2-Stroke Pipe Design Parameters

[jayzx10r]

Can someone explain 2-stroke exhaust design relative to powerband/RPM curve? I'm trying to see common ground when I look at different exhaust manufacturers products so if you can lay it out for me, I'd appreciate it.

 

As an example, when you compare Shearers to CPIs, they are (relatively) similar in RPM range/power delivery range but the CPIs look a LOT fatter and a bit shorter than the Shearers.

 

I want to be able to look at a pipe and determine the probable power delivery characteristics based on perceived design parameter!!

 

My path on the unending quest for knowledge continues forward....

 

Thanks, Jay.

[Snopczynski]

Your not going to be able to look at the pipe and tell when it comes down to say a top end pipe vs a top end pipe. Outlet diameter, exp chamber size, pipe length, cone taper, chamber length, and general design all play a part in how a pipe performs.

[FireHead]

You need to read the book, "Two Stroke Performance Tuning" by A. Bell. :geek:

[Snopczynski]

Firehead, you sure do like that geek smiley. :geek:

[Hilarious]

Here's a picture to look at. :geek:

 

From my experience, comparing the shearers to the cpis, the power

deilvery was not similar, on my bike. The powerband came on a little

later and kept going as with the cpis, the powerband came on sooner

and didnt rev out as much. And I cant really tell why by just looking at

em side by side. Thats just the way it is. :laugh:

[RZBansheeMan]

It appears in the pic there, that the CPI's have more belly length in the expansion chamber. If I'm not mistaken the longer the belly area the less peaky / less rpm the pipe.

[Bansh-eman]

man im having a bitch of a time fining the thing that explains it... ill keep looking to see if i can find it but basically what snop said its all about the diam's and the lengths and cone tapers at the locations as well as how aggressive the bend are and all that... ill keep looking hopfully ill find it again

 

EDIT: here is a small reading but this isnt the one im looking for Link

Edited September 9, 2007 by Bansh-eman

[FireHead]

Firehead, you sure do like that geek smiley. :geek:

...............I think it is because I am a raging geek. Seriously, I pretty much can't pass a booke store without going inside. :geek:

[bonbon]

...............I think it is because I am a raging geek. Seriously, I pretty much can't pass a booke store without going inside. :geek:

You need a group.........

 

 

EDIT: this link has some explaining on 2-stroke exhaust.

clicky

Edited September 9, 2007 by bonbon

[Snopczynski]

...............I think it is because I am a raging geek. Seriously, I pretty much can't pass a booke store without going inside. :geek:

 

I know why, its cause they sell playboy and penthouse in bookstores.

[FireHead]

I know why, its cause they sell playboy and penthouse in bookstores.

Apparently you are familiar with Portland and it's large population of adult book stores......... :ermm:

[Snopczynski]

Hell, on the way down to thew dunes in Oregon alone, you can see 1 strip club and 2 adult book stores from the freeway. I got off at an exit to eat at a McDonalds in Portland and the biggest porn store there is was right by the McDonalds. Oh yes, it was the Castle super store.

[FireHead]

Hell, on the way down to thew dunes in Oregon alone, you can see 1 strip club and 2 adult book stores from the freeway. I got off at an exit to eat at a McDonalds in Portland and the biggest porn store there is was right by the McDonalds. Oh yes, it was the Castle super store.

There is a Castle in Tacoma and Federal Way as well......................... :ermm:

[Bansh-eman]

You need a group.........

EDIT: this link has some explaining on 2-stroke exhaust.

clicky

i think that might have been copied from the site i was looking for. if i remeber correctly that sound exactly what i read before... only differance was the picts on the site to go with the explanations

 

edit: actually after reading it thats not the one i was thinking of....

Edited September 9, 2007 by Bansh-eman

[FireHead]

This subject is really no where near as straight forward this thread seems to be making it. You really need to read the chapter of the Bell book on expansion chamber theory. There is another book by Dixon that also has several good chapters of reading on expansion chamber theory. :geek: