Custom Exhaust, just want to see what people have done Options

[turnaround89]

I am wondering if it would be possible to fab up my own exhaust system for my 1.8L engine. I figure i might be able to save some money this way, instead of buying a brand new one from AA or whomever and i'll learn how to make an exhaust as well. Just wanted to see what other people have done and how they went about it. Pictures would be great. I plan on getting rid of the heat exchangers if that helps out at all!

Thanks in advance everybody!!

[r_towle]

Well, you need a header.

4-1 is easier to build and/or easier to find used, probably the cheapest bet.

For a 4-2-1 you need to call Chris Foley and step up to that system.

If you plan to fabricate the system yourself, you should probably do some general reading on how to build a header, what primaries are, how to measure these, routing etc.

This is information that people have obtained through trial and error in what is often called R&D and its not given away freely in any business manufacturing anything that they sell.

I always chuckle when people are mad that vendors or manufacturers wont share the information on how to make a product and the key decisions behind the design of a product...that information costs money.

I suspect that no one would ever flat out ask a manufacturer of microchips or software or rocket how they are built...basically you would never expect them to share that information.

Reverse engineering has its place and if you can get your hands on a header that someone loans to you, go for it, copy that persons work.
Its not ethical, its not always legal, but its done all the time. Big firms do it all the time but they BUY the product to test it and reverse engineer it.

The key things you need to read up on.
Volumetric efficiency
Tubing size and how it affects are speed and volume.
Thermo Dynamics and the behavior of exhaust gases
Scavenge based systems
Back pressure
Muffler design and baffling.

This information is the basics and no one will step up to teach you the basics, you need to learn this stuff first.

I suspect that once you are honing in on a specific design with specific questions, Jake, Chris, and others will respond.
They just dont have the time to teach the basics that they spent years to learn themselves...

Specific questions, specific ideas that may be a tweak on an exiting design will always spur healthy debate.

So, I advise you to re-state your question and educate yourself enough to pose some questions that may be answerable.

Rich