TRIZ

iTrader: (14)

I prefer ceramic coated because it not only as the benefits of a "heat shield" painted over the entire thing, but it just looks cleaner the more and more its used. KEEP in mind, I live in Oregon where we dont have crazy winters that require us to salt the roads, which is what 99% of the rust on cars is caused by. Here we do get rain about 80% of the year though- stainless will change colors when it heats up and when it gets wet, which is permanent. I've seen some nasty looking ceramic headers that have been used to ****- I have to admit. But I've also seen some really nasty looking stainless ones.

I know there are others that like stainless, like foos. It really comes down to preference. If they salt the roads around you then you'll prob have a different opinion.

Also, driving style is a factor. If your car is slammed and your driving over **** and scraping your header up (mainly just a problem with race headers due to the secondary collector meeting up after where the cat is on a stock EX) then you'll probably want stainless because the coating wont get scratched, which will cause it to rust and eventually fall apart.

Thats my take anyways.

madAd

My car isn't slammed, and I don't plan on lowering it, mostly because of the Michigan winters. But I just like the stock height too. But I probably will go with ceramic for the lower running temps , plus it's quite a bit cheaper. The ceramic race header goes for 375 on summit, not sure about the stainless, but the stainless one piece is over 450. My main problem I'm trying to solve with this is I have a huge crack in my stock LX mani, and it's cheaper to replace it with a good exhaust system than with the stock repl., which I've seen a lot of people on complaint sites say that these crack pretty commonly. Thanks for your input guys.

TRIZ

iTrader: (14)

I have a DC sports race header, I just pulled it off the car on saturday because I got emissions coming back up. Its in fine condition, no cracks or anything. Get at me if your trying to get a race header. Keep in mind, you'll need an EX catback to run an EX race header.

madAd

pm sent

unTuned

once you pass emissions what are you putting back on there triz?

TRIZ

iTrader: (14)

Nada, just rocking stock for a while till an s2000 magically appears or I have enough to buy one (which wont happen soon)

ProjectMayhemR

iTrader: (1)

Has anyone swapped the 2001 dx/lx front sway bar for the ex one? I"m wondering if it mounts in the same place. I'm tired of my resonator rubbing on the one I have now.

TRIZ

iTrader: (14)

People have. It does. Get it.

ProjectMayhemR

iTrader: (1)

sounds like a plan

madAd

I just looked up the sway bar on majestic, they are the same for the LX and EX sedans, but the LX coupe's is diff., and the EX coupe's is even a different part number from that, so there are like two different part #'s for each one, which makes 5 or 6 different sway bars. Is it the one for the EX coupe that is supposed to fit an EX exhaust better. Or since I have an LX sedan and the EX sedan's bar is the same, I shouldn't have any problem right? But the EX coupe's is bigger, 25.4mm, mine is 22.2 so that may be a reason to upgrade.

madAd

Just wanted to give props to TRIZ for hooking me up with the DCRH. Just arrived today, which was pretty quick for shipping from OR to MI. Was packaged nicely, and is in great shape for a used header, just as he said it was. Thanks man.

Here's a picture of the header, and the DC exhaust I got to hook it up to.

Cleft_Asunder

iTrader: (1)

What I want to know is why I should buy a more expensive cat like the random tech high flow cat as opposed to some new $100 one on ebay. Does high flow mean less back pressure or is it gain on both low and high end because it eliminates traditional cat limitations?

I'm also confused about why you say it's a stupid idea to do the below. Because the DX/LX downpipe has 1 pipe instead of 2 like the EX?

If you want an EX header and stock DX/LX exhaust with a cat, buy a cat and take it to a muffler shop and they will connect the header to the rest of the exhaust and weld the cat in line. This is kind of stupid- see backpressure. You'll also run a check engine light. To avoid this- see O2 extenders / defoulers.

And also, everyone talks about welding the cat into place. Is there a way the mufler shop can make it so that the cat can be bolted and unbolted on both sides? Or is one side of the cat going to have to be welded to the mid pipe no matter what?

