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Discussion Starter · #1 · (Edited)
Finally got around to weighing the muffler and dissecting it. I was blown away by how performance oriented it's NOT. When I cut it off I saw that there are some flappy things just inside the inlet which I thought were just held closed by gravity so they could easily open when you hit the gas. However, they are spring loaded and they are actually not that easy to open. This muffler seems like it was designed specifically to kill the performance of the turbos! I'll let the pics give any further explanation.

The weight I got was 41lbs. Not as heavy as I thought, but certainly not light.

edit: don't mind the random welds/molten metal. My buddy got a new welder and was practicing/playing on this.
 

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Oh look! the trash can strapped to the back of our cars is full of garbage! How fitting! Jeeez

how awful. come spring this thing is GONE.

Thank you for the show and tell. Much appreciated!
 

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I purchased a Magnaflow Cat-Back for my 2.7 which included a resonated x-pipe and a DI DO suit case muffler. Not sure what the internals are but the system made a mild improvement with no drone or rasp. Later I swapped out the resonated x-pipe for straight tubing and it added rasp so I put the x-pipe back on.
 

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I purchased a Magnaflow Cat-Back for my 2.7 which included a resonated x-pipe and a DI DO suit case muffler. Not sure what the internals are but the system made a mild improvement with no drone or rasp. Later I swapped out the resonated x-pipe for straight tubing and it added rasp so I put the x-pipe back on.
Not trying to be mean, just a friendly word of advice, when you're posting about your setup/mods please preface what you say with "my Edge" not just "my 2.7" on a forum where that is the only engine...

On first glance I thought you were talking about a magnaflow setup for a Fusion, which was a lot more exciting until I realized you don't have one...

I tend to just skip over people's signatures...

carry on!
 

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Discussion Starter · #8 ·
Not trying to be mean, just a friendly word of advice, when you're posting about your setup/mods please preface what you say with "my Edge" not just "my 2.7" on a forum where that is the only engine...

On first glance I thought you were talking about a magnaflow setup for a Fusion, which was a lot more exciting until I realized you don't have one...

I tend to just skip over people's signatures...

carry on!
They ARE pretty much the same thing, to be fair.
 
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Not trying to be mean, just a friendly word of advice, when you're posting about your setup/mods please preface what you say with "my Edge" not just "my 2.7" on a forum where that is the only engine...

On first glance I thought you were talking about a magnaflow setup for a Fusion, which was a lot more exciting until I realized you don't have one...

I tend to just skip over people's signatures...

carry on!
If I was promoting a model I could understand your frustration, but I wasn't. I was just trying to make it aware without a resonator you may experience rasp with OUR motor. Also figured the big bold signiture would have me covered. :D
 

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Discussion Starter · #10 ·
What a mess that muffler is. The only thing that comes to mind regarding those flap springs is that some engineer thought we need some back pressure on the low end until there is enough force to open them. I know there has been a lot of debate on whether turbos need back pressure or not. I am kinda leaning towards that they do. I don't think they have anything to do with noise reduction.
Back pressure is the enemy of turbos. The only "debate" is coming from people that haven't read books about turbocharging.
 

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Awesome Bot, thanks. Excuse my ignorance to muffler design and what not, but what the heck is with the wig?
 

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I know some BMWs have them for cold starts and to aid in noise reduction.
 

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Discussion Starter · #13 ·
After doing a little research, I am thinking that those flaps, when partially open might be used to increase the velocity of the exhaust causing the turbos to spool up faster.
The gas would be faster as it passes through the restriction because that's how fluid dynamics work, but that does not help the turbos spool faster. The only thing that will help the turbos spool faster it a bigger pressure difference from one side of the turbine to the other. The lower the pressure on the outlet side of the turbine and the higher the pressure on the inlet side, the faster the gas will move through the turbine, thereby spooling it faster. You could weld a washer in the tailpipe with a 1/4 hole in it and the gas would be moving insanely fast to squeeze through the hole, but it's causing a massive restriction, thereby decreasing the difference in pressure between the inlet and outlet sides of the turbine. The faster you can get the gasses through the turbine to the other side the better. Creating a bottleneck post turbo is bad for performance. That's why chambered mufflers are frowned upon in the turbo world. The only reason people run any muffler at all is because the noise would be intolerable otherwise.

The backpressure debate is a very misunderstood concept. Cars don't need backpressure. That is a myth. The reason people think having no backpressure causes your engine to burn itself up is because cars that cant self correct their fuel will run super lean if they aren't tuned for the increased airflow. What NA cars DO need is exhaust gas velocity so the gas has momentum for the purpose of scavenging. The way you get velocity is to run smaller diameter pipes, not by creating a cork. Smaller pipes=more scavinging=more low end power. Bigger pipes=more flow=more high end power. Backpressure is a side effect of the smaller diameter pipes. It is not what gives you more low end power.

Forced induction engines don't care about scavenging because their intake air is getting pushed in during the valve overlap rather than being pulled out by exhaust gasses.

As far as I can tell, the flap is there strictly for noise reduction, and it does a helluva good job at that.

edit: and for cold starts maybe.
 

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Discussion Starter · #14 · (Edited)
Awesome Bot, thanks. Excuse my ignorance to muffler design and what not, but what the heck is with the wig?
If you follow the path of the exhaust gas (blue) it has to travel toward the sides of the muffler, then make a U turn to enter the pipes that cut back across the entire muffler before exiting. Because sound waves (red) travel straight until they bounce off something, they go through the perforated ends (yellow) and are absorbed by the fiberglass. That's my assumption anyway.
 

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If you follow the path of the exhaust gas (blue) it has to travel toward the sides of the muffler, then make a U turn to enter the pipes that cut back across the entire muffler before exiting. Because sound waves (red) travel straight until they bounce off something, they go through the perforated ends (yellow) and are absorbed by the fiberglass. That's my assumption anyway.
Yep, its just sound deadening material.
 

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Thanks for the lesson on turbos. It does help a picture in my head. Almost as complicated as elronino on temperature control. Lol
 

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As far as I can tell, the flap is there strictly for noise reduction, and it does a helluva good job at that.

edit: and for cold starts maybe.
I don't understand the cold start part. The flaps are only pressure activated, right? So wouldn't they open under the same pressure regardless of what the outside temperature is?
 

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Discussion Starter · #20 ·
I don't understand the cold start part. The flaps are only pressure activated, right? So wouldn't they open under the same pressure regardless of what the outside temperature is?
I don't know either. Gjb89 suggested that bimmers have flaps for cold starts, so i figured it's a possibility. My guess is that the exhaust gasses cool slower if they are under pressure as they make their way back, therefore heating the emissions system faster. Just guessing though.
 
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