"Of Flowmasters and Super Traps"

[makin chips]

The chart does not specify diameters - they do not appear to all be the same size. e.g. a race muffler flowing 2600cfm the same diameter as a OEM muffler flowing 225cfm???? Really?

No. Hence their listing of part #'s, I think. Those signify which is which. You'd have to decode part numbers to know for sure.

For example, the Borla XR-1s at the bottom. 40450 is 3" and the next, 40741 is 4".


Youll have to decode part numbers to know for sure which is which. Also, you're comparing a likely 2.5" turbo muffler to a straight through design. There's no comparison there except they're both called "mufflers" lol.

[pdq67]

What does this one flow?

Jegs PN 24214 for the W/D/T 2.5" ID x 28" OAL with a 4" OD x 23" long body glass pack.

pdq67

[makin chips]

What does this one flow?

Jegs PN 24214 for the W/D/T 2.5" ID x 28" OAL with a 4" OD x 23" long body glass pack.

pdq67

2.5" Thrush Magnum Glasspack?

Likely 507.9 cfm

http://67-72chevytrucks.com/vboard/show ... p?t=263014

[David Vizard]

It's a bit late now as I started work today at 10:30 and I am now plum tuckered. My next post here will be my Super Trapp (is it one or 2 'P's') adventures. These will not only detail the less than impressive performance produced by ST's but also some of their most powerful physiological, and apparently effective sales techniques.
DV

[68post]

Great thread

I looked at their website and can't find any specific cfm and hp ratings for their mufflers, just a generic "flow up to 2000cfm/up to 1900hp on their Dynomax Ultra series - claiming the same for 2.5" inlets as larger lol... I wonder if they stopped being specific as I seem to recall 20 years ago it was more common to know what certain mufflers could flow

IIRC, years ago(sometime in the last 20) a 3rd party did a test of a bunch of different mfg's (likely somewhat outdated)mufflers in different sizes. It was passed around automotive forums like gospel for a while. I'm sure it's easy to find, still.


Turns out, it's extremely easy to find. Here's the condensed version with just the results. I believe there was also text to go with the original but I didn't spend the time to look.




Side note: Is this the entire article, David? Anything missing from it? Thanks.

https://www.musclecardiy.com/performanc ... ail-pipes/

So which one is the true, smooth perforated inner pipe glass pack that I am talking about flow rate?

pdq67

None of the above within the Dynomax brand, that would be the "Race Bullet" style. Quite loud on our single exh stockcar, I used the 3-1/2" w/12" case ( thought we would get cited for too loud on the racetrack...LOL)

[RCJ]

Any ideal on quieting an exhaust after it has exited the pipes.The exhaust that gives the best power won't meet a decibel rule.

[David Vizard]

Any ideal on quieting an exhaust after it has exited the pipes.The exhaust that gives the best power won't meet a decibel rule.

Guys,

I am not fully aware of some of the characteristics of the current crop of mufflers so let me re-state what to do for best no powder loss noise suppression.

Just look for a pair of mufflers that will give 2.3 cfm per open exhaust HP and. with the use of a balance tube, that will keep the power up.

As far as the noise level is concerned don't go too much over the required CFM. It won't help the power but it can reduce the mufflers ability to muffle.

If you are using a straight thru muffler then be aware that the bigger the internal pipe is the less interaction there is with the through flow of the exhaust. It becomes possible at much over 2.5 inches to have a slug of gas pass right through the muffler with very little noise attenuation.
DV

[makin chips]

IIRC, years ago(sometime in the last 20) a 3rd party did a test of a bunch of different mfg's (likely somewhat outdated)mufflers in different sizes. It was passed around automotive forums like gospel for a while. I'm sure it's easy to find, still.


Turns out, it's extremely easy to find. Here's the condensed version with just the results. I believe there was also text to go with the original but I didn't spend the time to look.




Side note: Is this the entire article, David? Anything missing from it? Thanks.

https://www.musclecardiy.com/performanc ... ail-pipes/

So which one is the true, smooth perforated inner pipe glass pack that I am talking about flow rate?

pdq67

None of the above within the Dynomax brand, that would be the "Race Bullet" style. Quite loud on our single exh stockcar, I used the 3-1/2" w/12" case ( thought we would get cited for too loud on the racetrack...LOL)

That Thrush piece I referred to earlier is produced by Dynomax. As far as I can tell, and without buying one to cut it open, it appears their glasspacks are made that way. It looks to be some sort of packing surrounding a smooth, inner tube with round perforations straight through and not the angled louvers you find in other brands. Unless he's talking about something else and I misunderstood.

[David Vizard]

So long as the packing density is up to scratch that thrush muffler should work pretty well. If the perforations are clean edged on the bore of the pipe a 2.5 inch unit should flow about 570 cfm. That means a pair of these will handle about 500 hp while containing the loss from back pressure to within 1% of open exhaust power.


However do not forget the this type of muffler is also contributing to the length sensitive secondary pipe/collector length. This means a pressure wave termination box will be required.
DV