Headers VS Exhaust Manifold
03-16-2005
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Originally Posted by taz757
The cat is in-between the downpipe and the exhaust. That's why the people that get EX exhausts get a cat-back.
You can convert your DX/LX into an EX. You'd just need to get the exhaust manifold, downpipe, cat and exhaust from an EX. Probably need an O2 sim too, since there's no 2nd O2 sensor under the car for the cat.
You can convert your DX/LX into an EX. You'd just need to get the exhaust manifold, downpipe, cat and exhaust from an EX. Probably need an O2 sim too, since there's no 2nd O2 sensor under the car for the cat.
Good information here as well.
You can use an O2 sim or you could just extend the wires on yours so that you can route it to the O2 bung in the back.
03-30-2005
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Rep Power: 261 why would a header be different than an exhaust manifold just because it flows more and is made of a different material? A header is an exhaust manifold. They are two words for the same thing.
04-08-2005
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Originally Posted by 2blu
why would a header be different than an exhaust manifold just because it flows more and is made of a different material? A header is an exhaust manifold. They are two words for the same thing.
Sorry but they are not the same thing.
04-08-2005
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Originally Posted by 2blu
why would a header be different than an exhaust manifold just because it flows more and is made of a different material? A header is an exhaust manifold. They are two words for the same thing.
The differences are explained in earlier posts.
04-08-2005
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Yeah, I am confused. Why is a header different? Just because it is aftermarket and flows more? I read on valvoline's site that headers are just called tubular exhaust mainfolds. So is it because of their shape, size and material that makes them called something else?
04-08-2005
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Originally Posted by robbclark1
Yeah, I am confused. Why is a header different? Just because it is aftermarket and flows more? I read on valvoline's site that headers are just called tubular exhaust mainfolds. So is it because of their shape, size and material that makes them called something else?
Originally Posted by nindoo
ohhhhhhhhhhhhhhhhhhhhh! Is there a diff betwwen an exhaust manifold and headers?
Where is the catalic converter on the EX?
Where is the catalic converter on the EX?
Originally Posted by HondaChevy
At the end of the down pipe.
But yea there is a diff between headers and manifolds. The exhaust manifold which comes stock on our cars is made of cast iron and has a design flow best suited for economy. When it was designed it was done so for ease installation. The performance aspect of the manifold was a minor importance when it was designed. Standard exhaust manifolds usually consist of a common runner with each cylinder having a short runner. In short built solely for the purpose of expending gases and saving gas mileage. The design of our stock manifold is a little better in the fact that the runner tubes or primary tubes are a little longer but man are they puny in diameter. And the bends are not designed for performance but as stated early on for more economical reasoning.
The header has a completely different design--performance is the main factor. An exhaust header utilizes individual tubes to extract the exhaust gases from the engine as efficiently as possible. Exhaust headers are manufactured using mild steel, or stainless steel tubing and even Ti or treated aluminum. The choice of the material to be used is determined by the application it will be used on. Exhaust headers utilize their tube size and length, which is specific to engine models, to efficiently remove all the exhaust from the cylinder reducing pumping loss--which a pumping loss is the power required to move the pistons through the strokes of the cylinders that are not producing power. This is commonly referred to as parasitic loss. If you do not have a header designed to do its job efficiently then you are not making power. There is a proven theory about exhaust gases and exhaust waves and how both improve or hurt performance. This theory also encompasses the design of headers, size of the tubing how the tubing is positioned in relation to the exhaust chamber of the head, if it is port matched in size and shape so forth and so on.
04-08-2005
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Rep Power: 388 Yeah I read that. But they still do the same thing. An intake is an intake regardless if it is a CAI or SRI or stock. A spring is a spring, a shock is a shock even though they are different in the aftermarket. Why do we need two names for the same fricking thing.
04-08-2005
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Rep Power: 261 so how come turbo cars usually use a turbo "manifold"? If a manifold and header were different, people would buy a turbo"header" so they could get more horses.
Last edited by Nick; 04-08-2005 at 09:32 PM.
