06cobalt racer

iTrader: (11)

so i will have a poll up. but... what would the difference be if any between these two choices.

1. full magnaflow cat back

or

2. or replace the stock res and muffler with magnaflow pieces? also replace the 2.25 over axle section with 2.5.

so would these both give the same results? any input or opinions?

Erick161

I'd go with stock exhaust, replace the over axle pipe and throw on a dynomax. I think the magnaflow muffler sounds like complete ass, especially paired with a catless downpipe

olivecj

I just bought the over the axel piece from ottp and it only cost 95 bucks then you just buy a muffler of your choice like borla or dynomax. Plus remember unless your putting out over 300hp your stock exhaust is more than enuff so yeah save your money on a full catback and get the over the axel kit instead.

http://www.ottperformance.com/store/...ler-54p233.htm

06cobalt racer

iTrader: (11)

yeah what i was thinking too. because the stock exhaust is all 2.5 except the over axle piece and its already mandreal bent i believe. plus the res and muffler is 148. so like 243 for pretty much the same thing as the full cat back.

Stiner

Don't even bother swapping out the stock resonator just do over the axle with whichever muffler you want

Staged07SS

iTrader: (25)

Don't forget that the inlet of the stock catback at the resonator is only 2 1/16" i.d.



I would get a full catback if I were you. It doesnt matter if you replace the muffler or over axle piping. In the end you will still have the 2 1/16" restriction/bottle neck unless you buy a full catback exhaust.

G11

iTrader: (11)

i did a magnaflow 3" resonator and muffler and like it...i don't know if im going to swich or not...like the idea of the over the axle piece!

06cobalt racer

iTrader: (11)

ok so if i replace that like i was going to it would still be the same as
the full catback. i would replace the res, over axle, and muffler.

Staged07SS

iTrader: (25)

Yes, but after replacing all of those parts, it would prob. be cheaper/make more sense to just purchase a full catback.

06cobalt racer

iTrader: (11)

with the res, muffler and over axle piece it will be 243. less then half the price of the catback system.

Staged07SS

iTrader: (25)

Did you include labor for welding all of that on ?? I still think it is a waste of time to hack up the stock exhaust and weld pieces in when you can just buy a good used catback and bolt it on with ease for even cheaper than $243.

06cobalt racer

iTrader: (11)

where would i be able to find a magnaflow cat back for less then 243?

rcorona8

Is this true also for the GMPP Cat Back Resonator???? I know the over the axle is 2.25 but im giong to replace it with 2.5. But i won't do it if the a inlet for GMPPP resonator is 2 1/16....please let me know.

bump

Staged07SS

iTrader: (25)

I've seen people sell them on here for $200 many times. Search the classifieds. I'm not a fan of piecing an exhaust system together. Your idea of a setup (replace muffler, axle piping, & resonator) will more than likely perform just as well as a catback, but the quality/sound wont be there.

I never measured a GMPP catback, but I would assume that restriction is not there. The GMPP catback should be 2.25" all the way through from the resonator to the muffler

Dash71121

yeah do a full stainless 2.5" catback so people can admire it underneath the car and you can polish up up for shows... haha jk my vote is replace the restrictive peices, but no way of getting around the restrictive exhaust manifold and downpipe

catback is mainly for sound, you still have the major bottle neck in the downpipe

06cobalt racer

iTrader: (11)

sorry should have said. i already have zzp shorty and a catless downpipe

Staged07SS

iTrader: (25)

A catback is not mainly for sound on the SS/SC. You would be surprised the difference in how your car will pull with a catback exhaust. My car gained a good amount of mid-top range power from my Corsa Catback. Corsa dynoed their catback for the SS/SC, and they produced 12 hp & 8 tq on a stock car. Hell, even the GMPP catback exhaust gained 12 whp on a GM Stage 2 car. Yeah, they are only for sound ....

OP do what you want. You will more than likely gain the same amount of power from replacing those pieces. I just like to make sure I have the best quality parts on my car so I dont have to worry about **** breaking down the road.

06cobalt racer

iTrader: (11)

yeah i understand man. just that i dont really have the money for the full cat back. but yeah i figured that the results would be about the same.

Staged07SS

iTrader: (25)

I understand, and good luck with what ever setup you choose.

Dash71121

should be the same, can you weld?


http://www.mandrelexhaustsystems.com...EXHAUST/Detail <<not a bad option for the price


staged07ss- didnt know an exhaust leak could leave you broken down haha jk

but i do have a question what diameter is the gmpp exhaust? is it 2.25? if so, just replacing the muffler should yeild good gains. i'd be down for 12WHP from replacing a muffler lol dont believe everything manufacturers tell you

http://www.gmhightechperformance.com...lt/page_3.html


yes this was done on a 2.4, but when advertised is 12 and they gained pretty much nothing.. kinda see my point.

Staged07SS

iTrader: (25)

I didnt mean broken down on the road .... I meant the parts breaking, because they were of shitty quality

The GMPP is 2.25". You will not gain 12whp from just replacing the muffler. There are other restrictions within the production catback other than the muffler.

I've read that article many times. If you read carefully they said the production catback flows pretty well for the 2.4L. That is on the 2.4L though. The 2.0L is a different story. You are talking about a F/I car vs. a N/A car. Our site admin JonyyB made 12whp with a GMPP catback on his car.

Read:
https://www.cobaltss.net/forums/show...p+catback+dyno

P.S. I never said I believe what manufactures claim when it comes to horsepower. I was simply stating their numbers. Did my Corsa catback give me 12hp like they claim? Who knows .... I never dynoed after installing it. I did feel a nice bump in power from it though, and the sound it makes is beautiful.

TexasTieaga

Well, here's my opinion. I love this setup so I'm gunna say custom 2.5 piping with a magnaflow muffler. I myself have a 2.2 and run 2.5 dp as well, with stock exhaust mani. But I've had gains in power even though I haven't been on a dyno, I can feel. And I use a high flow cat (cobalt-addiction I think) for inspections.

Dash71121

http://www.youtube.com/watch?v=2CZR7OGk0AM

just found that, i have my header and dp on the way, im going straight pipe to the muffler and only replacing the over the axle portion and muffler.

judging from that vid, the stock muffler has gotta be extremely restrictive. so i retract my statement that cat backs are just for sound lol.. definatley wanna get my car dyno'd and see what kind of gains i get with h/dp/muffler

olivecj

Yeah I got the over the axel kit from ottp, I can definetly notice the difference on my top end. I still gotta get a muffler though probably dynomax or magnaflow.