Went with a Maganflow XL Turbo:

YouTube - 2008 Cobalt SS Magnaflow Exhaust

couldn't justify spending $500 on a cat back for relatively no gains under 475whp(for an upgraded 3") so I just bought a muffler and new tip instead, ended up getting a Borla Rolled Tip

 

Hey this sounds great!

Perfect day to put up a vid as I'm just currently deciding on this. Is this with factory resonator as well as factory catted DP?

 

this is a ZZP 3" downpipe that is catted, and yeah stock resonator

this is the muffler I got:

http://www.autoanything.com/exhausts...A5794A0A0.aspx

you need the center Inlet/offset Outlet in 2.5"


also got this tip:

http://www.autoanything.com/exhausts...A2445A0A0.aspx

I got the Outlet Size 4 x 4", Inlet Size 2.5", Length 6" tip

 

Thanks for the info... that is exactly the DP I will be using. Call me a copy-cat, but this is exactly what I'm going to do.

 

he has a zzp 3 inch dp with a 23 psi trifecta tune, and a cai. As I told ya you don't need a catback for these cars unless your running major power. Just get a free flowing muffler and your good.

 

i'm biased of course, but so far its the best sound option i've heard...

I'm not into the Catless/no resonator sound... ENTIRELY too loud, not what I was going for, I just wanted something deeper than stock that sounds good engine braking... that is what I got with this setup

 

A catback can gain you around 10 hp on stock tune. The stock one is not that sufficient for a custom tuned balt.

 

no it won't on a stock tune... on the stock tune, its going to cut your boost to keep you at 245/245 anyway once it relearns...

they give 6-8whp, which is NOT worth $500

I'd rather have my muffler and a KY clutch with $500...

stouter clutch and i'll feel more comfortable with E85

besides truthfully, i'd like to see a car with a stock catback and aftermarket muffler vs a catback car anyway on the dyno... i'm thinking that land barge of a creation known as the stock muffler is where there are "gains" to be found, no doubt the car is faster, I just shaved 15lbs lol

 

The stock exhaust bottles down below 2.5" in some areas. Also a 2.5" exhaust isn't that good for 300+whp. You can gain up to 15whp or more with tuning just from a catback. Makes your powerband better as well.

 

Agreed!

 

and I honestly believe its the removal of the stock muffler causing the gains because if you notice the GMPP exhaust which is 2.25" and SMALLER than the stock exhaust gives just as much gains as a 3" Hahn, MPX, etc.. because it too replaces the stock muffler with a better flowing, lighter muffler... common sense will tell you if smaller piping is giving gains over stock, its not the piping that is the problem.....

and my full mod list is:

Catted ZZP downpipe
Hahn CAI
Injen IC piping
Forge Motorsport BPV
23psi Trifecta Tune

hate to swing the topic but for anyone with those mods, I recommend the Forge BPV... my car sounded so much healthier with a simple switch to it, the stock unit seems to hate 23psi and i'm fairly sure mine had taken a turn for the worse

that is probably the best $125 i've spent just in clearing up the attitude of the car


but enough of that talk

 

So your saying just the muffler males gains? Lol. Tell me, how many turbo cars use 2.5" exhaust when making 300whp. Subaru enthusiats go 3" exhaust after tuned, evo guys, srt4's, any turbo civic making decent power, the 2.0T genesis coupe guys, ms3's, ms6's etc. They don't do it cuz its cool, it flows better and makes power. Your not going to gain 20 or 30whp just from a catback, but Youl make more power. Especially if u plan to run e85.

 

I never said you wouldn't however you are not at risk out outflowing the 2.5" catback until about 500whp...

therefor the gains will be minimum...

and yes, I do think the stock muffler is very restrictive, the fact it has a bend to the stock exhaust tip is a restriction, also the fact its just so damn bulky, like I said its hard to argue when SMALLER diameter piping is putting down a gain over stock as well....


