Another chainsaw dyno...

[Nutball]

I wonder if the long pipe worked best because of tuning length, while the shorter pipes peaked at a lower rpm on an upper harmonic twice the frequency of the exhaust pulses?

 

[NightRogue]

I wonder if the long pipe worked best because of tuning length, while the shorter pipes peaked at a lower rpm on an upper harmonic twice the frequency of the exhaust pulses?

Theoretically that should be correct?
Long pipe should create better "pull" more velocity laminar flow and stuffs....
Megaphone and no muffler makes it leave and lose direction and velocity?

 

[Red97]

Boy did I pick the wrong one! Lol looks like a tighter cone mount work better. Was the flange to cylinder matches on the cone, it looked smaller than the rest, could be my eyes! Lol

great test! Can believe the limp unit won! But I have lost 20hp on 100hp builds from dumb ideas on the dyno gained 20hp with a cdi box, the oem box make more power with a smaller motor and the aftermarket cdi lost power on the smaller mount, the bigger mount made 10 hp less with the oem cdi, and gained back the power and gained 10 more with an aftermarket cdi, it was crazy!! Lol the dyno

The flanges were all very similar, just mine was thinner and smaller outside dimensions.

 

[Red97]

Theoretically that should be correct?
Long pipe should create better "pull" more velocity laminar flow and stuffs....
Megaphone and no muffler makes it leave and lose direction and velocity?

Problem with a true "tuned" megaphone is the length is supposed to be 8-12 bore lengths. Supposed to be pretty long like a true pipe.

 

[NightRogue]

Problem with a true "tuned" megaphone is the length is supposed to be 8-12 bore lengths. Supposed to be pretty long like a true pipe.

Yeah i think that size will suit a top handle or anything under 30cc

 

[srcarr52]

The flanges were all very similar, just mine was thinner and smaller outside dimensions.

Do you have a run with a standard muffler mod to see there that lands in the mix?

 

[Nutball]

Yeah i think that size will suit a top handle or anything under 30cc

Except the small saws don't rev up much higher than the big ones, they share the same useable peak power rpm range as far as tuning goes. I'd like to see a wider flare, it's flare that is supposed to pull the exhaust out faster as far as I know.

 

[Red97]

Do you have a run with a standard muffler mod to see there that lands in the mix?

Not yet, gathering 4-5 diy front cover/can mods next

 

[wcorey]

I'd hazard a guess that using test mules with significantly higher/lower blowdown numbers (along with the other 'variables' that would typically accompany it) may very much rearrange the pecking order of the pipes.

 

[Red97]

I'd hazard a guess that using test mules with significantly higher/lower blowdown numbers (along with the other 'variables' that would typically accompany it) may very much rearrange the pecking order of the pipes.

I would guess so too.

 

[Ketchup]

Hey Joe
Could you tell us the total length of the straight pipe vs the curved?

 

[wcorey]

I would guess so too.

I'm in awe of how much time and effort you put into all of this and how well thought out it all is.
More than anything I appreciate you 'putting yourself out there' and making it all accessible to everyone.
Best thing that's happened in the community in a long time, maybe ever...

Particularly as being someone who had a dyno for a short time, I was decidedly envious when you first set yours up. I had a lot of grand plans for mine that never materialized...
It's more than ever starting to sink in that "with great resources comes great responsibility" and I've actually been spared from a huge weight, lol.

Keep up the good work!

 

[Red97]

What do you think about the quality of that long Forester bar? Oregon equivalent? Better or worse? How close is the gauge to .063?

I liked it when you used higher contrast colors on the graph like bright red, gold, green, blue, instead of 2 reds, 2 blues, and a black which sometimes kind of blends in with the blues. It all depends on what screen I'm watching from, and what quality of video I'm getting.

Idk, I've not used it, or bought a chain for it yet

I'll see if I can pair the brighter colors, try and keep it separated a bit better.

I'm in awe of how much time and effort you put into all of this and how well thought out it all is.
More than anything I appreciate you 'putting yourself out there' and making it all accessible to everyone.
Best thing that's happened in the community in a long time, maybe ever...

Particularly as being someone who had a dyno for a short time, I was decidedly envious when you first set yours up. I had a lot of grand plans for mine that never materialized...
It's more than ever starting to sink in that "with great resources comes great responsibility" and I've actually been spared from a huge weight, lol.

Keep up the good work!

Thank you.

Some people realize what all goes into it.
Most everyone here has been along for the ride since day one.

Some days it is frustrating. But why have this machine if not to share with others?

Appreciate the compliment, and I try my best to keep everything even and unbiased.

Would love to see a day that none of my stuff is on the dyno, and it is all others builds/products to show off.

Also wish more would invest in a dyno so I'm not the only one.... Go yell at some other dyno guy for not doing it right lol

Thank you Bill. I appreciate the compliment.

 

[Sawrain]

Also wish more would invest in a dyno so I'm not the only one.... Go yell at some other dyno guy for not doing it right lol

I've just finished working away, so will have some time to dyno.

Just working out some harmonic vibrations issues.

I have run a Stihl MSA220 though, very close to the same peak torque as a MS180, but more power.

 

[Red97]

I've just finished working away, so will have some time to dyno.

Just working out some harmonic vibrations issues.

I have run a Stihl MSA220 though, very close to the same peak torque as a MS180, but more power.

View attachment 324387

Can't wait to see what you come up with. Hopefully we can get some close ish numbers/readings.

 

[Sawrain]

Can't wait to see what you come up with. Hopefully we can get some close ish numbers/readings.

I will have to test some stock saws from your catalogue of testing, has the MS500i been consistent as far as peak power goes?

I started with something easy.

 

[Red97]

I will have to test some stock saws from your catalogue of testing, has the MS500i been consistent as far as peak power goes?

I started with something easy.

The 500i has but it's tune can fight my setup.

You being able to walk it back may be even better.

That have all been around 7hp. Lots of time light load they really spin the rpm and as I increase load, the saw will quickly richen up causing a dip in the graph.

 

[srcarr52]

I will have to test some stock saws from your catalogue of testing, has the MS500i been consistent as far as peak power goes?

I started with something easy.

Did I see that correctly, you are at 65% of your braking capacity with 3.2hp? Can you upgrade to a larger alternator?

 

[Sawrain]

Did I see that correctly, you are at 65% of your braking capacity with 3.2hp? Can you upgrade to a larger alternator?

Yes and no, the brake is 65% activated, but not at 65% capacity, it’s controlled braking power is somewhere around the square of percentage applied voltage, also linearly increasing with rpm.

This 100 amp alternators successfully braked a TM661, I think the excitation voltage was a little higher though, but it really brings the load on at 10+ volts excitation to the alternator.

I do have a 180A alternator to fit, I think this might be needed for high torque low rpm saws, I’m not sure if it would regulate the entire power band of a CS1201 or Stihl 090 as it sits, peak power yes, maybe not down to clutch slippage.

 

[srcarr52]

Yes and no, the brake is 65% activated, but not at 65% capacity, it’s controlled braking power is somewhere around the square of percentage applied voltage, also linearly increasing with rpm.

This 100 amp alternators successfully braked a TM661, I think the excitation voltage was a title higher, but it really brings the load on at 10+ volts excitation to the alternator.

I do have a 180A alternator to fit, I think this might be needed for high torque low rpm saws, I’m not sure if it would regulate the entire power band of a CS1201 or Stihl 090 as it sits, peak power yes, maybe not down to clutch slippage.

Oh, I see, so that's 65% of your excitation voltage.