Piped Stihl 028 AV...!

[troutfisher]

Here's a good page on piped 2 stroke engines, with a good animation.......

http://www.southernskies.net/page_info/runningtwostrokeengine.html

 

[Junkrunner]

To hell with hating on the guy for it this is were modding starts.


I want to see a video!!!:greenchainsaw:

You got that right. not everybody can be a "born" expert. Hope it works out for ya!

P.S welcome to the forum.

 

[blsnelling]

To hell with hating on the guy for it this is were modding starts.


I want to see a video!!!:greenchainsaw:

+1 Bring on the vids!!! We all know he didn't build a properly designed pipe. That doesn't mean it won't sound cool, and it just might suprise us with it's performance. Who cares if it doesn't. He obviously had fun with it.

 

[GASoline71]

I am a basic shade tree machanic not formally trained . can someone explain the purpose of the muffler having a large area in the middle then reducing down . doesnt seem to me to increase the flow of exhaust at all !
Thanks
Mickey

The idea of a "tuned exhaust" is not nesserally to increase overall exhaust flow, but reflect back into the cylinder some of the lost charge within a certain RPM. the pipe is "tuned' to use the pressure wave to do this. By varying the lengths, diameters, and angles of the different components, a pipe designer can alter when and how long(rpm range) the charge is reflected back, thereby changing the characteristics of the power band.
CSW

Yep... just look at 2 stroke dirt bikes... the bigger the bore of the engine, the bigger the expansion chamber will be. Also custom pipes can be had to either increase low end grunt, or top end power.

Gary

 

[woodshave]

The idea of a "tuned exhaust" is not nesserally to increase overall exhaust flow, but reflect back into the cylinder some of the lost charge within a certain RPM. the pipe is "tuned' to use the pressure wave to do this. By varying the lengths, diameters, and angles of the different components, a pipe designer can alter when and how long(rpm range) the charge is reflected back, thereby changing the characteristics of the power band.
CSW

I thought the idea of a "tuned" pipe was similar to that of a pipe organ. The pipe is shaped to create a resonance or "standing wave" which will aid in quicker discharge of the exhaust gases.

I can't conceive of how, at 10,000+ rpm, you could reflect anything back into the cylinder. Why go through all that when you can simply increase what's coming through the "in" door?

 

[chainsawwhisperer]

I thought the idea of a "tuned" pipe was similar to that of a pipe organ. The pipe is shaped to create a resonance or "standing wave" which will aid in quicker discharge of the exhaust gases.

I can't conceive of how, at 10,000+ rpm, you could reflect anything back into the cylinder. Why go through all that when you can simply increase what's coming through the "in" door?

Tomorrow, I'll reread the section in "Jenning's" book that explains the theory.
I could have misinterpreted it.
Jim

 

[SpaayDawg]

I thought the idea of a "tuned" pipe was similar to that of a pipe organ. The pipe is shaped to create a resonance or "standing wave" which will aid in quicker discharge of the exhaust gases.

I can't conceive of how, at 10,000+ rpm, you could reflect anything back into the cylinder. Why go through all that when you can simply increase what's coming through the "in" door?

Due to the necking down of the chamber in the pipe it acts more like a supercharger from the exhaust side to cram some of the lost charge that would have just gone out the muffler.

 

[Adam_MA]

Nice work, very creative! I can't wait to see the videos!

 

[woodshave]

Due to the necking down of the chamber in the pipe it acts more like a supercharger from the exhaust side to cram some of the lost charge that would have just gone out the muffler.

Very cool animation spaaydog I think that clears up a lot. Still, hard to believe things could bounce around in there that fast but you can't argue with what works.

 

[Grqnbech]

Remember I build this saw just for fun.... here is a little video

http://www.youtube.com/watch?v=bWZnzUERxWU

 

[thechknhwk]

Sweet, it sounds like the holeshot at a pee wee moto! If wasn't watching the video I would have guessed it was a KTM SX50

 

[Thorcw]

Seems to run good might want to try extending the sticker a bit. From the video seeming to hold rpm nicely. Mustve done something for the good even thought its not "right".

 

[jester8118]

That looks and sounds good. not bad for a first try.

 

[oscar4883]

Nice job. I think it did real well. Pretty good sized wood for that saw too.

 

[KD57]

I think you did good, saw sounds sweet and seems to cut well, not to mention the "cool" factor.

 

[gink595]

What did you do with the porting? Did you raise the export any? The first pipe I built was a flop and it was designed from a pipe program specifically for my porting, to me it showed that pipe building is a trail and error. You don't know until you try!

 

[Grqnbech]

yes I did raise the export.... but I didn´t take any pictures... big mistake...

I´m glad you guys like the saw...

 

[blsnelling]

yes I did raise the export.... but I didn´t take any pictures... big mistake...

I´m glad you guys like the saw...

No, that's part of the recipe for a piped saw. Lots of blowdown.

 

[parrisw]

Looks good!

Do you guys think it would be easier to build a pipe, to just get one of those bike pipes, then cut it and lengthen it or shorten it to suit the saw? Would be much easier that way.

 

[ms290]

way to go on the pipe, she friggin runs. :chainsawguy::chainsawguy::chainsawguy: