So the time finally came and my catalytic converter and plenum now needs replacing. I figured while I'm at it why not replace the headers and y pipe as well. I've done some research but figure you guys could help as well. So far i'm interested in the the following below. I will then run the y pipe to a 3" thunderbolt highflown cat to a 3"- 2.5" pipe reducer. Are these the correct parts and am i missing anything? Also will this be a direct fit? So far as i know i will only have to cut some of the existing 2.5" pipe to for the cat to replace it, but i am not 100% positive on this.

 

http://www.carparts.com/details/Pace...4072C2213.html

I found the headers even cheaper here but when looking at the specs they show the collectors outlet being 2.5". Is this a typo or does pacesetter make two sizes? Any help would be appreciated because i'd like to have the truck up and running asap

 

Well, one of 'em is a typo......

Best bet is to call where you want to buy 'em from, and ask. So far as I know, I think there is only one version..... but, not like I haven't been wrong before.

What size inlets on the y pipe?

Things fit, but, rumor has it, they are a bit close to the front driveshaft on 4x4 models.

 

I called and after the most confusing conversation of my life they acknowledge that it was a typo. The y pipe inlet/outlet are both 3". I will then run it into a 3" cat and reduce it back down to 2.5" after, if this sounds okay? And as far as fitment I'm fine with it as long as it fits.

 

Why not just stick with 3" all the way back? Little bit better flow, and slightly deeper tone.

 

Funds are a bit tight. It'll cost me about the same for the shop to do these upgrades as it'll be for them to just replace the y pipe and cat with stock parts so i figured why not and i can go all 3" in the future.

 

So i have everything,just looking at pipe reducers now. Which would you guys recommend? One is a softer steel but has a smoother bend while the other is 409 stainless steel but the reduction is very sharp. Is the softer steel with a better transition worth the extra $10?


http://www.carparts.com/details/Univ.../D2241974.html

 

If you are going to have a muffler shop do the install, they should be able to make one for just a couple bucks.... (or even for free, with a piece of scrap pipe.)

 

You didn't indicate if the reverence is to a I6 cumins 5.2 or 5.9.
the only issue with jumping from having the OE config of 2.5>2.25 pipes to running 3" from head to tail, is there is likely to be a noticeable fuel consumption increase, ESPECIALLY in the 5.9's.
I have noticed they love their backpressure perhaps a bit too much. I went a bit overkill compared to the OE muffler when I replaced mine. I went from getting roughly 5MPG to the OE 13MPG prior. Sadly it no longer sounds like a truck or a V8 one, but it will light the tires without hesitation or much warning that you got in it too deep.

ANYWAY, If you don't mind hitting the pump more often then by all means run 3's as they will bring out the Magnums natural throatiness, and add some old school Bass and rumble to it's tone.

 

No. Back pressure is bad.

Keep you foot out of the pedal and you'll be able to drive past a gas stations.