# 2005 Altima 3.5 exhaust upgrade



## skootz1 (Oct 12, 2005)

I have a 2005 Altima 3.5SE and i am thinking about changing my pipes from 2 1/4in to 2 1/2in and i am curious to know if anyone else has done it already and could enlighten me on the HP gain if any. I have put on Sebring mufflers and wanted to know if anyone else has done an upgrade with any info.


----------



## Marvin (Oct 16, 2002)

You aren't going to notice much of a power difference. It will sound a bit louder, but thats about it. If you really want to add HP, you need to add an intake of some sort, change out the exhaust manifold to a free flow header and downpipe, and change the exhaust as well.


----------



## skootz1 (Oct 12, 2005)

Well i have an AEM cold air intake. I have Sebring mufflers. So basically i would to change the pipping from the cat back?


----------



## skootz1 (Oct 12, 2005)

*Thanks*

Ok, i got it. Change my down pipping and my headers and then change the pipping from the cat back. Now what is the limit of the size pipe that i should go? No larger then 2.5in or could i go as far as 3in without hurting the performance?


----------



## Marvin (Oct 16, 2002)

skootz1 said:


> Ok, i got it. Change my down pipping and my headers and then change the pipping from the cat back. Now what is the limit of the size pipe that i should go? No larger then 2.5in or could i go as far as 3in without hurting the performance?



I would send a private message to the name Ruben and ask him. He would know more than I and he doesn't spend much time on the board anymore.

Let us know what he says.


----------



## Ruben (Oct 15, 2002)

Marvin said:


> I would send a private message to the name Ruben and ask him. He would know more than I and he doesn't spend much time on the board anymore.
> 
> Let us know what he says.



I'm here.... 

Ahhhh exhaust... there aren't many HP #s coming out of that exhaust... There are 2 main restrictions, the Y pipe, and the stock resonator. Replacing the Y pipe does the most for power, and the resonator second. Pretty sure the oem mufflers are variable flow, meaning they have a spring loaded flap that opens under full throttle, so noise will be the main result in replacing those.

Get a stillen or custom altima Y pipe, and save your $$ to get an underdrive pulley, and a rear sway bar. Those two mods do the most for a daily driving. You fell them immediately.


----------



## skootz1 (Oct 12, 2005)

*Thanks Ruben*

Sweet, so far i have a CAI and Sebring mufflers. These mufflers are open flow. I will increase the Y pipping to about 2in (or should i go for 2.5in?), remove the stock resinator and open the pipping from the cat back to about 2.5in. I will definantly invest in the underdrive pulley. I will also get the fromnt and rear sway bars. I will post pics soon. I plan to leave my car looking like stock so that cops do harrass me and so others think its stock and not a sleeper. Thanks Ruben


----------



## Ruben (Oct 15, 2002)

skootz1 said:


> Sweet, so far i have a CAI and Sebring mufflers. These mufflers are open flow. I will increase the Y pipping to about 2in (or should i go for 2.5in?), remove the stock resinator and open the pipping from the cat back to about 2.5in. I will definantly invest in the underdrive pulley. I will also get the fromnt and rear sway bars. I will post pics soon. I plan to leave my car looking like stock so that cops do harrass me and so others think its stock and not a sleeper. Thanks Ruben


Get the largest resonator you can afford to repace the stocker, the incease in piping diameter will really resonate like hell inside your car. Tust me I know... spent a shitload looking for the right sound.


----------



## skootz1 (Oct 12, 2005)

Any suggestions. I want it to sound like a race car kinda deep but not too much. I dont want it to sound like a Honda, weeeeeeeeeeeeeeeeeeeeeee. I want a nice, deep WAHHHHHHHHHHHHHHHHHHHHHH and some gargulling to go with it.


----------



## Ruben (Oct 15, 2002)

link me to your rear mufflers.


----------



## skootz1 (Oct 12, 2005)

Thanks Ruben. A friend of ours or a friend of mine? I will post pics when i am done. I just want to get this straight. If i increase the pipe diameter at the Y, i will get more HP and more noise. Get a better resonator. Do you know how wide i should make the Y pipping? Do you know if i will end p hurting the performance? Does the compression become a factor after increased pipping? Thanks again Ruben.


----------



## Ruben (Oct 15, 2002)

I'd buy a y pipe from stillen or custom altima, there is a cross bar that limits the piping size.










Its not a simple part.


----------



## skootz1 (Oct 12, 2005)

Sounds good, i checked at customaltima.com and i didnt see if there were any street legal restrictions on it. Is it street legal?


----------



## Ruben (Oct 15, 2002)

It removes two underside cats, so in CA, I'd say no. It wouldn't pass the visual test, but the sniffer probably would be no problem.

The Cats nearest the engine are left alone.


----------



## skootz1 (Oct 12, 2005)

Ok, i will probably have to do just a catback mod. I will just open up the pipes to about 2.5in. Do you know if its going to add HP if i make the pipes that go to the mufflers bigger? You know, right where they split into each muffler. Would that be a good or bad idea? I will get a great resinator. I will deffinatley take your advice. Let me know and i will get the mods going and post some pics for everyone.


----------



## skootz1 (Oct 12, 2005)

In conclusion, i learned that:

A) You get what you pay for at a muffler place.
B) Mossy Performance exhaust is awesome.
C) Always use stainless steal over Aluminized pipping.

I hope i helped someone in the future. If anyone wants to know about exhaust for an 2005 3.5 Altima, let me know! Thanks Ruben and Marvin for you initial help.


----------



## agito (May 18, 2015)

Hi I know this is an old post buy I'm looking to change out the mufflers ony 05 3.5se just for sound purposes. Are there any ebay stainless steel setups for under $300 incl. Labor anyone would recommend That would give me a kind of muscle car growl that's not too loud?


----------

