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Pypes Off-Road X-pipe (99-04 GT)

AmericanMuscle no longer carries the Pypes Off-Road X-pipe (99-04 GT). Please check out 1999-2004 Mustang Stock Length X-Pipes for an updated selection.

Features, Video & Details

  • Balance Out Exhaust Gases for More Power
  • Raspy Race Car Growl
  • Pypes Modular Construction
  • For Off-Road Track Use
  • 2.5" 409 Stainless Steel Tubing
  • Fits 1999-2004 GT Mustangs

Review & Installation Video

Review & Install Video

Hey everyone, I’m Justin with AmericanMuscle.com and this is our power pack bolt on build up series, for all 99-04 Mustang GTs. With this power pack, we’ve put together some products that we feel are great first time mods, that would give any 99-04 GT a serious boost in power. So we’re going to get a quick baseline run, then hand our GT over to the crew so they can get started installing our power pack. Hey what’s going on Mike? Mike: Hey man, nothing, just finished the installation of our mods and we’re about to make another Dyno run. Justin: Very nice, yeah it looks good under here, what you got installed under the hood? Mike: Well first we installed Airaid cold air intake kit that comes with a high flow reusable air filter, so you never have to replace it. The Airaid’s going to increase air flow for the engine and allow it to breathe better and make more horsepower and it’s also going to help on fuel efficiency. Justin: Yeah, if you can stay off the pedal, right? Mike: Yeah. Justin: I see we’ve also got the BBK installed, what’s up with that? Mike: This is the one piece throttle intake, that features the throttle body and the plenum, that way you can have a bigger throttle body and not worry about restricting the air flow with a factory plenum. Justin: Mike, I know with this generation and these mods, we shouldn’t really need a tune right? Mike: Right, we don’t require a tune, but we are going to install a Bama performance custom tune, just to kind of tie everything together. Especially on our automatic, it’s going to help with our shift firmness, our shift points, and overall. Justin: That’s awesome, I know in conjunction with these mods we also have the Pypes off road X pipe going on, along with that Flowmaster American Thunder series Cat-Back as well, what kind of numbers are you expecting from all these mods? Mike: We should expect to see about 20-25 horsepower. Justin: Sounds good to me man, you ready to do another run? Mike: Absolutely, let’s do it. Justin: So our baseline run on our automatic 2000 GT gave us 222 horsepower and 260 ft/lbs of torque, with our powerpack installed, we made 249 horsepower, and 295 ft/lbs of torque, giving us a peak gain of 27 horsepower over our baseline numbers and gains of 35 horsepower and 54 ft/lbs of torque throughout the curve. So as you can see we’ve just finished off our second Dyno run and we’re definitely happy with the results, the best part is all these mods are installed easily in just a few hours using basic hand tools. Now let’s get our GT off the Dynojet and onto the streets, so we can hear that Flowmaster in action, and see what these mods did for our motor. Alright, now we’ve got our GT out of the shop and onto the streets and been able to put it through its paces a little bit, it’s easy to see why these bolt ons are such a popular first choice with so many Mustang owners out there, especially these 99-04’s. Those bolt ons really woke up our 2 valve motor, especially when paired with our Bama tune, which has really firmed up our shifts as well. So be sure to check out some of our other 99-04 bolt on build ups where we improve our handling, work on our acceleration, and dress up our GT a little bit.

Balances Exhaust Gases. Pypes Off Road X-Pipe is second to none when it comes to balancing out the gas pressures in your exhaust system. This Pypes off road x-pipe creates more power and torque than a traditional H-pipe. Why? Because the exiting exhaust pulses are merged at the "X", resulting in less exhaust back pressure for more power.

Race Car Growl. This free flowing Pypes x-pipe for the 1999 to 2004 GT's not only increases power, but it also adds a raspy, race car growl to the sound of your exhaust with its modern "X" crossover pipe design.

Modular Construction.   Pypes unique three piece modular construction makes it quick and easy to add or remove a catalytic converter to your exhaust system in just minutes depending on your driving needs.

