Muffler Information

[kenamond]

I haven't searched exhaustively (no pun intended), because I'm not sure of the best search terms. I'm asking for a link if anyone knows one...

I ordered a G-Power 3" O2-back from eBay ($299 shipped) and I want to replace the muffler with a twin-tip that looks fairly stock (look at the 2g rear bumper cover, and it screams twin tip!). So I'm searching for mufflers.

I don't want to stand out with a loud exhaust, and I don't want my car's exhaust note interfering with my stereo too badly.

At the same time, I don't want to add a bottleneck, power-wise. The models I've been looking at are 3" inlet, dual 2.5" outlet. I've looked at Magnaflow, Flowmaster, and a bit at Dynomax. The design of the muffler's interior surely affects airflow, but not all of the vendors go into much about that (they have turbo vs. non-turbo mufflers for example, but I don't know what the difference is).

As far as material, I'd prefer SS, but I'm not sure how well aluminized steel holds up. I'm thinking of painting the muffler flat or satin black which might pose a problem for SS, but polished SS would be a backup plan (I assume I can paint aluminized steel).

I'd prefer bolt-on tips, and have found something I don't mind that fits 2.5" outlets, isn't too long, has slant-cut, rounded edges and is 3" OD just like the stock tips, and is cheap ($22/tip). I'm avoiding weld-on tips for cost (I don't own a welder nor do I know how to weld SS).

Finally, I got the G-Power exhaust because I'm strapped for cash and like cheap. That's a big factor in my muffler selection; cheap, power, sound all in one package is the goal.

So given all of that, I'm wondering what I need to worry about. I found a Magnaflow that was short, had the correct inlet and outlet diameters, and cost $54, but the more I look, the more I wonder about sound and performance.

So I'm looking for threads that discuss these aspects of mufflers. If you know a thread that tackles one of the topics, post it. Thanks!

 

[JusMX141]

If the rest of the system is stainless, I'd feel like an idiot advising you to install an aluminized muffler that will probably rust out around the inlet/outlets in a year. I know your part of the country doesn't see the harsh winters and road salt that we do here in western PA, but the ONLY exhaust systems that hold up here are stainless. No doubt about it.

I'm well aware that with your request of having dual tips, you'll probably end up with an oval muffler. This is good for you because the oval mufflers are normally the quieter of the two when comparing round to oval.

We sell Walker/Dynomax at my workplace, so they're the only brand I'm 100% familiar with. Of the products that Dynomax sells, I'd recommend the "Ultra Flo SS" for your application. They're a straight-through design so they won't rob power like the cheap turbo mufflers will. I DON'T know, however, if they have one with a single 3" inlet and dual 2.5" outlets.....although I'm sure they do. I can check the catalog and get back to you with a part number tomorrow.

Dynomax :: Mufflers :: Ultra Flo SS

 

[kenamond]

If the rest of the system is stainless, I'd feel like an idiot advising you to install an aluminized muffler that will probably rust out around the inlet/outlets in a year. I know your part of the country doesn't see the harsh winters and road salt that we do here in western PA, but the ONLY exhaust systems that hold up here are stainless. No doubt about it.

I'm well aware that with your request of having dual tips, you'll probably end up with an oval muffler. This is good for you because the oval mufflers are normally the quieter of the two when comparing round to oval.

We sell Walker/Dynomax at my workplace, so they're the only brand I'm 100% familiar with. Of the products that Dynomax sells, I'd recommend the "Ultra Flo SS" for your application. They're a straight-through design so they won't rob power like the cheap turbo mufflers will. I DON'T know, however, if they have one with a single 3" inlet and dual 2.5" outlets.....although I'm sure they do. I can check the catalog and get back to you with a part number tomorrow.

