Flowmaster Vs Magnaflow Mufflers >> From My Real Experience..

**woolveren** · 12-25-2011 01:14 PM

Hi all,

I've been asking a lot of questions in this forum ever since I joined here. And all the time, I've got great and helpful responses from you guys.:)

This time, I thought of posting something which may be useful to some new owners. I know most of you here are well aware of the mods and facts for B5.:)

In the last 1 year, I have used 4 different mufflers on my car( 98 Audi A4 1.8t): Two Magnaflows and two Flowmasters. So here I am writing about the performance of all these mufflers..

1. Magnaflow Muffler- When I bought the car, it came with an aftermarket Magnaflow muffler(don't remember exact part number) with stock resonator. And I used this for couple of years. I don't know which model was it. It had a loud sound and performance was okay, but not that great. Tired of the loud noise, I planned of getting a new muffler. I went to a muffler shop(the best muffler shop in my city) and asked them about mufflers and my needs. They suggested me to get a Flowmaster muffler which has a nice rumble and is not too loud. They also said that this Flowmaster muffler will increase my Horse Power by 10- 15 %. I didnt take their words directly, but I went home and did a research on the model they said.

2.Flowmaster 60 Series Delta flow Muffler- This was the muffler suggested by the shop. I did some research on internet and found out that this one has a smooth sound. Also, this muffler is designed for 4 Cylinder engines. But I didn't find any real comments about the HP gain anywhere in net. Anyway, I went online and bought it from autoanything.com. Muffler arrived and took it to the same shop and fixed it (kept the stock resonator). Started the engine and liked the sound straight away. The sound was deep and very very low compared to my old magnaflow muffler that was loud like anything. Got out from the shop, drove the car through the city and finally took the higway to get back to home. This is where I really got impressed, the car seriously got a gain in the horse power. And I was able to feel it.
.

Uploaded with ImageShack.us
.
With the old muffler, it takes a while to get to 75MPH from 55 MPH and I was used to that. With the new muffler, I was pressing the gas pedal hard having this in my mind. But all of a sudden car was gaining speed so fast. There was a real difference in acceleration and was well noticeable. With gas pedal engaged halfway compared to what I usually do with the old muffler, the car reached almost at 95 MPH. I was really happy and tried this again. Came down to a lower speed around 60 MPH and just pressed the accelerator..Man, the car reached 110 MPH with in no time. My car never used to do this before. And all I changed is my old Magnaflow muffler with a new Flowmaster Chambered muffler.

3. Flowmaster 50 Series Delta flow Muffler- I went on with the second muffler(60 series delta flow) for some 5 months. I had real fun times driving on highways with the increased horse pwer(stock turbo, stock resonator). If somebody just shows off, you can make them look like ass by showing the real power. Boommm...70 to 110 MPH in some seconds...:) I used to do that a lot of times when people continue driving slow in the left lane for no reason. Get to the right lane, overtake, come back to the left lane and GOOO...:).
With the flowmaster muffler, the speed gain is very quick compared to the magnaflow muffler which was very slow to get to 110 MPH mark. But with the Flowmaster, the car is willing to gain any speed above 100 MPH easily.
.

Uploaded with ImageShack.us

.
4. Magnaflow 14815 Muffler- The 50 series muffler is bulky and it was not a perfect fit under the car. So after some 4 months, I decided to move on to Flowmaster Hush power dbx series muffler, which is their new technology based muffler. But before buying that, I came here to know whether anybody used this muffler before. And everbody suggested to buy the Magnaflow 14815 muffler in th thread. I saw couple of videos in youtube and I liked the sound & the dual exhaust tip. And the reviews were also good. So I had this impression that the magnaflow might have came up with some good performance mufflers in the mean time. So without going for the Flowmaster, I thought of trying my luck again in Magnaflow. Went and ordered the muffler. Fixed it, started engine and was straight away impressed with the sound. Got out from shop, went on to highway.....and only one feeling came in my mind...I wasted another 200 dollars for a dumb muffler. This 14815 is just good for sound and no HP gain at all. I think it reduced my HP and the car was difficult to accelerate in higher RPM's. Sick of all these, next week I went back and put the Flowmaster 50 series back....Seriously guyss, the entire power just came back..
.

Uploaded with ImageShack.us
.

From this near $800 swapping of mufflers, I came to know one reality.

If you want to really improve the performance and sound of your car, you need to get a Flowmaster muffler. Or if you are just considering sound, with no increase in HP, go with a Magnaflow muffler..Their sound is slightly more good compared to that of Flowmaster..

Anyway, I am going to get a Flowmaster Hushpower dbx Series muffler mext month. And hope that it will perform beyond my expectation..:)..

**biketsai** · 12-25-2011 01:49 PM

10-15% increase in horsepower is highly unlikely by changing out the muffler out on these cars.

**woolveren** · 12-25-2011 01:55 PM

Originally Posted by biketsai

10-15% increase in horsepower is highly unlikely by changing out the muffler out on these cars.

That's the figure that muffler shop guy said. I am not saying there is 10- 15% exactly, but seriously there is a large difference in HP when using Flowmasters..

**SN95Audi87** · 12-25-2011 02:48 PM

I believe it. More flow = more power. It's like trying to fart thru a straw vs a paper towel pipe lol. Anyways, thanks for the feedback. I desperately need to change out the stock exhaust system because of the poor performance in passing power, takes forever.

**rebelbowtie** · 12-25-2011 03:16 PM

flowmaster has been proven to be inferior muffler time and time again, also this post is absolutely useless with your "seat of the pants" dyno. glad you like the sound of flowmaster mufflers, its your car you should do what you like best.

**ballinb5** · 12-25-2011 03:19 PM

exhausts are just mental, when the car sounds louder or meaner, it feels faster even though its not.

**witwer4444** · 12-25-2011 03:40 PM

I actually didnt get any gains with a magnaflow muffler in my 2001 2.8 when I had it. Sounded better yes, but the 2.8 actually performs better with back pressure from the stock exhaust. Now I know a Turbo car is different....

**rebelbowtie** · 12-25-2011 04:01 PM

Originally Posted by witwer4444

I actually didnt get any gains with a magnaflow muffler in my 2001 2.8 when I had it. Sounded better yes, but the 2.8 actually performs better with back pressure from the stock exhaust. Now I know a Turbo car is different....

No engine needs back pressure

**TConklin821** · 12-25-2011 04:05 PM

I am running an eBay test pipe, no resonator, and this muffler:

http://www.034motorsport.com/fabrica...out-p-581.html

holy shit. it's loud. Not just a little loud, but apparently when I really get into it when I leave my house my windows rattle, lol. Anyway, it isn't too bad inside the car, I've owned straight piped diesel pickups and all kinds of funny things, so that doesn't bother me. But man, it feels like a whole different car.

Edit:
I also run a LaBree down pipe and 2.5 inch custom exhaust from there back to the muffler. That test pipe and muffler freed up a lot of power. Boosts earlier, pulls harder up top. I love when I'm doing 70+, downshifting into 4th and getting into it. It just pulls. Getting tuned soon. Excited.

**rebelbowtie** · 12-25-2011 04:19 PM

before someone tells me i am wrong about back pressure, i will put it simple. back pressure is just that, pressure that is pushing back about your engine, hindering the exhaust from clearing the combustion chamber. the key to a good performing exhaust system is exhaust gas VELOCITY. that is where the myth began, prime example is say take a 4 cyl engine, johnny ricer puts a 3" exhaust on his honda civic and noticed he lost power. he didnt lose power because he eliminated his back pressure, he lost power because he eliminated exhaust velocity. wider isnt always better….

**TConklin821** · 12-25-2011 04:24 PM

So basically it's like a garden hose with a trigger handle on the end. Opens too much it'll just pour out all slow, try to close it off too much and you hinder the amount of water able to come out. Gotta find a nice happy medium, sound about right?

**rebelbowtie** · 12-25-2011 04:25 PM

Originally Posted by TConklin821

So basically it's like a garden hose with a trigger handle on the end. Opens too much it'll just pour out all slow, try to close it off too much and you hinder the amount of water able to come out. Gotta find a nice happy medium, sound about right?

yea buddy

**TConklin821** · 12-25-2011 04:28 PM

That's kind of how I always thought about it. When I got my downpipe (2.5in) , everyone was like, "you need 3inch all the way back!". I'm saying "no". lol. The most power I'll ever make is about 300chp, maybe. Not a huge amount.

