Author Topic: Flowmaster Mufflers  (Read 448 times)

Night Wing

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Flowmaster Mufflers
« on: May 09, 2019, 08:14:52 AM »
My 2001 Chevy Silverado LS 1500, 2 x4  extended cab (4 doors) truck's factory installed muffler finally wore out. It had a hole in it. And I was glad. I used to own a 1988 short bed Chevy Silverado 1500 (2 doors), 350 CID, 250 HP truck which had a nice "growl" to it when it was started.

My 2001 Chevy has a 4.8 liter engine in it. It was so quiet, I could barely hear it when it was idling. Sometimes it was so quiet, I almost tried to start the engine when it was already running. But looking at my odometer told me the engine was running.

I'm not into metric measurements. I'm old school so I looked up my engines specs for the 2001 model. I found my 4.8 liter engine was 294 CID with 270 HP. This engine has always given me very good gas mileage even though it is a truck.

I looked at Magnaflow and Flowmaster mufflers and I also looked on YouTube to see if there were any videos showing how the sound comparisons were between Magnaflow and Flowmaster. I like the sound of the Flowmaster so I went to the Flowmaster site to see if they had a muffler for my 2001 truck.

https://www.holley.com/brands/flowmaster/products/exhaust/mufflers/street_chambered_mufflers/

I wanted a muffler that had "that growl", but not a droning sound in the cab. The 50 Series Big Block does not fit my truck. But the next one up from that does. A 70 Series did fit my truck so I ordered one from my local muffler shop and they also did the installation.

The owner of the muffler shop was quite familiar with Flowmaster mufflers. He told me I would have my "growl", but he said around 70 mph, I would notice a slight droning sound inside the cab of my truck. But he also said once I drive about 200 miles, the droning sound in the cab would disappear.

So I needed my new beach parking permits for Surfside, Galveston Island and the Bolivar Peninsula. I got up early and left my home at 5:00 am and went to all three places to get my beach permits and was back at my home at 11:50 am.

I did notice the droning sound in the cab around 70 mph, but when I was almost back home, the droning sound at 70 mph disappeared. Anyhow, I like my new muffler for my "beach vehicle".  ;) The only time I notice the sound of my new muffler now is when I start it up, when it shifts gears (automatic transmission) and when I get behind a slow poke on the road and "hit the gas pedal to pass the poke".

BTW, this is what a Flowmaster 70 Series muffler sounds like after it has just been installed.

SUP Sports Hammer: 8'11" x 31" x 4" @ 140 Liters
SUP Sports One World: 11'1" x 30" x 4.5" @ 173 Liters

NorthJerzSurfer

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Re: Flowmaster Mufflers
« Reply #1 on: May 09, 2019, 02:18:18 PM »
NW-

I have had a bunch of these on similar vintage cars/trucks/jeeps.  Let the muffler break in a bit.  True- you may have a drone at Highway speed(most do) but the muffler will settle in and real have a great sound on the low to mid end after a few thousand miles.

Great truck and choice....

Dusk Patrol

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Re: Flowmaster Mufflers
« Reply #2 on: May 10, 2019, 09:34:22 AM »

I once bought a used Toyota Sequoia, which has a V8. The previous owner had installed a Flowmaster.
Let me tell you, a Toyota product with a loping, growling V8 is borderline hilarious.

It was a great surf car tho' as the back window rolled down into the gate.   

Wing - a Texas question - think of 10 guys you know... approx what percentage of them drive pickups?
Bullet V2; RS 14x26; New Deal 9'6; BluePlanet 9'4

Night Wing

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Re: Flowmaster Mufflers
« Reply #3 on: May 10, 2019, 10:46:09 AM »
Wing - a Texas question - think of 10 guys you know... approx what percentage of them drive pickups?

That is an easy question for me to answer. I've got 10 friends and they are all like me which means they are outdoorsmen. Some hunt, some fish, some crab, some kayak, some are into archery like I am (them: compound bows, me: recurve bows), some own sailboats and some own center console fishing boats.

All of my 10 friends drive pickup trucks so the percentage is a cool 100%.  8)  In Texas, pickup trucks are DEFINITELY the "Kings of the Road".  ;D
SUP Sports Hammer: 8'11" x 31" x 4" @ 140 Liters
SUP Sports One World: 11'1" x 30" x 4.5" @ 173 Liters

SurfnCJ8

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Re: Flowmaster Mufflers
« Reply #4 on: May 10, 2019, 06:24:21 PM »
When I was younger a few of my friends had fox body 5.0 mustangs ( late 80s, early 90s). First thing they all did as soon as they had the cash was flowmasters and Hurst shifters. Those cars sounded great with that muffler. I Put a set on an old Pontiac and really like the sound but mine does drone/resonate some at highway speeds. Not enough to bother me though, I love the sound of a V8 with that rumble.

Night Wing

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Re: Flowmaster Mufflers
« Reply #5 on: May 10, 2019, 08:47:04 PM »
@ SurfnCJ8

The next step up from the 70 Series is the 50 Series and there is more drone for this series of mufflers. The owner of the muffler shop where I took my truck for service, for what I wanted, he told me the 70 Series was the better choice than the 50 Series. Look at the video below which shows a sound test with a sound meter.

SUP Sports Hammer: 8'11" x 31" x 4" @ 140 Liters
SUP Sports One World: 11'1" x 30" x 4.5" @ 173 Liters

The Kernel

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Re: Flowmaster Mufflers
« Reply #6 on: May 10, 2019, 10:45:27 PM »
I also have geeked out on aftermarket mufflers, even on my minivans.  They seem to have increased performance, fuel mileage, and of course have a nice exhaust note.  (At least that's what I like to believe.) 

I DID learn the hard way that taking off a factory resonator (IN ADDITION to swapping out for a high flow muffler) caused an aggravating drone under load at 2,500 RPM on my V6 Honda Odyssey.  Thankfully I had actually listened to the owner of the muffler shop and held on to the resonator, "in case I ever wanted it reinstalled due to excessive drone".  After a week of driving without it, I realized that he was spot on; he graciously put the resonator back in at no cost.  That's the type of advice and service that keeps a customer for life. 

Still sounds way better than stock though, but in a respectable, "...old dude must have done that because he tows a trailer" way.    Good luck with yours; I have a friend with a V8 GM pickup that he put high flow mufflers into.  It has no separate factory resonators, so just the cat & mufflers; it is music to a car guy's ears.  Yours probably sounds similar.
« Last Edit: May 10, 2019, 10:49:43 PM by The Kernel »
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Night Wing

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Re: Flowmaster Mufflers
« Reply #7 on: May 11, 2019, 03:43:01 AM »
@ The Kernel

I always do my homework when I'm going to purchase things.

I already knew about "not" taking off the resonator because of the excessive droning sound it would create in the cab of my truck if it was removed. A "before" and "after" video is below.

SUP Sports Hammer: 8'11" x 31" x 4" @ 140 Liters
SUP Sports One World: 11'1" x 30" x 4.5" @ 173 Liters

SurfnCJ8

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Re: Flowmaster Mufflers
« Reply #8 on: May 15, 2019, 12:22:00 PM »
I have had that car since the late 90's and I put mine on long ago, I want to say they may have been 40 series but not sure. If not then they are the 50's.  Now it has a tic / leak at the manifold that drives me crazy. I hear it over the exhaust note.