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Low end torque loss with Magnaflow kits?

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Old Jun 11, 2010 | 12:21 AM
  #16  
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Originally Posted by mSaLL150
Id be less worried about torque loss and more worried about drone with that huge trailer. Under stress the engine drone is far worse (like 3x louder) when I tow, and if the tips are straight out the back the sound will reflect off the trailer and be even louder. With the magnaflow it might not be too bad, but even with my Roush the drone is pretty loud when towing and it was unbearable with the flowmaster I previously had.
The system I ordered is the SI/DO with the same side exit behind the passenger rear wheel. So I don't have to worry about the bounce back off the trailer. I had a SI/SO Magnaflow on my old '03 F150 and it had a little drone but not too bad. Flowmasters to me are only good if you want a LOUD system. If I wanted to put a system on an old muscle car I would look at Flowmaster. But for my daily driver I know I would get tired of the noise. Once I get the system and put it on I will report back what I find. I tow, but realistically probably only 5-10% of my total mileage will be with the trailer behind me. The rest will be my normal daily stuff. Oh yeah, the trailer looks huge, which it is pretty big, but it is a lightweight model. When I pull it fully loaded it's only about 7000 lbs. If you look at the pic of it too, you can tell it sits low to the ground. It is more aerodynamic than a lot of the trailers I see. My sister has one the same length, but weighs 10,000 lbs loaded and sits probably two feet higher than mine. I wouldn't pull that one with my truck. Way too much.
 

Last edited by IL6fan; Jun 11, 2010 at 12:26 AM.
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Old Jun 14, 2010 | 09:36 AM
  #17  
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Originally Posted by 4.6 Punisher
You will not lose any low end torque with this kit. The 2.5" vs 2.25" argument is for true duals, not a simple cat-back. You might gain a bit of power and torque, but the bottleneck will be the Y-pipe and intermediate pipe.

EDIT: You always lose power with chambered mufflers (Flowmaster, Cherry Bomb, Thrush) but never with straight-through mufflers (Magnaflow, Borla, Corsa, Bullets).
Never say never.. last two kits were a simple 18" magnaflow cut in DO with 2.25" run straight out the back. Both trucks lost lowend via seat-o-pants meter and mpg'd dropped.
 
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Old Jun 14, 2010 | 02:22 PM
  #18  
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Originally Posted by SMOKEin
Never say never.. last two kits were a simple 18" magnaflow cut in DO with 2.25" run straight out the back. Both trucks lost lowend via seat-o-pants meter and mpg'd dropped.
Explain the truck and exhaust setup.
 
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Old Jun 14, 2010 | 04:39 PM
  #19  
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07 ram 1500 quad cab hemi 4wd.. cut out stock muffler, put in 18" maggie si/do 2.25" pipes with classic dual out the back look, slashcut tips, sorry don't recall size..

08 gmc sierra extended cab 2wd 5.4L V8.. same exhaust as above minus the tips, had both pipes cutoff and turned down about 4" before the bumper..

The Dodge had a bigger mpg loss, however the GMC had a greater felt power loss.
 
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Old Jun 14, 2010 | 04:50 PM
  #20  
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YOU WILL LOSE LOW END. I have a 2010 5.4 and install the magnaflow si/so system. Stock pipe and YES YOU DO LOSE lose end.... but is very little anyone that tells you different is just flat out full of **** or in denial.... but man it sounds great!
 
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Old Jun 14, 2010 | 06:55 PM
  #21  
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The reason it feels like low end power loss is due to the truck being louder. A lot of the time, people think that because the engine is getting louder sooner, that it's having to work harder to get there. It's all subconscious, nothing more.
 
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Old Jun 14, 2010 | 07:33 PM
  #22  
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Originally Posted by 4.6 Punisher
The reason it feels like low end power loss is due to the truck being louder. A lot of the time, people think that because the engine is getting louder sooner, that it's having to work harder to get there. It's all subconscious, nothing more.


I think the reason people with straight thru mufflers think they are getting more power is because the truck is now louder. Which subconsciously makes them believe they are going faster and have more power...

 
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Old Jun 14, 2010 | 07:57 PM
  #23  
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From: Douglasville GA
Right, and I guess back pressure is real too?
 
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Old Jun 14, 2010 | 08:13 PM
  #24  
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cmon.. because i dont buy your theory on subconscious power loss, i don't understand how exhaust systems work?
 
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Old Jun 14, 2010 | 09:10 PM
  #25  
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Yes. You're trying to say that a less restrictive muffler does not perform as well as an ultra restrictive baffled OEM muffler.
 
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Old Jun 14, 2010 | 09:15 PM
  #26  
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My butt dyno tells me I have more horsepower this evening with my Roush Off Road exhaust. Oh wait, I had Taco Bell for lunch, nevermind...
 
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Old Jun 14, 2010 | 10:26 PM
  #27  
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Originally Posted by 4.6 Punisher
Yes. You're trying to say that a less restrictive muffler does not perform as well as an ultra restrictive baffled OEM muffler.
I'm not going to argue what cant be proved. What I stated was fact. The last two trucks that I put 18" magnaflow mufflers on dropped power and mpg, no question about it.
 
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Old Jun 14, 2010 | 10:33 PM
  #28  
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Originally Posted by SMOKEin
I'm not going to argue what cant be proved. What I stated was fact. The last two trucks that I put 18" magnaflow mufflers on dropped power and mpg, no question about it.
Couldn't agree more. Been there and done that, it is a fact.
 
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Old Jun 14, 2010 | 11:19 PM
  #29  
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Unless you can prove it with dyno sheets, it's not a fact.
 
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Old Jun 14, 2010 | 11:30 PM
  #30  
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I know there are dyno sheets that prove performance gains as well as MPG gains.
 
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