04-08-2005
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Rep Power: 344 guess I'll throw in my 2 cents.
like HondaChevy, I think manifold and header are two different things (IMO). but the terms are used interchangeably a lot. and they're quite similiar and a lot of times its a bit vague on what u can call one thing or another.
here's the term from webster:
header: a conduit (as an exhaust pipe for a many-cylindered engine) into which a number of smaller conduits open
manifold: a pipe fitting with several lateral outlets for connecting one pipe with others; also : a fitting on an internal combustion engine that directs a fuel and air mixture to or receives the exhaust gases from several cylinders
header are usually individual tubes straight from the exhaust port.. then it connects to more tubes/pipes depending on the header configuration.
thats why we also have intake manifold, but there's no term for intake header. taking a look at the intake manifold will give you an idea on what a mnaifold is. (http://www.hondaautomotiveparts.com/...13S5P0_E03.gif)
a manifold generally has small tube/pipe length and goes from some openings (depending on cylinder exhaust port numbers) into one opening quickly. a good example of this would be the LX exhaust manifold, which goes from 4 to 1, without really any individual tubes for each exhaust port. (refer to pic below) as mentioned already, notice how it goes to the cat. convertor immediately.
DX/LX/D17A1:
the stock EX exhaust manifold, although refer to as a manifold (cuz generally stock exhaust are more manifold than header) is more of a header..
EX/D17A2:
you can find that in most Honda application, the extra horsepower in the EX models not only comes from the variable valve timing, the different intake manifold and different exhaust manifold and system gives the extra yield. I've mentioned this time and again, remember, its not just VTEC that gives those silly 12 flywheel hp rating. there really is an increase in power throughout the RPM ranges, not to mention different gear ratio to utilize that.
anyways I'm getting off track, the EX header is more individual pipe, and is geared more towards performance. hence thats why the cat is further down in the exhaust pipping system.. to allow for more room to design the exhaust header length and bent.
if you check previous generation exhaust system, you'll notice that for our EX models, we have a system thats more restrictive, in terms of design and aftermarket ability. since the downpipe and cat convertor are together in one pipe. giving less room available for different design. our intake manifold could also be better, previous generation's EX have different intake manifold than compare to their DX/LX counterparts, but the same couldnt be said for our much more compacted engine.
I hope this clears it up a bit, to be honest, I cant give too clear of an answer too, because at times I was confused myself and to this date, I dont really think much of it. I find myself using the terms interchangeably too, but again, i generally refer to the stock system as manifold (even if they have header characteristics) and aftermarket ones as header.
like HondaChevy, I think manifold and header are two different things (IMO). but the terms are used interchangeably a lot. and they're quite similiar and a lot of times its a bit vague on what u can call one thing or another.
here's the term from webster:
header: a conduit (as an exhaust pipe for a many-cylindered engine) into which a number of smaller conduits open
manifold: a pipe fitting with several lateral outlets for connecting one pipe with others; also : a fitting on an internal combustion engine that directs a fuel and air mixture to or receives the exhaust gases from several cylinders
header are usually individual tubes straight from the exhaust port.. then it connects to more tubes/pipes depending on the header configuration.
thats why we also have intake manifold, but there's no term for intake header. taking a look at the intake manifold will give you an idea on what a mnaifold is. (http://www.hondaautomotiveparts.com/...13S5P0_E03.gif)
a manifold generally has small tube/pipe length and goes from some openings (depending on cylinder exhaust port numbers) into one opening quickly. a good example of this would be the LX exhaust manifold, which goes from 4 to 1, without really any individual tubes for each exhaust port. (refer to pic below) as mentioned already, notice how it goes to the cat. convertor immediately.
DX/LX/D17A1:
the stock EX exhaust manifold, although refer to as a manifold (cuz generally stock exhaust are more manifold than header) is more of a header..
EX/D17A2:
you can find that in most Honda application, the extra horsepower in the EX models not only comes from the variable valve timing, the different intake manifold and different exhaust manifold and system gives the extra yield. I've mentioned this time and again, remember, its not just VTEC that gives those silly 12 flywheel hp rating. there really is an increase in power throughout the RPM ranges, not to mention different gear ratio to utilize that.
anyways I'm getting off track, the EX header is more individual pipe, and is geared more towards performance. hence thats why the cat is further down in the exhaust pipping system.. to allow for more room to design the exhaust header length and bent.
if you check previous generation exhaust system, you'll notice that for our EX models, we have a system thats more restrictive, in terms of design and aftermarket ability. since the downpipe and cat convertor are together in one pipe. giving less room available for different design. our intake manifold could also be better, previous generation's EX have different intake manifold than compare to their DX/LX counterparts, but the same couldnt be said for our much more compacted engine.
