trey ss

i am thinking about buying a magnaflow muffler, just the mufler.. will this sound good or give me any power gains.. im trying 2 buy it at like advance auto or ordeer it off magnaflows web site.. is this a reasonablely cheap substitute 4 the cat back???

thanks,
Trey ss

Supercharged Guy

iTrader: (1)

Just the muffler..power wise no you mise well go with a 2.5 inch magnaflow catback, if your gonna get any exhaust part you should start off there

Micro

I replaced my stock Cobalt SS/SC muffler with a Flowmaster muffler and gained 11 hp. Proof is on this video: http://www.youtube.com/watch?v=2CZR7OGk0AM

You won't regret replacing the muffler. Why spend the extra money on a cat-back exhaust when you can get nearly the same hp gain by just changing the muffler?

trey ss

r u serious!

Supercharged Guy

iTrader: (1)

11hp thats hard to believe I mean a couple but not 11 dyno dynamics = high reading lol
way to ruin the car man what the hells up with all the stickers

D4u2s0t

haha, bro, you can't honestly think you gained 11 hp by swapping your muffler... you most likely gained less than 1 hp. You can't simply go to a dyno on different days and call that "proof". It's not abnormal at all for your hp to fluctuate on a dyno by 5% or so just because of the weather or other conditions.

To the op, if you're looking for power, then don't just get a muffler. You will feel no difference, there will be no power gain, the car will just be louder.

trey ss

i dont see how it wouldnt, what r the differences between stock and aftermarket.. the only big one i can see is the muffler..

D4u2s0t

primaries, cat, bottle neck where dp and cb meet, resonator, crush bend over axle. A muffler is the least of your performance worries on a cobalt's exhaust.

trey ss

oh.. i didnt know all that

D4u2s0t

now ya know!! There is almost nothing to be gained by swapping the muffler. Any gains that people "feel" are in their heads.

SCcobaltSS

iTrader: (2)

oh come on! the butt dyno has been proven to be the most accurate.. Its not in peoples head!

Micro

The dyno is not high reading. When I did the GM Stage 1 upgrade, I only saw an increase of 3 hp over stock. Here again, nobody else has dyno evidence of before and after runs of a stock Cobalt going to Stage 1 (with no other mods).

To the others who say I didn't make 11 more hp by swapping the muffler; give it a try with before and after dyno runs. If you don't see an increase of hp at the wheels after swaping the muffler, then I am wrong. All dyno runs were done at ~ the same temperature on the same dyno and corrected for any slight temperature differences. I stand by the results.

You seem confident in discrediting my "results" with your "logic".

D4u2s0t

learn about cars, exhausts, dyno's, etc... you'll learn VERY quickly that this is not an accurate way to determine gains, at all. Majority of people would never before & after dyno for a muffler, because it's known that it's a sound mod, not a performance one. you wouldn't gain 11whp by doing a full catback, let alone a muffler swap.

as I said, your "results" are flawed. This is not proof at all. I'm 100% confident, and anyone that knows anything about how dyno's work, and what a muffler can really do would agree.

Micro

as I said, your "results" are flawed. This is not proof at all. I'm 100% confident, and anyone that knows anything about how dyno's work, and what a muffler can really do would agree.[/QUOTE]

What are the flaws of before and after dyno testing under controlled conditions? The reason nobody else knew about this (hp gains from just a Flowmaster muffler swap) is because nobody else tried it (with before and after dyno runs).

D4u2s0t

ok, you're right. You gained 11whp from swapping a muffler, but only 3 from going to stage 1 lol.

Short answer? the dyno is obviously not accurate. Unless you can honestly believe that you'll get almost 4 times as much power gains by swapping mufflers as opposed to getting a stage 1.

Supercharged Guy

iTrader: (1)

agreed, 11hp is way to much just for a muffler man sorry I dont care if you said same day, same temp etc. 11hp is just far fetched

Micro

I am amazed how people reject truth because it doesn't match what they expect.

Supercharged Guy

iTrader: (1)

Im saying that most people gain 10-15 on full exhaust setup's, maybe a little more it depends, and you say that just with the muffler you gained 11hp (Just with the muffler)

D4u2s0t

lol, it's not truth, it's people knowing what they're talking about trying to convince someone else that they're wrong. a full catback won't even get a real 11 whp.

let me ask again... you can truly trust a dyno that said you gained 3 hp by adding a stage 1, and 11 by swapping a muffler?

nicksredline

i am amazed ur still fighting... rilly do u think you can get 11 hp from a muffler... if ur freind was to tell you that would u beleave him?... i sure wouldent lol... but if u rilly think u do get 11 hp from it wait till u put the K&N on its like instant 40 hp easy... maby ur s/c was hot and or heat soaked so u did not get the same iat as before... could posably be knocking and backing ur timing down... not much on the tuning side but i am pritty sure it had something you did not expect happned.

in short 1st pull - ur car was hot /heatsoaked from driving there.( s/c was hot... lose quite a bit of power)
2nd pull - ur car cooled down after putting muffler on and the ait's where alot lower(NOT OUTSIDE TEMPS... but the temps inside the intake manifold) posably making more power because everyone knows the colder the air the dencer the air the dencer the air the more fuel the more fuel=more power... if u dont get that than quit arguing and listen to people on here. ( definatly not the smartest one on here but i HIGHLY disagree with you )

Micro

In order to confirm or negate these results, we would need to have someone else perform the same tests on another car. That is not very likely since GM Stage 1 sucks, and most people won't pay extra money to dyno a muffler swap. So, we are at an impass. Your and my logic both say these results shouldn't be so, but the data says otherwise. If you watched the videos you will see my big dissapointment on the GM Stage 1 dyno runs and my surprise after the muffler swap.

I am a scientist, so I get to experience being wrong all of the time. People can argue with opinions all day, but it is more difficult to dispute reproducible results. All we are lacking is the reproduction of these results. Sometimes good science can refute common wisdom. All I can say is on my single sample, I saw X happen. I shouldn't have used the word "proof" in my 1st post. I think that is what I would change.