Flowmaster Outlaw muffler - anti-reversion?

[BradH]

Flowmaster's round Outlaw mufflers have a series of "attenuation rings", instead of packing material or other sound reduction devices. They don't claim that this design does much for the decibel level, but the rings appear to create a row of "mini anti-reversion steps".

Anyone have experience using them, and if there is an AR effect from this design? I was thinking the short 3.5" ID version would fit in between my collectors and the X-pipe of my exhaust system, instead of the standard straight pipes. Thanks - Brad

[Newold1]

Read the posts on here on "Merge collectors and anti-reversion devices" and Calvin Elstons post about that subject.

[David Vizard]

Flowmaster's round Outlaw mufflers have a series of "attenuation rings", instead of packing material or other sound reduction devices. They don't claim that this design does much for the decibel level, but the rings appear to create a row of "mini anti-reversion steps".

Anyone have experience using them, and if there is an AR effect from this design? I was thinking the short 3.5" ID version would fit in between my collectors and the X-pipe of my exhaust system, instead of the standard straight pipes. Thanks - Brad

Brad,

The further the 'anti-reversion' element is from the port the worse it works. Any A/R device needs to be right at the port to work at it's best.
As for Flow Masters my experience has, in the main been that they don't 'master flow'!

[MadBill]

David, per your old Performance With Economy book and S/T circa 2010: http://www.speedtalk.com/forum/viewtopi ... =1&t=22507 is there any better understanding now as to why the concept of AR primaries hasn't seen more widespread use?

[midnightbluS10]

Would it be somewhat similar to the mufflers with the discs that you load and unload to adjust the sound, etc? I can't recall the name, even though it's on the tip of my tongue.

Edit: Supertrapps? Didn't know they bought out Jardine Performance Products in '12.

[GARY C]

David, per your old Performance With Economy book and S/T circa 2010: http://www.speedtalk.com/forum/viewtopi ... =1&t=22507 is there any better understanding now as to why the concept of AR primaries hasn't seen more widespread use?

I think they fell prey to the Bigger is Better mind set.

[BradH]

Read the posts on here on "Merge collectors and anti-reversion devices" and Calvin Elstons post about that subject.

I've followed that thread, too, but didn't want to hijack it with my question.

My application has 2" x 3.5" headers that connect to a 3" X-pipe about 20" after the collector flange. It has full-length tailpipes and Dynomax Utra Flo mufflers in the typical before-the-axle location.

Things I've been considering are replacing the short 3.5"-to-3.0" collector adaptor with a longer tapered style, or incorporating some style of anti-reversion device into the same section. The cam is 266 at .050", so reversion at low RPM, especially with a full exhaust, is very likely.

[BradH]

Would it be somewhat similar to the mufflers with the discs that you load and unload to adjust the sound, etc? I can't recall the name, even though it's on the tip of my tongue.

Edit: Supertrapps? Didn't know they bought out Jardine Performance Products in '12.

No, a different design than Super Trapp. I'll post a pic I found of the style I'm asking about later for those who aren't familiar with it.

[GARY C]

You could make an insert like this to reduce your collector or cut one end off to create a A/R device.
https://www.schoenfeldheaders.com/uploa ... 51.gif?233

[GARY C]

I did this followed by a reducer in a 3" but I have no idea if it helped but it seemed like a good idea at the time. also a picture of the collector in my Kooks Headers.

[BradH]

Should an AR device also attempt to mimic a merge collector by reducing the ID right at/after a straight collector? That wasn't my understanding, and was expecting to maintain the 3.5" ID off the collector flange until it transitions into the rest of 3" system. I'm all ears...

[BradH]

As for Flow Masters my experience has, in the main been that they don't 'master flow'!

So I've heard...

[GARY C]

Should an AR device also attempt to mimic a merge collector by reducing the ID right at/after a straight collector? That wasn't my understanding, and was expecting to maintain the 3.5" ID off the collector flange until it transitions into the rest of 3" system. I'm all ears...

Good info here on Calvins blog.
http://www.exhausting101.com/?p=68

[MadBill]

I did this followed by a reducer in a 3" but I have no idea if it helped but it seemed like a good idea at the time. also a picture of the collector in my Kooks Headers.

Neatly done, but might not the effect be similar to two short segmented megaphone-like pair of ~2" and 4" primary extensions?

[GARY C]

I did this followed by a reducer in a 3" but I have no idea if it helped but it seemed like a good idea at the time. also a picture of the collector in my Kooks Headers.

Neatly done, but might not the effect be similar to two short segmented megaphone-like pair of ~2" and 4" primary extensions?

Not sure, the thought was like a 4 into 2 into 1 into a merge collector for $10.00 on a $166.00 set of headers.