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Basic Bolt ons: Exhaust Headers/Flex Pipes

128K views 244 replies 70 participants last post by  felixthecat 
#1 · (Edited)
In this section I will go into detail describing the kinds and brands of exhaust headers and flexpipes.

When it comes time to choose an aftermarket header for your car you have a few things to consider. Mainly you want to decide if you are going to stay emissions legal. If you are going to stay emissions legal then don't install a header. Due to the combination Catalytic Converter/Exhaust Manifold, or Mani-Cat, you are unable (technicalities aside) to pass emissions with an aftermarket header installed. If meeting emissions requirements isn’t necessary then a race header is one of the best bolt-ons for the Duratec engine.

Here are some of the headers you are likely to see on the market.

FocusSport
OBX
Cosworth (discontinued)
F2 (discontinued)
Weapon-R

PROS
For the money, if you plan to make serious NA power a header is absolutely necessary. Also they cannot be beaten when it comes to price. Average headers go for between $325 - 375

CONS
Installing a header requires removal of the catalytic converter. Many folks cannot remove their cat for emissions reasons. This makes a header impossible to use. Also, noise is drastically increased with the installation of a header.

All of the headers listed come with the Flex Pipe included (except the FocusSport which is available seperately). Keep in mind there are different flex pipes for ATX and MTX so be sure to select the proper piece!


Comments, discussion, and corrections welcome!
 
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#198 ·
I have an 08 SES and it's shift points are much better than my 07 SES. Can the 07 be flashed as an 08 ?
I have an 08 SES and it's shift points are much better than my 07 SES. Can the 07 be flashed as an 08 ?
You'll need to hit up the tune section of this forum for those answers.
 
#203 ·
well I personally am about to be in the market for putting a few thou. in my car. I'm looking at a long tube header (weapon-R) ( item #953-117-103) and a weapon-r intake manifold (can also be found on their web) I'm very very curious to know IF anyone has used them?
 
#204 ·
Ive not heard of anyone using either (for an 03-07.) I believe the weapon-r intake manifold only works on 08-11 focus due to drive by wire. If you want an intake manifold, that leaves you two choices; Cosworth and there is a generic clone of that one also sold.

As for headers, FSwerks and OBX are used the most often.
 
#207 ·
i've literally read through this entire thread and what im thinking now what i wanna go with is an fwerks stealth exhaust system, fwerks cool flo intake, and an obx header. im still confused on what tune i need to buy, or how to use it/install it. And is there any other parts im gonna have to buy in order to make thhis all work? i just bought a d20 sedan and really want to make it into something i can be proud of
 
#208 ·
emissions are not are pproblem for me by the way! im just curious on exactly what ill need to buy to make that all work.. honestly right now it seems like a huge amount of work. but dont get me wrong i absolutely love working on cars!

also maybe i should go with a new tb?
 
#209 ·
Usually the tune is added when you add the header. This is usually because after market headers do not have a provision for EGR and it also eliminates one (or two if you had three to start) O2 sensors. Also, once you are into the header after adding a CAI/Exhaust, it makes sense to have the tune as your stock ECU could struggle to provide the right amount of fuel/air with the increase in breathing of your motor. However, you can add a tune at any stage, just need to update tune after each mod to make the most of them.

Tuning is easy to install, just plug in SCT xcal into ODB2 port and it flashes the tune to your ecu. It also is a good idea to tune for 91 or 93 octane, will make the most of power/drive-ability. I dont suggest, imo it just hinders drive-ability and not worth the extra money. The two biggest tuners are Focus Power (sponsor on this site) and FSWerks, reach out to either, they will both be eager to help.
 
#221 ·
A desent muffler shop should be able to fab up a center exit for you.
Im looking in to purchasing. The fswerks 4-1 header for my 2.3 liter st. Is anyone. Else running this on there's. And if so will it pass emmisions?
Yea, I have a fwerks header, flex & stealth w/ their tune. Have them turn off the rear 02 sensor & egr. For emissions= if they plug into the obd2 connector to look for codes, your golden.
 
#222 ·
This may sounds crazy but is there anyway to determine what kind of header is on your car? I bought my car that already has a header on it. Since then I added a COI and exhaust and have a programmer ordered. But I would love to know what kind it is and know what exactly I have. Any way I would be Abel to determine that?

2007 zx4 2.0 COI, header, exhaust, eibach racing kit, and massive bars
 
#223 ·
Throw up a few pix in your profile album,,,,,,, I have a few of mine to give you a idea, go to my profile & click on the pix on the right,,,,,,,,
 
#224 ·
Its most likely one of 3 or 4 brands. FSWerks, Cosworth, OBX(Cosworth knock off), or F2.
Post a pic, or do a google search on each one and compare pics you find with yours
 
#229 ·
Hate to tell you Bruce, but you're wrong. It's an F2. Based purely on the location of the o2 bungs. I've never seen an obx with a bung there. The F2 had 3 bungs on one version, same one I have
 
#235 ·
I found an old, unused F2 header on ebay almost 4 years ago now for dirt cheap. I painted it, wrapped it, and have been running it ever since. The wrap is starting to fall apart, and I had to replace the flex pipe with a custom made piece I had a local exhaust shop make earlier this year, it completely gave out and was leaking everywhere.

The F2 got a bad name for fitment issues around the firewall and more specifically the alternator, also famously known for crap flex pipes. However, functionally it certainly works better than the factory manifold and most versions have at least two, if not three o2 bungs.

If you already have it on your car, leave it alone until you run out of other stuff to change out... but you might want to check out the flex pipe, make sure its not leaking. The flex part leaks or sometimes the flange will warp making it impossible to seal with your midpipe.
 
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#237 ·
Can you even run a header on your car down there? Do they do visual's(look underneath the hood). If all they do is check for codes, thats one thing. You'll need a tune also. Have you done a bsd on your 23?
 
#238 ·
I have a bone stock D2.0 im looking to have the exhaust flow more freely while still remaining legal. I'm looking at replacing the stock header with the magnaflow one ( includes factory cat placement) *flows more freely that a stock cat though* and behind that I would like to go with the magnaflow street exhaust . In front the intake will be a steeda ram intake. Im curious if people have had good success with a similar setup . Im also looking to get an idea on a good setup for the intake manifold. I heard weapon r makes a good one, not sure if it would be too free flowing, or what kinda nd of difficulty could arise with installing the weapon r intake manifold. Thanks in advance!
 
#239 ·
I need some help here. I have a 2005 2.0 ZX3 with a FSWerks header and race exhaust. I would have gone with the stealth exhaust but I needed to be able to add the cat in. I put a Flowmaster cat on it, just past the exhaust hanger and a small resonator behind it. It is still wicked loud. I guess it would be great if I was still 17 but that was many years ago.

What I would like is to get back to the exhaust level it had before. I had the FSWerks header into the stock exhaust, with the rear muffler cut off and straight piped. Appearance wise, the exhaust was very similar to what is on the car now. I'm at a loss as to why it is so much louder now.

Anyone have any ideas?
 
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