Is there a big difference in a 2-14" pipe and a 3" pipe for a catback exhaust? I am getting a catback put on this weekend and I am trying to decide what pipe size to go with. I will use a magnaflow muffler with a 4" double walled polished stainless tip.

 

i think 3" is too big

 

There is a big difference. It all depends on what mods you have already. Your probably not going to need a 3" pipe unless you are using forced induction (turbo). The reason is because you need some back pressure. The 2" 1/4 should be enough. The pipe will give you more power but wont sacrafice much back pressure.

 

stick with the 2.25" because if your not running a turbo you're going to just lose a lot of torque with 3" piping.. hell most turbo owners still use 2.25/2.5".. so that's the best way to go in my opinion..

 

2.25 is best for N/A or Turbo

 

Cool, thanks everyone for your help. I think I am going to go with the 2.25" pipe. Does regular pipe bending and mandrel bent pipe make a difference as well?

 

Yes, Mandrel bent tubing is the same width through out the entire piping. Pressure bent piping gets smaller around the bends. However, mandrel bending is very expensive and the machines to do it cost a quarter of a million $$, so dont expect a local shop to have it.

The main difference is that since pressure bent tubing shrinks, you actually get a smaller tube than 2.25, maybe 2.00" around the bends, so you get less air flow. Mandrel bent tubing doesnt shrink, so there is no decrease in air flow.

Go here to find out more: http://www.rogueengineering.com/Merc...gory_Code=BEND

Here's a prime example...

 

Cool, that site helped a lot.

 

what kind of exhaust are you getting anyways?

 

I am getting the Magnaflow muffler with a 3-1/2" or 4" double walled polished steel tip. I think I am going to go with the shop that quoted me $292. I think I can talk him down some since another shop said they would do it for $240.

 

Will thay pressure bending really make a difference? No one here locally can mandrel bend, so should I go with a 2.5" pipe so when bent, is more like 2.25"?

 

i went with the 2.5 when i got mine pressure bent
you can go to a speed shop and buy 2.25 inch mandrel u bends and have the muffler shop cut the bends out of it id say you might need about 2

 

Good idea, though I am not quite sure what you mean by "speed shop". Do you have any specific names of places?

 

like a store that seels stuff for your car not like pep boys or auto zone, like a road race motor sports or something along those lines
i belive road race engineering has some mandrel bends under there DIY part index

 

JCwhitney also has mandrel bends.... you can buy a couple online for pretty decent prices.