I hope this clears it up a bit, to be honest, I cant give too clear of an answer too, because at times I was confused myself and to this date, I dont really think much of it. I find myself using the terms interchangeably too, but again, i generally refer to the stock system as manifold (even if they have header characteristics) and aftermarket ones as header.
04-08-2005
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Originally Posted by robbclark1
Yeah, I am confused. Why is a header different? Just because it is aftermarket and flows more? I read on valvoline's site that headers are just called tubular exhaust mainfolds. So is it because of their shape, size and material that makes them called something else?
04-08-2005
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Originally Posted by CapYoda
and er.. i guess the easier explaination is yeah, the shape and size is what makes them called different things.
04-08-2005
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Rep Power: 344 like i said, the ex exhaust manifold is pretty much a header. calling it one wouldnt be wrong.
if u take apart the LX manifold from the cat. convertor.. you'll see why its more of a manifold.
and the DC is pretty much the EX with a bit larger diameter, and its not really a 4-2, its 4-1 like the EX.. its just the point where the pipes meet is a bit different, but I know what u're talking about. the bends are a bit different too, and it also gives a bit longer length.
if u take apart the LX manifold from the cat. convertor.. you'll see why its more of a manifold.
and the DC is pretty much the EX with a bit larger diameter, and its not really a 4-2, its 4-1 like the EX.. its just the point where the pipes meet is a bit different, but I know what u're talking about. the bends are a bit different too, and it also gives a bit longer length.
04-09-2005
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Originally Posted by robbclark1
Ok, still not clear. I mean, I have an EX and the DC "header" looks very similar to my "exhaust manifold" besides the 4 to 2 instead of the 4 to 4. I dunno, I guess I see the point, sorta.
That would be because the EX acutally has a header (a crappy one at that)from the factory, all others have a cast (< key word here) manifold meaning it is different becuase of the way it is made and the material used. It is in my posts...not that clearly cut pertaining to our make and models of Civic...simply because I assumed that you guys would get it. Sorry.
Just in case: cast means that there is a mold made for the production of something (in this case a manifold) and then molting iron is poured into this cast to make the end product after the metal has cooled inside the cast.
Header -- two or more tubular pipes that were welded to a mounting flange that is bolted to the engine leading off of the exiting exhaust ports of an engine to be eliminated out through other piping typicaly toward the rear of a car. note this was not made from a cast but rather stratigically bent piping (mandrel) that is welded to a now a days water jetted flange that has port matched holes and then they either step down 4-1 or 4-2-1 into a collector.
Any questions?
04-09-2005
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Originally Posted by HondaChevy
Any questions?
Thanks for the clarification. That makes more sense now.
Manifold - cast
Header - welded
04-09-2005
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Rep Power: 344 ah thats the good clarification. lol. 
I did not remember that at all.
cast and welded.
cast is generally cheaper, more durable, easier to produce by the masses. hence more stock rides comes with cast manifold than a stock header system.
especially econobox like our civics.
IMO I dont think the stock EX header is that bad, at least the weld job is much better than some aftermarket make.. and it'll last forever.
speaking of which, one of my bolt from the header heatshield fell off.. now its all rattling like a *****.. ack.
off topic but, remember after installing/replacing header.. to come back and check torque on bolts/nuts again because they get loose from heat expansion and engine vibrations.
I did not remember that at all.cast and welded.
cast is generally cheaper, more durable, easier to produce by the masses. hence more stock rides comes with cast manifold than a stock header system.
especially econobox like our civics.
IMO I dont think the stock EX header is that bad, at least the weld job is much better than some aftermarket make.. and it'll last forever.
speaking of which, one of my bolt from the header heatshield fell off.. now its all rattling like a *****.. ack.
off topic but, remember after installing/replacing header.. to come back and check torque on bolts/nuts again because they get loose from heat expansion and engine vibrations.
04-09-2005
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Originally Posted by robbclark1
How'd you get to be so smart?
Thanks for the clarification. That makes more sense now.
Manifold - cast
Header - welded
Thanks for the clarification. That makes more sense now.
Manifold - cast
Header - welded
I appologize if I seemed a little rough I have had a bad personal day and I displaced a little anger. Sorry.
Last edited by HondaChevy; 04-11-2005 at 08:55 AM.
04-09-2005
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Originally Posted by CapYoda
off topic but, remember after installing/replacing header.. to come back and check torque on bolts/nuts again because they get loose from heat expansion and engine vibrations.
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