Well I've currently got a custom "dual" exhaust that's axle-back, and it's, meh...okay.

And I was shopping for ones like the magnaflow and the rksport...when I got an idea.

(BTW I have an '04 Fire)

Can I order the factory-option dual exhaust from the '03 or so Fire? I believe they quit offering it on the '04...
So I can then use a brand new factory style exhaust pipes, utilizing the factory hangers and what not, and then just put new mufflers on the end? Since I am putting a high flow cat on and new headers...so anyways...


any ideas? anyone know where I could find that exhaust?


Big plans for the '04 Fire.

All I need are is Time (sigh...)Money(sigh...)Know-how (workin on it!)

Stupid old keyboard. spelled exhaust wrong in the title. mother f***er


Big plans for the '04 Fire.

All I need are is Time (sigh...)Money(sigh...)Know-how (workin on it!)

Try looking for a single inlet/dual outlet muffler like the Flowmaster Deltaflow 80 or something from Dynomax for a deep, quiet tone with a pair of mandrel-bent style turn-down tips (Or straight if you perfer). Use one of a inlet diameter the same or not much bigger than the extention pipe leading up to it, or else you'll have a megaphone effect, which will make it unneccessarily (and maybe undesirably) louder. You may even consider using resonator tips with the dual outlets for an even more refined deep tone (It's been done before). The real trick here is to keep in mind that for best results with whatever buildup you have in mind the prts choosen should have a flow rating of a number double that of the engine's horsepower peak. David Vizard of Popular Hot Rodding Magazine did an article on this (Damn, where did I put it?) that specifies at what pressure drop the flow rate should be measured at for said number desired. He also put in a brief on the silencing effects of using a tuned pressure-wave chamber in the same article, but I doubt you'll be looking to get into that. This is the best advice I can give you, and I hope it helps you in making a well-tuned machine with a nice tone to the exhaust with an acceptable level of loudness (I say that as everyone is getting tired of that cheap, cheezy, ridiculously over-sized "tuner" bolt-on fart-can exhaust sound. Geez, what classless ignorant is into that?).

Go beyond the "bolt-on".

Very respectable reply. Duely Noted...


....however

It didn't really asnwer my question as to the availability of that particular GM Part. I honestly should've first asked how exactly that particular exhaust is bent, i'm assuming that after the axle, it splits and one pipes goes to the right side and one side goes straigh out? or does it go towards the center in a single inlet dual outlet fashion? In which case it would pretty much ruin my plan. Be it the former, I would see this as being a good option for me...


Thoughts, anyone?


Big plans for the '04 Fire.

All I need are is Time (sigh...)Money(sigh...)Know-how (workin on it!)

I'm not sure if I understand the question completely...

But your exhaust pipe comes back over your axle on your drivers side. There is just enough room there right after the axle for one muffler. You can not run one right there and then another on the passenger side because of a space issue. Your best bet would be like previously stated, running a 1 in 2 out muffler and preferably something like a flowmaster 80 series.

I run a single out 40 series on my car with a high flow cat, Pacesetter header, and custom 2.25" piping on an Eco Cav. That setup is way to loud for daily road usage. It's also very raspy and high pitched in my opinion. My friend has a honda with a full exhaust setup and my car sounds allot deeper than his but it's still to ricey for me. I'm going to buy an 80 series dual out for my car so I can not only put an exhaust pipe on each side but have a much deeper sound. I am also running an RKSport lip kit that has a setup for dual exhaust but it's a wide area for the pipes so I'm running all four C5 corvette tips to fill the space.

Pilz-E wrote:I still dream of the day when I can do a rear-engine, rear drive V12 in my sunflower.

whats the point of a "high flow" cat and mufflers on stock piping?

if the sizing is the same, what makes one pipe flow better than another?
I'm 98% sure that eco stock exhaust sytems are 2.5", i believe i remember reading that.

My question is...the factory dual exhaust how is the "dual" configured. does it run into a 1 in/2out muffler, like you guys suggested I do? or does it run the way the rksport dual exhaust does, where it splits at the axle, and runs two seperate pipes to two seperate mufflers. So basically is it one muffler or two?


Big plans for the '04 Fire.

All I need are is Time (sigh...)Money(sigh...)Know-how (workin on it!)

The stock exhaust is 1 7/8" not 2.5".

On the "dual" systems it splits after the axle. The pipe to the right hand muffler is slightly smaller than the pipe to the main muffler. The "dual" system was just for looks and not performance.

1 7/8? I'm guessing the pipe to the muffler is bigger then? because my muffler(s) are 2.5" inlets because that was supposed to match up to the stock pipe.

Pardon my ignorance....still learning.


Big plans for the '04 Fire.

