New Exhaust
 

What should I expect from my new exhaust set up? Long tubes, No cats, X-pipe, and dual flows. Its 2.5 all the way back.. Or should I have gone with 3inch.. both dump down before diff.

around $800 which $400-$450 for headers, $100 per muffler, x pipe $70 plus install. This is a rough estimate but pretty close.

I dont know about the dual 2.5....
 

It seems like a little waste of money. From what I HEAR one 3 inch will outflow 2- 2.5inch and will save you a LOT of money. I am currently runnin one 3 inch and i love it! Noticed a lot on top end!
Derek

Well, let's think about that one second...

pi(r)^2 = pi(1.5)^2 = 7.06 sq inches for 3" pipe
pi(r)^2 = pi(1.25)^2 = 4.91 sq inches times 2 for duals = 9.82 sq inches

You would actually have more flow with dual 2.5's. If you're gonna mod your motor, a single 3" or dual 2.5" would be fine. I think if you already have a 3" catback, keep it and not worry about the dual 2.5 unless you want duals. I don't think it can really hurt you if it's modded.

And I agree with Virgils post, a single 3" will see a lot of top end. I noticed it when I put my JBA exhaust on my Yukon. It seemed to just run better overall and you can feel it pull a lot harder in the upper rpm range especially when you're on the highway passing people. Good luck with whatever you do!

Unless your going a stroker motor or forced induction, I wouldn't go true duals. I originally had them on my truck, took them off after I had the LT's installed and went to a single 3". Just switching from the 2.5" TD's to a single 3" I noticed a ton of re-gained low end power and torque. If I had to do it again, I would only go single 3"

Right now I have a single 3 inch.. Was just thinkin maybe I can get more out of it by goin to x-pipe with 2.5 dual. Im gonna be runnin this with my Nitrous set up.

flow doesn't increase linearly with diameter. because of fluid friction the exhaust against the tubing walls is almost stagnant with the very center flowing the fastest. a single larger pipe has a better surface area to volume ratio which means a larger flow of fast moving gas. take an example of an extreme case such as running (4) 3/4" exhaust pipes. just image how much friction there would be against all of the walls. :drive:

http://universe-review.ca/I13-23-laminar.jpg
heres a quick pic behind the idea. the lines represent velocity of the medium. the longer the line the faster the velocity. because velocity = 0 at the walls, a larger diameter pipe allows for high velocities in the center because its further away from the walls.

Yes this is correct! Listen to L33Z71.....he has a good point on that. Just get an offroad Y Pipe and run a single exhaust into a dual outlet muffler or run a resonator like the Lopudmouth and the Y it into dual tailpipes. Great sound....and you won't loose too much bottom end torque.

Stick with the single 3" on an N/A 4.8. Youll be shooting yourself in the foot if you dont.

I had on my 5.3L(new motor now, unsure how it will work with exhaust) LT headers, no cats, and a magnaflow round body(21" long) dumped before axle, 3" from headers back whole way.. I also noticed more top end vs my old stock diameter setup.

-Lurius