Now first of all.
I was smart enough to search for exhausts threads before I did this, but had some trouble finding advice in one place, everything seemed a bit all over the place, so I have a few questions still.

I want to get my exhaust done on my Magna. It is currently fully stock.
From what I have gleaned, it seems that getting 'cat to back' (or something of the like) is the way to go, with a Lukey or Magnaflow muffler.
But that is a jumble of words to me haha. Could anyone explain what that actually means? So I'll be able to know exactly what I should be asking for when I go ask people for quotes.
I know this is a pretty naive question haha, but I don't wanna get jibbed.

Thanks!

Cat back means catalytic convertor back. So thats replacing the piping from the cat and replacing the rear muffler. The centre muffler is either kept or replaced with a hot dog resonator if you want more sound.

So exhaust layout goes:
centre muffler--pipe--catalytic convertor--pipe--rear muffler--tip ?

When doing an exhaust 'cat back' does that include replacing the catalytic convertor? Or just the piping and rear muffler?
When doing the exhaust like this, does it increase performance in any way? If it doesn't, what do you have to do to increase performance? Or does doing your exhaust never increase performance? haha.

Again, sorry for so many simple questions but when it comes to engines I really have no idea :(

A CAT back does not replace the CAT. Having a straight through muffler will improve performance slightly. I would keep the stock piping and just replace the stock muffler with a straight through muffler.

Exhaust layout goes like this:

Headers - Flex Pipe- Cat Convertor - Pipe - Centre Muffler - Pipe - Rear Muffler.

Most people only bother with everything from the cat back.

You will see a performance increase by replacing the rear muffler with a straight through design. After that you won't really see anything but sound unless you get extractors/headers (same thing) done.

Are you driving a 3.5 or 3l

I'm driving a 3L TF.
So to increase performance I replace rear muffler with a straight through design. That's easy to understand.
Does replacing the center muffler do anything or is that just for sound?

Also, do you need to replace the piping in-between, because my car got a new exhaust 5000kms ago with a roadworthy so they should all be almost brand new.

Also, does getting a straight through muffler make it sound nicer? Or do you need to get the center muffler replaced with that 'hot dog resonator' that you mentioned?

Does replacing the center muffler do anything or is that just for sound?

that depends on how restrictive the factory center muffler is. if it's restrictive, replacing it with a free flowing straight-through design will improve performance (and make it louder). if it's not, it won't do anything.
i've been led to believe center mufflers on Magnas are pretty free flowing already and not worth replacing unless you want the exhaust to be louder?


Also, do you need to replace the piping in-between, because my car got a new exhaust 5000kms ago with a roadworthy so they should all be almost brand new.

seeing as you've got new pipes already i wouldn't waste them by replacing it. exhaust shops can cut out existing mufflers and weld new ones in place. i think the lukey and magnaflow rear mufflers you're looking at are direct fit so no welding required, just bolt off and bolt on.

also the Magna exhaust piping is already pretty big from factory - it looks about 2.25"-2.5" on my TJ sports, which is generally as big as you'll need on a V6.


Also, does getting a straight through muffler make it sound nicer? Or do you need to get the center muffler replaced with that 'hot dog resonator' that you mentioned?

yes a straight through rear muffler will be louder and sound different to the factory box. also replacing the center muffler with a resonator (which is a straight through muffler without the sound deadening material inside it) will make your car even louder.

Alright, things are making sense now haha.
I'll go to some places nearby and ask them for a quote on how much it will cost to get my center muffler replaced with a resonator, and my rear muffler
replaced with either a Lukey or Magnaflow, high-flow muffler.

Any ideas on what kind of cost I would be looking at for that setup?

id say around the upto around 350.00 based on what ive seen charged in my local area when i was looking at a new exhaust on the 2nd gen. im curious what exactly are you wanting to adcheive.

the performance gain from the exhaust isnt going to have you win little races with friends on its own and you must be wary about going to loud, find out what your states decibal limit is for cars and add that into your ideas. personaly id just stick to changing your rear muffler for now and see how that goes for you, change the centre muffler over later if you need to.

Excellent. Should now probably ask:
Does anyone know any good places that do exhausts in the Frankston area?

never had to use anyone down that way but frankston exhausts are supposed to be ok, i dont know where you are compared to mal aka madmagna ( see mitsfix) or even if he does exhausts but might be worth a ask. never had any work done by him but every member i have seen have work done has been happy,

95ts has a good point. performance gains from a cat-back exhaust on a N/A car are usually pretty mild. you're talking one or two tenths of a second over 400m due to the free flowing exhaust maintaining torque at the top end - and top end power is nice on the track, but means little on the street. also, done wrongly, it can be quite loud. i'm guessing a resonator + straight through rear backbox will give you a pretty loud Magna.

i mean if you want to do it for shits and giggles, go for it, but don't expect it to turn your car into a tire-shredding monster.

i've been there, done that, and with our TJ i haven't touched the factory exhaust and have no intention of doing so. the factory Sports/VRX system seems pretty good and it's also nice and quiet. might be due to me starting to get old though!

i'm guessing a resonator + straight through rear backbox will give you a pretty loud Magna.

