This is my first post to this site. I recently added an AFE Magnum Force Intake and I'm going to be getting my exhaust done this week. I'm looking to do either a full 4" Magnaflow system or a full 4" straight piped system.

My question is this: I was told that a straight piped system would actually decrease HP and torque due to a loss in backpressure and although the Magnaflow system is a "straight through" design, the perforations in the muffler provide just enough backpressure. I would prefer to straight pipe my exhaust however not a the risk of losing HP and torque.

A performance shop in Vegas that does a lot of work with diesels said they have ran Cummins on their Dyno with both setups and the Magnaflow system produces an increase while the straight pipe produces a decrease. I have not seen numbers. Is there any merit in what he's saying or is he just trying to sell a muffler and make a few more bucks?

Will straight piping my exhaust decrease HP & torque?

Lastly, will a 4" full straight piped system give me some more sound? I've heard the 4" Magnaflow system and it still sounds very light and airy.

Thanks in advance!

 

Well, I am not the sharpest tool in the shed but everything I have ever learned and seen and know says any backpressure to a diesel will have a negitave effect. It will get louder with a stright pipe, and sound better if you ask me.
Welcome
Heath

 

Anyone else have any comments to this? I'm going to be getting the exhaust done tomorrow and would really like to have as much feedback about this subject before deciding. Thanks.

 

From experience with running a straight pipe,I have come to find that it increses power stock and or modified, also it all depends on the type of truck. Dodges dont seem to have backpressure problems , on the other hand the 7.3l powerstroke does have problems when running a straight pipe. But i think running it straight will help. Ohh and def makes it loud , i mean a real mean sound.

 

Is there really that much difference in sound between a 4" straight piped system and the 4" Magnaflow system, which is a "straight through" design?

 

Did you have it done yet? Which one did you decide to go with?

 

go straight!!!! sounds better IMO less heat too

 

Well, my 4" Magnaflow system came in this morning. I installed everything and started it up. The sound wasn't to my liking so I went to a muffler shop here in town and had them cut a 4" piece of pipe to replace the muffler. Bolted that up, started the truck and I'm much more pleased now.

The straight pipe really makes a difference and it now sounds like a diesel exhaust (not light and airy). I had a little drone around 2,000 RPMs with the Magnaflow setup and its still there with the straight piped setup. The sound inside really isn't any different between the two setups.

Anyone have any ideas how do decrease the drone? Like I said, its not bad, but if there is a cheap, quick way to decrease or eliminate it, I'd do it.

Anyone want a new Magnaflow Muffler? It was on my truck for five miles so its basically brand new.

 

Oh man, my neighbors are going to hate me. The weather in Vegas right now is around 80 and its perfect for sleeping with the windows open. This morning, around 7 am, I went out to start my truck before work and all of a sudden I noticed that the windows on the houses around me started shutting. I wonder what kind of commotion this is going to cause with my HOA?

I have to say that the 4" full straight piped setup is definitely LOUD, especially when it has something to echo off of! My exhaust pipe exits out the side, similar to the stock setup. When I drive by cars, the exhaust echoes off the car/truck and the people inside look at me like I'm going to blow out their windows.

I came across a guy in parking lot by my house who had a 4" straight piped 03 Cummins and he wanted to know what I did to mine because it was louder than his. What would cause this? I hate to say it, but I may have to tone mine down a tad. Would putting a turndown tip on it help at all? Aeroturbine?

 

You might want to check your joints. A exhaust leak could make it sound louder.

 

You might have asked the guy with the 03 if he still had a stock intake. If he hasn't done anything to help his intake that may make a difference in the sound between his and yours. Was his an HO?

Where in Vegas are you at? I would like to hear your truck, been thinking about getting rid of the muffler as a step before getting the exhaust I want.

 

I like the straight pipe idea, has anybody considered running it out the side in front of dual rear wheels??? short, REALLY straight, and it'd look cool I think, just worried about the exhaust smell getting into the cab at stop lights!
Chadrock, keep the pipe pointed out the side, its fun in traffic to position your truck so the exhaust blows in car windows!

 

chadrock, where you located?

I just want to put a 4 inch muff in the stock pipes.

i'm in SE Gaw-gha

 

ViperSBT & 04CTD

I'm located in Las Vegas, NV. If anyone wants to hear how loud this setup is or how it sounds, I'd be happy to meet up and let you listen to it.

 

Chadrock, what's your schedule like. I work over near Summerlin and live out in NLV.