Just changed over the Flowmasters this morning. Went with a generic turbo muffler. A lot quieter, no drone and has a nice rumble.

Brother had a friend who had a Camaro with Flowmasters on it and the car picked up several tenths once he removed them. People buy those based on what they sound like. Nobody I'm aware of that has a dedicated race car uses those things. They are very popular with Mustang and Camaro guys for some reason.

Hooker Aero Chambers are good.

I don't like mufflers with packing material in them. They end up getting louder over time. Motorcycles come that way and you have to rebuild the mufflers every so often. Can't do that with a sealed car muffler.

I don't believe muffler flow bench numbers and I don't believe cylinder head flow bench numbers. Some made up machine cannot duplicate the airflow capacity of a running engine.

Hmmm...sounds like the words from a guy representing Flowmaster!

Well, you're likely right about that, specifically. But a "made up machine" CAN produce airflow, measure the amount of airflow that it produces, and measure resistance put on it by (in this case) a muffler. You can, however, argue how that measured resistance affects an engine's performance. Actually, I take the last part back.

Flowmasters sound good on fox body 302 mustangs. They had a unique sound to them on the roller 302.
I have ran them on 340's but they are loud for sure. Now im running TTI exhaust on both of my cars and the dynomax super turbos that came with the kits.
I can say one thing about these mufflers. When I first put them on I did not like them much. After about a month or two they got a little louder and sound really good.

anyone try the MF = magna flow?

I run a single 2.5 in/out offset/center one on my 98 grand Cherokee 5.9

I liked it a lot and thought I would swap out the cheap FM knock offs. which do sound ok on my truck and are not loud but not the tune I like.

Purple Hornies are still available....

I have been running the DynoMax mufflers on the Plymouth for years, great sound and holding up well, no interior drone to speak of.

Regarding Magna Flows I am running one on my Diesel and it has been great, nice flow and build quality, nice sound and not loud. Not sure about their Muscle Car applications though.

Magna Flows are cheaper knock-offs of Dynomax Ultra Flo welded - they used to be called "Race Magnum" series. They don't do ANY tuning at all as the exhaust passes through. To me, they sound FLAT, but get louder under WOT.

I have always have at least one car with a pair of Flowmasters on it since around 1985. Mainly because they were always cheap. No seeing the actual flow data I may have to change them up to some Ultra Flows.

so, what about tests on a car?http://www.pontiacstreetperformance.com/psp/exhaust.html

Tests on a car, the same car, is as believable as it gets.

Best flowing muffler would be something crazy like a 5" race bullet. Does not mean that muffler is right for most applications, or would even make it a car run any better if it's just the wrong one to pick. People take the whole flow bench stuff too seriously. It's just a tool to measure change or differences between things, but it can't tell you what it will do on a specific engine, at a specific altitude, at a specific rpm range, ect. It's all about a combination of parts working together that you have to look at.

I can say the Aerochambers are good because my brother has them on a low 11 second car and it runs very close to the same with them off. So much so that it's not worth the effort to remove them. They are a baffled muffler that won't score high on a flow bench, but on a running car they do what they say they do.

Did you read the link?

Nope, pressed send right before leaving work. Just finished reading it now.

Dynomax mufflers work well. Only thing I don't care for is the insulation inside that can break down over time. In an old car that isn't driven a lot this is a non issue.

Interesting how the Supertrapp does everything just as good, or better in the case of a flow bench reading, than the Dynomax, but ends up being one of the 3 loudest. I would never buy a Supertrapp muffler for an old car, but I do like the fact that they are serviceable and adjustable. They are very popular with dirt bike and ATV racers.

The Borlas flow bench within a hair of the Dynomax, but are a 'slower" muffler down the track.

Muffler companies don't seem to talk about decibel control as that's not as sexy as flow rate, or the type of patented aggressive sound they produce. If they came right out and said our mufflers are super quiet, most would think that would mean a loss in power.

Not trying to bust any chops but I don't quite get this response as Magnaflows and Borla Pro XS's are both within a few dollars of each other at Jeg's and Summit. The XR-1's are quite a bit pricier, but that isn't what most guys would run anyways. I've strayed from Borla's a few times on some different projects but always wound up coming back to them as they fit all my needs. Great sound at idle, mellow enough when cruising, bark when getting on it, have minimal impact to my E.T., and last forever. I just switched back again after letting someone con me into getting Flowmasters and probably will never stray again. I guess this is why there are so many brands out there. Exhaust is very subjective for sure. :-)

I'd like to point out that in our chart, when you see StraightLine Performance, those are Magnaflow mufflers.

Another very important point is that the mufflers we tested (those with chambers and "V"s inside them), were offset in and offset out or center out. The first jog the exhaust gas has to take to get into those mufflers really affects its flow. And it should as the exhaust gas pretty much hits a flat surface as it first enters into the muffler.

All the cars we tested them on acted the same way, performance dropped compared to straight through or center in mufflers. Center in versions of chambered mufflers work much better although the sound level did not change much. Hooker Aerochambers, when offset in (are made differently) flowed better and ran better than some others.

We tested other mufflers but chose not to share them in this chart since we were doing mufflers that typically are used on street cars. At the time, very few cars used center in and center out rectangular or oval mufflers so we did not publish results.

We learned that overall, it was pretty simple: when the air can get in and out smoothly, the power level seemed to stay higher. When the mufflers had sound "absorbing" materials in them (more so than only stainless steel) they were quieter. So, combine a good perforated tube pattern, high flow potential, and good sound "absorbing" material and you get sound control, nice sound, and better performance. In other words, you get a muffler that truly muffles and ones that let the engine run well and the car perform at the strip. If you need more sound or roar or rumbling, it is often a tradeoff with power output but, in life, it's all a tradeoff anyway right? :):)

Tom Hand

I like the way my 40 series flowmasters sound on my Challenger with an H-pipe, they are a not for everyone though and are a bit loud. I do plan on an x-pipe and ultraflows for my charger though just to mix it up and have a different sound/pick up some hp.