Durable Stainless Steel Construction.   Pypes uses sturdy 16 gauge 409 stainless steel mandrel bent 2.5" tubing for improved flow and features welded reinforcement plates for additional strength.

Application. This Pypes Off-Road X-pipe is designed to be a direct bolt-on for the 1999 to 2004 4.6L V8 GT Mustangs with either aftermarket short tube headers or the factory manifolds installed. Intended for off-road, track use only, does not include catalytic converters.

Technical Note: 2004 model year Mustangs will require the use of 18" O2 sensor plug-in extender wires!

Fitment: 1999 2000 2001 2002 2003 2004 Details

MPN# XFM16

CA Residents: WARNING: Cancer and Reproductive Harm - www.P65Warnings.ca.gov

What's in the Box
Hardware included:
  • (2) 2.5" clamps
Installation Info
Tech Specs
Mid Pipe Specifications
Style Mid Pipe: Standard length "X" Type Headers Required: Shorty
Piping Material: 409 Stainless Steel Piping Size: 2.5"
Catalytic Converter: "No" - For off-road use only Fitment: 1999-2004 GT Mustangs
Will it fit my Mustang?

    Customer Photos (12) Submit Your Photo

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      Questions & Answers (29)

      5 Top Rated Questions

      Will my check engine light stay on if i use this X-pipe? If I was to use this pipe will It keep my check engine light on or will it stay off? And if it does stay on is there anything I can get to get it to go off?

      • Using this Off-Road X-pipe will cause your CEL to turn on due to removing your catalytic converters. You have two options to turn off the CEL, both of which I've attached below for you. You can purchase the MIL Eliminators, which sole purpose is to turn off the CEL caused by off-road mid-pipes. The other option is to get a custom tune for your Mustang. It will turn off the check engine light as well as improve the overall performance of this mid-pipe upgrade. It automatically enrolls you in our Free Tunes for Life Program so you can receive updated tunes when you do any future mods as well! Feel free to contact us with any further questions!

      Helpful (15)

      will this fit the slp loudmouth cat back exhaust?

      • The Pypes Off-Road X-pipe will fit with any aftermarket or stock catback, and will attach on the other end to stock exhaust manifolds, or to any aftermarket shorty header.

      Helpful (3)

      I currently have BBK long tube headers, to high flow cats, to a stock h-pipe(i believe it's stock), then straight out(no mufflers). All custom piping. Should I be able to have my exhaust guy weld this on with a little custom fab work??

      • Since your exhaust is custom and welded, we would be unable to determine if this would work or what modification may be required.

      Helpful (1)

      Will this x pipe fit around a auto trans?

      • These Pypes Off-Road X-pipe will fit both automatic and manual transmission applications.

      Helpful (1)

      Will this fit with my pypes longtube header?

      Post Your Question
      10 More Questions
      Can this X-pipe set up be used with BBK shorty headers? 1 answer
      Does it work with stock headers 1 answer
      I know this says "offroad use only," but let's be honest, people who use this on their daily, how loud is it? Can you even get by on the road or is it a total cop magnet? 1 answer
      Will this bolt up to the v6s BBK 1-5/8 in. Chrome Shorty Headers here on the site 1 answer
      I ordered this X pipe along with an SLP exhaust kit , and wondering later on I wanted to install long tube headers , will I able to do that or I would have to change my set up 1 answer
      i currently have mac pro dump 2.5 inch exhaust after my stock midpipe. will this fitt with dumps? 1 answer
      will this with with mac pro dumped exhaust? 1 answer
      Why won’t these fit on a bullitt? 1 answer
      Will this bolt right up to my borla catback ? Have an 03 5 speed 1 answer
      If i bought this then bought cats after how much do i need to cut to make it fit 1 answer

        Customer Reviews (100+) Write a Review

        Overall Rating 4.3

        out of 5 stars

        Installation Time:Afternoon

        Installation Cost:$100-$250

        • Loudness / Volume 4.666667 4.7
        • Exhaust Note 4.76 4.8
        • Fit & Finish 4.44 4.4
        • Bang For Your Buck 4.693333 4.7



        • 5/5

          Installation Time: Afternoon

          April 05, 2019

          Fits and sounds great

          I've had this part on another Mustang and is same great fit, sound, and quality. Americanmuscle no longer sells this part unfortunately...

