# 2-stroke exhaust pipe **URL:** \ **Category:** Factual Questions\ **Created:** [March 18, 2001, 6:34pm UTC](https://boards.straightdope.com/t/2-stroke-exhaust-pipe/58487 "2001-03-18T18:34:22Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![Enola\_Straight](https://avatars.discourse-cdn.com/v4/letter/e/dec6dc/32.png) [@Enola\_Straight](https://boards.straightdope.com/u/Enola_Straight)\ **Post date:** [March 18, 2001, 6:34pm UTC](https://boards.straightdope.com/t/2-stroke-exhaust-pipe/58487/1 "2001-03-18T18:34:22Z")
With a regular 4-stroke engine, the exhaust pipe is an ordinaru steel tube of uniform diameter. But a 2-stroke exhaust is a convoluted pretzel-like thing that gets fatter and skinnier as the exhaust travels through it. What is the rational behind this strange bit of engineering? ---
**Author:** ![Una\_Persson](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/una_persson/32/346_2.png) [@Una\_Persson](https://boards.straightdope.com/u/Una_Persson)\ **Post date:** [March 18, 2001, 7:33pm UTC](https://boards.straightdope.com/t/2-stroke-exhaust-pipe/58487/2 "2001-03-18T19:33:51Z")
Not on any 2-stroke I have ever seen. Are you sure what you are seeing is not specific to a particular engine and/or application? ---
**Author:** ![Shiva](https://avatars.discourse-cdn.com/v4/letter/s/85e7bf/32.png) [@Shiva](https://boards.straightdope.com/u/Shiva)\ **Post date:** [March 18, 2001, 7:39pm UTC](https://boards.straightdope.com/t/2-stroke-exhaust-pipe/58487/3 "2001-03-18T19:39:15Z")
How Two-Stroke Expansion Chambers Work, and Why You Should Care: [http://www.motorcycle.com/mo/mcnuts/em-pipes.html](http://www.motorcycle.com/mo/mcnuts/em-pipes.html) ---
**Author:** ![Anachronism](https://avatars.discourse-cdn.com/v4/letter/a/e56c9b/32.png) [@Anachronism](https://boards.straightdope.com/u/Anachronism)\ **Post date:** [March 18, 2001, 9:40pm UTC](https://boards.straightdope.com/t/2-stroke-exhaust-pipe/58487/4 "2001-03-18T21:40:35Z")
Most two-stroke dirt bikes (that I have seen) have an exaust pipe like the one **enolancooper** describes, **Shiva’s** link does a very good job of explaining them. I guess complicated exhausts are mostly seen on high performance two-strokes.