03 Cobra exhaust upgrade HELP!!!!!!

Discussion in 'SVT Tech Forum' started by JMetro64, Aug 8, 2009.


  1. JMetro64

    JMetro64 New Member

    Joined:
    Aug 8, 2009
    Messages:
    1
    Likes Received:
    0
    Trophy Points:
    0
    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
     
    #1
  2. tag4car

    tag4car Member

    Joined:
    Nov 21, 2005
    Messages:
    412
    Likes Received:
    0
    Trophy Points:
    16
    Location:
    Birmingham AL
    if it helps YouTube - M4H00056 you could always have a set of high flow cats welded inline to the chamber
     
    #2
  3. VEE EIGHT

    VEE EIGHT New Member

    Joined:
    Apr 27, 2009
    Messages:
    89
    Likes Received:
    0
    Trophy Points:
    0
    Location:
    Texas
    You don't have to worry about backpressure when you're run a forced induction setup. FI totally eliminates the concept of backpressure.
     
    #3
  4. cronin49

    cronin49 Banned

    Joined:
    Aug 13, 2003
    Messages:
    442
    Likes Received:
    0
    Trophy Points:
    16
    Location:
    SC
    I know that the '03-'04 Cobra's were underated by Ford at 390 hp, but I would like to know where did you get all that hp from a couple simple mods?? 480 hp at the wheels??? That's nearly 560 hp at the motor. I don't think Ford underated them by 170 hp. Most stock Cobra's dyno at around 360-370 at the wheels, so they probably put out about 425 at the motor. No disrespect mister, but help me out here.
     
    #4
  5. joshjwc9

    joshjwc9 Active Member

    Joined:
    Jun 13, 2006
    Messages:
    1,105
    Likes Received:
    17
    Trophy Points:
    39
    Location:
    Palm Harbor, FL
    It might be pullied, we do not know, but I wouldn't jump to conclusions since he is only talking about exhaust, and not other engine mods.
     
    #5
  6. JMetro64

    JMetro64 New Member

    Joined:
    Aug 8, 2009
    Messages:
    1
    Likes Received:
    0
    Trophy Points:
    0
    it is not stock. i am not certain everything that has been done to it since i am currently in mass. and all the paper work is in a folder at my home in vt. but what i do know is it has a stage 5 port. 2.8 upper, 63lb injectors, mac o/r h pipe and mac catback. custom Sct tune, sct intake. it pulled 480hp at the wheels and 470tq at the wheels. all the work is done at quinton brothers motorsports in vermont.
     
    #6
  7. cronin49

    cronin49 Banned

    Joined:
    Aug 13, 2003
    Messages:
    442
    Likes Received:
    0
    Trophy Points:
    16
    Location:
    SC
    OK, sorry, that helps in explaining it.... you got yourself a beast my friend. She should run deep into the 11's. Either combo is fine, backpressure is a non issue when your blown.
     
    #7
  8. JMetro64

    JMetro64 New Member

    Joined:
    Aug 8, 2009
    Messages:
    1
    Likes Received:
    0
    Trophy Points:
    0
    do you know of any other exhaust combo that could possibly allow me to make more of a hp gain than the two combos i mentioned?
     
    #8
  9. COBRA90GT

    COBRA90GT Mod Dude

    Joined:
    Sep 22, 2001
    Messages:
    6,841
    Likes Received:
    0
    Trophy Points:
    87
    Location:
    HOCKEYTOWN ® , MI

    Don't take this the wrong way, but you're not going to experience any real significant horsepower differences between all of the other numerous aftermarket exhaust combinations that exist out there once you have replaced your factory exhaust system.

    Again, it's worth repeating - significant horsepower differences. You may see a 5 hp gain here with one brand or a 5 hp loss there with a different brand when comparing aftermarket exhaust vendors. Make sense?

    Once you replace the factory exhaust system, you have already yielded the biggest exhaust system horsepower gains (due to the restrictive factory exhaust system's smaller diamater piping, catalytic converters, mufflers, etc).

    However, there are a couple of factors that you could still play around with though (depends on your setup/car purpose, ie - strip only, race track car, etc):

    You can tweak the diameter of your exhaust plumbing (2.5" or 3" seem to be the popular choices) and the style of mufflers you run, ie - straight through (ex: Magnaflow, Bassani, etc) or chambered (ex: Flowmaster). Straight through mufflers are generally less restrictive.

    G'luck with your decision, but try to save yourself some grief and avoid making "chess out of checkers," so to speak. :cheers:
     
    #9
  10. JMetro64

    JMetro64 New Member

    Joined:
    Aug 8, 2009
    Messages:
    1
    Likes Received:
    0
    Trophy Points:
    0
    ya. price is also an issue. since i am only 19 years old i do not have too much money to spend especially with car payments. I am looking for a 3" catted X-pipe that would fit a 3" Mac catback and with the much cheaper hooker headers. Also How are Flowtech long tubes? i see them for only $299, there must be a reason for them being so cheap
     
    #10
  11. JMetro64

    JMetro64 New Member

    Joined:
    Aug 8, 2009
    Messages:
    1
    Likes Received:
    0
    Trophy Points:
    0
    i was thinking of BBK lt's SLP catted x and a mac 3" catback. would this setup fit together?
     
    #11
  12. peepeeskillz

    peepeeskillz New Member

    Joined:
    Mar 23, 2009
    Messages:
    171
    Likes Received:
    0
    Trophy Points:
    0
    Location:
    texas
    i dont think so i don't know about cobra exhaust but i know for a gt slp and bbk LT's and mid-pipes have different flanges
     
    #12
  13. JMetro64

    JMetro64 New Member

    Joined:
    Aug 8, 2009
    Messages:
    1
    Likes Received:
    0
    Trophy Points:
    0
    What catback do u think would be a louder? A Mac 3" catback or a Borla stinger catback?
     
    #13
  14. Nutty 5.o

    Nutty 5.o Founding Member

    Joined:
    Apr 17, 2000
    Messages:
    419
    Likes Received:
    0
    Trophy Points:
    0
    Location:
    SE PA
    The 3" MAC is louder. Stay away from the headers unless you go Whipple or Kenne Bell blower. The lt's will give you some power, but the car should be re-tuned and then you got more money to spend. Get yourself the cat pipe of your choice with the 3" Mac.
     
    #14

Share This Page