550xp or 365

[omahaalex]

What is an MM?

 

cheers

 

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[Daniël Bos]

What is an MM?

 

cheers

 

Sent from my HTC Desire X using Arbtalk mobile app

 

Man-Minge...

 

Or Muffler Mod...

[wyk]

Impressive dyno chart.

Have you got any pics of his dyno set up?

 

This is his first iteration. He is on Dyno 2.1 or so right now, but I imagine it doesn't look much different:

 

[SawTroll]

Here's a dyno chart a bud of mine stateside did with a 660 stock VS the factory 660 dual port(DP) muffler. He used his own purpose built hydraulic chainsaw dyno:

 

 

That's 23% more HP at 10,000 RPM with a simple bolt on.

 

How does he know that dyno is calibrated correctly?

[Stubby]

How does he know that dyno is calibrated correctly?

 

Doesn't really matter for a strait comparison . Just showing the difference between stock and MM .

[wyk]

Doesn't really matter for a strait comparison . Just showing the difference between stock and MM .

 

Exactly. Most use dynamometers simply to compare modifications. Your baseline is the unmodified saw.

 

It's worth noting that some newer saws like the MS461 benefit very little from muffler mods. Others benefit significantly

Edited June 24, 2014 by wyk

[spudulike]

Exactly. Most use dynamometers simply to compare modifications. Your baseline is the unmodified saw.

 

It's worth noting that some newer saws like the MS461 benefit very little from muffler mods. Others benefit significantly

 

Interesting stuff Wes - bet his neighbours love his "Garage antics":lol:

 

I thought about making similar but there just aren't the hours in the day!

 

.....and agree that the comparison shows over 15% increase in HP and it is perhaps the comparison rather than the true figure that is useful - damn sight easier than timing & cutting wood a thousand times over:lol:

[Garyjp]

i guess you can take manufacturers values to use as a baseline figure and as mentioned actual figure isnt really all that important, more about the difference.

 

looks like an awful lot of metal work (the excess weight will have an affect) and fluid transfer will give results that are probably variable. good fun tho! looks a good effort. better than i could rustle up thats for sure 😃

 

 

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[wyk]

To be fair to the manufacturer's specs, the dyno would have to be normalized, or at least calibrated for losses. Right now, Chad only has a rudimentary calibration, which doesn't take into account drive train losses due to heat, environment, or inertial resistance for the dyno itself. Thus, it's main importance right now is straight comparisons. It's a good thing his readings are on the low side. If they were on the high side, without taking into account the losses, then he would really have serious calibration issues.

 

Personally, I like his numbers. I look at them sort of like BHP numbers. It's the HP the wood itself would likely be experiencing. I mean, if wood could talk it would say something like "Yeah, that there feels like right bout 5.7 HP, or so, I reckon."

Edited June 24, 2014 by wyk

[SawTroll]

Doesn't really matter for a strait comparison . Just showing the difference between stock and MM .

 

Likely true - just don't read too much into (or out of) the results without knowing the reliability of them.