I have an 05 silverado 4.8 and I was looking to change my entire exhaust. My idea was to get coated pacesetter headers, the pacesetter ORY and mod it a little to fit some test pipes in, into a borla xr-1 muffler and exit in front of rear passenger tire in a dual corsa tip. My question is should I make the entire exhaust 3 inch or put a reducer in there somewhere to help with back pressure? I know the pacesetter lt collectors are 3 inch but I was just curious what everyone thought.

 

hmm, personally i would go with 2.5, but im curious what others suggest.

 

Single 3" or dual 2.5"

 

dual 2.5" is too big for a little 4.8. Do the math and you'll see that dual 2.25" has just a hair greater cross-sectional area than a single 3".

Personally, I think the primary size of the Pacesetters (@ 1-3/4") is too big for a 4.8, but lots of people go with them.

 

2.25" pipe wouldn't sound good IMO. Whats the point of doing an exhaust if it's not going to sound good. Dual 2.5" would be fine, the 4.8 doesn't make **** for torque down low anyways.

 

Obviously a good sound is subjective. My truck is dual 2.25" with a x-pipe, and I think it sounds damn good. Folks compliment it from time to time. And the point of doing the exhaust is for sound and performance. The goal is to try and balance both. You are right in that a 2.5" dual system would be deeper and likely sound better, but I'm not complaining about mine one bit.

And no, dual 2.5" will make a bad situation worse. You agree the 4.8 lacks low down torque, so why would you want to exacerbate the situation by slowing the exhaust gas velocity that much more?

 

Well I'd assume most people on this website are planning on doing more mods in the future. A stall converter fixes that problem and then some

 

let me be more specific be saying im doing a single muffler from the pacesetter offroad y pipe. sound is always key to an exhaust but i want it to perform better as well.

 

You got me there. Since mine's a stick shift, I always forget about that ol' stall converter that lets you flash right on by any lack of low-end. Good call.

 

Stock pipe is around 2.75". I would get rid of all the stock pipe and get someone to do a mandrel bent 3" exhaust system, or purchase one and install it yourself. A single 3" exhaust would sound great, and would perform just as good, especially with a good muffler.

Now the only problem is convincing the OP to spend $600+ on a quality converter + supporting mods and labor