**rebelbowtie** · 12-25-2011 04:31 PM

Originally Posted by TConklin821

That's kind of how I always thought about it. When I got my downpipe (2.5in) , everyone was like, "you need 3inch all the way back!". I'm saying "no". lol. The most power I'll ever make is about 300chp, maybe. Not a huge amount.

on that note dont ask me what i think about CAI's

**TConklin821** · 12-25-2011 04:33 PM

Originally Posted by rebelbowtie

on that note dont ask me what i think about CAI's

I'm going to, because this has been an ongoing debate between me and people I know. I say they do pretty much nothing, especially on turbo charged cars. It doesn't matter how cold the air coming in is, because it's still being sucked into a 1400 degree turbocharger.

**rebelbowtie** · 12-25-2011 04:35 PM

Originally Posted by TConklin821

I'm going to, because this has been an ongoing debate between me and people I know. I say they do pretty much nothing, especially on turbo charged cars. It doesn't matter how cold the air coming in is, because it's still being sucked into a 1400 degree turbocharger.

your friends are right, i can post a great write up i have saved on my computer about it. its sparked much debate on multiple forums.

**TConklin821** · 12-25-2011 04:51 PM

That's not my friends, that's me, lol.

**rebelbowtie** · 12-25-2011 04:54 PM

Oops misread that, yea posted the thread and PM'd you a link. Sorry to the OP for mucking it up off topic.

**TConklin821** · 12-25-2011 04:56 PM

Yeah, sorry about the thread-jacking.

**Seerlah** · 12-25-2011 05:06 PM

redtelbowtie: Many 2.8 owners have played with the exhaust setup, and they all found that they lost low end hp/tq when they added added HFCs or free flowing downpipes. It made up for it on the top end, but they found that you had to scrifice the lower end torque and horse power for it.

And OP, don't listen to the mechanic on saying a simple muffler will add 15% hp. That's jibberish. The most restrictive part on the stock 1.8t exhaust system is either the stock cat converter (can't recall exact cell count it has, but it was up there) or the measly sub 2" OD piping. Unless you have dyno numbers proving the 10-15% increase in power, then it will be nothing but speculation and well wishing.

If you really want an increase in power, the ECU flash is the proven effective route. I have been like that for years now with a labree HFC, into custom 2.5" downpipe, into Milltek resonated 2.75" exhaust. Do I think my exhaust at 2.75" is more effecient than another with 2.25" on my power levels? Absolutely not. But I chose this system for suitability on future goals, and the sound note was simply my favorite when shopping. And $800 is rather pricey. You can get a full custom exhaust built for $500 with either of those mufflers you chose, along with many other variations that you would choose.

**TConklin821** · 12-25-2011 05:12 PM

It's true. My TP was $110 after shipping, DP was $180 (used but in amazing shape), muffler was about $120, and the custom work to hook it all up was $180. All in all about $590, but it made a hell of a difference. I've got a friend who's completely stock, except for an APR stage 1 ecu flash. All I have is my exhaust mods and cone K&N filter, and we stay pretty neck-and-neck on the highway. The difference in power the exhaust made was awesome.

**rebelbowtie** · 12-25-2011 05:25 PM

Originally Posted by Seerlah

redtelbowtie: Many 2.8 owners have played with the exhaust setup, and they all found that they lost low end hp/tq when they added added HFCs or free flowing downpipes. It made up for it on the top end, but they found that you had to scrifice the lower end torque and horse power for it.

And OP, don't listen to the mechanic on saying a simple muffler will add 15% hp. That's jibberish. The most restrictive part on the stock 1.8t exhaust system is either the stock cat converter (can't recall exact cell count it has, but it was up there) or the measly sub 2" OD piping. Unless you have dyno numbers proving the 10-15% increase in power, then it will be nothing but speculation and well wishing.

If you really want an increase in power, the ECU flash is the proven effective route. I have been like that for years now with a labree HFC, into custom 2.5" downpipe, into Milltek resonated 2.75" exhaust. Do I think my exhaust at 2.75" is more effecient than another with 2.25" on my power levels? Absolutely not. But I chose this system for suitability on future goals, and the sound note was simply my favorite when shopping. And $800 is rather pricey. You can get a full custom exhaust built for $500 with either of those mufflers you chose, along with many other variations that you would choose.

