Anyone have any experience with these?
How do they flow? Is the sound deep or is it high pitched and raspy? Specifically, with an OR y-pipe and the i-pipe replaced with a Sweet Thunder muffler of equal length? Thanks for any help.
Edit - forgot to mention cam and Grots.

<small>[ October 23, 2002, 07:17 PM: Message edited by: Silver99Z ]</small>

 

I haven't heard the sound, but I do know that the pipes are pinched and the largest core you can get in one is 2.5". Long story short, they couldn't flow very well just by the nature of the design.
You get a nice deep muscular sound from a DynoMax race bullet, and you get over 2200 cfm of flow with it. For comparison, Borlas flow about 950 cfm, Magnaflow about 1100 cfm, and Flowmaster around 350 cfm. I don't know the flow on these, but they are all pinched and choked with small pipe, you decide.
My .02
Dave

 

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by ratio411:
<strong>I haven't heard the sound, but I do know that the pipes are pinched and the largest core you can get in one is 2.5". Long story short, they couldn't flow very well just by the nature of the design.
You get a nice deep muscular sound from a DynoMax race bullet, and you get over 2200 cfm of flow with it. For comparison, Borlas flow about 950 cfm, Magnaflow about 1100 cfm, and Flowmaster around 350 cfm. I don't know the flow on these, but they are all pinched and choked with small pipe, you decide.
My .02
Dave</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Thanks Dave, especially for the flow rates. I also am concerned about the Sweet Thunder being restrictive. Enjoyed your site. The headlight mod is next on my list. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

 

The Dynomax Bullets and The Dynomax Ultra-Flo Welded flow the same. They use the same core but the Ultra-Flo has more packing around the core for more sound absorbsion. Just a FYI.
Later,
Bart

 

The pinch in the Sweet Thunder is no different then the pinch in the GMMG. And the GMMG flows well. I only gain 5hp when I use my cutout instead of flowing through my GMMG. The picture below is of one of the Sweet Thunder's that I'm going to be installing on my El Camino for it's LT1 conversion. It's a 2 3/4 with a 2 1/2 inner core. As you can see it's pretty open for flowing no twists and turns to inhibit flow. I don't know flow rates for the STs and probably never will. Also when I talked with Mike at S.T. he told me that he can custom build if wanted. If you wanted a 3.5" unit with a 3" inner diameter I think he could do it. FWIW

<img src="http://www.mindspring.com/~rob.hagga/_uimages/ElkyPics/Engine/SweetThunder.jpg" alt=" - " />

 

I have one of Mike C's (Sweet-Thuder) mufflers on order right now. Mine is going to replace the 18" Dynomax Bullet (that replaced my SLP Resonator <img border="0" title="" alt="[Roll Eyes]" src="images/icons/rolleyes.gif" /> .) So far my only complaint is that production is really slow, I ordered this over 3 weeks ago. <img border="0" alt="[judgement]" title="" src="graemlins/gr_judge.gif" />

I wouldn't worry too much about flow here. Though obviously they aren't going to flow as well as an open 3" pipe but remember that it is still a completely hollow muffler and you can still see straight through it. It will still flow better than most of the traditional cat-back systems on the market anyway. For me, cleaning up the tone and eliminating much of this high-pitched drone is worth losing 5HP over.

Besides, if you are that worried about it... order the chambered muffler the same size as a Dynomax bullet and put the whole system together with stainless steel strap-bands. This is what I am doing, my muffler can be unbolted and switched in a matter of 5 minutes <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" /> .

<small>[ November 14, 2002, 11:51 AM: Message edited by: BlackHawk ]</small>

 

I wish someone could post a pic just like that of the inside of a DynoMax 24222. Then you would see just how crazy restictive that thing is. Every one of those louvers in there cause flow reversion and restrict... that is without going into how small the inside is.
Also, my comment that the muffler is too restrictive to put in the I-pipe had nothing to do with the GMMG. The GMMG splits the exhaust in half before putting it through TWO of those mufflers. I was refering to the idea put forth about putting ONE of these in the I-pipe, clearly a bad idea.
As for the Thunder website, it shows special order diameters, but footnotes that even large pipe will have a 2.5" core... Doesn't matter, you would need a 3.5"+ core to flow decent with all that disruption going on in there.
Dave

 

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by ratio411:
<strong>I wish someone could post a pic just like that of the inside of a DynoMax 24222.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Why? It is completely hollow <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" /> . Just imagine a 3.5" hollow tube with a very thin 3mm layer of fiberglass glued to the inside wall.

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">
<strong>
Then you would see just how crazy restictive that thing is. Every one of those louvers in there cause flow reversion and restrict... that is without going into how small the inside is.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">There is absolutely no argument that the Dynomax muffler will outflow the chambered design... By far! But it will also do some actual "muffling." A trait that both the SLP resonator and the Dynomax muffler don't do much of. I am betting that this chambered design will still out flow most aftermarket traditional cross-flow types of mufflers. Have you ever looked inside of one of those? <img border="0" alt="[barf]" title="" src="graemlins/gr_barf.gif" /> Heck the Flowmasters have been rated at only 350cfm and this is supposed to be better than stock! <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" /> .

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">
<strong> Also, my comment that the muffler is too restrictive to put in the I-pipe had nothing to do with the GMMG. The GMMG splits the exhaust in half before putting it through TWO of those mufflers. I was refering to the idea put forth about putting ONE of these in the I-pipe, clearly a bad idea.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">I agree that the GMMG design with two smaller chambered mufflers off of a split is a better design. But I am just trying to temporarily quiet down an old LM system here. This placement design is not an option for those of us.
Besides, correct me if I am wrong but doesn't GMMG use two 2.5" mufflers here? This would mean that the center core inside each is smaller than 2.5"s and when you factor in the layer of turbulence created by the "louvers" each one of these mufflers will flow less. In this case, there needs to be two in order to make up for the lack of volume. I do think that the GMMG design will flow better, but I don't think that there will really be that big of a difference here. Provided you are not plugging up the exhaust port directly, the location of the muffler in the pipe should make no difference. Exhaust will flow at say 350cfm (example #) at the I-pipe and (provided there are no leaks) it should at exit the end of the pipe at about the same cfm. Where in the rear that you stick this restriction (muffler) doesn't make much difference.

But I do agree with your concerns, and really I am just experimenting here, that's why nothing is getting welded <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" /> . I will take pics of everything as soon as all of the parts come in. And since I can just swap mufflers back and forth via 4 bolts, at some point I can also throw this whole thing on a dyno and get back to back numbers to see what the real story here is... not just theories.

If your car is lowered like mine you really have fewer options, space is really a limitation for mufflers like the Borla XR1 and just about impossible for one of those 6" mufflers. At only about $60, the fit and price of these mufflers might be a good alternative option... We shall see.