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Dyno tested....Mastermind's ported 261cm vs Stock 261cm Gotta see this one.

Duane(Pa)

Duane(Pa)

It's the chain...
Joined
Sep 15, 2011
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2,093
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Centre Co.
Very cool, and thanks for taking the time to do all this. I would love to get you my screw carb 261 that Randy Masterminded to see how it compares to the Mtronic. You rock Chad! What does Randy say? Something about the kind of feedback that's good to get....
 
Duane(Pa)

Duane(Pa)

It's the chain...
Joined
Sep 15, 2011
Messages
2,093
Location
Centre Co.
I don't know a lot about this stuff, and feel kind of stupid to ask, but what size rim were you using and would the Torque and/or HP numbers change if you switch rim sizes?
 
weedkilla

weedkilla

Ain't no guru of nuthin'
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Apr 20, 2013
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1,683
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South Australia
Wow! Never got the ported saw high enough to see the power drop off!!

I've said this in other dyno threads - but I'll repeat it anyway - it's not peak power that shows work capacity of an engine, it's area under the graph. And that's an amazing increase in area under the graph!!!!!!!

Seriously, from 8000ish up it's making more than standard at peak.
 
Dieselshawn

Dieselshawn

ArboristSite Operative
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I don't know a lot about this stuff, and feel kind of stupid to ask, but what size rim were you using and would the Torque and/or HP numbers change if you switch rim sizes?
Duane: it's a small spline 7 pin for 3/8 chain on smaller saws. There's not many selections for different sizes.
 
Terry Syd

Terry Syd

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Dec 24, 2008
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Looking at the linear rise of the power, there is a sudden dip. I wonder in this this case if it might have been some light detonation. If so, then that dip might not be there when cutting wood.

A dyno puts an extended load on an engine and the heat builds up. Maybe a flash run up to the dip might tell us more.

Chad, that dyno of yours is truly fantastic.
 
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