1st off you need to realize not all catback are created the same, on some cars you may go from the factory 2.5" to a 3" catback and see a 15whp+ gain, or outflow your stock 2.5" exhaust at 315whp........ we won't see those gains with a 3", we are in no danger of outflowing our factory catback anytime soon


I did the research and had the money ready to drop... the money wasn't the problem, I just used common sense


so in other words, how many cars use 2.5" catbacks for 300whp? well, I can name one:


LNF Turbo Cobalts


guess which forum you are on

 

Yeah really, haha... you'd be hard pressed to make me believe that a stock LNF sees a real 15whp with a cat-back exhaust. Even with the GMS1, I have a hard time believing again that the stock exhaust as a whole is being overly restrictive. If anything, the DP is what's holding the car back.

Before I ever joined this forum, I had a thought of just replacing the DP, as well as the muffler. I also am a big fan of catted DP's, as I really don't feel a high flow catalytic converter is going to hold back a car unless it is making HUGE power. And by huge power, as we are talking about a Cobalt here, is anything above 400whp. I daily drive this car, haha... if I want that kinda power I'm going to buy a dedicated toy. Something that's RWD... the torque steer in this car is retarded as it is.

Can't really hurt the wallet to just replace the muffler and tip and see what happens. Will replace the OEM resonator as well, with again a Magnaflow. I want free flowing, but I don't really care for it to be loud.

I really like the sound of your car, OP, good ****. BTW... love that red.

 

according to this thread my muffler delete and cat less down pipe iz like 20hp... I'd be happy with over 5...meanwhile on planet earth..

 

no, i'm saying there is little power to be gained over stock with ANY setup minus the downpipe(which is where most of the gains in the exhaust are to be found)... way to totally misinterpret every thing i've said in this thread, and what I did say is the "gains" you see with a Hahn or MPX exhaust for the most part has to do with ditching the muffler, NOT the sizing of the pipe, which is evident in the fact a 2 1/4" exhaust setup from GMPP which is a 1/4 smaller than stock and 3/4" smaller than the Hahn and MPx is giving roughly the same gains over stock as the 3" Hahn and MPx....

throwing a catback on a LNF will give you less than 10whp... its not worth $500

I didn't do this mod for the gain in power, because there is very little to be found

 

If you're not on stock tune you should be happy-that's 10-15 easy.

 

yeah I just realized he said muffler delete AND downpipe.... the downpipe itself is about 10-15whp by itself, not to mention removing the offset bend at the end of the exhaust after the stock muffler

it probably would be close to 20whp with a tune with both.... and that is here on planet Earth, now with no tune... well, you probably would make power on a dyno immediately after bolting it on, but give it 200 miles for the ECM to relearn and you'll be back to stock numbers boosting less boost

 

And how about a tune? Im sorry but most guys who mod aren't going to stay stock tune.

 

.....we mentioned that, a downpipe is good for about 15whp alone with a tune

there is your big gainer with exhaust on these cars, not the catback or changing the muffler

 

I have a treadstone 3" catback without a muffler coming in the mail. I will be testing it out on the dyno pretty soon when I get the meth setup finished up. My car is a full bolt-on 08 making 318whp on a dynojet and I will post the results how my car reacts to the 3" catback...regardless if it makes power or not.

I've searched and searched but I can't find any actual proof if the ss/tc's pick up power with an aftermarket catback. I ran out of the simple bolt-on's and the catback was the last thing to buy. I'll put this to an end with some dyno charts...give me about 2 weeks for results.

 

Can't argue facts, only opinions. Let us know what you find, always interested to see.

 

Im interested in a dyno sheet. Remember, peak numbers aren't all that.

 

Do we need E85 to run the 23psi Trifecta tune? What's the most boost that can be run on Shell 93?

K&N intake
Injen Boost Pipes
Catted MPx DP
Forge BPV

Now you guys got me thinking about that big **** muffler. I might copy this muffler/tip combo. I like the rolled 4" tip (that's what she said).

 

No, 93 octane is fine.

Its not a matter of how much boost you can run but rather run effeciently on the K04.

Most run 23 psi, I ran 26 psi for a year on 93 Octance with no ill effects. But I made sure my **** was datalogged and checked often.

BYT did a test once and while you don't gain much whp over 24 psi, you do gain torque.