03 Cobra exhaust upgrade HELP!!!!!!

[JMetro64]

I recently purchased a 2003 mustang cobra with a few mods, and would like to upgrade the exhaust. The car pulled 480rwhp and 470rwtq. it currently has a mac o/r h pipe and a 2.5" mac catback. I do need cats for i live in vermont and need them for our state inspection. There are 2 exhaust combinations i have been thinking of getting. Either Kooks 1 3/4" long tube headers with a kooks 3" catted X pipe, with a Mac 3" catback. Or SLP 1 3/4" long tubes headers with an SLP 2.5" catted X pipe, and a Mac 3" catback. i am not sure if i would lose torque from the 3" x pipe because of the decrease in back pressure. I am trying to get the most performance that i can out of an exhaust combo so if any of you mustang experts out there could give me some advice on my issue it would be greatly appreciated.
-James

 

[cobracide]

I'd stick with 2 1/2 and no headers unless you are going big power like 600+ hp. You need to define some goals other than just with cats. Loudness, type of sound you're looking for, ect. What mods are there now. There are lots of OTHER things you can do before headers. What is wrong with the exhaust you have now? Where do you want to go with the Cobra (goals, again)?

 

[JMetro64]

well i am planning on eventually getting a Kenne Bell 2.6, when i can afford to do so. i am aiming for around 700-750hp. i am just getting headers and exhaust so i can have atleast around 500 at the wheels until i can get the kenne bell. i want it to be very loud, but not so loud that i get sick of it. the exhaust it has on now can't get me an inspection sticker. they man i bought it from didnt need car inspections so he didnt need cats. i am just going for bang for your buck power for now until i can swap off my eaton. although it does have a stage 5 port.

 

[cobracide]

I think you will definately lose power on 3" exhaust now. With you end goal in sight, 3" may be the way to go. Some big hp guys need to jump in. What pulley/boost are you running now? 500 with a ported blower is typically possible without headers. I know you don't want to do things twice.

 

[SVTDom]

no headers, no 3".

2.5" catted x-pipe, and your 2.5" mac catback, unless your buying a new one.

 

[JMetro64]

i have a 2.8 upper pulley and i am running 15lbs of boost. it pulled 480rwhp on the dyno so its approx. making 560 crank hp.

 

[OrangeCobra2004]

I'm running 1 3/4 ARH Longtubes, 2.5 ARH Catted X and Borla Stingers. I love the sound!

 

[JMetro64]

those headers are very expensive. i was thinking now along the lines of BBK long tubes, and BBK catted X with a mac 3" catback. would the SLP shorty X pipe fit with a BBK long tube?

 

[Stalker27]

There are plenty guys on this site running 3" Mac that state they have not lost any low rpm tq due to the blower. If you are that concerned about losing tq just take it to get it re-tuned

 

[JMetro64]

i was thinking of BBK lt's SLP catted x and a mac 3" catback. would this setup fit together?

 

[JMetro64]

What catback do u think would be a louder? A Mac 3" catback or a Borla stinger catback?

 

[03cobra#694]

Stingers,the Mac`s are chambered.

 

[rwingate03]

I have Bassani header back. It not really loud but sounds clean and still has that nice "crackle" when you let the RPM's wind down. I would stick with 2 1/2. I dont know about on a cobra but i know when I went with big piping on my foxbody I lost backpressure and power in my lower RPM. I would think it would be the same on a cobra. I also would hold off on the headers. I think the would be a bit of overkill at this point.