Make straight pipe quieter

[NDear]

Hi everyone.

I just bought a 2008 F250 6.4l with a 5" straight pipe. It's been deleted/emissions modified I guess but no changes appear under the hood. I love the truck -- engine runs great, transmission is smooth, 4x4 works well, etc......but it's WAY TOO LOUD for me. I love diesel engines, but diesel mods that interest me involve increasing engine life, fuel efficiency, quieter, etc. I'm not into coal rolls, smoke, etc. -- nothing against it, just not what I want on a daily work/driving truck. Maybe at the truck pull.....

I have a diesel mechanic buddy that is worried about any reduction/obstruction to the exhaust because it's been deleted and fuel economy reduction. What options might be a good compromise to make it quieter but have little impact on fuel economy and engine life? I like a little turbo whistle but I think it's just obnoxious as-is -- especially when I have to go to the city. I feel like I can't even enjoy hearing the engine over the exhaust noise.

Any suggestions would be welcome, I'm here to learn.

 

[jgillott]

MBRP and similar companies make some really good free flowing mufflers that work great on these diesel trucks. They offer a nice sound without being excessively loud.

 

[AH64ID]

I’m curious how much of “diesel mechanic” he really is based on those comments.

A muffler will not have any different effects on a motor that’s deleted vs one that’s not.

I’ve always been a fan of Donaldson. They have several 5” models with proper flow ratings and good attenuation.

 

[dieselshadow]

I’m curious how much of “diesel mechanic” he really is based on those comments.

A muffler will not have any different effects on a motor that’s deleted vs one that’s not.

I’ve always been a fan of Donaldson. They have several 5” models with proper flow ratings and good attenuation.

That was my thought also. Many, if not most bigger diesel mufflers, and pretty much all “performance” mufflers are a straight through design like an old school glass pack. Zero effect to the engine.

 

[NDear]

Thanks for the suggestions. No, he's legit -- Ford certified, former military mechanic, he has a garage. He hasn't even seen the truck yet, just talking about it over the phone. I think what he was referring to was: if extra air intakes, etc were added under the hood, the current exhaust might be matched to it. But that's not the case.

I see some people have had good luck adding a wider diameter or different shaped tip to change the pitch and make it less annoying. What do you think about that?

I'm thinking I'm going to drive it for a couple weeks while until I decide. And start checking out exhausts when I pass others truck!

 

[NDear]

I should clarify, as I watch more YouTube videos and read more forums: it's not the volume (db) of the exhaust that I really object to but the sound/tone. It's the "air-rush" sound that's so prevalent. None of my dad's diesels that I drove years ago ever had that sound -- but they were stock. I like to hear the pleasing sound of a diesel engine and a little turbo whistle.

 

[Wiredawg]

Fords sound TERRIBLE straight piped and most performance mufflers. They sound like loud POPCORN poppers. Stock or near is good.

Cheers, Ron

 

[BigPapa]

I should clarify, it's not the volume (db) of the exhaust that I really object to but the sound/tone. It's the "air-rush" sound that's so prevalent.

Welcome to the world of V8 diesels. The turbine noise is very pronounced on the Fords and D-Max's. I can't say I've ever heard a Cummins where the turbine noise is louder than the exhaust note and I've heard a lot of them, even the pullers with a hood stack.

And, as others have said, if your buddy's worth his salt, he should know diesel exhaust and gas exhaust are totally different animals.

 

[mfurrh55]

What about a resonator, think that would tone it down?

 

[Wiredawg]

I have a used BD performance muffler and Aero Turbine performance muffler I'm happy to let go cheap.

 

[Ozymandias]

Ad a Muffler, Donaldson for example.
Be done.

 

[mfurrh55]

I have a used BD performance muffler and Aero Turbine performance muffler I'm happy to let go cheap.

What size are they?

 

[KATOOM]

I have a diesel mechanic buddy that is worried about any reduction/obstruction to the exhaust because it's been deleted and fuel economy reduction. What options might be a good compromise to make it quieter but have little impact on fuel economy and engine life?

A muffler no matter how "performance" it is will have an affect on the exhaust flow. How much is dependent on size, design, and engine performance. Even at that, you'd need a dyno to tell you how much. Really all you'd want to be concerned with is EGT's, but since you have a 5" exhaust, there isnt going to be much of anything which will affect anything.

The most common and most positive reviews are Donaldson mufflers and/or FTE resonators. I dont think you could go wrong with either.

 

[Wiredawg]

What size are they?

Both are 4".

 

[mfurrh55]

Both are 4".

Was hoping 5", I now have 5" dual exhaust on mine, I have a 4" Aero, Thanks though, Monte