# Stock exhaust ?



## Bigiron383 (Jun 21, 2010)

Any pic's ? What does the stock exhaust system look like > Where are the pit falls / draw backs ?


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## GM4life (Mar 18, 2007)

What year?
Both LS1 and LS2 Goats have really good stock exhaust set-ups. The LS1/04 GTO may choke out quicker than the 05-06 2 1/2" cars when you start modding. 04 GTO's have 2 1/4" that necks down to 2" in some places. The crimps in the pipes are minimal and don't have much of effect on the exhaust. Articals have proven about a 5hp gain with aftermarket over stock 05+ exhaust on a stock or mildly modded car.


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## Bigiron383 (Jun 21, 2010)

2005. Just trying to get an idea what's going on. I thought they came with an "X" pipe, and was wondering why some one would want to add an "H" pipe ?


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## dustyminpin (Jun 19, 2006)

Stainless Borla exhaust on left (20 pounds lighter then stock), rusty ugly ass stock exhaust on right, bad ass guard dog from hell, Maverick the King of miniature pinschers, also on right.
Stock exhaust came off in one big ass piece. Borla went on in 3 pieces (x-pipe, left side, right side).


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## Bluegoat05 (Mar 22, 2010)

the factory does not have an x pipe. its just a resonator it is basically what looks like a muffler but on the inside all it is is two straight tubes threw with holes in the tubes to tie the two together.. i put an x pipe on my car once and didnt like it because it made too quiet. also the x pipe is a more european sports car sound where h pipe or straight pipe sounds pure american muscle hope that answers your question


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## Bigiron383 (Jun 21, 2010)

I know what you mean, 3" , Flowmasters, and an "H" pipe.


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## Poncho Dan (Jun 30, 2009)




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## svede1212 (Nov 1, 2005)

Don't know about the LS2s but the '04 came with a stainless exhaust and probably has the best sounding stock exhaust on any recent car. . .


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## silversport (Mar 23, 2007)

I would agree svede on the stockers...the Magnaflows that came on my SAP seem only a bit louder than the OE regular exhaust...a lot nicer looking when underneath but the stockers aren't bad...
Bill


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## jpalamar (Jul 22, 2008)

svede1212 said:


> Don't know about the LS2s but the '04 came with a stainless exhaust and probably has the best sounding stock exhaust on any recent car. . .


I agree. LS1 soudns so much better then the stock LS2 exhaust.


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## GM4life (Mar 18, 2007)

You folks must don't know that GM spent alot of R&D on the 04 GTO exhuast using a 64 GTO and a C5 Corvette to tune the exhuast. The tuned resonators, tuned different mufflers, the routing of the pipes and even the faux "H" pipe had a purpose.


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## Bigiron383 (Jun 21, 2010)

*Sap?*

Just when you think you have it figured out. What is an SAP ?:confused


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## silversport (Mar 23, 2007)

Sports Appearance Package... http://www.gminsidenews.com/forums/f14/pontiac-gto-sport-appearance-package-pics-9713/ full package was different front and rear facia, different grills, different side skirts, different rear wing and Magnaflow dual mufflers from the dealer with full warranty...
Bill


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## danfigg (Sep 27, 2009)

*re*

The 04 gto exhaust was engineer to sound as close to the classic GTO as possible by GM engineers. But I would almost bet that if the 05 -06 GTO's muffler were placed in the same spot as the 04 and run tail pipes with Maryland speed muffler delete pipes Im sure the 05-06 sound would be improved to everyone liking. Mufflers as close the the back of the car will give a different sound and better top end power. A muffler farther forward to the car and then run tail pipes to the back of the car will give a (Harley) sound.-----danfigg


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## 68OldGoat (Nov 23, 2009)

My 06 BOM is running the stock exhaust with the stock mufflers deleted. It is very throaty and noise controllable around town under 3000 RPM but really lights up after that. The resonator (H crossover) does hold the noise down around town and at highway speeds but the car sounds like straight pipes when you get on the throttle above 3000 RPM's. It sounds like a 50's or 60's muscle car with the old Thrush mufflers..... it even has the pop on deceleration. Has anyone else tried this setup for a real muscle car sound?


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## Poncho Dan (Jun 30, 2009)

The stock system is super heavy... 68 pounds. I'm glad I went aftermarket.


