Here's one for all the guys out there that are currently in the process of buying, or thinking about buying a set of headers for you NA. I'm not going to go into the reasons why you'd ad these as it's already been discussed heavily in other threads. If unsure as to why you'd install these, or what cars they fit, do a search on Headers, or header extractors.
Now, firstly, this DIY doesn't have pics - I know, kinda useless of me but my camera sh@t itself at the time of installing these! The only visual aide I have for you is the pic I ripped off ebay from a set of headers that is for sale - this is not a pic of my install.
Tools/equipment required:
- New headers - make sure they arrived with nuts and bolts and gaskets. If no gaskets came with them, go out and get some new ones to fit!
- Ramps/hoist/jack and stands
- 14mm socket
- 12mm socket
- 14mm ring spanner combo
- 12mm ring spanner combo
- 10mm socket
- heavy duty ratchet
- approx 20/30cm ratchet extension
- approx 5/10cm ratchet extension
- adjustable spanner - just for good measure
- wd40, or equivalent
- plenty of patience
- plenty of muscle.
Step 1 - Preparation
Get the headers.
Jack the car up and place on stands - don't use the jack that you use to change the tyres, it's just not sturdy enough.
If you don't have jack and stands, buy some ramps. I picked up a set from Autobarn for about $60. It's worth having these lying around anyway, they'll come in handy again one day. If you have access to a hoist - even better, use it.
If using ramps, take it easy driving up them, you don't want to drive all the way over the top of them - that would be a nasty experience.
As soon as the car is up on ramps, make sure you leave it in gear, engage the hand brake and chock the rear wheels - safety first!
Find something comfortable to lie on - you'll be spending a bit of time under the car.
Now, you'll need to remove your bash guard to gain access to undo the OEM headers. If you are unsure what this is, it's the big black plastic thing that is bolted to the underside just behind the bumper. There are 5 bolts and 2 screws in all that need to come off. 3 are in front, just along the underside of the front bumper, 2 are at the rear of the guard and there are 2 screws, one on either side up into the wheel well area.
A 12 mm socket will see the bolts out and a 10mm socket will see the screw out.
This is the easy part, the guard should come away with relative ease.
Get out your WD40 or similar and give the bolts on the headers a spray, there are 3 on each side.
Also give the bolts that attach the headers to the cat a liberal spray, these are on really tight and may even be rusted on - mine were
Go off and have a cuppa, or a ciggi, or a beer, or perhaps all three. Let the lubricant soak in for a while.
Step 2 - Removal of OEM headers
Now - it has been suggested that you need to take the OEM headers off all the way through to the mid exhaust - not true, if you've got the right equipment, it is easier to undo the headers from the Cat system. Another bonus of doing it this way is that you don't need to d**k around with removing the o2 sensor from the cat (at least I think it's an o2 sensor).
Start off by getting your heavy duty ratchet, your long ratchet extension and your 14mm socket.
Armed with this weapon, you can easily get the ratchet into position to start undoing the bolts that connect the OEM headers to the OEM cat. You will need to use quite a bit of grunt to get these bad boys undone, but be patient. Last thing you want is to strip the outside of the nut or strip your knuckles.
You might find (as I did) that no amount of lubrication is going to get these bolts off as they are actually rusted tight. This is where the heavy duty ratchet comes in handy. If you're tough enough and your ratchet is tough enough, it should strip the bolt where it's rusted and still unscrew the nut.
Use a combo of the ratchet and the ring spanner combo on either side of the bolt to make sure that it's not just spinning around when you crank it with the ratchet.
Don't worry if you stuff these bolts and nuts as your new headers should have arrived with spare nuts and bolts.
Hopefully at this stage, you should have both bolts off and the headers should be clear of the cat.
Now you move onto removing the nuts from the OEM headers mounting points. You will need to be more careful here as you don't want to strip and nuts or bolts - replacing a stuffed nut in this part is easy enough, but replacing the nuts that hold the headers to the engine block is a tricky task. So, in a nutshell you want to use the original nuts and bolts that held the OEM headers in place for your new headers.
Having said that, you shouldn't have as much trouble removing these as you did with the cat.
There are 6 nuts to remove altogether, 3 on each side and again, use the 14mm socket and long extension.
Once these are undone, the OEM headers should pretty much fall away - be careful that they don't drop on your head.
Once they are off, make sure that the old gaskets are off too - you should have received new gaskets with your new headers!
Step 3 - Installing the new headers
Get the new headers prepped by ensuring the the new gaskets are on hand and that all of the nuts and bolts that came with it are removed. You may need to keep the bolts and nuts on hand that bolt up to the cat if, like me, the old ones were stripped during the removal process.
Firstly, sit the gaskets on the front part of the headers, ready to place onto the engine block. They should pretty much slide straight on, but may need a little bit of pushing and shoving to get them to sit right.
Screw on the 6 nuts that you removed earlier. Note that you will have a little bit more trouble tightening the inner most nut on the left hand side due to the re-configuration of the new header pipes - again, be patient, make sure that you have a good grip on the nut before you tighten it, other wise you might strip it.
No need to tighten the nuts fully at this stage as you still have to screw the headers onto the cat.
Screwing the nuts and bolts back onto the cat are a walk in the park compared to removal. It's pretty much just the reverse process of take them off. Make sure you do these up tight!
Go back around and tighten the nuts all over - check and re-check them.
The plastic guard that you removed at the start will no longer fit properly due to the new configuration of the pipes.
Well, it will fit on, but you will need to do some chopping of it to make sure that none of the plastic is touching the exhaust - I haven't traveled down that path yet, so I will ad notes on how to do that at a later date.
Step 4 - Clean up
This is simple and sensible step to take before you even think about starting the car.
Remove all tools away from under the car and into a clear location. That way you are going to know whether you have all of your tools accounted for and that nothing is left in the under carriage of your car.
Step 5 - Start 'er up!!
Go nuts, start the car.
Initially, you won't notice much difference. Let the car warm up a bit, then give it a bit of a rev.
Hello Boxer rumble!
I wondered where you were hiding!Don't be surprised if you see a bit of smoke coming out of the exhaust - it's just the crap burning off from the heat being generated in the new pipes. There will also be a bit of a burning smell for about half an hour.
Be aware that you car is going to sound different, not just your exhaust note, but it's going to be noisier at the front end.
You've pretty much gone from thick cast iron headers, wrapped in heat shields to stainless jobbies with no shields on them, so you are going to hear the engine working when you plant the foot, as if you can hear the exhaust rushing through the headers.
This noise should subside a bit as soon as you get some carbon deposits built up on the new pipes.
Performance wise, you should notice that the car breathes a little more easily and it takes off a lot more easily from stand still (doesn't get bogged down as easily in the low rev range) and that the torque curve is more responsive throughout the rev range.
You should also notice a bit of an improvement in your fuel economy.
Finally - Make sure that you get your car up on ramps again after a couple of days to make sure that all of the nuts are still nice and tight.
I hope that some of you find this DIY helpful. If you think anything needs to be added, or if you have any questions, just let me know.
Cheers,
Chris
you sure are serious about this supacheap moneh 
