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Header FAQ

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Old 10-01-2007, 03:33 PM
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Default Header FAQ

Header FAQ

First and Foremost, its header, not headerS. You drive a 4 cylinder, not an 8.

Q. What's the best brand of header?

A. There is no definite answer to this question. Everybody has different preferences, but I think everyone can agree that generic header off of eBay is a bad idea.

Q: What is the difference between a 4-2-1 and 4-1?
A: 4-2-1 brings the exhaust runners together into two pipes, and then into one. 4-1 goes directly from 4 to 1. 4-2-1 gives better mid-range gains, and 4-1 gives better top-end gains.

Q: Two Pieces or One Piece?
A: A two-piece header quite literally comes in two pieces, and you bolt it together in the middle with 4 bolts and a gasket. This technically makes it easier to install, because you can bolt the top of the header to the block, the bottom half to the mid-pipe, then bolt them together from there. In my experiences though, I assembled the header and installed it as one piece, and it was easy.

Note for installation of a two piece header, this is referring to the gasket between the two pieces of the header:
Torque the middle bolt first to 15 ft. lbs. Then the remaining to 15 as well. Then after throttling the engine a few times to break the gasket in, torque all bolts down to 25 ft. lbs.


Q. Will I still pass emissions with a header?

A. DC Sports and Comptech are both technically SMOG and/or CARB certified. There are others as well, such as Headman header's also have some sort of emissions approval, but DC is generally what you'll want if you are going to have to pass an emissions test, especially in California. And also, the DC Race Header is not emissions certified.

Q: How many HP do I gain if I get a header?
A: Gains will probably be minimal, 5 hp is probably a realistic number. DC, GReddy and other large companies sell headers that have been dyno tested and designed for the best gains, so those will obviously give better results than some pipe welded together and sold for $50 on eBay.

Q. Ceramic or Stainless Steel?

A. Theoretically ceramic coated will hold in heat better, which will keep your engine bay cooler, which in turn will create more power, not to mention you can never lose enough heat in your engine bay. If you can find them for the same price, I’d say go ceramic, but other people prefer the look of stainless.

Q: Header Wrap: A good or bad idea?
A: Wrapping/Coating your header seems to be quite an argument. The theory is that it keeps in heat better (similar to Ceramic coating) and keeps your engine bay cooler. Some people say it causes the header to get molten hot and actually melt holes in the header, but this is usually only true on race cars. Some people also say it causes the header to rust faster, but there have been cases in which it is completely opposite, as in the wrapped part stayed in good condition and the unwrapped part rusted really bad. If sealed and wrapped properly, there shouldn't be any moisture getting in anyway (to cause the rust). Stainless is more suceptable to cracking if a cheap wrap is used as well. These cheap wraps contain chlorine, which causes micro-fractures in the steel, and when combined with the heat of the engine can cause the metal to crack. In other words, spend the extra $10 on a good wrap that doesnt include chlorine. On the other hand, this guy seems to be absolutely against wrapping/coating. Wrapping/Coating could also be used to protect oil/fuel lines from the heat, so there is more than one pro of it. Also, header wrap sometimes void warranties on headers, so it's kind of a "Do it at your own risk" thing.

Q. Why are the four top runners of my header turning blue?
A. When stainless steel gets heated up time and time again, it is natural for it to turn blue. Nothing is wrong with your header, it happens to almost every one.

Q: How much is a good header?
A: A good header? Expect to pay atleast $150. Megan is the lowest “Name Brand” header I can think of. DC headers can run $350+, but that’s what you have to pay to drive a modified car in California. GReddy will run $400+ as well. Hedman Chikara headers can be had for under $200, and I’ve seen it as low as $150. EBay headers are usually around $50, which leads me to the next question…

Q. $8 for a header on eBay?? What, is it made of plastic?

A. First off, eBay stores get their money from the shipping. The shipping will probably be like $40, which is totally unrealistic. So the total ends up being about $50 for a brand new header. With eBay, it’s always a risk. You USUALLY get what you pay for, although in come cases you might get lucky. The header might serve its purpose very well for a long time, or it could crack within a month. You will probably have fitment issues, either with the doughnut style gasket not lining up or o2 sensor’s not reaching (amongst other things), so it’s a risk.

Q: How do I install a header?
Header Install DIY

A: Either put your car up on ramps, jack it up with a jack/jack stands, or use a lift to get it up off the ground. You’ll need to get underneath it to access the mid-pipe. Unclip your o2 sensor(s), and using an open-ended wrench, unscrew them from the OEM exhaust manifold. NOTE: If the sensor is still in working condition, DO NOT use a spray lubricant to loosen them up to unbolt them. This may damage the sensor itself and you may need a new one because of this. Unbolt the exhaust manifold from either the cat or the mid-pipe, unbolt the manifold from the block and remove. Be careful with these bolts, snapping one of will be a bitch to get out. Installation is the reverse of removal, just use a new gasket and tighten the bolts on the block from the middle to the outside. Plug in/screw in the sensors, and reset the ECU (disconnect the negative battery terminal for about 15 minutes for best results). If all went well, you shouldn’t have any CEL’s unless, you’re in the 6th generation DX situation….

Q. I’ve a got 96-00 DX/LX/CX. I just installed my header, and now my CEL is on. What happened?
A. What happened was when you installed your header you simultaneously removed your catalytic converter. Look at your OEM exhaust manifold. See the huge bulge about halfway down with an o2 sensor in it? That’s your catalytic converter. From here, you have a few options. #1: Buy the Magnaflow Header/High Flow Cat combo. Magnaflow is only company i've heard of that makes an aftermarket header complete with a cat with the D16y7. The price is around $550, so you're gonna have to pay to keep it simple. #2) Convert your whole exhaust system to EX. Get an EX header, an EX cat, and an EX catback and install them. Also grab an o2 sensor extension (Cutting/Splicing/Extending the sensor wires is risky, but possible if done carefully and you just maintain the wires continuity. If you can find an extension, you will be thankful you got it though.) and plug it into the harness, then plug the sensor into that. Bolt on the new header, bolt the cat to the header, and then bolt the catback to the cat (NOTE: for this gasket, use Loctite, as gaskets are prone to blowing if not tightened correctly). Plug the sensor into the new cat and you’ll be good to go (after resetting the ECU). EX cat-backs are about 16.25” shorter than the DX (or however long a catalytic converter) is, since the EX’s have the cat bolted on right after the header instead of up in the exhaust manifold like your D16y7. Option #2: Get an o2 simulator. These are wired into your secondary sensor (the one that goes into your cat) and trick the ECU into thinking everything is going good with the cat. From here, you can leave your car cat-less (bad for exhaust tone, bad for exhau
 

Last edited by trustdestruction; 02-24-2010 at 08:16 PM.
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