2 Stroke engine performance resources. Books, and other things.

[Dr. Kit]

Thanks. Yes, pulsejets are great.

Here is a link where you can see an animated GIF showing 2 Stroke engine in a dynamic way (bottom of page) :

http://www.vf750fd.com/blurbs/stroke.html

The effect of the negative shock wave from the expansion chamber, extracting more gaz directly by the transfert ports and the carb, is very visible in this GIF. It's exactly like in a pulsejet : the violent depression wave following the burnt gasses has the capacity of admiting fresh gases, without the action of any mobile element like a piston. It's a way of using "free energy" from the exhaust gasses which would have been lost, to obtain a certain degree of "overfeeding". It can be seen like a kind of "sonic supercharger". And so the filling of the cylinder is better. And I think this is the secret of the incredible power of modern reed valve 2 Stroke engines. In fact, 2 Stroke engine is a kind of pulsejet!

Here are two Youtube links. The first is a mega-tuned Kreidler 50cc, the second is a small pulsejet. The sounds are from the same family...

http://www.youtube.com/watch?v=8QdSf...rom=PL&index=1

http://www.youtube.com/watch?v=oPevraef4gI

Hum, I hope this kind of post is okay in the "Mad Scientist Lair"!...

Billy Golightly, I readt your first post, concerning two stroke tuning ressources. I had readt yet the book "2 Stoke performance tuning" by Graham Bell, and found it very interesting. But, after reading your post, I readt (in fact I read it now) "2 Stroke tuner's hand book" by Gordon Jenning. And you are right : this book is really the bible, it is very very interesting, ALL the problems are explained, or at less, seen, by the autor. And this book is very clear, simple and of high level at the same time, and very nice to read, also, nice style.
I think I'll spend some time reading the others books, after... (Okay, maybe I'm a "2-Stroke nerd")

[tecate 250rr]

Thanx you guys for this thread and all the contributuions .I am a knowledgeable mechanic and this stuff is just amazing i wish i could absorb more faster , thanx again

[MonroeMike]

Two Stroke Performance Tuning by A. Graham Bell

http://www.kreidler.nl/artikelen/per...raham-bell.pdf

[Dr. Kit]

Another little contribution in the pure mad scientist style, about “Kadenacy effect”…

If I undersdand well (wich is not very sure…), the Cadenacy effect is a “storage” of energy from the previous stroke (cycle), under the form of pressure differential, to use it in the following stroke. This pressure differential is created in the crankcase by the negative wave generated by the diverging part of the expansion chamber. This phenomenon exists particularly in pulsejets and in two stoke-expansion chamber engines

Some links :

http://en.wikipedia.org/wiki/Kadenacy_effect

http://jetzilla.com/topic_003_01.html

(“a kind of reciprocating air pump without any moving parts!”)

http://jetzilla.com/topic_003_02.html


And I think that Gordons Jennings, in fact, speaks about this phenomenon, page 91 in “Two Stroke Tuner’s Handbook” :

http://dl.free.fr/tSiiCNIuL