Why a pipe makes more power

[HUSKYMAN]

This is what Ken Dunn has been trying to beat into our puny minds for the last couple of days. This is the best animation I have seen to date. http://www.maximumsled.com/mountain/garage/2strokeprinciples/two-stroke_animation.gif

 

[thacket]

Hi,

Great animation! I already had a good idea of how this worked, but a picture is worth a thousand words.

Best,
John K. Emmons

 

[Gary N Carter]

Thats Good stuff there. A picture is worth a lot. The only thing I did not see is the power band. HA Ha

 

[kdhotsaw]

Expansion Chambers- Pipes

Hello Huskyman
Thats a good picture. 2 stroke motors, kart engines,motorcycle,rc motors, snowmobiles.watercraft and chain saws, if they are 2-stroke motors they will get a 35-60 percent hp increase with a expansion chamber. what else can you bolt on to the outside of a motor and get that much more power? you just have to match your overall length to your exhaust duration and rpm to make it work.
For you guys that want to know more about engine porting, engine building, pipes and anything else about 2-stroke motors check out this site.
www.macdizzy.com

I know it sounds hokey but its the only site I've found that gives you port timing specs, tells you how to port and has dyno charts of before and after modifications. also has page after page of tecnical articles.

Ken [email protected]

 

[jokers]

Hi ken et al, I`ve really got my heart set on having you modify a 372 for me, but since I`m already facing a divorce and my darling wife has already cleaned out my bank accounts, that saw must wait. At any rate, I still consider myself lucky to have a brand new un-fired 372 sitting in my shed and I`m having obscene thoughts about what I could do to it myself, low dough. The point is, can you go too far in opening up the stock exhaust? I saw John`s pic of the Walkerized muffler with two additional 5/8s ports and the stock port closed, and I can do that. Are there any tips you would care to share? Thanks for any replies, Russ Ps: I am an amatuer rocket scientist, so I know I could handle anything you suggest. LOL

 

[kdhotsaw]

unfired 372

Hello Jokers
Wow! a 372 sitting on the shelf and has not been run yet. about 5 years ago when the 371 first came out I bought the first one my dealer got in, took it home, put some newspapers on the dining room table, disassembled it, degreed the port timing and damn near got divorced. these women just don't understand. anyway, we did 3-4 a month for the loggers for quite a time. still do the 372's. this particular saw takes well to porting and muffler mods. we get 40-45 percent power increase . you get around a 20 percent increase just porting the muffler. yyou need to open the existing top port of the muffler. every one i've ever done is pushed down. pull the top up and grind the rolled over lip up to llevel with the top. there's also a little dam on top of the muffler under the top of the outlet you need to grind off. then put a exhaust port in the front of the muffler thru the muffler and brace 1.5 inches long and 7/16 tall. this allows you to put a screen between those two pieces if you are in a area where the forestry requires a screen. we used to put little outlet pipes in and also put in a port with a deflector shield they all work but this method seems to produce the most power and looks like it came from the factory that way. I'm sure walker's method works well also.

Ken Dunn [email protected]

 

[jokers]

Thanks for the info Ken, I`m going to tackle that muffler ASAP and see what happens. As far as port mods, I think I`d leave that to an expert such as yourself, but if winter drags on too long you never know what might happen. Russ

 

[Gypo Logger]

Hi Ken, how ya makin out? Did you get my piped 346KD Dunn yet?
John