TRIZ

iTrader: (14)

Cheap cats tend to fail sooner then higher quality cats- which is due to the materials they use to filter the "bad" out of your exhaust. So when you step up to a higher quality cat, your doing yourself a favor because not only will your cat last longer, but your emissions will be cleaner- helping everyone on this planet enjoy it a little longer (my green pitch). The whole back pressure thing has been argued as a myth in the past. I'm not sure if I completely agree with it or not, but I've provided the info in the FAQ for just representing that the idea exists. I also must add this: the "high flow" cats are great because they give you the benefits of being able to quickly get your exhaust gasses out of your system as quickly as they are created (just as fast as not having a cat altogether), but you also have the added fact that your exhaust is filtered of the harmful **** thats killing the planet, which is a huge draw back to not having a cat and the reason why they are legally required.

What I was saying about that is this... Buy an EX header, stock or aftermarket, it doesnt matter- just buy it, bolt it on. You'll see you lose your stock header of course, but the stock header includes a built in cat, so that goes with it. You could just have a muffler shop connect a pipe between the EX header and your DX/LX exhaust, but its pointless for two reasons. 1) you just lost your cat, and 2) why did you upgrade your header but leave a pea shooter exhaust- that did no good.

If you want to upgrade your header and keep the stock exhaust, for whatever reason, and you want to keep a cat on your exhaust, then do this. Buy an EX header, bolt it on, and have a pipe made to connect between your header and exhaust. Somewhere in there you want to have a cat welded in the exhaust path, and you'll also want to extend the wires to get accurate O2 sensors readings so you can pass emissions, have your ECU correctly determine your AFR and all that.

Now you can have a cat "welded in" wherever you want. Instead of welding it in, you could have them weld flanges on either side of the cat and your exhaust pipes where its going to connect, so you can bolt and unbolt it. This would be cool if you want to remove your cat for track use, or if you think its going to be something you need to replace frequently, or whatever the reason, yes its doable and probably a better idea then straight up having it welded in.

speedfoos

iTrader: (17)

An inexpensive Magnaflow cat from Summit costs $70 and flows just as well as that over-priced Random one...

When I had my Civic I welded flanges on both sides of my cat, and also had a same-length pipe with flanges on it. This way if I needed a cat for emissions purposes it was a 30-minute job to drop my test pipe out and pop the cat back into place. V-bands make it really easy to do this.

[attach][/attach]

Cleft_Asunder

iTrader: (1)

Okay, I understand most of it now, thanks. But I'm wondering about the DX/LX exhaust past the down pipe. Is the pipe ID different from the EX? Is that what you mean by "keeping the stock exhaust for whatever reason," because ideally I would want an EX mid pipe and muffler? Or is the mid pipe and muffler on the EX the same ID and same specs as the DX/LX?

There's a guy selling a 1-piece 4-2-1 DC header for 120 in town. Is that a good deal? I wonder if it will line up on the 6th gens unlike the 7th gens. Then all I would need to do is shorten the mid pipe for the cat. I also found a stock EX setup on ebay starting at 20 dollars, so I may just go with that.

Oh and I also wanted to ask, can a cat be installed both ways, or is there a front and back?

speedfoos

iTrader: (17)

All cats typically have an arrow indicating direction of flow. If they don't have that arrow, then it doesn't matter.

madAd

I was wondering, since I just put that race header on my car, would it make sense at all if I got a high-flow cat and got pipe and flanges welded on it so I could bolt it in place of my resonator on my DC exhaust? Or should it be near the front of the vehicle for some reason? Or would my car be even louder without the resonator?

TRIZ

iTrader: (14)

Its typically near the front of the vehicle closer to the engine is because its easier for the wires to reach where they need to go. If you put it back 3/4ths of the way where your resonator is, then you would have to run longer wires for your O2 sensors... a pretty easy fix. It owuld be a good idea to have a cat you can bolt in place like that.

TRIZ

iTrader: (14)

Well whats the point of upgrading a header if your not going to upgrade the rest of the exhaust? I"m not sure about the ID diam of your civic's exhaust, but the exhaust pipes are pretty small- like 1.25 inches if that. You typically want to have larger exhaust pipes for better flow and performance, which is the main reason ppl upgrade the header in the first place, for better flow and performance. The main reason you would need to change it with a DX/LX is because there arent very many DX/LX specific exhausts out there to choose from, they are all LX.

mmajimmy19

im so lost with this lol... RElax im learning. What excalty do i need if im going to convert my lx to ex headers and exhaust? and why?

speedfoos

iTrader: (17)

The cat is closer to the engine because of the cat "light-off". The catalyst element inside needs to reach a certain temperature to function properly - burning up all the contaminants in the exhaust stream - and to do this quickly, it needs to be as close to the exhaust ports as reasonably possible. The closer it is to the motor, the hotter the exhaust stream, facilitating the cat light-off. It has nothing to do with wire length.

