Porting questions

[Chainsaw Pete]

I've read a number of the old porting posts, and it seems to me the way one measures the increase in power is two fold. One is the rpms attained compared to the unported saws top revs, and the second is by porting and then timing cuts in one reference log. Back in the day when motorcycles were running two stroke engines, the science of porting and polishing was pretty thoroughly explored and modifications were compared by hooking the engine to a dynamometer.

Has anyone done this with chain saws? What kind of percentage increase can be attained by this kind of tuning for an everyday saw (not a racing saw)? How about for a racing saw? I realize that the % increase will depend on the motor, size, etc. but some generalizations can surely be made.

 

[NSEric]

Check out dynojoe on youtube.
Porting is a cheap hobby for most, spending money on a dyno isnt an option so they use a test log and do timed cuts.

On the smaller saws more rpm equals faster cuts even if you dont add peak hp as it doesnt take a lot of hp to cut small wood.

 

[Matt81]

Someone beat me to it. Dynojoe has plenty of vids on difference between stock and ported as well as improvements from different muffler mods on the same saw etc...