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## jpalamar (Jul 22, 2008)

68OldGoat said:


> My 06 BOM is running the stock exhaust with the stock mufflers deleted. It is very throaty and noise controllable around town under 3000 RPM but really lights up after that. The resonator (H crossover) does hold the noise down around town and at highway speeds but the car sounds like straight pipes when you get on the throttle above 3000 RPM's. It sounds like a 50's or 60's muscle car with the old Thrush mufflers..... it even has the pop on deceleration. Has anyone else tried this setup for a real muscle car sound?


Buddy of mine has a n 06 TR that he did a muffler delete on his. Has stock cats but welded in an X pipe. I like the sound but too much popping for me on decel but sounded good at WOT and was VERY LOUD and droned horrible. I'm sure a tune would get rid of much of it but he moved away before I got into tuning and even then, I don't know if I trust myself to do someone elses car.


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## Gotagoat (Jan 6, 2006)

I'm still thinking stock with Afterburners. I've heard the vids but I'd sure like to hear it live before making the change.


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## iwant2buyaGTO (Dec 17, 2009)

I just bought a used 04 GTO about 5 months ago. When i got it i noticed the exhaust was pretty loud. I thought this was cuz its a GTO and i assumed they all came like that. About a week ago an 05 was driving right next to me. We both nodded to each other. I noticed that my exhaust was way louder than his. i could barley here his. I started thinking maybe my exhaust was modified. So i looked under the car and i saw SLP. Street legal performance. I dont know much about exhaust. This is my first muscle car. I wanted to know if there where packages that Pontiac sold with exhaust upgrades when they came out? If they did was SLP in there exhaust packages? Any help would really help. Thank you.


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## Poncho Dan (Jun 30, 2009)

iwant2buyaGTO said:


> I just bought a used 04 GTO about 5 months ago. When i got it i noticed the exhaust was pretty loud. I thought this was cuz its a GTO and i assumed they all came like that. About a week ago an 05 was driving right next to me. We both nodded to each other. I noticed that my exhaust was way louder than his. i could barley here his. I started thinking maybe my exhaust was modified. So i looked under the car and i saw SLP. Street legal performance. I dont know much about exhaust. This is my first muscle car. I wanted to know if there where packages that Pontiac sold with exhaust upgrades when they came out? If they did was SLP in there exhaust packages? Any help would really help. Thank you.


Aftermarket. Previous owner modded the car. Watch for that in other places, you might have hidden goodies, like a shifter.

Mine was 100% stock, which was what I really wanted - unmolested machinery. I verified this by going over it with a fine-toothed comb. No evidence of demodding, nothing deleted, stock tune, strut rub & spring sag (lulz)... but my clutch seems to slip a little changing gears hard.


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## iwant2buyaGTO (Dec 17, 2009)

Poncho Dan said:


> Aftermarket. Previous owner modded the car. Watch for that in other places, you might have hidden goodies, like a shifter.
> 
> Mine was 100% stock, which was what I really wanted - unmolested machinery. I verified this by going over it with a fine-toothed comb. No evidence of demodding, nothing deleted, stock tune, strut rub & spring sag (lulz)... but my clutch seems to slip a little changing gears hard.


I think i might take it to a friend or someone who knows a lil more about stock exhaust on a 04 GTO to see what they exactly did.


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## iwant2buyaGTO (Dec 17, 2009)

These are my pics of my exhaust. Can anyone tell me what i got done? I see SLP on picture #3. I think its the resonator. Correct me if im wrong. Its a lil hard to see in pics. Any help would be greatly appreciated.












































My guess would be either SLP loud mouth 1 or 2.....
http://www.pfyc.com/GT5004.html?Category_Code=GTEXH


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## mficco77 (Jul 13, 2010)

I have an 04 with Corsa exhaust with a large oval tip. not to loud but noticeable when getting on it or letting off of it.


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## GM4life (Mar 18, 2007)

iwant2buyaGTO said:


> These are my pics of my exhaust. Can anyone tell me what i got done? I see SLP on picture #3. I think its the resonator. Correct me if im wrong. Its a lil hard to see in pics. Any help would be greatly appreciated.
> 
> y guess would be either SLP loud mouth 1 or 2.....


You have stock mid pipes with SLP LMI catback. LMI is basicly just a resonator, the system is made so you can swap between LMI resonators and LMII muffs.


