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3 1/2" DownPipe. Worth while?

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Old Feb 12, 2006 | 08:59 AM
  #1  
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3 1/2" DownPipe. Worth while?

Has anyone tried just replacing the stock 3" downpipe with a 3 1/2 inch one to match the rest of the stock exhaust?
I have a 2002 7.3 Excursion that I use to tow a small TT and would like a little more power and economy.
Will a downpipe improve power or egt's or is it a waste of time?
How about a different muffler? I don't want a loud aftermarket exhaust.
Regards,
PAul Low
 
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Old Feb 12, 2006 | 09:08 AM
  #2  
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From: New Hampshire
Originally Posted by Pablo69
Has anyone tried just replacing the stock 3" downpipe with a 3 1/2 inch one to match the rest of the stock exhaust?
I have a 2002 7.3 Excursion that I use to tow a small TT and would like a little more power and economy.
Will a downpipe improve power or egt's or is it a waste of time?
How about a different muffler? I don't want a loud aftermarket exhaust.
Regards,
PAul Low
Increasing your downpipe size is going to help lower egt's a little. A full turbo back straight thru system is going to help egt's a lot. Along with a better intake. Threre is very little noise increase in the cab with the right combo of exhaust components. Negligible mpg increase with improved intake and exhaust.
Running a blue CPS and an econo tune chip from Jody Tipton is going to help
the most.
Nut
 
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Old Feb 12, 2006 | 09:10 AM
  #3  
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from what I have found, if you put a straight through muffler on it helps out tremendously. I have searched for infomation on the 3.5" DP as well, and come up inconclusive, everyone (sales reps/shops) pretty much said to go 4" all the way. I am very happy with the results I got with a walker BTM 3.5" muffler, blackcloud.com a fte sponsors has them, as well as any NAPA retailer can get them. In the end, I still want a 4" exhaust, toying with 5" just cuz it sounds cool, you know, Yeah, its a 5 INCH Exhaust with 6 INCH tip, just rolls off the tongue nicely.
 
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Old Feb 12, 2006 | 09:14 AM
  #4  
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Originally Posted by cangim
from what I have found, if you put a straight through muffler on it helps out tremendously. I have searched for infomation on the 3.5" DP as well, and come up inconclusive, everyone (sales reps/shops) pretty much said to go 4" all the way. I am very happy with the results I got with a walker BTM 3.5" muffler, blackcloud.com a fte sponsors has them, as well as any NAPA retailer can get them. In the end, I still want a 4" exhaust, toying with 5" just cuz it sounds cool, you know, Yeah, its a 5 INCH Exhaust with 6 INCH tip, just rolls off the tongue nicely.
Hey Can...u might want to put a screen over that BIG 6" opening as the critters
might think it's a home....LOL!
 
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Old Feb 12, 2006 | 09:25 AM
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When you guys say straight through 4 inch, do you mean with or without muffler?? I purchased my 99 with a full 4 inch system ( Dynomax ) from the previous owner and i think it has a muffler... Also could I expect any difference if I took it off?
 
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Old Feb 12, 2006 | 09:37 AM
  #6  
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PSNut
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From: New Hampshire
Originally Posted by CLStewart144
When you guys say straight through 4 inch, do you mean with or without muffler?? I purchased my 99 with a full 4 inch system ( Dynomax ) from the previous owner and i think it has a muffler... Also could I expect any difference if I took it off?
Yes...straight thru is with a muffler that is basically an expansion chamber design. Straight thru with mandrel bends will give u the optimal results.
Nut
 
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Old Feb 12, 2006 | 09:41 AM
  #7  
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Also, your going to hear that turbo whistle much better.
My neighbor has an '03 F-350 with a 4" staight thru system with
the catalytic converter removed. Man sounds incredible! Like a jet engine...WOW!
Nut
 
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Old Feb 12, 2006 | 11:42 AM
  #8  
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Cheapest way to get about 80-90% of the effect of a full 4" system is to simply switch out the stock highly restrictive muffler with a Walker BTM. About $50 plus install. It will be louder outside - but not like a loud non-turbo gasser. Hell, if take off the muffler completely and run a straight pipe it won't be nearly as loud as a non-turbo gasser with a 'custom' exhaust system.

Remember - the turbo acts as a very effective muffler. In fact, in Texas, a turbo meets the state's definition of a muffler!
 
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Old Feb 12, 2006 | 11:43 AM
  #9  
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On the 99+ 7.3, the muffler is the worst part of the exhaust. If you go to the expense to replace the DP and the muffler, you might as well buy an entire system.
 
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Old Feb 12, 2006 | 12:21 PM
  #10  
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Originally Posted by PSNut
Also, your going to hear that turbo whistle much better.
My neighbor has an '03 F-350 with a 4" staight thru system with
the catalytic converter removed. Man sounds incredible! Like a jet engine...WOW!
Nut
A straight pipe sounds awesome outside the truck, but the drone it gives inside the truck grows old quickly, especially on the highway and even more so when pulling a load.
 
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Old Feb 12, 2006 | 03:27 PM
  #11  
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Pablo69,

At best you're patching the issue, with flow items if you have any one place that's a restriction then the rest of the system isn't able to work efficiently!! Do yourself a favor, you can get an aluminized "quality" system for 350.00 like an MBRP. You'll be glad you did in the long run. Heck we even have a sample system, new never installed Magnaflow 436 stainless system that retails for over 900.00 that we'll sell you for 550.00. Has a few scratches etc but is brand new otherwise!

Mark @ DPPI

Mark @ DPPI
 
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Old Feb 12, 2006 | 03:58 PM
  #12  
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From: LA and CO
Originally Posted by jtharvey
A straight pipe sounds awesome outside the truck, but the drone it gives inside the truck grows old quickly, especially on the highway and even more so when pulling a load.
Mine doesn't have a drone at all. All I have is a factory exhaust with a straight pipe instead of the muffler. It's louder at idle, but really loud when you put your foot in it.


IMO, I'd change the muffler first....
 
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Old Feb 12, 2006 | 06:30 PM
  #13  
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mine has a drone about 50 mph. I never can go that slow it seems, so I deal with. Its fun to roll the back window on the passengers side down and hear this thing roar with the straight pipe.
 
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Old Feb 12, 2006 | 09:51 PM
  #14  
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Originally Posted by whitesdford
mine has a drone about 50 mph. I never can go that slow it seems, so I deal with. Its fun to roll the back window on the passengers side down and hear this thing roar with the straight pipe.
There's no drone when you're towing a trailer?? That's when mine was the worst. I do have a long bed crew cab though, so maybe the longer exhaust would have caused a drone in mine where it wouldn't have in others.
 
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Old Feb 13, 2006 | 08:44 AM
  #15  
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I tend to be a lead foot. Trailer on or off, my baby likes 70, haha. Yeah, there is a drone, and it gets old, but only if your at 50. I have a crew cab, and you can notice it pretty easy at 50.
 
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