yokev

nolagtime

there are lots of pictures of the stock system floating around on the forum to show that the majority of the system is 3". From the downpipe there is a flange that drops to 2.5" into the resonator, out to a 2.5" flexpipe, then back up to 3" in and out of the muffler, then 3" tailpipe. The factory system is only restrictive at the 2.5" section. Replace this with a 3" resonator or even a piece of 3" piping and you are as good or better than most of the aftermarket systems without any of the annoying buzzing or droning. I'm getting old I guess... I want high flow without the noise.

turbo35

I as well......no noise just better flow

02reaper

iTrader: (2)

It actually drops down to 2.75" OD after the 2.5" section, through the muffler. The only 3" part is the tailpipe itself.

O2brich

The original turbo muffler was designed for the turbo charged Chevy Corvair. It is the basis of most performance mufflers of the 70's. It is not a glass pack but a more traditional design with perforated tubes and flow routes thought the body.
Companies like Dynomax, Hooker and Thrush still make them.

Spadey

^^^^^^^^^^^^^^^^^^^^^^

BoostedFitz

Very correct. Performance muffler lineage kinda goes like this to my understanding:

Glass packs (cherry bomb, purple hornies, etc)
Turbo style (typical '70s performance muffler with the perf tubes inside)
Chambered (Flowmaster and those that came after)
Free flow (magnaflow, Etc etc)

Now there is some that combine the ideas of each if these styles. Solo has a muffler that is free flow with a chambered section.

That is my understanding of the way things progressed.

engineermike

Yep. Chevy realized with the Corvair that a turbo engine didn't need as much muffling in the muffler, so they designed one that didn't cancel as much noise. People immediately assumed they flow more since they are louder, and started retrofitting them onto v8 muscle cars. I had a Vizard book that stated, however, that most "turbo" mufflers either didn't flow, didn't muffle, or didn't do either.

The design is typically a perforated tube, but the flow makes 3 passes in the muffler and two 180's. For sure, a single-pass perforated tube, packed muffler like the Magnaflow will flow better...or the stock muffler.

O2brich

You just got to laugh at this!
As it is so true in a lot of performance myths and perceptions :-)

Joewee3.5

Arti is both right and wrong about the aero. It roars but does make noise. I was the first to use it on the Ecoboost in both the 3" and 4" setup. If you want a great sounding and flowing exhaust then by all means set yours up like my sig. If you want quiet and 4" then buy a 4" Donaldson for a diesel. It's straight through and come in many sizes. You would probably be the first to try this.