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## iwant2buyaGTO (Dec 17, 2009)

GM4life said:


> You have stock mid pipes with SLP LMI catback. LMI is basicly just a resonator, the system is made so you can swap between LMI resonators and LMII muffs.


I see what you mean. So i have the SLP LMI catback. Do you know if my tips are stock? What would be the next thing to enhance my exhaust system?


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## GM4life (Mar 18, 2007)

iwant2buyaGTO said:


> I see what you mean. So i have the SLP LMI catback. Do you know if my tips are stock? What would be the next thing to enhance my exhaust system?


Your tips are not stock they look double walled. 

Improving on your exhaust system depends on what you want and were you live. You can go with LT headers with catted mid pipes or if emissions is an issue and sound go with JBA shorties with JBA catted mids. I tell you for a fact LT headers, catless mids and LMI cat back will make your car sound like a full on race car.


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## iwant2buyaGTO (Dec 17, 2009)

GM4life said:


> Your tips are not stock they look double walled.
> 
> Improving on your exhaust system depends on what you want and were you live. You can go with LT headers with catted mid pipes or if emissions is an issue and sound go with JBA shorties with JBA catted mids. I tell you for a fact LT headers, catless mids and LMI cat back will make your car sound like a full on race car.


JBA shorties are headers correct?


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## GM4life (Mar 18, 2007)

iwant2buyaGTO said:


> JBA shorties are headers correct?


Yes sir.


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## iwant2buyaGTO (Dec 17, 2009)

GM4life said:


> Yes sir.


Thanks. So if i go with JBA shorties with JBA catted mids how much horse power will i gain(estimated) and i will gain better sound obviously.


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## jpalamar (Jul 22, 2008)

Don't get headers with your LM1. There is a local guy that has long tubes with his and it sounds like just loud crap and drones horribly from what I've been told.


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## Bigiron383 (Jun 21, 2010)

GM4life said:


> You have stock mid pipes with SLP LMI catback. LMI is basicly just a resonator, the system is made so you can swap between LMI resonators and LMII muffs.


So what's the difference between a resonator and a muffler ?:confused


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## GM4life (Mar 18, 2007)

iwant2buyaGTO said:


> Thanks. So if i go with JBA shorties with JBA catted mids how much horse power will i gain(estimated) and i will gain better sound obviously.


Shorties don't change the sound much, the catted mids will a little. The JBA mids have smaller highflow cats, larger diameter pipes 2.5" from 2.25" and they get rid of the stock resonators. Hard to tell how much of a gain those are worth maybe 10-15 extra. 


Bigiron383 said:


> So what's the difference between a resonator and a muffler ?:confused


The SLP LMI's are resonators just a flow through pipe without sound deading materal. The LMII's are mufflers that are alittle bigger than the LMII in diameter, flow through pipe with preferations in the walls that contain sound deading materal.


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## iwant2buyaGTO (Dec 17, 2009)

jpalamar said:


> Don't get headers with your LM1. There is a local guy that has long tubes with his and it sounds like just loud crap and drones horribly from what I've been told.


Thats what im afraid of. i dont want it to sound loud and crappy. I like how my car sounds right now with the SLP Cat back and my tips. I just wants more! Im looking for a deep mean sound. Just trying to see what else i cant do to it.


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## Bluegoat05 (Mar 22, 2010)

you can make it sound MUCH better with takin out the x pipe and putting in straight tubes, true dual the change is dramatic! and then if you dont like it just change it backarty:


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## iwant2buyaGTO (Dec 17, 2009)

Bluegoat05 said:


> you can make it sound MUCH better with takin out the x pipe and putting in straight tubes, true dual the change is dramatic! and then if you dont like it just change it backarty:


Any suggestions on which straight tubes to get?


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## GM4life (Mar 18, 2007)

Bluegoat05 said:


> you can make it sound MUCH better with takin out the x pipe and putting in straight tubes, true dual the change is dramatic! and then if you dont like it just change it backarty:





iwant2buyaGTO said:


> Any suggestions on which straight tubes to get?


How much popping you have now? 

If I remember tomarrow I can post up some vids on how a 04 GTO sounds with LMI without an X pipe. Sounds ok for the most part but the popping and romping on it above 4.5K sounded like ass.


