Lenn

Is the loud nature of the 3" exhaust more due to mufflers like the Flowmaster's being installed or is it just the size of the pipe? As stated, I want to go Magnaflow and I know they are inherently quieter.

flareside93

the size of the pipe is part of it, not all of it.
if you have a smaller pipe the velocity of the air is increased i do believe because its pushed closer together. in a little bit bigger pipe, the air flows more freely and isnt as pressured. it has more to do with the dB output of your muffler baffling.

For instance:
Flowmaster custom made my muffler to cut the sound level by 5dB. so its -5x quieter than it would have been on straight pipe and gives it the rumble. mines loud enough to set off car alarms by driving by @ 2000 RPM.

you would be looking at a muffler that has at least a 10-20 dB cut in sound levels. you would still have the low rumble and all the good things just not as loud.

Lenn

Cool, thanks. Is -10-20dB reduction about standard range for aftermarket "performance" mufflers?

flareside93

ahh well i have no idea. you would have to look a the manufacturers specifications on the particular product that you have in mind. i do believe that they have that marked on the boxes or in there mauals.

jpunani

Dynatech sells an insert that can be installed in the header collector or muffler outlet that reduces noise but does'nt create much if any power loss. It comes in sizes ranging from 3,3.5,4,4.5 inch insert. I found it in the summit racing equipment catalog under dynatech vortex cone inserts.

ford4wd08

fluid flow from a small pipe to a big pipe is goin to loose velocity, (yes air is a fluid in case some people didnt know), its the equation of continuity states that VA = VA, velocity times area of one pipe (for this example ) = the second velocity times the area of the second pipe. for this equation to be true if velocity goes up area goes down in the next pipe and vice versa, so if you start from a bigger pipe and go to a smaller it will speed up the flow

anyways its laws of physics i should know im a engineering major

SinCityFX4

Wow...dont know how I missed your thread here Lenn....Looks like you have your answer though..

I have 3" going into the muffler and then 2-2.5" exiting to 3.5" tips.