman
Addicted to ArboristSite
The saw has a 7 tooth sprocket and the driven sprocket is a 24 tooth. The the large sprocket is turned 0.29166 times for every turn of the saw sprocket or crank revolution. I have an rpm sensor on the driven shaft. My torque arm is 18" or 1.5' from the center of the pump shaft to the bolt where the arm dropping to the scales is. I watch the saw rpm with a tach on the saw. I crank the needle valve down to pull the saw to 9000 rpms or so then I record the shaft rpm and the weight on the scales. I multiply the weight on the scales by 1.5 for my longer torque arm then multiply the converted weight by the shaft rpms and divied by 5252 to get the hp.
The exhaust does not make the oil temp rise much if any. Most dyno runs are 30 seconds or so and the oil barely gets warm. If the saw is run under load for 5-6 min then the oil temp is getting a little high but the saw will run out of gas before the oil gets to hot. The oil should cool enough in between the dyno runs enough for me not to worry about.
That would depend on the settings of the jets, now wouldn't it? And I didn't realize that's how mix was pumped into the carburetor, but that's another discussion for another thread.
The real issues are the gains relative to the adjustments required to optimize the results of any modifications which are designed to increase performance characteristics, whatever the modifications may be.
Seems like there is now a means by which such can be qualified and quantified given enough testing and repeatable results with this dyno. Once some baseline criteria and further refinement of an actual process are established with this thing, a whole new measurement world opens up.
Too much air is still too much air if not appropriately compensated for..., whether it comes from the intake, a too lean "H" setting, a bad crank seal, or a muffler mod.
Not wanting to stir anything up..., Just sayin'.
I'm diggin' the dyno.
This is exactly what i was trying to point out, and one thing the dyno can't help you with if you test it with a single tuning. Tune it fat once, lean the other time, just right the third you should get different results from the same saw. If you had the saw running fat, pulling off the filter maybe just made the perfect fuel/air mixture. If it wasn't too lean when you removed the filter then you were definitely running her way fat. Have you tried runing it with the filter and tuning it a bit leaner? You would probably get similair (altho probably a bit lesser) results.
Im thinking you should actually use the dyno to find the sweet spot while tuning at WOT for every change you make. Only then the data would be objective which is the purpose of dyno testing in the first place
Agreed....more or less.
Until baseline criteria are established for any measurements, they will all just be ballpark numbers. Relative measurements of + or - changes are one thing, absolute measurements of specific performance characteristics on a repeatable basis is another story. With enough work on this thing, either one should be easily attainable under specifically controlled conditions, but each need to be viewed in their respective contexts to provide consistently meaningful results, either relative to specific variables, or absolute based on constant measurement conditions.
The possibilities for this project are pretty awesome to think about. Very, very cool.
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