Why is it that the 3rd gens are really quite? Is it that they added a cat and muffler or are they just made differantly so they quite the truck alot more. Is there anyways to bring back the loud sound of the diesel without messing with the cat or muffler or is that the only way?

 

Nope.
Thanks to all the new fancy injection technology the diesel engine has really hushed up. My I6 FJ60 idles louder than my dads 6.7.

As far as bringing the noise back, who knows, maybe theyll make a chip for it.

 

I make plenty of noise with my 3rd Gen with the 5" Straight pipe and the silencer ring and intake kit put on it. Overpowers the engine noise everytime.

 

mines pretty loud, 4" factory pipe from the down pipe to just under the passanger seat, then its necked up to a 7" bull hauler stack that exits right before the dual rear tires, the cat and muffler are m.i.a.

 

The first injection event (pilot) is one of the things that make them quiet if you are talking about engine noise.

 

I like mine quite, it makes it easier to work around it.

 

He is asking about engine noise, not exhast noise. Two different sounds.

Personally, I do not like loud exhaust on a diesel; I would rather here the turbo singing.

 

I personally prefer more engine noise with just a hint of turbo whine. It reminds me of the tractors I grew up driving.

 

Personally I want my truck as quiet as a Lexus. I installed an ATP oil pan and valve cover acoustic blanket to quiet the engine even more. Also to reduce the noise inside the cab, I am working on wrapping the entire cab with Dynamat Xtreme. I just finished all 4 doors and will attack the rear of the cab next weekend. I don’t know how you all can stand straight piped trucks. It will rattle your front teeth off.

 

don't know how anyone can stand a quiet truck

 

i enjoy my quiet 3rd gen. i never have to turn it off at the fast food place so thats good, but my exhaust and turbo do sing the the tnue of my right foot when i want them too

 

With the new injection technology the first injection pulse or pilot injection keeps the rattle down. The quick pressure ramp on the old style injectors that causes a spike in cylinder pressure is what causes the rattle.

 

Bansh-eman,

Multiple injection events vs just the one in the older style. In the 06 (your sig) you have a pilot or pre injection event, a main and a post injection. This is part of the emissions technology but also why it is quieter. 3 events rather than the one big pop.

Hope this helps.

 

I cant belive how much quieter my 08 is than my 06 was, its almost as quiet as a gasser.(almost)

 

FYI, not all 3rd gens have cats. They came as part of the '04.5 325/600 package. The 305/555 HO and the SO lower rated engines in '03 and '04s did not have cats.