Hm, perhaps just getting the straight through rear-muffler will be enough. I want some noise, but I don't want it to be overpoweringly loud haha.

A straight through muffler is an excellent choice since the stock item is very restrictive. You should see a 5kw increase from this and a bit more torque and a meatier sound. Stock pipework is good as has been mentioned. There is a small gain when replacing headers and cat with aftermarket stuff, and pipework with mandrel bent, but not as cost effective as the muffler swap. Look for a lukey LR2779 muffler which is well made and doesnt cost the earth. Lukey even make the same straight through muffler with a flange so you can even chuck it on yourself with a new gasket

whatever you do please do NOT put a damn cannon on it, be smart and get get a decent muffler, lukey or magnaflow are both great choices

Also, does getting a straight through muffler make it sound nicer? Or do you need to get the center muffler replaced with that 'hot dog resonator' that you mentioned?


yes a straight through rear muffler will be louder and sound different to the factory box. also replacing the center muffler with a resonator (which is a straight through muffler without the sound deadening material inside it) will make your car even louder.

Just to clarify this up a bit, a straight through exhaust system from the cat will be VERY loud- what i mean by straight through is removing the center muffler and not replacing it, going to a high flow rear muffler. if you've got an auto it will drone like there's no tomorrow, i had my Varex muffler fitted without a middle muffler and even on its quietest setting it was loud and it droned. replacing the center muffler with a resonator will quieten the noise a bit, but it will still definitely be louder than standard.

my suggestion is to keep the standard piping, replace the middle muffler and rear muffler and you'll be all set for a nice exhaust with a reasonable gain from an exhaust mod. from memory standard piping is just under 2.5" anyways so it's not really worth replacing the piping unless it's needed

...some like em loud some don't it depends on what you want but most of the noise will come from the size of the pipe you stick out the back........as 95ts said cannons
personally i like to hear my stereo and be able to have a conversation without shouting
that's slightly incorrect.. it depends on the muffler size than the pipe size. the bigger the muffler, the quieter the exhaust will be

its not about noise when i say dont touch a cannon, yes it drones and puts out a crappy boring note unlike the lukey muffler which will give you a nice note ( see their whole lukey growl thing) but also becuase canons are crap, they look horrible and in most cases people actually will lose performance over a standard exhaust with them. i suggest canons be saved for poor people with crappy 2 door imports and fanboys.

as hojo stated pipe has very little to do with the noise you get, the only thing to keep in mind with pipeing is to small and you will restrict airflow, to large and you dont get the right amount of back pressure

what i meant was that if you get a system done and then just change the size of the pipe that comes out the rear muffler at the very back of the car then this will change the noise but because it is so far back and that pipe piece is usally only a couple of inches it will not change performance........like using a bull horn.....as for what looks crap well that is up to the individual some like that look and they aren't hurting anyone by doing it. i would agree that pipe is more about flow and mufflers about noise there is no argumant there and i didn't say any different
like i said talk to a pro
are you referring to the muffler tip? coz that has no effect on the noise that comes out- it has to do with the mufflers size and how the muffler is designed (well, this is what i've understood..)

http://c3.ac-images.myspacecdn.com/images02/139/l_59907eaaeee24cba8063873d9944287a.jpg

yeah talking to a shop that's done Magnas before is a good idea, or to someone here who has a cat-back and knows what makes a good combination on the 3.5.

i think a few things posted above aren't quite correct. in general:

* of the same design, a larger muffler is quieter than a smaller muffler
* larger pipe size = louder exhaust, smaller pipe size = quieter exhaust. common mistake made is people go for an exhaust with too large a pipe diameter and they can never get it quiet whatever combination of mufflers they put on it.
* too small a pipe size will restrict top end power. too large a pipe size can reduce low RPM torque but its NOT due to lack of back pressure. it's due to the gas cooling down too much and slowing down too much before exiting the tailpipe - reducing the scavenging effect of the headers

ok mate i kno this thread is a few days old but just for ur knowledge... i got a full cat back done on my TJ sports about a month ago i had all new piping 2.5 inch from the catalytic convertor back but i had the rear muffler removed and replced with a hotdog and then a much smaller straight through muffler put on the rear with a nice tip and the bumper cut out as the sports dont have the indent in the bumper this cost me 420 all up and boy it is deep, loud and tough for just a cat back i would reccomend this, but it might not be as deep as u have a 3 litre not to sure if it matters a huge amount anyway... and to answer ur performance question i did feel a small gain (about 3-4kw) i kno people are saying dont worry about piping but i got it done anyway as im looking at doing the whole exhaust high flo cat and pacemaker headers.. but for 420 might a well get new piping haha ;)

i hope this answer anything ur not to sure on

Regards mate