Mr. MMA. If you are not going to do a custom exhaust setup, then you need everything forward of the midpipe section on an EX. The difference between the LX and EX - from head to midpipe (1st part of a catback system) - is that there are different components of varying length. The LX header is longer than the EX header, and as such, the LX downpipe (which goes between the header and midpipe) is shorter than the EX downpipe. Make sense?

madAd

Yeah, that's what I was wondering about. As far as the wires go, I could have just left them where they are in my race header, even though there's not a cat between them, they think there is. But I guess the cat would be pointless if it's affected by being too far down the exhaust stream.

speedfoos

iTrader: (17)

Not so much pointless as inefficient. It will eventually reach light-off temperature, but depending on the type of emissions testing, it might not pass right away. They would have to hot test it.

madAd

Well, I'm not worried about testing, they don't do it in Michigan. I just thought maybe I should have a cat, even though I'm still probably putting out a fraction of the emissions of some vehicles.

TRIZ

iTrader: (14)

Thanks for that info speedfoos, I had no idea about that. I figured it made more sense to have it closer, but never came across any reasoning saying it had to.

So at what point is light-off? And when you say light off, you mean any emissions codes that would come up because the cat is inefficient, would then go off because the cat is efficiently doing its job, or am I totally off on this?

And if thats the case, then why wouldnt they go ahead and put a mini cat in each of the exhaust runners, or build it into the exhaust port side of the engine some how? I'm sure there are performance drawbacks, but would this yielder less polution/ cleaner emission vehicles?

Cleft_Asunder

iTrader: (1)

Well the point would be when you're in a situation like mine where your stock header is cracked, but you can't find a direct replacement nor have a desire to. So cheaply, I can replace it with an EX setup. Though the EX header is cast iron, if it cracks it can cheaply be replaced by a steel one.

Any way thanks for the help, I have a good idea what I will do. But other than my idea, could I redo the whole exhaust with aftermarket for under 500? Would you go with a cat back exhaust?

TRIZ

iTrader: (14)

You could as long as you pick up some used parts to meet your budget instead of new parts. Most of the time theres just a few scrapes on them and a bolt missing- cosmetic and easy fixes. Def doable tho.

speedfoos

iTrader: (17)

Here's a good link to how a catalytic converter functions.

http://www.aa1car.com/library/converter.htm

The light-off temperature occurs between 400-600 degrees. Copied from that link is the explanation for why a P0420 pops up.

"On 1996 and newer vehicles with OBD II onboard diagnostics, the OBD II system has a catalyst monitor to keep an eye on converter operating efficiency. The OBD II system compares O2 sensor readings upstream and downstream of the converter. If the downstream readings start to match those of the upstream O2 sensor, it indicates a drop off in operating efficiency and sets a catalyst code P0420. Other converter faults may set codes ranging from P0420 to P0439"

There is a delay built-in to account for the time it takes for a cat to reach operating (aka light-off) temperature so you don't throw a code every time you do a cold start on the car.

Be careful what you suggest on cats for every exhaust runner. The enviro-***** might think it's a good idea.... But there are a couple reasons they don't do this.

1. It's expensive to stuff the individual runners with enough catalyst material to be effective. Think of how much surface area is in that 14"x 4" cat and now figure how much of each individual runner would have to be stuffed to reach that same surface area. Not to mention how would you get in to the small runner and secure it so the engine vibrations don't just knock it loose.

2. Balance between emissions and power. It's a trade-off. Sure, if you run 8 cats in a row, your exhaust stream will be as clean as a whistle, but holy back-pressure Batman. Nissan and some other manufacturers do something similar. For instance, my 2004 Frontier has 4 (count em 4) cats. Two coming off each cylinder bank. Luckily the secondary O2 sensor is before the secondary cat so I can remove it without having to worry about tripping a code, but Nissan decided cleaner exhaust was better than more power.

Make sense?

TRIZ

iTrader: (14)

^ Nice, good info. I read most of it and just Bookmarked it too!

Cleft_Asunder

iTrader: (1)

What exhaust brands should I look for?