Yea sure I believe certain exhaust set ups will flow too much will decrease power down low, but it's not because of back pressure. Finding the perfect exhaust gas velocity is a balancing act. Every little thing in the exhaust system can effect the over all performance and sound of the exhaust. This is especially true with the placement of mufflers and on v6 and v8 engines the placement of a cross over pipe if you choose to use one.

You need to choose an exhaust set up that matches your engines power band, it's not necessarily true in forced induction but larger diameter pipes and high (bench) flowing mufflers such as Borla or other straight through designs promote higher RPM power increases. Again that doesn't mean back pressure is good, just means you need to find the correct balance in exhaust pipe diameter and muffler type.

Regardless of all that, back pressure is bad, period.

**Seerlah** · 12-25-2011 05:28 PM

Originally Posted by TConklin821

It's true. My TP was $110 after shipping, DP was $180 (used but in amazing shape), muffler was about $120, and the custom work to hook it all up was $180. All in all about $590, but it made a hell of a difference. I've got a friend who's completely stock, except for an APR stage 1 ecu flash. All I have is my exhaust mods and cone K&N filter, and we stay pretty neck-and-neck on the highway. The difference in power the exhaust made was awesome.

Not all cars drive the same, not all engines are the same, not all cars are in the same mechanical condition, not all drivers drive the same, not all tunes are the same, etc. There are simply too many variables. Unless "back to back" dyno numbers prove it, then it is still speculation and well wishing. And the OP did not state anything about a "full" system. He only stated the muffler. As I stated previously, the stock cat and sub 2" piping is the most restrictive part of the system.

There is no denying that an exhaust will clear up back pressure. That is the purpose of adding one. But you def aren't going to get 10-15% power increase from just a muffler. It is advertised that my exhaust grants 10-15% increase in power also. But mine attaches to the cat converter, and is a full cat back system. Then I replaced the stock cat with high flowing unit. I'm even spektical of it granting 15% increase.

But in all reality, it does not really matter. Do a mod that will make a substantial difference. For example, I like my suspension mods way more than I like my ECU flash. BT on the way, but you get the point.

**mysman** · 12-25-2011 07:58 PM

Appreciate you sharing your experiences, but without sound files and dyno runs, it's all subjective.

**TConklin821** · 12-25-2011 08:02 PM

Judging by how much dyno runs cost, it doesn't make sense to run on a dyno every time a muffler gets changed.

**MarcMiller** · 12-26-2011 10:25 AM

flowmaster mufflers on our cars sounds like ass though. magnaflow is deff one of the best mufflers to get. you said the 14815 muffler doesnt fit good? well i have that same muffler and mines sitting perfect.

**GOODBYNAAIR** · 12-26-2011 10:57 AM

Originally Posted by TConklin821

I am running an eBay test pipe, no resonator, and this muffler:

http://www.034motorsport.com/fabrica...out-p-581.html

holy shit. it's loud. Not just a little loud, but apparently when I really get into it when I leave my house my windows rattle, lol. Anyway, it isn't too bad inside the car, I've owned straight piped diesel pickups and all kinds of funny things, so that doesn't bother me. But man, it feels like a whole different car.

Edit:
I also run a LaBree down pipe and 2.5 inch custom exhaust from there back to the muffler. That test pipe and muffler freed up a lot of power. Boosts earlier, pulls harder up top. I love when I'm doing 70+, downshifting into 4th and getting into it. It just pulls. Getting tuned soon. Excited.

hey could you put up a sound vid im looking into a new exhaust ? prob going to go with custom, something like u got ? thanks

**GOODBYNAAIR** · 12-26-2011 11:14 AM

Originally Posted by TConklin821

Judging by how much dyno runs cost, it doesn't make sense to run on a dyno every time a muffler gets changed.

good point and if you only have a car that is all stock but a muffler or maybe a full exhaust, no point unless you get a free dyno( save ur money) just give urself maybe 5% ish on stock chp depending if the car is NA or not? just my 2c off of the searching I've done coming from a v6 NA and now have a 1.8t

**TConklin821** · 12-26-2011 02:51 PM

Originally Posted by GOODBYNAAIR

hey could you put up a sound vid im looking into a new exhaust ? prob going to go with custom, something like u got ? thanks

I'll get up some clips as soon as I can, keep an eye out for the thread.