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## Bluegoat05 (Mar 22, 2010)

my car pops quite a bit but i like it.. when it sounds like a back fire i dont like it.. you know just one big POP. but when it has several small pops i like it when im next to buildings the echo sounds like thunder its great! but its all a matter of personall opinion.. there are a few people that dont like it and there are a few people that think its awesome.. but you will learn sertain ways you can drive it to avoid popping.. i love going under over passes or parking structures and rolling the windows down ha ha! but like i said if you do it right you can just change it back easily enough.. what i would do to change it is buy a stock resonator, for the flange. then take that resonator to an exhaust shop and have them cut the resonator off the flange and just put straight 2.5" tubing then flair out the ends so you can just take the x pipe off and put it on.. just use exhaust clamps


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## Bluegoat05 (Mar 22, 2010)

ok i just looked at the pictures you posted again and your car is an 04 so the exhaust is different for some reason that fact skipped my mind.. so.. what i would do in your case is just some how get the flanges you need that are in front of the x pipe.. then take your x pipe off take it to an exhaust shop so they can duplicate the section of pipe without tying the two together.. sorry for my mistake. but that would still be easy to change back and prob only cost maybe 100 bucks


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## iwant2buyaGTO (Dec 17, 2009)

Bluegoat05 said:


> ok i just looked at the pictures you posted again and your car is an 04 so the exhaust is different for some reason that fact skipped my mind.. so.. what i would do in your case is just some how get the flanges you need that are in front of the x pipe.. then take your x pipe off take it to an exhaust shop so they can duplicate the section of pipe without tying the two together.. sorry for my mistake. but that would still be easy to change back and prob only cost maybe 100 bucks


So would i need to do a cat back? or just change this x pipe i have circled?


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## Bluegoat05 (Mar 22, 2010)

yes exactly that section.. but some how you need the flanges to bolt to the cat side of the exhaust.. maybe the exhaust shop could just build the flanges.. what i would do is take your x pipe section off and take it to the exhaust shop and tell them to make one with out an x pipe.


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## iwant2buyaGTO (Dec 17, 2009)

Bluegoat05 said:


> yes exactly that section.. but some how you need the flanges to bolt to the cat side of the exhaust.. maybe the exhaust shop could just build the flanges.. what i would do is take your x pipe section off and take it to the exhaust shop and tell them to make one with out an x pipe.


k i got you. Is this really gonna make a difference in sound?


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## GM4life (Mar 18, 2007)

Dude I wouldn't worry about your cat-back, get yourself some JBA catted mids and JBA shorties. That way it will sound alittle different and have more flow. Naturlly the larger mid pipe will change the sound of the exhaust system and the cats will keep it from being too loud. You have an X-pipe in there now and that pretty much helps with the sound.


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## iwant2buyaGTO (Dec 17, 2009)

GM4life said:


> Dude I wouldn't worry about your cat-back, get yourself some JBA catted mids and JBA shorties. That way it will sound alittle different and have more flow. Naturlly the larger mid pipe will change the sound of the exhaust system and the cats will keep it from being too loud. You have an X-pipe in there now and that pretty much helps with the sound.


That was my initial idea at from the start. First im going to get my AEM Brute Force then worry about this. So how much am i looking at for JBA catted mids and JBA shorties?


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## Bluegoat05 (Mar 22, 2010)

Yes the sound will be dramaticly different... However I'm gonna agree with gm4life on one part the high flow Cats will make it a lot louder too.. I have jba shorties and I love em they did good. A buddy of mine has the same truck I do. With the same exhaust set up but he went catless and his sounds a LOT meaner! So I belive high flow cats will have the same effect.. A lot of people say long tubes sound so much better but I personally think most of it is that most long tubes have high flow cats or nocats at all so if you were to go wiht shorties and high flow cats you would get a better sound but I personally would do both delete x pipe and shorties n high flow cats


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## GTOMOE9 (Jun 14, 2010)

i think the spintech with an h pipe sounds the best but its all what you like


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## magpie5 (May 23, 2015)

jpalamar said:


> I agree. LS1 soudns so much better then the stock LS2 exhaust.


How do you get an 05/06 (LS2) to sound like an 04 (LS1)? What combination of Exhaust parts would work best?

Somewhere on this forum I though I saw a diagram of the GTO exhaust. Am I tripping, or could someone help me find it? Thanks.


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