          Josh

          Year: 2004 Submodel: GT

          Helpful (0)

        • 5/5

          Installation Time: Afternoon

          January 01, 2019

          A small fitment problem

          The passenger side pipe connected a little short and messed my exhaust tips up a small bit, but with new tips it will be just fine. Other than that, highly recommend for the price

          LisaH

          Year: 2000 Submodel: GT

          Helpful (2)

        • 5/5

          November 02, 2018

          very loud

          love this product! definitely made a difference in sound and i now sound like a beast shifting 3rd to 4th wooooo

          AngieV

          Year: 2001 Submodel: GT

          Helpful (3)

        • 5/5

          Installation Time: Less than 1 Hour

          October 31, 2018

          Perfect

          I love the way it sounds. Gives the car a mean race car sound. Paired with a slp loudmouth and comp stage 3 cams it sounds perfect.

          JeremyG

          Year: 2003 Submodel: GT

          Helpful (2)

        • 2/5

          Installation Time: Shop Install

          Installation Cost: $500-$1000

          October 23, 2018

          Get what you pay for

          Firstly, the fitment is an absolute pain. I was chasing leaks and check-engine lights for weeks after installing this, even with MIL eliminators for the rear O2 sensors. For some reason it also makes the exhaust hang super low to the point where I was scraping on speedbumps even at stock ride height. Then there's the sound. It's ok. It peaks at 2500RPM and honestly sounds kind of raspy. My exhaust system is stock other than Flowmaster Super 44 mufflers so this was a surprise. It's certainly louder than it was with only the muffler mod, but not by a ton. With just the mufflers and the x-pipe I won't get into any trouble on the street if I'm careful. My advice: If you're going to get this to put on a street car just accept that you're going to want to get some cats to go with it to make the smell go away and to make the car run right. It makes it quieter but it's worth it. With no cats my car would not idle right and would even stall out sometimes. When you get the cats installed, I also recommend you have the shop cut a section out of the x-pipe to raise it up. Without either of these supporting mods the x-pipe feels like an absolute mess. All in, this ordeal cost me the price of the X-pipe and $600 in various parts and labor, and over a month of being in and out of shops. If AM could simply tell us the info we need to know about running this product on the street that would be great, because lets be honest that's what most of us will be using it for. Beating around the bush calling this an "offroad" x-pipe does nothing but leave us in the dark about what we will actually need to make this product usable.

          Nick

          Year: 2000 Submodel: GT

          Helpful (2)

        • 5/5

          Installation Time: Less than 1 Hour

          August 31, 2018

          x pipes

          Fast shipping and in great shape!! thank you very much!

          Claire

          Year: 2004 Submodel: GT

          Helpful (2)

        • 5/5

          Installation Time: Afternoon

          August 15, 2018

          Great sound with stock mufflers!

          Wasn't sure how it would sound with stock mufflers but has a great sound! Install would have been quicker if it wasn't for not having went ahead and purchased the optional hardware for mid-pipe to cat-back(mine was seized to old mid pipe). Also instructions say to get 3/8-16x2 1/2 bolts and hardware but when I got home from purchasing these they were short by at least half an inch and small for both holes so I went ahead and got 7/16 by 3" and they were a lot better. Looking at Pypes Pype bomb cat back in the near future but for now I'm very impressed by the sound that these have when paired with stock mufflers.

          AaronS

          Year: 2004 Submodel: GT

          Helpful (4)

        • 5/5

          Installation Time: Less than 1 Hour

          August 13, 2018

          Bang for the buck

          My car had an xpipe on it that someone had put "converters" on.. and it droned so bad inside the car. This pypes xpipe is awesome.. super simple install and fit great. And the best part.. no more drone inside the car. Took less than an hour to install in my shop on a lift while replacing the entire exhaust.