Originally Posted by Seerlah

Not all cars drive the same, not all engines are the same, not all cars are in the same mechanical condition, not all drivers drive the same, not all tunes are the same, etc. There are simply too many variables. Unless "back to back" dyno numbers prove it, then it is still speculation and well wishing. And the OP did not state anything about a "full" system. He only stated the muffler. As I stated previously, the stock cat and sub 2" piping is the most restrictive part of the system.

There is no denying that an exhaust will clear up back pressure. That is the purpose of adding one. But you def aren't going to get 10-15% power increase from just a muffler. It is advertised that my exhaust grants 10-15% increase in power also. But mine attaches to the cat converter, and is a full cat back system. Then I replaced the stock cat with high flowing unit. I'm even spektical of it granting 15% increase.

But in all reality, it does not really matter. Do a mod that will make a substantial difference. For example, I like my suspension mods way more than I like my ECU flash. BT on the way, but you get the point.

Yeah I get you. Our cars are the same. 2001 1.8TQM AWM code, but there are still differences and other variables. I just remember he used to be able to walk right by me, and once I did the turbo back things changed.

**GOODBYNAAIR** · 12-26-2011 05:34 PM

yeah like i said cars with turbo it can help alot or not, i get what ur saying. im doing revo stg1 tom and Custom exhaust soon so im trying to see what ppl think works well. u said ur exhaust gave u that much maybe i would like to do somthing like that?..... more supporting mods for a gt2871r in the spring? my bro has an "APR stg1+" on a 99 b5 and he walks away in every gear on a ko3 something like 12-14psi. ps im stock with cone filter and heat shield

**flynnr** · 12-26-2011 05:52 PM

side note - those are some TERRIBLE welds LOL

**SN95Audi87** · 12-27-2011 11:08 AM

I dont think you will lose exhaust velocity by upgrading too a 2.5" pipe all the way to the exhaust tip. When you go past that size, and the engine can't push a lot of air out thats when you start loosing perfermance. Plus half of you guys are chipped with double the psi from factory so its imperative that you have bigger exhaust system.

**OMEGA SUPREME** · 12-27-2011 11:11 AM

Borla.... Or nothing.

**Xlr8nrg** · 12-27-2011 12:24 PM

To the op If ya want more power swap a real turbo in and/or tuning..... When I swapped in a gt28 (long ago) my borla (strait through) exhaust got twice as loud with twice the power seriously. And I tried to make it a little less noisey with a flowmaster and it killed my spool drastically! They flow like garbage!!! (Hence no flow rating) Magnaflow for the win! The strait through design flows way better! I vote put the money toward REAL power adders like tuning and turbos that flow more than a micro hairdryer :) 0-100 would blow your mind! Just my experience

**redline380** · 12-27-2011 05:38 PM

Originally Posted by rebelbowtie

No engine needs back pressure

I beg to differ. My snowmobile or any two stroke for that matter needs back pressure

**flynnr** · 12-27-2011 09:17 PM

Originally Posted by OMEGA SUPREME

Borla.... Or nothing.

i sold my borla because i didnt like it all that much.... like my magnaflow a lot better IMO

**rebelbowtie** · 12-27-2011 09:30 PM

Originally Posted by redline380

I beg to differ. My snowmobile or any two stroke for that matter needs back pressure

Not necessarily true either, but positive pressure in a 2 stroke engine exhaust ie expansion chamber will help promote scavenging. It's not really back pressure per say.

**viceprp** · 12-28-2011 08:47 AM

The OP made me giggle. Feels like a Honda forum. I hear adding flame decals add 6% HP and 3% ft-lbs.

**Raistlin** · 12-28-2011 07:08 PM

So if I want to upgrade my exhaust on my 01 2.8 with no performance mods for a cheap as possible, what should I get? I know an exhaust will not give me much gains, but what exhaust can I get that will improve performance on my car and not take away from current performance?