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Flowmaster or Magnaflow?


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16 replies to this topic

#1 J35

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Posted 16 February 2010 - 09:10 AM

Just recently i found out that the muffler on my 97 3.8 v6 firebird is coming apart and im gonna have to have a new one soon im gonna have to have a one in two out but i cant make up my mind on who i wanna go with to me flowmaster has the best sound but ive been told by experts that flowmaster can be very restrictive on horsepower and then again maganflows sound pretty good on a 3.8 firebird or camaro im just not sure what to go with any other muffler recomendations would be appreciated too im lookin for somthin a lil louder than ur average v6 just not so loud it sounds like crap
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#2 79/6.6

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Posted 16 February 2010 - 10:08 PM

I recently sold a 95 Firebird, with the 3.4 litre V6. I did not go to the expense of a name brand muffler just for the sound. You can get the same result in sound with an ordinary " TURBO " muffler, without the expense. Now on my 6.6 I had headers installed and all new exhaust. I tried the Borla, and settled on the flowmasters. After about 1000 miles over a years driving, they sound really good.
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#3 J35

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Posted 18 February 2010 - 09:05 AM

I recently sold a 95 Firebird, with the 3.4 litre V6. I did not go to the expense of a name brand muffler just for the sound. You can get the same result in sound with an ordinary " TURBO " muffler, without the expense. Now on my 6.6 I had headers installed and all new exhaust. I tried the Borla, and settled on the flowmasters. After about 1000 miles over a years driving, they sound really good.



would u happen to know if flowmaster restrict ur cars horepower or not i mean for the sound id go wid flowmasters but ive been told they can be very restrictive
Josh W.

#4 TransAmer99

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Posted 18 February 2010 - 09:48 AM

If you were to look at the entire system, you'd find that the mufflers aren't nearly as restrictive as the factory Y-pipe. The sudden bends, flattening out right past the merger of left & right branches (for ground clearance) and transition back to round does nothing for scavenging whatsoever. Not to mentions the restrictions if you have the factory exhaust manifolds. It's the old 'garbage in; garbage out' syndrom. I agree with Larry up above, not worth the dollars unless you are upgrading the whole system.

That being said, in my experience with V8's, I prefer the sound from the Magnaflows over Flowmasters. But if I was going to replace an entire system, I'd probably go with something higher-end than either of those two. That's my plan for LadyHawk, which is currently equipped with a Flowmaster (I'm the 5th owner and it came to me that way).
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#5 alicia

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Posted 21 February 2010 - 02:45 PM

i had flowmasters on my '99 (V8 not V6) but i had the whole exhaust kit on it. it actually improved horsepower. but as far as just a muffler, i don't know. i think larry made a good suggestion though :30tens:
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#6 Zaxximus

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Posted 08 May 2011 - 04:58 PM

I had my exhaust redone on my 87' 5.7 V8 to remove the converter and make it a true dual. I ended up settling with flowmasters. It was tough for me to decide between the Super 44 or the 40 series, ended up going with the 40 series and it was well worth it. I haven't noticed a restriction in power, much the opposite. Just a hair better gas mileage too.



I forgot to mention, the 40 series is better known as the American Thunder series.

#7 Byrd

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Posted 09 May 2011 - 02:15 AM

Just remember if you can not see thrue the muffler then it is a restrictive muffler. Yeah flowmaster sound pretty cool but that is about it. Im not sure how much back pressure V6's like but I know V8s don't much care for it. Dynomax,Magnaflow,Borla are all very good performance mufflers. Even the cheapo turbo mufflers will flow better the a Flowmaster or any weld chamber style muffler. But I'm sure on a street car you will never see the difference.

#8 tallguy34260

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Posted 20 May 2011 - 08:21 AM

Just remember if you can not see thrue the muffler then it is a restrictive muffler. Yeah flowmaster sound pretty cool but that is about it. Im not sure how much back pressure V6's like but I know V8s don't much care for it. Dynomax,Magnaflow,Borla are all very good performance mufflers. Even the cheapo turbo mufflers will flow better the a Flowmaster or any weld chamber style muffler. But I'm sure on a street car you will never see the difference.



