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Changing stock muffler....

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Old Jan 24, 2005 | 06:23 PM
  #1  
Pylda's Avatar
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Changing stock muffler....

Suggestions for what to do with my 2005 STX with 4.6L

For those of you that have changed out your stock muffler to a free flowing exhaust and kept the stock pipes (or stock size).......

What muffler did you go with? (brand, part #)

How happy are you with it?

What would have done differently?

I believe I have 2.25" pipes stock, can someone tell me if this is wrong?
 
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Old Jan 24, 2005 | 08:08 PM
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I went to my local muffler shop and had them remove the stock muffler and replace it with a flomaster 40 series. Then had them put a tip on it. I kept the stock pipes except just before the muffler. They had to add a piece in.

It could be louder to suit my taste, but its fine. I dont know the stock pipe size, but the muffler shop will. Just go shop around your town for the best deal, and talk with the guys at the muffler shops. They generally know what the best set up is to fit your taste.
 
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Old Jan 24, 2005 | 10:42 PM
  #3  
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Originally Posted by Pylda
Suggestions for what to do with my 2005 STX with 4.6L

For those of you that have changed out your stock muffler to a free flowing exhaust and kept the stock pipes (or stock size).......

What muffler did you go with? (brand, part #)

How happy are you with it?

What would have done differently?

I believe I have 2.25" pipes stock, can someone tell me if this is wrong?
Pylda, do a search for my Magnaflow thread. You can get it by clicking on my name and finding "All Threads started by Toreador". I did a complete review and love the Magnaflow muffler.
 
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Old Jan 24, 2005 | 10:45 PM
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Plyda, a quicker way to find my review is go to the "Advanced" search feature. Type exactly "Maganaflow +muffler" in the search box and pick this forum to search. You'll find my review under the "Magnaflow muffler installed this morning" thread. Good luck.
 
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Old Jan 24, 2005 | 11:45 PM
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I just had my muffler changed to a 24 inch Magnaflow and it sounds awesome. They also changed the tailpipe to a 3 inch. I couldnt believe the difference in sound and power. The muffler guy said that if you keep the stock muffler the heat build-up forward of the muffler will eventually crack and warp your right manifold. Probably the Cat too. He also said the new new muffler would give me about an additional 50 HP. Sure feels like it.
Anyway, this is the best mod I have done so far and well worth the $200. bones.
 
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Old Jan 25, 2005 | 02:48 AM
  #6  
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Boy Get Me One Of Those Mufflers ,change Muffler Get 50 Horspower And I Got Some Land To Sell You,realy Belive The Muffler Guy???
 
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Old Jan 25, 2005 | 09:05 AM
  #7  
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If a 24" = 50 horsepower will a 36" = 75 horsepower or do I use an 18" ?
 
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Old Jan 25, 2005 | 09:20 AM
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Magna Flow today

I am getting an 18 inch, 2.5" Magnaflow this afternoon. The shop told me that the 14" (my original choice) was just as loud as the Flowmaster, which I do not want. The warden told me she did not want a loud truck ! They did say that there is about a 1 to 2 mpg increase and approximately 20 hp. We'll see this afternoon...and I'll post back tomorrow with the results.
 
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Old Jan 25, 2005 | 01:22 PM
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Great choice. I had the Magnaflow installed on my truck and love it.
 
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Old Jan 25, 2005 | 01:40 PM
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I had a magnaflow 18" welded into the stock stainless pipe on my 4.6 4x4 and maybe it picked up a couple of HP but not 20 or even 10. The mpg did go up some. Maybe .5 to 1 mpg but that is hard to tell because since it sounds better you will put your foot into it more. It will drone a little in the cab between 1700-2000 rpm just so you know. Nothing bad. The drone is more noticable from the drivers seat than the passenger seat. Must be something to do with the sheilding.
 
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Old Jan 25, 2005 | 05:29 PM
  #11  
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Can someone tell me what size the inlet and outlet is on the stock STX 4.6 muffler? I have now been told that it is a 2.5" but was originally told it was a 2.25". I want to order my muffler but now dont know what size to order, I want to keep stock size pipes.
 
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Old Jan 25, 2005 | 10:27 PM
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Originally Posted by HighTekRedneck
I am getting an 18 inch, 2.5" Magnaflow this afternoon. The shop told me that the 14" (my original choice) was just as loud as the Flowmaster, which I do not want. The warden told me she did not want a loud truck ! They did say that there is about a 1 to 2 mpg increase and approximately 20 hp. We'll see this afternoon...and I'll post back tomorrow with the results.
I ended up going with the shorter Magnaflow and yes it gave me more hp, but I don't think it was a full 20hp (remember I'm not the expert on mechanics here either). But you will feel a little more oomth and better torque at take off. As for the sound, I don't think it's that loud, but that's probably a personal taste. In fact I love the brruummm sound it gives. After you get past 50MPH it really settles out and does not sound any louder than your stock on the highway. I think you made a good choice and will like it.
 
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Old Jan 25, 2005 | 10:33 PM
  #13  
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Originally Posted by insynco
I just had my muffler changed to a 24 inch Magnaflow and it sounds awesome. They also changed the tailpipe to a 3 inch. I couldnt believe the difference in sound and power. The muffler guy said that if you keep the stock muffler the heat build-up forward of the muffler will eventually crack and warp your right manifold. Probably the Cat too. He also said the new new muffler would give me about an additional 50 HP. Sure feels like it.
Anyway, this is the best mod I have done so far and well worth the $200. bones.
Well, I guess I feel pretty good I got mine done for $160. Anyway I seriously doubt you can get 50hp from just a muffler. Maybe with a new intake, headers, and muffler. You definitely get some added hp, but 50?? I'm not sure about the manifold story keeping the stock muffler but one thing for sure is your engine now works less hard and will run cooler and more effieciently. At least that's the way my engine "feels" it's running more smoothly.
 

Last edited by Toreador; Jan 25, 2005 at 10:35 PM.
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Old Jan 26, 2005 | 12:17 AM
  #14  
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Yada Yada Yada
The point the muffler guy was making is that you dont gain any HP from changing the muffler, you get back the loss of HP from the restrictive stock muffler. Sorry I implied that you gain anything. It just feels a lot smoother.
Since all Magnaflows are wide open, I dont think the length is all that critical to performance, just maybe a different tone.
 
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Old Jan 26, 2005 | 08:06 AM
  #15  
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Grrroowwwlll

Oh yeah...this new Magnaflow is nice. It's got the lowend growl that I was wanting and the resonance isn't too bad unless you are cruising around 2000 RPM's, but you can just turn up the radio, right ! As for the HP gain...I'd say I got about 10 extra ponies. I nearly rearended a guy that I was passing this morning because the throttle response is much quicker. It is still too early to tell about the mileage but will be watching it more closely as time goes on. Next up, a K&N filter...
Stay tuned.
 
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