Dynomax :: Mufflers :: Ultra Flo SS

Thanks. I'm looking at their eCatalog and see a few 3" inlet, dual 2.5" outlet Ultra Flo models. Some say "welded" while others are "SS". Are the "Welded" once aluminized steel or are they both stainless but the "SS" ones are crimped or something other than welded? The models that seem reasonable as far as dimensions are concerned are:

• 17228, Ultra Flo, Welded, 4 1/2 tall x 9 3/4 wide, 19 long (total), 14 long (shell), 3" in, 2 1/2" out (2), Center inlet, Dual outlet
• 17519, Ultra Flo, SS, 4 1/2 tall x 9 3/4 wide, 19 long (total), 14 long (shell), 3" in, 2 1/2" out (2), Center inlet, Dual outlet
• 17661, Thrush, Welded 4 tall x 9 1/2 wide, 19 long (total), 14 long (shell), 3" in, 2 1/2" out (2), Center inlet, Dual outlet

The 3rd one is a Thrush, not Ultra Flo. But the shell length is 1" shorter which might be needed if space is limited. It is also 1/2" shorter in heighth and 1/4" narrower in width.

They also have a side inlet welded version (17227), but the shell is 6" longer and might be an issue (the sheet of paper with the stock muffler size is at home...but I'm still trying to track down dimensions for the G-Power muffler to get a better idea of how much room I have to work with when I cut the G-Power muffler off).

I don't see any specs telling me how far apart the dual outlets are. I need to know that when I'm shopping for tips.

Finally, I'm not sure how much these cost.

 

[mavisky]

The dual outlets are real far apart and don't look right. Your best bet is a muffler with tips. Here are some Hooker Header dual 3" slashcut tips I bought and slapped onto a dynomax ultraflow.

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[kenamond]

The dual outlets are real far apart and don't look right. Your best bet is a muffler with tips. Here are some Hooker Header dual 3" slashcut tips I bought and slapped onto a dynomax ultraflow.

I'm confused. Did you get a single outlet Dynomax and put a slashcut split tip on it (if that's what a 1-to-2 "forked" tip is called)?

I know that some of the Magnaflow mufflers have 4" outlet spacing (center-to-center), and some have 3.5". If I put 3.5" tips on, I'd go with 4" spacing, and do 3" tips for 3.5" spacing (keep the space between tips to about 1/2"). Something with the tip proportions in the image below (from Magnaflow's site) is close to what I'd want:

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[DSMunknown]

What's the math behind finding out the smallest dual tip diameter available from a single 3 inch pipe (so as to not create a bottleneck at the end of the exhaust system)? I do remember this discussion, and it does answer part of my question. Still, I am wondering if there's a threshold.

 

[mavisky]

Mine is a single inlet, single outlet, with a a Y tip on it

 

[kenamond]

What's the math behind finding out the smallest dual tip diameter available from a single 3 inch pipe (so as to not create a bottleneck at the end of the exhaust system)?

The short answer would be that the area of the two outlet circles should be greater than or equal to the area of the single inlet circle. But in reality, you probably want the outlets larger than that.

Ai = pi*Ri^2 (Ai, Ri are inlet area and radius)

Ao =2*pi*Ro^2 (two outlets)
Ai = Ao
Ri^2=2*Ro^2 (the pi cancels from both sides)

for a 3" inlet:
9=2*Ro^2
4.5=Ro^2
Ro=2.12"

So for a 3" inlet, two 2.12" outlets would have the same area.

I've seen 3" inlet mufflers with dual 2.25, 2.5, and 3" outlets. But many mufflers have even smaller internal tube diameters than the inlet or outlet. Not all of the vendors advertise these sizes, but you might get an answer if you ask them. And then you have the fact that the pipe is perforated, going around turns, etc., so exhaust will flow through the perforation into the shell, passing through additional bends (act as restrictions), etc. So all I can do is give the simple answer and consider mufflers that others have used and like.

 

[DSMunknown]

So for a 3" inlet, two 2.12" outlets would have the same area.

Hope you did the math right. I just got my own Vibrant Performance Stealth Muffler with the three inch inlet and dual three inch outlets. Will be reducing them to 2.25 inches. Definitely will post up photos when it's complete.