05 Muff Delete 2 weeks /then decided to Kill cat

[lethal injection]

I figured I would give my opion to those who are still in question of what to do with your exhaust on 2005's. I did the muffler delete and drove around for a few weeks. I was quite impressed by the sound difference and sound quality.

I deceided last night to replace the cat with a test pipe. Well after doing it I was not impressed and a bit upset. It has a hissy sound to the exhaust and is a little louder than I would like after a couple of beers. It may be in my head but it actually feels like it lost power, I know by watching my boost gauge it confirms it.



So the break down on a 05 IMO is just delete the muffler and leave the cat, it sounds great!



I will be putting cat back on tonight.

 

[DaveK98]

What pipe did you use for the muffler delete?



I'd like my 05 to be a little louder but afraid of the drone

 

[lethal injection]

I took it to local shop and they put a piece of 4" in place of muffler. No drone empty have not towed yet. I ordered cat delete from place in california but dont have the name of it in front of me. They also had muff delete pipes. Very nice quality!

 

[Forrest Nearing]

I have a differing opinion...



the muffler delete on a catted 3rd gen makes the truck sound like an Acura V6 w/ fart cans out back... you can't hear the turbo and there's no rasp to the exhaust.



straight piped doesn't really make the truck any louder, it has a crisper sound, you can really hear the turbo big time, and often there's less interior resonance without a cat than there is with a cat!

 

[Mark Craig]

Forrest Nearing,



We tend to get more reposonses like yours too when the muffler is deleted, cat or not cat. We have had great success and response with the MBRP replacement muffler that fits the stock rubber mounts with welded hangers and is a direct replacement. We do sell a lot of cat test pipes too, but mostly the muffler replacement.



Mark @ DPPI

 

[lethal injection]

I have a differing opinion...



the muffler delete on a catted 3rd gen makes the truck sound like an Acura V6 w/ fart cans out back... you can't hear the turbo and there's no rasp to the exhaust.



straight piped doesn't really make the truck any louder, it has a crisper sound, you can really hear the turbo big time, and often there's less interior resonance without a cat than there is with a cat!

I have to disagree with you on the turbo part but I have a AEM BRUTE FORCE on the truck and without the muffler and the cat in place I can really hear the turbo. With the cat gone I dont hear it as much due to the crappy sound from exhaust (imo) But I am new to diesel's. (Sounds like a v-6 with open headers echoing off buildings) Is that the sound everyone is shooting for? I came from high horse power gassers which always had a flowmaster on them.



As for the truck not being louder without the cat... . I want what your smoking. Maybe you have not had your windows down. Your right there is no difference in the cab but there sure the hell is outside.



As for the rasp I am not sure what kind of sound that is..... Before cat was cut out it had a nice deep sound to it. After the cat was taking out it has a loud air blowing sound to it (thats what sounds like crap) No rumble just a soild air sound.



I will admit that going down the road and in top gear when you load it down it sounds awesome but at idel it dont.



Can you describe to me what the rasp sound is? Or if anyone is local that has a really good sounding truck I could meet to check out the sound would be great.



Like I said I am new to the diesel sceen, maybe the way this truck sounds without cat and muffler is what everyone is shooting for in diesel sounds. I guess in time I will find out forsure.

 

[Forrest Nearing]

I guess on a 3rd gen, that raspy sound is what you're calling an airy sound...



and when I'm talking about hearing the turbo, I'm talking out of the exhaust, not from the intake side...



I love the sound of the turbo spooling down through the exhaust pipe!



the cat kills that sound completely



also, when I said removing the cat might make it quieter, I was talking inside the truck, not outside... I want my truck as loud as possible outside and quiet as possible inside



to each their own, I'm glad you found a combo you like

 

[lethal injection]

I guess on a 3rd gen, that raspy sound is what you're calling an airy sound...



and when I'm talking about hearing the turbo, I'm talking out of the exhaust, not from the intake side...



