Next week, I plan to buy the exhaust components that I'll need for the exhaust system I plan to have installed in the near future. I plan on buying two 4"x18" stainless steel exhaust tips, and a Flowmaster 40 series delta flow. However, I had a question about the catalytic converters. I noticed my truck has two of them located within the y-pipe. I'm not sure if I want to replace them or not, but I had been planning purchasing a universal magnaflow catalytic converter from summitracing. I had one of those on my previous ram, and it did wonders for the performance and sound of the exhaust system. I'm just not sure what size inlets and outlets are on them though. They look to be either 2.25" or 2.50". If I buy two new catalytic converters, what inlet/outlet size should they be?

I plan to run all new piping from the y-pipe back; I was thinking run a 3" pipe. Then having a 3" inlet/2.5" dual out muffler. Does this sound like the right dimensions? Your help would be more than appreciated guys.

 

I am pretty sure that the cats on our trucks are already high flow and work fine. Buying new cats might be a waste of money, check the DIY and do a search for it I am almost postive I have read it. I plan on going true dual and I will be keeping the cats.

 

Leave the stock cats and forget the rustmaster mufflers and go with Magnaflows!!!!

 

First off, just leave the cats alone if you are doing a cat back system. They are already high flowing enough for your application. If you are doing all new pipe from the y-pipe back, you would probably be wise to consider putting in a new y-pipe. It is a big restriction in the stock exhaust system. Also, the pipe coming from the y-pipe running into the muffler should already be 3" pipe.

 

Yeah, what others have said but Ill just tell you how my system is. Ive got a catback system that goes from the y pipe to a DMH 3'' electric cutout. that then goes to a SI 3'' and DO 2.5'' Delta 40 Flowmaster to two 4*22'' tips. Hope that helps.

 

Where could I find a larger y-pipe for my truck? I just want to make sure I don't do anything that might mess with my warranty. I'm doubtful anybody would say anything as long as its not messing with the manifolds. If I got a larger y-pipe, your saying the cats are fine? I've always been pretty passionate about exhaust, and am not crazy about seeing anything stock in the system besides the manifolds.

 

Magnaflow makes some pretty good y-pipes. You can find them on Moe's, Jegs, Summit, etc. As far as the warranty, as long as you're not changing the cats, you're ok. If you're just changing the y-pipe and putting on a catback exhaust, it will void you're warranty on your exhaust from the y-pipe back, but that's it.

 

Autoanything has the y-pipe cheap.

 

So just buy the one that magnaflow makes? On my other truck, I ran a 3" pacesetter y-pipe with the pacesetter longtube headers, but that's probably not going to work with the manifold collectors. Can anybody direct me to the link of the y-pipe I should purchase? Will this replace the entire y-pipe, or just the part where the two pipes "mesh" together. Also, does anybody know what the dimensions of the stock catalytic converters are in case I do decide to replace them with magnaflow catalytic converters; such as inlet/outlet sizes + case dimensions.

It's probably going to increase the cost of parts and labor a little more by doing the y-pipe, but I'm not crazy about butting up a nice 3" system into a restrictive y-pipe. I'd do headers, but the company I'm warrantied with says it will void it.

 

So "Y" pipes are better for cat back and "X" pipes are better for true dual?