Magnaflow, Flowmaster or other - Impala Tech
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post #1 of 8 (permalink) Old 10-30-2013, 08:37 PM Thread Starter
Join Date: Sep 2013
Location: Spokane
Posts: 26
Magnaflow, Flowmaster or other

Has anyone had experience with performance of "modern" performance mufflers - and perhaps a recommendation?

My last "performance mufflers" were Purple Hornies (does that date me?).
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post #2 of 8 (permalink) Old 10-31-2013, 05:27 AM
Join Date: Jan 2007
Location: Lewisburg, Ohio
Posts: 2,909
I run Flowmasters on a couple of my cars. Mainly I like the sound.
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post #3 of 8 (permalink) Old 10-31-2013, 06:43 AM
Join Date: Jan 2006
Posts: 12,361
Like Larry said the choice of a muffler is personal. I personally run FlowMaster 70 series for a 454 pick-up truck. They are huge which is what you want to look for if you dislike noise. If you like noise you can buy competition FlowMaster mufflers that comply with NHRA's requirement to run a muffler. It is what all of the Pro Stock cars run. This is because it is a six inch long hollow tube the same diameter as your collector inside with fiberglass wrapped loosely around the out side like a Bandaid on a boo-boo.

I wrote a post a while back that outlined all of the current muffler designs with information and pictures illustrating the construction and how they work as well as reliability and back pressure. I also talked about the diameter of the exhaust pipe and the effect it had on the noise level.

I'm not saying I was a street racer but I subscribed to Teddy Roosevelt's Ideal of speaking softly and carrying a big stick. In my Impala I had a 582 cubic inch BBC with a heat wrapped exhaust system to keep the heat out of the car that exited at the rear bumper through two bowtie shaped stainless steel exhaust tips. I often told people I had a 305 with glass packs and a 3/4 race cam when asked what I had under the hood. If anyone looked they saw a big block with 402 decals

Big Dave
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post #4 of 8 (permalink) Old 11-22-2013, 12:49 PM
Join Date: Jun 2013
Location: Minnesota
Posts: 41
Rick, what are you considering putting them on? Give me some more info and I will make a few recommendations!

-engine size
-headers or not
-exhaust diameter

1965 Impala ss 283
Ermine White / Red interior

1970 Chevelle ss L78
Black Cherry / White Stripes
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post #5 of 8 (permalink) Old 11-22-2013, 09:12 PM
Join Date: Sep 2012
Location: IL
Posts: 65
Just for reference, a chambered muffler like a flowmaster has a greater tendency to drone on the interior. Mufflers like Magnaflow, Dynomox Ultra Flo's, and Borlas are a straigt through perforated pipe with packing and tend to drone less, are mellow at idle, but can get pretty loud when you stop on it.
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post #6 of 8 (permalink) Old 11-23-2013, 04:21 PM Thread Starter
Join Date: Sep 2013
Location: Spokane
Posts: 26
496 CI chevy (poked and stroked 454), hedman 17/8 headers, Howards .232/.236 (@.50) hyd. roller cam - no exhaust diameter picked yet - I'm leaning towards dual 2 1/2 out the back.

I don't like drone - thanks for that tip.
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post #7 of 8 (permalink) Old 11-24-2013, 01:10 PM
Join Date: Jun 2013
Location: Minnesota
Posts: 41
Hi Rick, I had a similar motor with about the same cam in my 72 chevelle ss and spent a lot of time choosing exhaust, granted it really comes down to personal preference, but some suggestions do help I've found. As stated before, chambered mufflers (with plates to deflect sound) do tend to produce a noticeable drone at certain RPM's usually during cruise speeds. Flowmasters are the most popular in this category, they tend to produce a "tinny" sound at idle and a real aggressive sound under throttle. They have several choices though from super aggressive to virtually stock quiet. There has been some research that these chambered mufflers actually flow worse than other mufflers such as Magnaflow, Pypes, and Dynomax; these are baffled with an inner steel tube similar to a glasspack, but are surrounded by an insulating ceramic layer to absorb sound. Much of the sound changes though by pipe diameter, the smaller the tube the "snappier" the sound, the bigger diameter the deeper the "bass" low tone. As "Alocker" pointed out in his post these non-chambered mufflers tend to be a little mellower at idle, but louder upon acceleration. On my chevelle I had Pypes 2.5" dual exhaust with their race pro mufflers. This system also had an X pipe to reduce the crackling and resonance. We could go crazy talking X and H pipes too! My car had a noticeable idle but when I punched it, it really came alive. Basically any muffler you choose is going to sound good but I would suggest going on youtube and listening to some different sound clips.

Chambered (tinny sound)

Baffled (richer sound)

Pypes (what I had)

1965 Impala ss 283
Ermine White / Red interior

1970 Chevelle ss L78
Black Cherry / White Stripes
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post #8 of 8 (permalink) Old 06-11-2014, 04:58 AM
Join Date: Jun 2014
Location: killeen texas
Posts: 28
There are a few youtube videos of Flowmaster sounds. They used an el camino with a BBC. im not sure what the video is called. but if you search something like Flowmaster sounds it should come up. Hope this helps
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