I love the sound of the turbo spooling down through the exhaust pipe!



the cat kills that sound completely



also, when I said removing the cat might make it quieter, I was talking inside the truck, not outside... I want my truck as loud as possible outside and quiet as possible inside



to each their own, I'm glad you found a combo you like

OK now I understand... .



I need to get someone to drive my truck down the road so I can check out the turbo sound from the exhaust before I make my decision to put kitty back in.



Thanks for explaning that to me. Iam still learning!!!

 

[CHolman]

I know to each his own, but I don't think there's anything meaner sounding than a Cummins stright piped. I've loved that sound from the first time I heard it and that's when I desided I had to get myself one.

 

[JCleary]

I know to each his own, but I don't think there's anything meaner sounding than a Cummins stright piped. I've loved that sound from the first time I heard it and that's when I desided I had to get myself one.

I have to agree, but the 2nd gen 24 valves sound the meanest. The 12 valves sound the happiest, if there is such a thing.

 

[Matt400]

I want my truck as loud as possible outside and quiet as possible inside.

Help me here. . if you don't want the noise, why do you want it for other people?

I know everyone is different and maybe I misread that.

I would like better flow with no more noise and haven't found that. I tried a 5" in/out 51" Donaldson Silent Partner and then a Donaldson 4" in/out 51" but both were more noisy than stock.



I tried to convince myself the big muff was doing what I wanted but in reality it was too noisy for me. I sold my 03 to my son and he straight piped it. I think it sounds horrible, like an expensive derby car I tell him.

But. . he sure likes it and its his truck now.

 

[Forrest Nearing]

Help me here. . if you don't want the noise, why do you want it for other people?

I know everyone is different and maybe I misread that.

I would like better flow with no more noise and haven't found that. I tried a 5" in/out 51" Donaldson Silent Partner and then a Donaldson 4" in/out 51" but both were more noisy than stock.



I tried to convince myself the big muff was doing what I wanted but in reality it was too noisy for me. I sold my 03 to my son and he straight piped it. I think it sounds horrible, like an expensive derby car I tell him.

But. . he sure likes it and its his truck now.

if I could listen to my truck from the OUTSIDE, I would love it!



but it sounds a lot different from inside... I drive w/ my pass window down all the time just to get to hear the exhaust...



the sound of the exhaust is a whole different animal from interior resonance...



I want as little interior resonance as possible, but I want the best sounding exhaust possible (and for me, that's straight piped... the bigger the better)

 

[lethal injection]

Well after being out cruising around for awhile I think it is going to remain STRAIGHT PIPED WITHOUT THE KITTY

 

[Forrest Nearing]

sounds good bouncin' off walls and other cars doesn't it!?

 

[lethal injection]

Your right!!! sure does.

 

[nick05]

can you tell any diff. when the kat is off?

sound wise. any louder, deeper, or raspy?

thinking of cutting it.



thanks

nick

 

[Forrest Nearing]

do it!!! sounds way better especially out of stacks

 

[MHorne]

I have mine straight piped and i love that sound when flooring it past a car on the passenger side. especially if they are on the phone. But the best is when your stopped at a light and you see them put their window up and let them get in front of you and watch them put their window back down. Its great. I think straight piping it was the best thing i ever did so far for my truck. I didn't know there were others out there who loved that straight flow loudness sound as much as me. This is nice to know. Have fun guys.

 

[BTighe]

I know to each his own, but I don't think there's anything meaner sounding than a Cummins stright piped. I've loved that sound from the first time I heard it and that's when I desided I had to get myself one.

i dont know, a strait piped 6. 0 sounds pretty mean

do the 3rd gen resonate in the same rmp as the 12v's. i have a 24" magnaflow on my truck and it still resonates in the cab like mad! could it be from the 3" downpipe. thats all changing in about 3 weeks but i might scrap the whole exhaust if i can find something loud and deep on the outside and not to bad on the inside.

cut the cat, it dont belong there

 

[ROGER/DODGER]

Why is there a drop in power and boost when the cat is removed ? I was told this was common by a long time mechanic on Cummins. I don't get it !