All I need are is Time (sigh...)Money(sigh...)Know-how (workin on it!)

ur stock piping accually did come on the 04 fires. we found one before we bought ours just wasnt the color choice. That exhaust system came on what is referred too as package 2004 Pontiac Sunfire Plus 2SB. which added not only the dual exhaust but the sunfire door still plates and the three spoke chrome mag wheels. basically the latest version of the perviouly discontinued sunfire gt. instead of the diff engine all u had the opt for was diff accessories.

^^Don't be suprised by it, guys. My 'dime with the tu-tu has the same goofy setup (1-7/8" to the cat, 2-1/4" out the cat to the muffler, 1-7/8" out the muffler on back). I hate it personally, and wonder what the General was thinking of by using such a restrictive exhaust on an app that could benefit from using even a slightly larger pipe like what is used with the 4.3 (2-1/8" to be exact). my best guess is to either pack as much into the muffler as possible to silence it (Doubtful) or to build as much backpressure as realistically allowable without choking the engine as to enhance whatever dilution the EGR can provide in order to curb detonation in this engine/vehicle combination however possible (I've got factory 4.10 gears, but... Hey, this year hasn't a knock sensor! What gives?). I can go with as free-flowing a muffler as I like, but unless the rest of the system is up to snuff (Old phrase) in the area of flow rating, it's a moot point. By the way, has anyone considered using Dynomax's Ultraflow? It's the highest flowing-quietest muffler on the market. Just remember to size the in's & out's on it in terms of flow rate at a certain drop of vacuum to be double of what your engine's true peak horsepower, not what you think it is (i.e.: Research & calculate!). And also remember: No one likes to here the sound of anything farting!

Go beyond the "bolt-on".

i had Dynomax Ultraflow's on my 2000 sunfire GT dual setup. with the pacesetter header, highflow cat and 2 1/4" piping it was still fairly loud and raspy (might have been a lot different with a resonator tho). Ultraflow mufflers are just a straight through glasspack so they're not as quiet as most ppl think.

True... Lord knows I learned the hard way about them on my 'dime, and about using an excessively large pipe (2-1/2"). Mileage slacked-off big time & it was just way too loud in the cabin. Still, I hear positive results from those whom use the Flowmaster Deltaflow 80. It's supposedly meant for heavy vehicle apps like V-8 trucks and RVs, but I guess the way the chambers are tuned to produce better harmonics dampening with a 4-cyl pulse than they would with an 8, with still less restrictive flow than a factory muffler. We should goto shopMUFFLERs.com to check them out & see if their is one that'll fit each of our apps. Oh yeah, before I go there's one more thing I wish to bring up for consideration: For those of you who think that using a resonator after the muffler seems silly, I would like to point out that older model Caddilacs (The one's built in the '60s, for example) used post-muffler resonators in the tailpipe to help quiet the exhaust note & give it a deeper, mellow tone. Alot of english sports cars (With the tiny 4-cyl engines they have) used them to back in the day just to meet the english noise laws, and reduce or eliminate the tinnyness of the note. Just something to consider when putting you system together.

Go beyond the "bolt-on".

its not back pressure its exh flow verses temp (or volume verses velocity) no matter what you want that exhaust outa the engine and the exhaust as fast as possible back pressure is an old term and not exactly right .....you can get more exhaust outa a smaller tube depending on the volume of exhaust that you are moving in each exhaust pulse .

the reas ion that you dont want to use duel exhaust on any 4 cyl engine is that you dont have enough exhaust pulses or enough volume in the exhaust pulses when u only use two cyl .

to properly set up the exhaust u need first a good header (one with equal length primary tubes with a size that will keep the exhaust from expanding and cooling to much) and then a collector that sets the primary tubes so that each cyl fires in order making a swirl in the exhaust kinda like this
cyl 1 cyl 3
cyl 4 cyl 2

(i think thats the firing order of the ln2 i could b wrong)
the rest of the exhaust should have a few bends as possible and b small enough to keep the exhaust from expanding to much but at the same time b large enough so that the volume of exhaust can flow with out restriction

when you separate the exhaust to create duel exhaust on a 4 cyl you disturb the exhaust flow rate and slow it down not good

so it all depends on weather you want a show car or a fast car that looks good

Thank you, sk8. that helped clear-up what was a little mysterious to me. Sure puts why the factory put 1-7/8" pipe on my truck in perspective. Now if only I could get the damn thing to average 24.5mpg again. Don't worry, I had a factory tailpipe installed with a 2" Dynomax (Better). Say, there's a guy with a LN2 Cavy (Or was it a Sunfire?) somewhere here on the board right now who's running a 2-1/2" cat-back system & having fuel mileage loss. Do you think it's for the same reason?

Go beyond the "bolt-on".