magnaflow question

[rickztahone]

i've had the magnaflows on my car for about 2 weeks i think it is. the question i have has to do with a raspy noise that happens when i hit the end of a rev. it's an annoying sound really. i love the deep sound but i guess i would say when WOT it's when it happens noticeably. would making the pipes bigger from cat back make this go away? i'm thinking it has to do with back-pressure but i can't be definitive about that. any suggestions or prior experiences w/ this would be much appreciated. and artur if you read this, what type of pipe is the magnaflow ones you put in your car, 2.5"?

 

[cammerfe]

My Magnaflow cat-back only purrrrrrs. I'm puzzled about your sound.
KS

 

[rickztahone]

yours is cat-back. mine is just factory size pipes and the resonator delete. the magnaflows are 2.5". that's why i'm wondering if i did make my pipes bigger if it'll do what yours are doing, purrrrring.

 

[BlueLS]

yours is cat-back. mine is just factory size pipes and the resonator delete. the magnaflows are 2.5". that's why i'm wondering if i did make my pipes bigger if it'll do what yours are doing, purrrrring.

The Magnaflow pipes are not 2.5". They claim that they are, but if you measure the pipes they are 2.25". I have the magnaflow cat-back system as well, but i've replaced the magnaflow mufflers with flowmaster 40 series (the magnaflows sounded to "ricey" to me).

Your may be getting that sound because you removed your resonators.

 

[LS8]

Yup, no resonators = ricer rasp.

 

[bigpappy33]

the cat back also comes with an x pipe, if you switch it to an h pipe you will get a deeper sound but lose a very little bit of hp

 

[cammerfe]

FWIW, it is the common position within the turbo community, that flowmasters cause enough restriction to be deleterious to the function of turbochargers. To each his own, sound-wise. I believe that the cats on an LS V-8 have 2.25 internals. My cat-back was very quiet at first. Now it is a few months old and is slightly louder.
KS

 

[BlueLS]

FWIW, it is the common position within the turbo community, that flowmasters cause enough restriction to be deleterious to the function of turbochargers. To each his own, sound-wise. I believe that the cats on an LS V-8 have 2.25 internals. My cat-back was very quiet at first. Now it is a few months old and is slightly louder.
KS

Wait a minute.....Your saying that having flowmasters on a turbocharged car restricts the exhaust enough to lower the HP enough to cancel out an gains from the turbo?? In other words, having a turbo + flowmasters is no better then having no turbo and stock exhaust (or magnaflow or whatever)??

I really, really hope that i read that wrong

 

[rickztahone]

here's the vid i was talking about my magnaflows having a rasp at WOT

 

[tyhackman15]

Wait a minute.....Your saying that having flowmasters on a turbocharged car restricts the exhaust enough to lower the HP enough to cancel out an gains from the turbo?? In other words, having a turbo + flowmasters is no better then having no turbo and stock exhaust (or magnaflow or whatever)??

I really, really hope that i read that wrong

I think he meant a turbo car with a magnaflow (or similar) with lets say 200 HP would go down to maybe 190 HP with flowmasters, a.k.a "detrimental" not terribly bad.

But I don't think the 3.9L's can outflow two flowmasters, however one single/single might be restrictive.

 

[cammerfe]

The more I look into the Turbo business, the more I find out about things not even dreamed of when I was first doing the 'T' thing back in the early-mid '80s. For example, there are racers who clamp a piece of expanded metal (like Quik's grille) over the 'cold-side' intake opening when racing. Someone did a series of dyno runs with the 'screen' in place and have found that it causes a loss of 20-50 HP. These runs were done while testing a variety of protective gadgets. Even hardware cloth with 1/4 inch openings makes a difference. And Flowmasters are among the very worst restrictions in the 'hot-side'. I'll be doing my own tests when I get to that point. Remote-mount TTs might well not need ANY mufflers.
KenS from Ben's Place