          DanB

          Year: 1999 Submodel: GT

          Helpful (5)

        • 5/5

          Installation Time: Afternoon

          August 08, 2018

          Sounds amazing!!!

          Easy to install took about 2 hours after fighting with passenger side manifold for about an hour. Other then that it fit perfect

          BrianC

          Year: 2000 Submodel: GT

          Helpful (2)

        • 5/5

          Installation Time: Less than 1 Hour

          August 04, 2018

          X pipe

          Great product. Made sound much louder. Loved it. Very easy installation. Very quick shipping. Overall great product suggest anyone get it if they are looking for meaner sound n a growl

          JS

          Year: 2004 Submodel: GT

          Helpful (3)

        • 5/5

          Installation Time: Afternoon

          July 28, 2018

          Great Product

          Woke the sound of the car up between 25-3000 RPMS, and gave it a nice, raspy tone. Not a ton louder at idle, but when you get on it, it really shines.

          JacobG

          Year: 2003 Submodel: GT

          Helpful (3)

        • 4/5

          Installation Time: Less than 1 Hour

          July 21, 2018

          Great product

          Pretty simple install and fit was good but I also used stock cat back

          RicardoC

          Year: 2000 Submodel: GT

          Helpful (3)

        • 5/5

          Installation Time: Less than 1 Hour

          July 17, 2018

          Great!

          It went on easy and and a huge improvement on sound and etc. no problems just that the end of the X-pipe did not really fit flush with my mufflers. But other then that great!

          JG

          Year: 2003 Submodel: GT

          Helpful (3)

        • 5/5

          Installation Time: Full Day

          July 07, 2018

          Pypes

          It was great easy fit sounds awesome I recommend this product

          TravisS

          Year: 2001 Submodel: GT

          Helpful (2)

        • 5/5

          Installation Time: Afternoon

          June 23, 2018

          X pipe

          Amazing tone, easy install, decent improvement on throttle responsiveness. Nice and loud

          ColeS

          Year: 2001 Submodel: GT

          Helpful (3)

        • 4/5

          Installation Time: Afternoon

          June 18, 2018

          Amazing sound

          This x pipe is great and sounds very aggressive. The only thing i am dissapointed in is the fitment was a little off, you will need some longer bolts to connect the midpipe and a passenger header gasket. Other than that not too bad for the price.

          GriffinL

          Year: 2001 Submodel: GT

          Helpful (3)

        • 5/5

          Installation Time: Afternoon

          June 05, 2018

          great fit and finish

          would have taken less time to swap if my hands weren't to big to get the o2 censers plugged back in. over all good product

          TimothyN

          Year: 2003 Submodel: GT

          Helpful (4)

        • 5/5

          Installation Time: Afternoon

          May 25, 2018

          Sounds awesome

          Really wakes up the sounds of the 4.6 L. Super easy to install comes with all parts you need beside passenger side gasket. Loved this product highly recommend. Took a couple hours to install just make sure you have a swivel socket for the passenger side header. Also pick up a gasket on the website for passenger header.

          WhitneyC

          Year: 2003 Submodel: GT

          Helpful (5)

        • 5/5

          Installation Time: Shop Install

          May 16, 2018

          Sounds mean !!

          Bought SLP loudmouths 1 for my 04 Mustang GT. Was happy with the exhaust but i was looking for a meaner kind of growl and this gave it to me ! Sounds great.

          Stephen

          Year: 2004 Submodel: GT

          Helpful (4)

        • 4/5

          Installation Time: Afternoon

          April 26, 2018

          Great sound

          Was a pain putting in on the passenger side but worked out. Paired up with a SR performance cat back and has a great growl to it. Breathes much better.

          MichaelR

          Year: 2003 Submodel: GT

          Helpful (4)

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