Straight Pipe Muffler

[Mopar1973Man]

Well I've gone and done it. I went and installed a muffler. But this muffler I was happy to install. It a 3" in and 3" out with straight pipe through it. Designed much like a glass pack but not. Best part NAPA has them in stock for super cheap price.

 

NAPA - Muffler - EXH 21468

http://www.napaonline.com/Catalog/Result.aspx?Ntt%3d21468%26Ntk%3dKeyword%26Nty%3d1%26Dn%3d0%26D%3d21468%26Dk%3d1%26Dp%3d3%26N%3d0

 

 

It really quiet after all the years of straight pipe it super quiet. People are going to wonder if I sold my truck.

[MnTom]

That looks a lot like mine, but mine is 4"in and 4" out. My truck is a bit louder than stock, but not bad even when towing.

[LiveOak]

I am still running a Farm Boy Performance 5" inch turbo back straight pipe exhaust.  A diesel symphony orchestra in motion. 

[Mopar1973Man]

I'll play with the truck a bit more tomorrow. I've got to head to work for a partial day. So I'll play a bit to see what its sounds like (barriers, hill banks, buildings, etc.). I love the idea of it being quieter now. But it sure didn't hurt the performance that I can see.

[joecool911]

Michael,

Are you stock other than the muffler? I thought we were different dimentions like 3.25 and 3" in various locations.

[Mopar1973Man]

Not as far as I know... It's 3" from turbo back. But stock muffler and resonator are 4" in-between the two units. But the pipe is all 3".

[TFaoro]

I'll play with the truck a bit more tomorrow. I've got to head to work for a partial day. So I'll play a bit to see what its sounds like (barriers, hill banks, buildings, etc.). I love the idea of it being quieter now. But it sure did hurt the performance that I can see.

How can you tell it hurt performance? And how is the drone inside the cab as compared to the 3" straight pipe? I have a couple buddies with 4" straight pipes and just cruising down the road you can't talk to the guy next to you because of the loud drone! Maybe 3" is different though....

[LiveOak]

Just in case anyone wanted to get an idea of what and how a 5 inch exhaust looks like being installed:

 

http://forum.tractorfarmandfamily.com/showthread.php?t=12825

[Mopar1973Man]

Damn that pipe is huge.   That's one thing about the 5" it puts the pipe too close to things with lots of heat.

[LiveOak]

Damn that pipe is huge.   That's one thing about the 5" it puts the pipe too close to things with lots of heat.

 

Actually it fit quite nicely.  The down pipe starts off at the outlet size of the turbo, in my case exhaust brake and gradually tappers up in diameter until it reaches 5 inches towards the end of the pipe.  From there, everything is 5 inch diameter pipe.  The only issue where the pipe runs close to anything is where the pipe transitions by the spare tire.  I have open diffs so I can use the OEM size spare tire.  Any tire larger than 285/75R-16 will not fit in the spare tire compartment anyway.  There is still a 3/8" approx. air gap between the pipe and the spare tire but that far back, the pipe does not get that hot.   

 

I went with the 5 inch pipe because the "alleged" EDM Mach 2.5 injectors smoked like a freight train and made my EGT's go through the roof.  I think they may have been mismarked.  Once the BHAF and 5 inch pipe was installed the EGT became very tame and manageable almost to being like stock.  I think the much larger pipe diameter and corresponding surface heat radiation area allows the pipe to run a good bit cooler than the OEM pipe.  This exhaust also allows for the later upgrade to twins or an after market performance turbo. 

[Utah Dually]

One thing about diesels, they respond to decreased exhaust resistance way more than gas motors. When I put the 4” exhaust on my truck it really woke it up. I could see if you have been running a straight pipe, putting a muffler on would be like throwing a 1000 lbs in the bed. 

[Mopar1973Man]

How can you tell it hurt performance? And how is the drone inside the cab as compared to the 3" straight pipe? I have a couple buddies with 4" straight pipes and just cruising down the road you can't talk to the guy next to you because of the loud drone! Maybe 3" is different though....

 

Opps. Typo. Didn't Hurt. Post corrected.

[bjytech]

I put a areo turbine 4040XL muffler on my truck a few months back to get rid of in cab drone I had while on the highway, and I really like it. I still have that nice sound at idle but it quieted the in cab noise down especial while cruising on the highway, it also changed the sound some to have a deeper grunt/tone when you get on it. here's a video I made to get a t-shirt/sticker pack from areo, towards the end I had a co worker take it for a drive by so I could hear it. http://youtu.be/yqRbHaSLmbQ

[Mopar1973Man]

Hmmm... I might have to get my tripod out and do a bit of video with the camera tomorrow or the next day.

[rlane547]

Hmmm... I might have to get my tripod out and do a bit of video with the camera tomorrow or the next day.

Here you go installing a muffler, when after we talked I chopped mine off. Ha Ha! I'm glad I did it though. Whatever aftermarket muffler the previous owner put on must have been extremely restrictive. My egt's dropped about 50 degrees and my cool down time is way faster down to 200 degrees. I have to admit I like the look of your muffler. I may consider it when I'm ready to replace the exhaust. Right now I'm getting everything ready to install a new torque converter.

[IBMobile]

I have the magnaflow 4" and the muffler is just a big long straight through resonator. It drones pretty good at freeway speed but I think that's a characteristic of this truck/engine combo.