So true duals....I've decided on the 18" Magnapacks sense I am going to be getting an Air Force 1 (AF1) CAI. I've read that 2.25" piping for true duals with an "x" helps torque. I just can't decide if I want 2.5" crush bent or 2.25" mandrel because I would have to order the mandrel piping from Mandrel Bending Solutions and I might not have a great fit. I am going stainless and putting money into this exhaust because I plan on having this one until I give the truck up. Crush bent 2.25" is an option too, any ideas?

 

2.25 mandrell will be better for you velocity pressure than 2.5" crush bent

 

Never get crush bent. Smooth and mandrel bent is the only healthy way to go. The 2.25" system sounds like the better way to go.

 

HIJACKED!

What's better, 2.25 mandrel pipes or 2.5 mandrel?

 

They say 2.25" for natural engines, 2.5" for performanced modified ones ( such as LTs, Supercharger.. )

 

Mandrel it is. should I get 2.5" going to the x pipe instead of 2.25 since it will be crush bent with 2.25 mandrel mid and tails?

 

why dont you justcut out the y pipe in the front and just go off of that. with 2.25" striaght pipe with the x pipe wherever, then more straight pipe and then the mufflers then have the 2 tial pipes that way you dont have to worry about crush bent pipes. its just an idea.

if theres something wrong with that i'd like to know

 

MIs read.

 

2.5" will sound better imo, wont perform as well until you mod up.

The axle prevents this type of set up from happening, and a damn near 100% straight system with no bends wont sound as good as a system with a few bends in it. Bends help with the deep note of sound.

 

no, i mean true duals with just straight piping off the factory pipes(without y pipe) up to the x, then pipe up to the mufflers then the tailpipes. sorry if i confused you there.

 

i understand that if you were to go all the way out with the pipe but he said he was going to get mandrel tailpipes didnt he?

 

yeah, i didn't understand what you meant. Thought you were meaning why not go with actual un-bent pipes to the back. Mandrel will perform the best since its its true size all around. My smooth bent system is almost as good as mandrel, its not crushed & crimped atleast.

 

...of course if performance is a factor at all you could go with a single 3" setup...

 

2.25"? Why? I'm almost positive stock is 2.5" so why go smaller? 3" is to big and allows for way too much back pressure without some kind of x/h pipe. I have 2.5" true duals on my 05 and it sounds great of course I have glasspacks too. Now the 05 has one bend where it's crushed since I didn't know about the mandrel websites but it still sounds great. My new 08 will have mandrel bends though.

 

Yes stock is 2.5" throughout, with the acception of a 2.75" tailpipe on '04+ trucks.

an all 3" single system would flow better than an all 2.5" single system would because its open enough to get the gases out, yet not too open to have a affect on velocity.

Going from a 2.5" single to 2.5" true dual system isn't very healthy for low end, but it is still decent. The scavenging is not high enough to achieve the full power a 3" system could. However, for true duals, 2.25" pipes scavenging are near equivalent to the low end of a 3" single system, but nothing will beat the 3" single systems performance for naturally aspired engines.