ubercooper

Hi.
I know this isnt on a 928 motor, but pretend that it is a bored out to 6.7L with around 550hp. Then imagine that you dont want a car that makes your ears bleed but also dont want the extra weight of 2 mufflers and an X pipe. Heres where this muffler comes in. I was wondering what people thought about this exhaust setup that I am currently running with a 3" dynomax ultra flo x muffler. My only concern is will this flow well enough for such a large, modified motor?






Thanks in advance
-Seb

ptuomov

I looked into that, from catalogs not holding the component in my hands. It doesn't flow quite enough for my purposes, but it's a pretty cool idea.

One experiment that would be interesting. Blow air thru one of the in-pipes. Does it suck or blow air from the other in-pipe? Does it blow the air out equally from both out-pipes? Or in the extreme, does it blow from one of the out-pipes and suck from the other out-pipe?

Now, would you put cats (humor me) upstream or downstream of it? I am thinking downstream, because less pulsing flow will be restricted less by the cats.

BTW, Dynomax was basically only muffler manufacturer that reported the CFM and depression at which it was measured for all their mufflers.

ubercooper

Ive heard this too, but cant actually find any numbers to match this muffler

odurandina

your muffler looks good.


you can also go with a single 4" hooker maxflow, an X design like you are showing but w/ 3" pipes, or 2 - 3" hooker maxflow mufflers. they flow the most on planet earth times about two.

here's some data on this bad boy. my 968 running straight 2.5" pipe into a maxflow sounds like no 4 cylinder car you've ever heard. it's horny.

can't imagine how a 928 would sound with a setup like mine times 2.


https://rennlist.com/forums/968-foru...ercharger.html



from that thread --- read this link:



http://www.broaderperformance.com/mu...flow_tests.htm




here's another link, the Maxflow and the Borla are the clear winners, though the Maxflow is louder at WOT.

http://www.carforums.net/showthread.php?t=51203

The results in HP order on Mustang:

1.Flowtech Warlock (open) 374.2 hp/ 333.1 tq [very loud track day muffler]
2.Bassani Real Street 373.7 hp/ 333.8 tq [very loud track day muffler]

3.Hooker Maxflow 373.5 hp/ 333 tq
4.Borla XS 373.3 hp/ 332.6 tq
5.Magnaflow 372.8 / 332.5 tq
6.MAC 372.3 hp / 331.5 tq
7.Flowtech Afterburner 372.3 hp/ 330.1 tq
8.Hooker Aerochamber 372.1 hp/ 330.4 tq
9.Bassani 372 hp/ 333.5 tq
10.Spintech 371.6 hp/ 332.2 tq
11.Edelbrock Performer RPM 370.9 hp / 331.3 tq
12.Borla XR1 370 hp/ 334 tq
13.Flowtech Terminator 369.5 hp / 331.3 tq
14.Dynomax Ultra Flo 369.4 / 333.2 tq
15.Flowmaster 369.4 hp / 331.8 tq
16.Flowtech Warlock 366.3 hp / 325.3 tq
17.No muffs 365.2 hp / 330.1 tq

Sound Off in Quietest to Loudest (Decibels):

1.Borla XS, 80db at idle, 90db at 2,000 rpm, 110db at WOT.
2.Hooker Maxflow, 80db at idle, 90db at 2,000 rpm, 120db at WOT.
3.Magnaflow, 82db at idle, 91 at 2,000 rpm, 114db at WOT.
4.Flowmaster, 82db at idle, 93 at 2,000 rpm, 115db at WOT.
5.Flowtech Warlock, 83db at idle, 92 at 2,000 rpm, 112db at WOT.
6.Dynomax UltraFlo, 83db at idle, 94 at 2,000 rpm, 113db at WOT.
7.Borla XR1, 83db at idle, 96db at 2,000 rpm, 118db at WOT.
8.Bassani Street, 83db at idle, 96db at 2,000 rpm, 120db at WOT.
9.Edelbrock RPM, 84db at idle, 93db at 2,000 rpm, 118db at WOT.
10.Bassani Real Street, 84db at idle, 96db at 2,000 rpm, MAX. (120+db).
11.Flowtech Afterburner, 86db at idle, 94db at 2,000 rpm, 115db at WOT.
12.Flowtech Terminator, 86db at idle, 94db at 2,000 rpm, 119db at WOT.
13.Hooker Aerochamber, 87db at idle, 94db at 2,000 rpm, 114db at WOT.
14.SpinTech, 87db at idle, 97db at 2,000 rpm, 116db at WOT.
15.MAC, 87db at idle, 98db at 2,000 rpm, 119db at WOT.
16.No Muffler, 91db at idle, 103db at 2,000 rpm, MAX. (120+db).

I am not suggesting you all run straight, 2 1/2 inch pipe into a large, glorified glasspack, as I have done... but my set-up is making at least an additional 20-30hp [w/ the K & N filter]... Highway acceleration from 70 to 100 mph is ridiculous...

The photo I added is a 4" Maxflow. the large inlet/outer diameter makes the muffler look very small. The muffler is bigger than the photo indicates.

I am willing to bet that this type of exhaust will make the supercharger work better than the 67hp that Carl got. just my .02 + foot firmly planted in mouth.

.

ptuomov

See the last page of http://www.dynomax.com/assets/2008ca...df/techref.pdf for their formula to convert SCFM and 20.3 inches of water to loss-free hp and back.

The 2008 individual product group files, such as http://www.dynomax.com/assets/2008ca...ultrafloss.pdf, still had the SCFM ratings. This file http://www.dynomax.com/assets/2008ca...lo_X_pg189.pdf has the numbers for your muffler, I believe.

Newer ones have only the "loss-free hp" rating, but I think you can still use the 2.2x formula to back out the scfm at 20.3 inches.

ubercooper

Got some time on your hands eh?

God knows how you found all this stuff but this is exactly what I was looking for. After doing some math, I believe this should flow well enough until I put new headers on... (and hopefully not blow the tranny)
Ill throw a video up when I get home of the exhaust note.

Thanks again, Rennlist FTW

ptuomov

I had to look this stuff up last year when deciding what components to use.

We ended up using a different brand mufflers (Borla), no x-pipe for simplicity since this is a twin turbo, dual 3" stainless pipes, and 100 cell metal matrix cats. Used Borla because John Kuhn had run those with good results in the past. Without that past experience, I would have gone with Dynomax that looked the best on paper.

RichS 1986928

Is this muffler right to use with an X-pipe in the system?