So.....exactly how crappy is Flowmaster???
I read a recent thread about a guy with a stroker motor gaining 30rwhp by opening the cutout in front of his flowmaster. So my guess is you *might* loose 15 or so on a stock motor vs. open cutout.
OK guys I have flow master on my car and I noticed a decent gain in performance when I teamed it up with an slp Y pipe. My car put down 310.5 HP and 326.4 Ft Lbs of Torque with a Mti lid and the flow master and y pipe. This was done at Speed Quest in Waukegan IL. the conditions were 86* and 31% humidity. The sound is to my liking and my car definatey did not perform worse when I put it on. I know that there is better performing exhausts out there like the slp one with the bullit muffler wich ever that system is but to me I dont like the sound its to raspy. Everyone likes different sounding exhausts. I think its unfair that everyone rips on flow master. I know plenty of people with flowmaster on there ls1s and none of them are dissatisfied. To me a cat back should be decided upon do to the sound that you like not buy numbers. Most likely if your into performance you will add a cutout anyway and then it dosent matter what muffler your running. Im not trying to offend anyone but im sure we can all agree that its better to like the sound of your vehicle over the numbers it throws down when your cut outs closed.
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From: Vancouver,[KITSILANO].B.C. Canada *WestCoast*
I was just looking at a graph..sorry can't post it..but many of you have seen it..flow. is only about 3-4 hp below magnaflow,dynomax,edelbrock,hooker,bassani,and some others..these are the ones made for our cars...CROSSFLOW MUFFLERS...SO..you don't lose much,but you gain the sound. flow= 369.4hp / 331.8 tq..versus ..magnaflow.372.8hp..332.5tq. for instance.... 
Last edited by NHRAMAN; Jul 10, 2006 at 01:10 PM.
Tech Resident
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From: Philly
meh, i honestly think flowmaster is underrated and magnaflow is overrated. i know the flowmaster isn't a performance exhaust - i had it on my V6 - but it did make that V6 sound pretty good for a V6! it had major backpressure when i stomped on it, but it was a good quality setup and tucked up well.
i'd never put either of them on my LS1. the slp dual/dual i have on now has nearly no backpressure. instant throttle response. i think all exhausts just need a cutout. only way to get peak flow.
i'd never put either of them on my LS1. the slp dual/dual i have on now has nearly no backpressure. instant throttle response. i think all exhausts just need a cutout. only way to get peak flow.
I have a flow muffler on my car because the previous owner put it on and i like the sound. I've always liked the sound of flows but it was just too quiet......so i put a cutout in the i-pipe and it sounds great. So once you run a open cutout the muffler doesnt really matter.
so i guess everyone who first gets an ls1 puts a flowmaster muffler on it? mine was the same. i had the 3" flowmaster catback on and i just chopped off the muffler and replaced it with an SLP resonator and dumped it.... now it sounds freakin mean as hell. 10X louder than before! blows the old flows away totally
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From: Vancouver,[KITSILANO].B.C. Canada *WestCoast*
Originally Posted by Mike2000Z28
I think it goes one of two ways 1)performance guys get SLP LM first mod then get headers and have to quiet the system down 2)sound/budget guys get Flowmaster.
LM..just sounds like noise to me.. 
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From: America, f**k yeah!
Well, I have to admit, I like the sound of the flows around town but, on the highway it has very loud drone to it.
I've been racking my brain about redoing the exhaust but, I'm constantly switching back and forth. Not having anyone around to compare sounds to doesn't help. I thought of the hooker but, everyone says it's too quiet. I then thought to go big money and get a GMMG but, it's expensive and I'm hearing a lot about rasp even with cats. I've been through about every clip on ls1sounds and I'm stumped.
Any thoughts on keeping the flows and just adding headers? Or, Flows w/ headers vs. Hooker w/ headers? Is one louder than the other? I don't need to scream but, I do want people to notice a bit.
I've been racking my brain about redoing the exhaust but, I'm constantly switching back and forth. Not having anyone around to compare sounds to doesn't help. I thought of the hooker but, everyone says it's too quiet. I then thought to go big money and get a GMMG but, it's expensive and I'm hearing a lot about rasp even with cats. I've been through about every clip on ls1sounds and I'm stumped.
Any thoughts on keeping the flows and just adding headers? Or, Flows w/ headers vs. Hooker w/ headers? Is one louder than the other? I don't need to scream but, I do want people to notice a bit.
Originally Posted by bob320fa
Well, I have to admit, I like the sound of the flows around town but, on the highway it has very loud drone to it.
I've been racking my brain about redoing the exhaust but, I'm constantly switching back and forth. Not having anyone around to compare sounds to doesn't help. I thought of the hooker but, everyone says it's too quiet. I then thought to go big money and get a GMMG but, it's expensive and I'm hearing a lot about rasp even with cats. I've been through about every clip on ls1sounds and I'm stumped.
Any thoughts on keeping the flows and just adding headers? Or, Flows w/ headers vs. Hooker w/ headers? Is one louder than the other? I don't need to scream but, I do want people to notice a bit.
I've been racking my brain about redoing the exhaust but, I'm constantly switching back and forth. Not having anyone around to compare sounds to doesn't help. I thought of the hooker but, everyone says it's too quiet. I then thought to go big money and get a GMMG but, it's expensive and I'm hearing a lot about rasp even with cats. I've been through about every clip on ls1sounds and I'm stumped.
Any thoughts on keeping the flows and just adding headers? Or, Flows w/ headers vs. Hooker w/ headers? Is one louder than the other? I don't need to scream but, I do want people to notice a bit.
On The Tree
Joined: Mar 2005
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From: L.A
When i bought my car i thought sound was a little on the silent side. I took it to the muffler shop to get flowmaster exhaust only to realize that it already had flowmaster exhaust, so I changed to dynomax and its been great ever since.
mine had a flowmaster on it when i bought it. i absolutely hated it. i don't even know if they have an actual sound because in the car all you hear is droning like crazy. it sucked ***. i ripped it off and threw it in the trash.
i bought mine w/ flowmaster as well and i still have them. after a year i put on LTs and it sounded better andpicked up a bit more power. last year i put a cut out in and could tell there was a difference
flowmasters are not the best or the worst.. I think more of the hatred towards flowmaster is from the amount of muffers that people put on just about every v8 performance car from 1995-1999. seriously I remember seeing lines of cars all with the same flowmaster mufflers then... it was really stupid.