I have an 01 1500 with the 3.9 V6. Previously, the exhaust was configured as the stock 2.5" exhaust out the cat to the muffler, then 2.5" out the other end of the muffler which then transitioned right away into a 3" exhaust all the way to the end.

I pulled the muffler, but left the cat. I did this mainly to see how it performs without it, and also for some added noise.

What would the best option be to fill in where I pulled the muffler?

1. Replace with 3" straight pipe, and use 2.5" to 3" adapters to connect to current pipes on each side.
2. Replace with 2.5" straight pipe, to keep same sizes with current pipes on either side.
3. Put muffler back on, but add a manual cutout between rear of cat and front of muffler.

Thanks for the help and if you have questions, let me know!!

 

I would go with option 1. Cutouts are nice, but, as they have nice hot corrosive exhaust gases running thru them, and they hang out UNDER the truck, and therefore see all sorts of nasty road 'stuff'..... I wouldnt expect them to last very long.

 

OK, cool. What would the major difference be putting the 3" pipe in compared to the 2.5" pipe in place of the muffler?

And if I'm correct, the longer the pipe, the less noise there is? Right now, everything's off, and the pipe pretty much ends after the cat. Its really loud! Haha

 

I really like the way my Firebird sounded with no exhaust after the cat....... very pleasant rumble. No, I didn't leave it that way. (much as I considered it....)

Only difference you will 'see' with different sized pipe, is the tone of the exhaust. (so, you won't really 'see' any difference, but, you would prolly hear it....) As far as power/torque goes though, I don't think there will be any difference at all.

 

The 2.5" pipe will be a little louder,or the exhaust note will be a little sharper sounding than the 3" pipe,because the noise will be compacted more.Also giving it more crack and pop when you let off the pedal.I would go with option 2,keeping the pipes the same size,keeping your truck in a better torque range than the 3" pipe....

 

I was thinking about keeping them the same size like that, but didn't know because how my exhaust was set up in the first place. It was a 2.5" pipe all the way from the cat until past the muffler, and then it turned into a 3" pipe all the way to the end.
So I didn't know if I should keep the same diameter pipes as before, but with the straight pipe (2.5"), or put a 3" straight pipe, so pretty much all the pipe past the cat is 3".

Hope that makes sense.

 

Also, if i want the sound to be more of a rumbling V8/diesel sound instead of the just plain loud car exhaust sound, would the smaller or larger diameter exhaust be better?

 

Anyone? Thanks to everyone who has helped me so far. Exhausts are one thing I don't know much about.

 

Not completely sure, but, I think the larger pipe translates to a deeper tone.

 

I have a 99 1500 5.9 and I have an open exhaust from the cat back. I'd say go with option number one. I continually get asked if my truck is a diesel because it "sounds" like one. It's loud, and yes, it pops and crackles but usually just on startup.

I personally don't think it sounds like one, but that's probably because my fiance owns one.