The flowmaster may not be the best flowing and a bit restrictive, but I installed mine about a month ago and have enjoyed the difference from the stock muffler. I was getting about 21.5 mpg before and am now getting 23-23.5mpg. I didn't use the the full exhaust kit though and I pieced it together myself which may have helped. Here's a link to the video and picture I posted earlier (near the bottom)

#9 Injuneer

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Posted 20 May 2011 - 08:47 AM

You really need to be careful with generalizations about mufflers. A lot of the trashing of Flowmaster is based on flow tests from at least 20 years ago, comparing brands of mufflers without even noting which specific muffler part # was being tested. Flowmaster makes a large number of different designs.

My only experience is with the Mufflex 4" catback, using the Flowmaster 30-series Race 4" single in/single out muffler. I pushed 800HP through it, and it did not reduce HP at all - dyno verified. Buddy of mine with the same setup pushed over 1,000 HP through the same muffler/catback, pulled the sytem off, and went to collector mufflers and dumps, and no change in HP at all - dyno proven. Biggest advantage of removing the system was getting rid of about 50# of excess weight. You can not see through the 30-series mufflers, they have a "delta" shaped baffle system.

As far as "liking" backpressure, that's a huge myth. Anything that causes backpressure causes reduced flow. The more you reduce flow, the less HP you make. Reduced power following removal of a muffler, or install of a larger exhaust system is usually due to failure to retune for the improved volumetric efficiency. You need to address gas velocity in the primaries of a tubular header system, but once you get past the collectors, you do not want backpressure.
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1994 FIREBIRD FORMULA
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https://www.firebird...9_698_32777.jpg

 


#10 84 T/A

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Posted 29 July 2011 - 06:33 AM

magnaflow IMO is betetr than flowmaster, i think it sounds better, and lets the car be less ceceptable to horsepower restriction.

#11 Jaysz28

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Posted 29 July 2011 - 06:45 AM

I have run both flowmaster, than mangaflow on the same car.




the magnaflow had less interior drone, but with a more aggressive tone..... and I stuck with the magnaflow




good luck with it



#12 69 lover

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Posted 06 April 2015 - 05:50 PM

MagnaFlow for sure

#13 Inspector

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Posted 16 October 2018 - 06:22 AM

I just put the magnaflow cat back system on mine.Replaced the factory y pipe with a slip one and I can feel and hear the difference.I like the sound of a magnaflow way better than Flowmaster.Just to loud.The system I put on mine said free flowing.They been at this a long time and one would think they would know what they are doing.Had a magnaflow on a 2nd gen Camaro also.Sold that car.Love both of them.

#14 Nightstalker88-98

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Posted 16 October 2018 - 07:59 PM

I'm very happy with my Pypes duals, quality, sound, and performance.

#15 JoePeek

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Posted 19 October 2018 - 03:14 AM

The think the old myth of engines "liking backpressure" comes from carburetor days. Back in the day, if you improved the exhaust flow with headers or even just a better flowing muffler, it usually required going up at least a few jet sizes. If you just did the exhaust changes without the jet change the air/fuel went a bit lean. The observation that you just did something the engine did not seem to like may have been correct, but the reason why was because now the air/fuel ratio was leaner, not that you took away some "needed" backpressure. Even in today's engines, if you change cams, intake, exhaust, compression, etc.....you will get the most of the modification if go into the tune and optimize the MAF curve, or VE table, ignition timing tables, cam phasers, etc. The same muffler will not sound the same when put on different cars because engine size, exhaust valve opening timing, compression, air fuel ratio and even ignition timing all effect how the exhaust will sound. If I say I put traditional Flowmaster 40's on my car and I think they sound great, that does not mean they will sound the same on your car. Furthermore, what your personal opinion in what you think a sweet sounding exhaust should sound like may be different than mine. 


Edited by JoePeek, 19 October 2018 - 03:15 AM.


#16 TOMR67

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Posted 21 October 2018 - 05:57 AM

First off you have a v6, and big exhaust you put on it will sound like crap because the are designed to flow more than your engine creates same with a 305

So unless your engine is very worked and you run headers any muffler is fine

Not trying to sound like a jerk but its the truth, i have decades of experience lol owned cars from all 4 generations with v6 and v8 , with the v6 and 305 the exhast will never sound like a muscle car ive tried all different pipes and muffler combos

#17 Injuneer

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Posted 21 October 2018 - 01:11 PM

People.... this is an 8-1/2 year old thread, that someone resurrected 3-1/2 years ago. The people who asked these questions on those dates have not returned to this site since a few months after they posted.

This entire thread is of very limited value, and maybe its time to close it.
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