[Question] Headers, cat, exhausts

m2zero · Postby **m2zero** » Tue Mar 17, 2015 12:44 pm

I don't know much about headers, exhausts and cats so I hope someone can offer some advice.
I have a pretty standard NB and am looking to replace the the whole back end, headers, cat etc. I just don't know what I'm looking for, my goal is to make a nicer sound, nothing to crazy, a few extra horses and help the car breath easier, I have no plans to add any type of forced induction on this car.

Postby **NitroDann** » Tue Mar 17, 2015 12:53 pm

Im not sure what you are asking, do you want someone to point at a system and say 'Buy that' ?

sailaholic · Postby **sailaholic** » Tue Mar 17, 2015 1:17 pm

Think they are looking for a buyers guide.

For the ops reference back end usually only refers to the last third which includes the muffler.

Headers are in the front of the car attached to the engine.

Cat is in the middle.

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m2zero · Postby **m2zero** » Tue Mar 17, 2015 1:23 pm

Yeah I would say more of a buyers guide. What size pipes. different types of cats. Can I buy the whole thing online and just get someone to install it, what kinda sounds to exhausts make. What experiences do you have if you have done any mods to these parts. Just anything really.

hks_kansei · Postby **hks_kansei** » Tue Mar 17, 2015 2:05 pm

The NB exhaust is made up of 3 parts.

The headers, the Midpipe, and the Muffler.
The midpipe consists of the cat, and a resonator, both welded in place. (on the NA the midpipe is simply a pipe, with the cat bolted on)

If you just want to change the sound, you will be looking at the muffler. The sound of different mufflers isn't that different, the volume can differ greatly.

The Cat can be replaced with a high flow item, or removed completely. A high flow cat can give a little more power, and can make the exhaust sound a bit rougher.

My car has OEM headers, a high-flow cat welded into the OEM midpipe, and an RSR exmag GT2 muffler.
Performance is about the same as stock, as most exhausts will feel on a car that's factory engine wise.
Noise, it's loud, the exhaust drones, the exhaust pops and bangs sometimes, once or twice a bit of flame comes out.

would I recommend a similar setup?
probably not.
The car sounds nice, and I do really enjoy the obnoxiousness some days.
BUT, it does get a bit old having to cringe whenever you pass an RBT, when you need to drive on the highway for more than 10mins, when you come home late and need to roll down the driveway to not wake neighbours.

m2zero · Postby **m2zero** » Tue Mar 17, 2015 2:21 pm

Thanks hks_kansei. Ok so would it be worth putting a high flow cat on, without changing the headers, and are new headers really worth it, without turbo-ing the car?

sailaholic · Postby **sailaholic** » Tue Mar 17, 2015 2:59 pm

Headers are only worth it with no turbo. Turbo manifold replaced headers.

Worth it depends on how much you want to spend per hp

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hks_kansei · Postby **hks_kansei** » Tue Mar 17, 2015 3:32 pm

Personally, on a car that is staying standard engine wise (ie: stock cams, bottom end, ECU etc) I wouldn't bother with the expense of headers unless you really like how they look.

High flow cat made only a minor difference, mine is some Japanese one I bought cheap from a friend, but I wouldn't have thought the new price was worth it.

My understanding is that unless you also tune the car to suit your mods (ie: with an aftermarket ECU) there is very little power to gain. Maybe 1-2kw or so.

Basically, if I wasn't able to buy the exhaust parts on my car cheaply, I wouldn't have done them.
If I were paying brand new price I would just buy a muffler for the sound, and leave my money aside for future when I went for bigger power mods like cams etc.

m2zero · Postby **m2zero** » Tue Mar 17, 2015 3:37 pm

I have no idea how old the cat on my car is. Do these things get clogged up after a while? should I at least replace it and then just get a cat back system?

MLR · Postby **MLR** » Tue Mar 17, 2015 3:39 pm

Stock manifold or headers to 2.25 cat to mid pipe with a muffler at the rear.

The stock manifold isn't that bad.

Mine is the above with headers, very high flow cat and no mid pipe, I like loud and obnoxious with cackles and pops and flames.

If you want it quieter without drone a resonator in the mid pipe.

Might make 5hp more somewhere in the rev range dependant on manifold selection.

Stock exhaust whilst only slightly restrictive sounds like a Hyundai excel.

I wouldn't go cams and ecu on a internally standard NA, lots of outlay for minimal gains.

But then that's me.

m2zero · Postby **m2zero** » Tue Mar 17, 2015 3:42 pm

Thanks MLR, where abouts did you source your parts from? and how much did you pay.

Postby **NitroDann** » Tue Mar 17, 2015 4:18 pm

MLR wrote:Stock manifold or headers to 2.25 cat to mid pipe with a muffler at the rear.

The stock manifold isn't that bad. Have you cut one open? They really are 'that bad'.

Mine is the above with headers, very high flow cat and no mid pipe, I like loud and obnoxious with cackles and pops and flames.

If you want it quieter without drone a resonator in the mid pipe.

Might make 5hp more somewhere in the rev range dependant on manifold selection.

Stock exhaust whilst only slightly restrictive sounds like a Hyundai excel.

I wouldn't go cams and ecu on a internally standard NA, lots of outlay for minimal gains.

But then that's me.

MLR · Postby **MLR** » Tue Mar 17, 2015 5:56 pm

NitroDann wrote:
MLR wrote:Stock manifold or headers to 2.25 cat to mid pipe with a muffler at the rear.

The stock manifold isn't that bad. Have you cut one open? They really are 'that bad'.

Mine is the above with headers, very high flow cat and no mid pipe, I like loud and obnoxious with cackles and pops and flames.

If you want it quieter without drone a resonator in the mid pipe.

Might make 5hp more somewhere in the rev range dependant on manifold selection.

Stock exhaust whilst only slightly restrictive sounds like a Hyundai excel.

I wouldn't go cams and ecu on a internally standard NA, lots of outlay for minimal gains.

But then that's me.

I never notice a difference except for the headers giving more noise.

I never cut one up to look though, are we talking NB?

My car is stock except for exhaust and intake though, a built motor with a higher rev limit might notice it more, or, are they really that asthmatic, I know they reduce internally at the joins but I ddnt think they really were that bad for a low power low reving motor, am I dreaming.

Do you have any pics of said culprits.

markwid · Postby **markwid** » Tue Mar 17, 2015 6:43 pm

Agree with Dan. While the stock header is not bad, having a good header opens up the mid range power of NB.

I am running xforce headers, high flow cat and xforce mufflers - basically what the OP is looking at. Much better mid range and just feels stronger, freer flowing than stock.