Engine/Transmission (1998.5 - 2002) Straight Piping

[J DeMaio]

Hi guys:



I'm wanting to straight pipe my new truck. Should I remove the catalytic converter? How much and what sized pipe will I need to replace the cat and muffler on a regular cab? Nothing like the sound of a muffler-less 5. 9L Cummins.



John

 

[Texas Diesel]

3" to replace both resonator and muffler. Your 01 doesnt have a kitty. Have fun!!

 

[Intelman34]

I just had the resonator and muffler taken off my '99. The shop used 3" and charged $40.



From inside the cab its still nice and quiet. People say its pretty dang loud from outside though

 

[johncameron]

Does removing the resonator and mufler change performance or economy in any way? If it does, I may do mine!

 

[Intelman34]

I didn't notice a performance or fuel economy increase, but it sure makes it more fun to drive.

 

[gsdog1]

Straight piped my 1999 turbo to tail in 4 inch. Sounds very nice. Next to a guy from work who just put in a 3" conversion (ie removed resonator and muffler), no comparison.



Matt

 

[alt]

I had a problem yesterday. I had to take my truck to get a state inspection. It failed b/c of no Muffler or resinator. So I had to put the muffler back on.

 

[jeepcjsrule]

Hey alt,



I work in pacific, wonder if i ever saw your truck?



Anyway are you talking about the safety insp? In missouri diesels dont need emissions, I never had any problems and have removed both the muffler and resonator I had a 94 2500 for a few years that was also straight piped and never had any problems.

 

[Rebel_Horseman]

Must have been some uninformed gas sniffer that inspected you. The vast majority of the people doing these inspections have no idea about diesel trucks. There is no need for mufflers or resonators on our trucks. I had mine totally straight piped and I LOVED it, but I later installed a glasspack to appease the *****y neighbors. From what I understand the turbo does count as a sound muffling device because there is not exhaust gases flowing straight from the manifold to the atmosphere. My advice is to find another place for an inspection.



Personal opinion... get rid of the muffler asap. I pulled mine and did notice an increase in performance and fuel economy. I personally think that is related to the fact that the turbo can spool up much quicker due to less back pressure, and that increase in spool speed means you don't have to work the motor as hard, hence the increase in economy. I'm debating on whether to go back totally straight right now. As it is, my glasspack is just slightly quieter than a straight pipe.



Brian [><]

 

[alt]

I went to the place I always went to with my other trucks. They said that the inspectors have been on them lately about the diesel trucks without mufflers. I call two other places. ANd one said they would pass it and the other said that they wouldn't. But the place wrote out a ticket saying that I failed so if I would have taken it to another place then that would have been suspisious. I just put 4" on it with a straight flow muffler. I needed 4" anyways.



Where do you work in Pacific?

Paul

 

[JBlackwell]

Originally posted by J DeMaio

Hi guys:



I'm wanting to straight pipe my new truck. Should I remove the catalytic converter? How much and what sized pipe will I need to replace the cat and muffler on a regular cab? Nothing like the sound of a muffler-less 5. 9L Cummins.



John

I straight piped mine a month ago and it sounded a lot better. No increase in mileage or hp, but spools a bit better for throttle response.



Later,

JD



P. S. 2 weeks ago, I added a 5" x 18" long tip and it sounds 10 times better then just being plain straight piped.