Exhaust Manifold and Header Question

[whateverjames]

Why is it a header when the car is naturally aspirated but it's an "exhaust manifold" when talking about turbocharging?

For instance if someone is asking about turbocharging and someone else says "I wouldn't go with the Greddy header if you're going to turbo charge your 240SX, because you'll need a different header for the turbo" then someone ELSE says "You idiot, turbocharged cars do not have headers, they have exhaust manifolds!".

I've always called them by their correct names but why we do we call them their given names, exactly? A header is technically an exhaust manifold right? So why can't a turbo exhaust manifold be called a header, as well, or turbo header? Just curious.

[Tubed4evr]

The stock exhaust manifold on the 240 connects to the "Y-pipe" which connects to the cat. A "header" replaces atleast the first 2 and goes from the exhaust ports to a single tube exhaust pipe . So a turbo exhaust manifold would not be a header since it does not carry the gas from the exhaust ports all the way to the exhaust pipe.


Another way to think of it is that the stock manifold is like the "upper half" of a header and the Y-pipe is the "lower half"

A turbo manifold would not have this "lower half"


That is just the way I see it and that probably doesn't mean much. I have never seen a formal definition of a header so thats just my 2 pennies.

[ca18guy]

They are one in the same I think. Its just easier to have one set for n/a and one for turbo, just look at the defination of exhaust manifold....

EXHAUST MANIFOLD

Definition: A set of cast passages or pipes that conduct exhaust gases from the engine

I don't see how a header is any different then that. I seen some sites call them turbo header before anyway, so its all in how you want to say it imho.

[240racer]

I say that anything that collects a fluid (gas or liquid) from more then one place and exits one place can be called a manifold. With that said, in general, headers are considered tubular. Whenever I think of header, it's a tubular manifold instead of a cast, formed, or shaped manifold. So in my opinion manifold always works and header works when it's tubular. However, to get that picky is ridiculas.

[mbmbmb23]

Since the turbo application has the 2 distinct parts (turbo manifold and downpipe), they've got different part names. In a NA setup, the header would most likely be a single, long peice which spans the exhaust ports to the cat.

Also....the word "manifold" means:

Main Entry: 1man·i·fold
Pronunciation: 'ma-n&-"fOld
Function: adjective
Etymology: Middle English, from Old English manigfeald, from manig many + -feald -fold
Date: before 12th century
1 a : marked by diversity or variety b : MANY
2 : comprehending or uniting various features : MULTIFARIOUS
3 : rightfully so-called for many reasons <a manifold liar>
4 : consisting of or operating many of one kind combined <a manifold bellpull>


It's probably named this way because the exhaust pulses are united within to power the turbo. Or...because its a docking point for any turbo with the correct flange you may decide to bolt up to it.

??

Online Dictionary (http://www.m-w.com/home.htm)

-m

[mrdirty]

Actually, there's a good reason:

If we call both items either manifolds or headers then think of how confusing ordering would be, this way you're sure that if u order a header, then that's what u get and not a manifold.