Rep Power: 304

Its looks like the DX/LX civic have headers and the EX has an exhaust manifold. What is the advantage of one over the other? Why do both cars have diff setups?


Picture courtesy of punkingcivic

 
Rep Power: 0

In your example which came off of which? I assume that the one on the right came off of the LX and the one on the left came of the EX?

The stock manifold that came off my car looks like the one on the left.

 
Rep Power: 304

Yeah sorry the headers are on the left. Atleast I think there headers.

 
Rep Power: 481

One on the left is the exhaust manifold for an EX. The exhaust manifold on the right is for a DX/LX. Reason why it looks so goofy is because that's the catalytic convertor.

 
Rep Power: 304

ohhhhhhhhhhhhhhhhhhhhh! Is there a diff betwwen an exhaust manifold and headers?

Where is the catalic converter on the EX?

 
Rep Power: 481

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.

 
Rep Power: 304

when you put aftermarket headers on an EX do you still put the heatshield on?

 
Rep Power: 481

Most of the time the heat shield won't even fit. The aftermarket parts are normally coated with high-temp paint to keep the heat down. You could always wrap it with thermal wrap or something.

 
Rep Power: 285

I dont think so. And a header and an exhaust manifold are the same thing.

 
Rep Power: 304

Do aftermarket exhaust manifolds effect the sound? I'm guessing there is no performance gain from modding the headers alone, maybe if you bore the holes where the exhuast manifold hooks up to on the engine?

 
Rep Power: 0

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.

 
Rep Power: 0

No they aren't.

 
Rep Power: 0

Manifolds and headers are different...they are not the same as I stated earlier. I have been building cars since I was 14, I was born in July of '77 (do the math) every time I have bought headers to replace the stock manifolds I take the time to clean up the ports with a drimel, I make sure there are no strange objects or pieces of weld or metal jetting up into the primary tubes...If you dont really care about fine tuning don't bother, but all I have to say is everyone who follows this and other fine tuning procedures always has a faster better performing car. Just my 2 cents.

 
Rep Power: 304

I guess my next question is difficult to answer, but what headers work well on the 7th gen EX civics from daily driver who is a bit of a driving enthusiast? If I have a 25.4 mm front sway bar can i run into trouble installing aftermarket headers? BTW thanks for the informative post.

 
Rep Power: 304

Yeah getting a few HP here and there and getting my car to perform optimally and reliably is what I'm looking for. I can see why it doesn't come like that from the factory since it would cost Honda more money to put so much effort into an exhaust system of a civic.

Maybe thats why other cars like the SI and rsx type S respond better to these modifications, since they were desinged for sportiness not economy.

 
Rep Power: 0

He's right.....they're the same thing......the only difference its that the one on the LX has the cat on the header..... they're both called exhaust manifold...

 
Rep Power: 304

HondaChevy isn't saying both cars don't have exhaust manifolds, he's saying that an exhaust manifold is diff than headers.

 
Rep Power: 304

Yeah I've seen some racing cars where the headers are wrapped.

 
Rep Power: 0

Not a problem, I don't know everything--but I do know a good deal and I like to be as helpful as possible--if one never asks one never learns.

Your question is a bit difficult to answer simply because I do not know what your style of driving is...if are looking for something all around go with a shorty style header and a good down pipe+ high flow cat...I believe HP and Kamikaze are the best in this department. I have a long tube header that is designed for higher RPM performance...I spend most of my time in the Honda driving at circuit tracks as opposed to the Friday night strip or at the drags (For that I use a Chevy). As for your larger sized anti-roll bar you should not have a problem if the header you choose was designed correctly. Again I have a long tube header and I have no clearance problems with my Suspension Techniques sway bars.

 
Rep Power: 0

Mine are wrapped, it helps minimize heat soak inside the engine bay. Plus this helps give you anything from .5 to 2 hp difference on rare occasions more can be gained from thermal wrap depending on the severity of heat soak inside the engine bay. I have seen cars loose up to 70 hp due to heat soak after consecutive dyno pulls. Again falls under the category of fine tuning.


* some circuit racers go as so far to wrap all the way to the muffler. When I get my car to the level I want I will take this extra step...not recommended for a daily driver*

 
Rep Power: 0

Correct...thank you for the back up.

 
Rep Power: 304

I guess with the shorty you don't loose as much power in the low end of the RPM spectrum as with a long tube header?

There is a downpipe, then there is also a pipe that goes all the acrooss the car to the back and it seems to hook up a box(I guess the cat) then there is a bit more pipe and a muffler. Now is it benificial to change the pipe that goes across the bottom to a pipe witha a larger diameter. I guess a straight pipe is the best for flow, but I think the straight pipe might interefere with my 22mm rear sway bar.

 
Rep Power: 0

I am running a 2.5" pipe from the end of my header all the way back to my muffler and I too have a 22mm rear anti-roll bar and have no clearance problems.

 
Rep Power: 304

Do you have an aftermarket muffler? Are aftermarket mufflers designed so that you can adjust backpressure or are they simply for asthetic and sound purposes.

 
Rep Power: 0

At the moment I am running a Supper Trap...it has a straight thru design and works on a plate and cap system. Most people when I started using it 3 years ago were like WTF is that? I would laugh and say it was a Savoy 2000 (named after the guy who helped me weld everything up). They would laugh and say it looks funny now days most people are familiar with it and most would agree you would be hard pressed to find a muffler that flows as good as it does...I don't do the bandwagon thing--because half the time the bandwagon is full of loose nuts behind the wheel. I am about to do a different setup for full circuit spec racing.

If you purchase an N1 style exhaust that has a silencer it will provide some back pressure. If you keep your cat you will retain some more back pressure. Try running just the header and see if you like what you feel. If it is not enough go with a 2.25" cat back (I say 2.25 because you seem concerned with back pressure and low end RPM power). I would suggest Thermal Research, Magna Flow or a Japanese brand with similar specs.

This one is supposed to be pretty nice and conservative sounding:
http://www.truehonda.com/inventory.p...ctdetail&id=27

 
Rep Power: 304

So you have gotten rid of your catalic converter, and you have a straight pipe all the way through the back? Is your exhaust very very noisy?

 
Rep Power: 0

Sort of, I have a cat delete pipe, but at the same time I ordered another cat delete and welded an OBDII cat in between so I could take it to the sniffer test once a year...at the time my car is a daily driver but making it's way to being a track only car. With all the plates and the cap removed the exhaust is a bit on the anti social side...but it has a deep tone with little blat. Does not sound like the average ricer mobile

 
Rep Power: 304

So you have your exhaust set-up in a way that can be setup for a day at the circuit and then resetup for the street.

What mods you have to your car, and have you gained signifgicant HP over stock?

 
Rep Power: 0

As for the setup that would be correct...I have a setup for the street and one for the track.

As for the hp gains and my mods I will list them after I get the dyno (which will be after I get some ecu gremlins resolved) done so I can hopefully stifle some remarks that will come my way when I share some of what I have done. Until then sorry...but I can say that yes I have noticed a greater increase over stock.

 
Rep Power: 304

great sounds promising, can't wait to hear about your dyno.