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Discussion Starter #1
So i have a true dual exhaust on my 4.6 bird. From the downtubes all the way back is dual 2 1/4 inch pipe. Into 2 flowmasters rear mounted BUT it does have exhaust cut outs just behind the diff pumpkin. Now this set up is fairly loud however when i REALLy get on the gas and it gets above maybe 4000 or so it starts to get quiet. Now from about 1700 to roughly 4000 it's pretty loud but after 4 it really quiets down. Does anyone know what would cause this? Does this happen because theres not enough flow (my pipes are crush bent not mandrel)? Whatever it is i want it gone... Because in my opinion when u floor a car it should get louder not quieter! Thanks for the help!
 

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when i put a flowmaster catback on my 89 gt stang it did almost the same as you described but mine stopped at 3 grand then after 4500 to when i shifted at 7200 it got loud as **** and almost sounded like a high pitch squeel. i think its just flowmaster and the way they are designed. just my .02


edit: and also when the mufflers are farther back your engine doesnt have that much of a load on it at high rpm's as it would down low so your motor isnt pushing as much exhaust notes then it would if the muffler was closer say like right under the tranny.
 

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You just decribed the flowmaster catback I used to have on my bird. I switched to Dynomax to get rid of the drone.

ANy difference when you open the cutouts? The birds I've been in who simply removed the mufflers still had the same drone, only louder.

If you don't have an X or H pipe, consider putting one in as that may help calm it down some. The ART exhaust is true dual with an X and rear mount mufflers and it sounds sweeeet.
 

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tailpipes also quiet it down at a higher rpm in some cases. my mustang had an offroad h-pipe and just the flowmaster mufflers, got tired of the tailpipes vibrating lol. after the tailpipes came off it got alot more aggressive cuz the exhaust was reflecting off the rearend so yea it droned like crazy but i loved the sound.

right now my 94 bird all i did was hack the from 3rd cat back off and put dual glasspacks right under the tranny x-member. it gets louder with higher rpms cuz the mufflers sit closer to the engine. kinda sounds like a pissed of truck but it works for now until i get something different on there:D
 

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aren't flow master more or less bought for the sound it looks almost like the muffler is designed to put out good sound at certain rpms my friend has them on his truck and has the same problem
 

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from what i've read its just mostly the sound and the way the chambers are designed to make the "flowmaster" sound lol and some performance increases over stock. on their website they got a diagram of a cut muffler to show what it looks like inside, mostly some V's welded in a row.


edit: heres a link to their site that shows what a 40 series looks like internally http://www.flowmastermufflers.com/40_orig.html others arent that much different.
 

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Discussion Starter #7
Well when i open the cutouts it gets fairly loud and raspy. It's kinda like a 03 cobra with longtubes and x pipe. It's not deep but raspy as hell... But yeh. Anyways i did try an X pipe and it sucked. Slowed me down 2nd and 3rd gear and sounded like a v6. I hated it. But uhmm hmm i guess i'll have to live with my exhaust... The thing is i would think with only cats on the downtubes and straight all the way back. Then no mufflers if have the cut outs open it'd be loud as balls. But i guess because i have the 2 cats on the downtubes it hinders the sound? Iunno... Anyways thanks alot guys!
 

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yea the cats will cut down some of the exhaust note. running true duals with just mufflers will make it noticably louder.

edit: and also the stock 4.6 exhaust manifolds suck balls compared to an aftermarket header, so pretty much with the stock manifold you wont get as much exhaust flow as you would with a different type of header.
 

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Discussion Starter #10
No surprising it doesnt drone at all... I thought it wuld because with the cut outs open it's pretty much all straigth pipe with no mufflers from the downtube cats. But it really doesnt drone at all... I guess the stock exhaust manifold and stock cats are holding me back.... Hmmm okay... Thanks!
 

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i see your in cali which i know they have inspections. your best bet would be some highflow cats for a little better increase over stock, if you can afford kooks headers than mo powa to ya lol. i still got the stock cats and downtubes on mine with dual glass's under the tranny x-member , kansas laws dont require a cat so i might delete them if i keep this bird:D
 
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