k heres the deal-e-o

I love the sound of my GMPP catback.....but since adding the ZZP midlenth with catless downpipe, the sound is VERY loud.

some would probably love it, but id prefer it to be quieter.

So my current plan is to get a QTP Electric cutout in my downpipe for track performance,
and somehow quiet down my exhaust for daily driving.

I thought maybe putting a cat in after the cutout would probably do it....

or i could maybe replace the GMPP resonator with a quieter muffler, so i would be running 2 mufflers


What do you think? cat? muffler? which muffler?

thanks for lookin

 

I find it wierd to see you asking questions now. I always seem to see you answering everyones questions. Just gotta say you are extremely knowledgeable, man. I'd trust you with my car. As for the question, I'd stick a resonator in there to quiet it down.

 

im not all knowing lol.
theres always someone that knows more and can help out, thats how we all learn

It already has a resonator in the GMPP catback...

 

magnaflowwwww

 

yeah this is kinda where im leaning so far

anyone have any thoughts of having a cat further downstream?
i only really ask because cats are far cheaper.

 

Go to ZZP they have a resonator that should quiet it down a good bit

 

ill tell you what NOT to get...magnaflow ...i almost regret my purchase...sounds nice, but too loud sometimes

whats our stock diameter for ss/sc again? 2.5 right?

 

magnaflow will be louder than ur GMPP....... i wouldnt change the muffler, i would just add another resonator along with what u already have.

 

magnaflow will be loud, however im thinking of the same thing you are, running 2 mufflers in series. im planning a magnaflow round body muffler in place of the resonator and the biggest oval body i can get on the back. i like a deep exaust note but i dont like the loud noise.

to be honest, i hate the sound of 4 cyl exaust, id much rather just listen to the blower whine

 

no no, not replacing the gmpp muffler....

replacing the gmpp resonator, with ANOTHER muffler.


Im still curious about adding a cat though....does anyone know if it would hurt to have the cat further away from the engine than they usually do?
i know the efficiency probably would be ****, because i know they need a certain heat range to properly function, but i dont really care about that.
i dont really care about its efficiency, just as long as it wont wreck it/clog

because a cat will generally do the same thing that a muffler does in deadening sound.
but they are about half the cost of a muffler...

 

dont bother with a typical ceramic core cat. i have heard of many people clogging the stock cat with stage 2 and a couple other light mods. if your going to put a cat on, use a steel core race cat. they are expensive but your not going to clog it with the richness of a forced induction engine. however, im not sure how much a steel core catt will deaden sound compared to a ceramic core.

 

I'm wondering if maybe it would be difficult to accomplish a cat further down... would the front and rear 02 sensors need to still be before and after the cat?

 

yes they would. the only purpose of a downstream o2 sensor is to make sure the cat is doing its job, therefore must be placed after the cat. i thinbk in this case though his downstream o2 is turned off as it is, best to leave it that way.

the downside to putting a cat farther down is it doesnt light off quick. thats only a worry if you have an effissions sniffer test. however my last car the one cat was about 6' from the end of the header and i had no issues emmisions wise. all i did was run the thing a tad richer than usual on warm up and it lit quickly.

 

emissions are a non issue for me.

and my rear O2 sensor has a permanant spot on the shelf in my garage

like i said, basically i would be using the cat as a cheap sound reduction.


thats some great info for me there sharky. thank you.

 

Just sell me your GMPP Exhaust and get a custom exhaust made completly of resonators and a muffler, just weld them all together......

 

lawl i considered selling the gmpp. but that ended up being a no go.
so im going to modify it some to what i like

 

ZZP sells a whisper resonator that is supposed to be quiet yet flow good .

http://www.zzperformance.com/cobalt_...=677&catid=155

 

well, like i said, i wouldnt do 2 mufflers, i would just do a extra/longer resonator......... i know how loud these cars are...... not really alot u can do, without restricting flow. you could always install ur stock catback, since ur gonna be using a cutout when u want performance anyway.

 

the answer is 42


get a couple resonators and stick on there.

 

if i had room for that i would :/
the only straight sections are taken up with a resonator and a muffler already on the GMPP.

 

dude slap a high flow cat on there. you would be surprised how much the cat muffles the exhaust.

 

lol, thats the business my father is in... corporation, to be more precise... we make stainless steele wire mesh catalytic converters with a special coating...mostly for diesel and truck engines tho...we also do work for US military

 

yeah i think thats going to be what i try first.

i have room in the GMPP before the resonator to fit one in, and they are cheap.

Ill update when i have results

 

Magnaflow STREET series are nice and quiet(er)... thats what is on my current setup.

Magnaflow RACE series are loud as ****!

 

post clips of your current set up a 36" resonator would really help.. magnaflow has been having some quality issues lately