I've come to the decision that I am going to run duals with an X-pipe for sure but I haven't figured out some of the other variable yet. Mostly size. I am leaning towards 2.25 right now, but have a couple ?'s first. First, is the stock piping going to the Y 2.5? If so when would I want to bring it down to 2.25? right after the cats or right before the X? Would it be stupid to go down right after the X? (Maybe help promote scavenging with the pressure differential) I want the most torque possible and I want it as low as possible so that is why I am planning on the 2.25, but is there anyone that has run both 2,25 and 2.5's or has a decent basis for comparison?

 

the 2.5 will be a little deeper. the 2.25 will be more raspier but probably better for performance.

but the performance is so minimal its worth it to go 2.5, i mean its not a drag car.

and i wouldnt waste your money on the x. your not really gunna lose anything running straight true duals. and it sounds badass, its like the dueling banjos its so distinct and classic. dueling 4 cylinders

 

You will need the X... Dont let anyone talk you out of it. The unbalanced piping length of the left and right banks is very uneven, the passenger bank will be too strong.

You will want 2.25" right off the cats for excellent low end, and the same volume as 2.5". There is barely a difference between the two,m except the 2.5" is more open/hollow like sounding under WOT.

I have 2.5" duals and I can give you an honest answer. The performance regular driving was ok with stock wheels, got a little worse with 33s, and is awful at towing 4000+lbs.

 

what darren said-performance is minimal?lol on that one,true you are going from 2.5" to 2.25', BUT, they are staying 2.25",. not as stock where the 2.5 merge into a single 2.5 pipe.

 

i got 2"inch piping. bad idea. sounds bad *** with only precats though (:

 

I don't think you can be any more wrong.

Several member on this site have 2.5 inch pipes and regret it, and don't even get us started on not having a cross over. On these trucks, that would probably be one of the worst performing systems that could be created.

 

Thanks for the input guys. I really appreciate your honesty darren, not a lot of guys in any forum will ever admit a shortcoming of a decision that they made. So I am going to need to have the muffler shop reduce down to 2.25 which should be easy enough and they should be able to do that for cheap. The local shop doesn't do mandrel bends so would it be worth it for me to pay for the premade bends for them to cut and weld in? It would be 2 bends I'm thinking, one after the cat and the one right before the X. I wouldn't need any on the passenger side would I? Does anyone know if the spacing on the magnaflow x lines up with any of the magnaflow DI/DO mufflers (it would make sense)? I want to find out EXACTLY what I would need to figure out if I'm better off getting online and paying more for labor or buying from the shop and paying next to nothing for the labor. Also if I can tell him the part number for the muffler I'll know what I'm getting instead of finding out he ordered one with different spacing and needs more bends or whatever. When they know you know what they need to do, it usually saves you some money. I have decided for cost effectiveness I am just going to dump it as close to the axle as possible.

Sorry, that was a little long winded for the simple questions
1. Is it worth it to pay extra for mandrel bends
2. Should the passenger side need any bends
3. Is there a magnaflow DI/DO muffler that lines up with the X-pipe without any bends.

 

I never complained too much except for towing when I got my 2.5" system done. After my custom tune it helped unleash power the computer held back so that helped even more, then I got the 33s and the lag came back. Towing still sucks.

As for your questions, mandrel is best for 2.25". You'll want it smooth and un-restricted. I would avoid the DI/DO mufflers unless you call Magnaflow and verify the one you want does not have the internal X crossover. You only need the X pipe once, and it should be immediately right where the original Y pipe was. The most bends will be required at tailpipes. If you exit it before tire, there will be less to bend, but if you get annoyed of it later down the road you will want to run tailpipes over the axle.

 

I have stock tire sizes and 2.5" with X pipe. I pull quite often, and DO NOT regret my 2.5" decision. It pulls just fine. I also have cats removed and tuned, not sure how much of a difference that makes though.

My suggestion for you is...
2.25" with X pipe, and a straight threw muffler!

 

Is there enough space to mount two mufflers vertically next to eachother without a bend before them after the X. What is the center spacing on the magnaflow 2.25" X pipe?

 

^ I'm not sure what your asking, but there is plenty of room.

 

Yes as Av said, turn them sideways so they are perpendicular, plenty of room.

 

Point is the performance loss is not a big deal. Its a truck not a race car, whats a couple horsepower matter.

The X is yall buying into crap you read online and everyone saying "awwww man you gotta have an x to balance it'll run like ****"

Thats just not true, the top end will actually be better with duals. The low end will be about the same or just a little worse.


I guess what Im trying to say is Im all about sound, I could careless about very minimal performance on my daily driver.

Thats why I like straight true dual 2.5 because in the sound department it wins IMO.

 

I'm sorry, I missed when you got to decide what a "big deal" was for MY truck. I was asking the others if I should use 2.25 or 2.5 for my dual setup. I VERY MUCH care if I lose power on my truck and its a hell of a lot more important on my truck than it would be on a weekend toy. If I need to pass with a full load, I don't want to pull out to try and pass and then have to think "damn I wish I had listened to the helpful info from people who actually knew what they were talking about." This isn't a chevy site and these aren't SBC motors that we are talking about. I think I will listen to the guys with the same truck/motor as me.

 

well man i order a di/do muffler, tru x pipe, and 2 high flow cats from magnaflow all are 2.5 inch. Also got some jba shorty headers. My truck is a 04 newer body style with the 4.6. Im hoping it will improve it greatly. Ill let you know when they finally come in lol I wonder could i use 2.25 piping for them?