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Mishimoto Catted Downpipe (15-23 Mustang EcoBoost)

Item 390291
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      Video Review & Installation

      Hey guys, Stephanie with here with this Mishimoto downpipe that's available for all 2015 and up EcoBoost Mustangs. The Mishimoto downpipe is going to be for the EcoBoost owners who are looking for a stainless steel downpipe to replace the restrictive factory downpipe. This is a catted downpipe that allows for a factory or factory-like catback setup. The whole point of an aftermarket downpipe is to relieve some of the restriction around the turbo, because from factory it's pretty constricting. Opening up some of the air flow from the turbo can give some nice performance improvements. Basically when it comes to the turbo, if you're looking for performance, you're pretty much going to want air flow as unrestricted as possible so the turbo can spool quickly. The faster the turbo can spool, the more gains that you'll see. Taking a closer look at this downpipe here, it's a full three inch 304 stainless steel mandrel bent pipe with an optional step down. To break that down some, stainless steel is always going to be nice for exhaust components. You won't have to worry about corrosion with the Mishimoto downpipe. The idea behind mandrel bending is to get smoother exhaust flow. Smoother exhaust flow means more power and better performance. The step down is optional, which is great. If you run the adaptor, it's going to reduce the three inch down to a two and a quarter inch which leaves the option of keeping a stock catback or running an aftermarket two and a quarter inch one. Or, you can pair the downpipe with a three inch catback now or even down the road some. That means you can pick up the downpipe for some performance gains without having to purchase a complete new catback while you're at it unless you want to. Then you have some room to grow and the ability to upgrade in stages. A three inch downpipe is definitely going to be larger than the factory downpipe, which means that you are upgrading here. You're going to notice a difference when you compare the factory downpipe to this one here. This particular downpipe has a high flow cat, but if you're looking to get around that cat, Mishimoto does offer a downpipe that comes noncatted which is going to cost a little less than the catted version here which is typical to see in all exhausts. If you pick up the uncatted version of this downpipe then it's going to be even less restrictive than the catted version. Like I said, this is a high flow cat which means that it is more free flowing than the factory cat is. Even though the main idea behind an aftermarket downpipe is to help give the turbo unhindered air flow, swapping out your factory downpipe is also going to give you more sound, too, especially if you're running the uncatted version. You'll hear a lot more turbo noise and get more of that turbo four cylinder sound. Also, be sure to keep in mind that a computer tune will be required to run either the catted or the off road version of this downpipe, so it is going to be necessary to tune for this downpipe. Even if you are going with the catted version of any downpipe, it's always recommended to run a tune, especially if you want to be able to realize the full power potential behind upgrading your downpipe. Another nice thing about this downpipe is that it actually has the 302 bungs. This gives you room for the two O2 sensors and then another spot for a wide band as well which is always going to be a good idea when you start playing around with custom tunes and additional boost. This is a two piece design that comes with a floating two bolt flange, a slip joint connector, and a V band flange. It doesn't get any nicer than a good old V band. If you take a look here, you'll see that Mishimoto designed the downpipe to put the flex pipe in more of a horizontal position instead of a vertical one like some other brands do. What I've noticed with the downpipe offerings across all brands, at least at this point in time, is that generally speaking the higher end players like Kooks and CPE share the same ideas Mishimoto does here, while the less expensive options like BBK have the flex pipe vertically positioned. This is just a little food for thought. Pair that with the knowledge of the two three and it's firing order. When we look at price, the catted Mishimoto downpipe is pretty much right in the middle of the pack. It costs between $500 and $550 which is less expensive than Kooks, Stainless Works and CPE, but a little bit higher price than BBK. The offroad version is about $100 less. There are more options as far as brands with offroad downpipes. Mishimoto is still right around the middle of the pack there, too. When it comes to the install, luckily this isn't a bad one. You're probably looking at a few hours to get everything done. I'm going to call it a one out of three wrenches on the scale. This is obviously going to be easier to do on a lift, but of course you can get the job done using a jack and stands if you don't have access to one. You won't need anything out of the ordinary, just a few sockets, wrenches and a short extension. You're going to be removing the front and rear O2s for the install and swapping them over to the new downpipe. I'd just unclip and leave them in the factory downpipe and switch them after you get the old pipe out. This way you won't be twisting wires and it'll make for a faster install. You're going to be reusing the gasket from the turbo outlet, so don't forget to make sure to grab the factory downpipe gasket before installing the new downpipe, since sometimes the gasket can stick to the turbo. The third bung comes plugged, so if you're going to use it just remove the plug and put in your wideband sensor. If you're not ready for this yet, then just make sure that the plug is tight before you install the pipe. It's going to be easier to install the pipe in sections starting with the first section with the O2 sensors. Then, move on to the second section and insert the adapter, if you're going to use it, and through your reband on. The only other thing I'd say is to line the new downpipe up first before tightening everything down, but that's about it. So, only a few bolts and about two hours time for the install. Overall, the Mishimoto downpipe is a three inch stainless steel downpipe that can work with either a three inch catback or it can step down to work with a two and a quarter inch catback. You have a choice between either catted or noncatted depending on what you're looking for. Not only is this going to increase performance, but it's also going to open up some sound on the EcoBoost as well. You can check this out more online for yourself and see what you think. I'm Stephanie, and for all things Mustang keep it right here at

      Product Information

      Features, Description, Reviews, Q&A, Specs & Installation


      • Mishimoto Catted Down Pipe
      • Increases of 65 RWHP and 108 RWTQ with a Tune
      • Aggressive Exhaust Note
      • Free Flowing 3" Diameter Mandrel-Bent Tubing
      • 304 Stainless Steel Construction
      • High Flow Catalytic Converter
      • Additional O2 Bung - Ideal for Adding a Wideband Sensor
      • Includes 3" to 2.25" Step Down Adapter
      • A Tune is Not Required, but is Recommended
      • Intended For Off-Road, Track Use Only
      • Is NOT CARB Certified
      • Compatible with Factory or Aftermarket Cat-Back Systems
      • Fits 2015-2023 2.3L EcoBoost Mustangs


      More Power And Performance. Release all the hidden horse power and torque your Turbocharged 2.3L EcoBoost Mustang has to offer with a Mishimoto 3" Performance Catted Down Pipe. Mishitmoto has seen dyno proven power gains of 65 horse power and 108 foot pounds of torque at the rear wheels with a custom tune.

      More Aggressive Sound. A Mishimoto Down Pipe not only helps improve power and performance of your S550 EcoBoost Mustang, but it also adds a much more aggressive exhaust note when compared to the factory down pipe.

      Stainless Steel Construction. Manufactured from high quality 3" diameter 304 stainless steel tubing for superior strength and corrosion resistance, this Mishimoto Down Pipe features smooth mandrel bends throughout the entire piping to improve exhaust flow for more power and better performance.

      High Flow Cat. Mishimoto includes a high flowing catalytic converter that features a 200 cell spun metallic core that is specifically engineered for maximum flow and surface area, perfect for force inducted applications such as the turbocharged EcoBoost Mustang.

      Three O2 Bungs Built-in. Mishimoto designed their Down Pipe with three O2 bungs to accommodate the two stock O2 sensors as well as to give you the ability to easily add a wideband sensor if so desired.

      Required Upgrade. Although a custom tune is not required for this Down Pipe. To achieve maximum power potential this Down Pipe, it is recommended to reprogram the vehicles computer. AmericanMuscle recommends a custom tune with a Mustang Handheld Tuner to reprogram the vehicles computer (ECU) for proper operation.

      3" to 2.25" Adaptor Included. This Mishimoto Down Pipe can be installed onto an aftermarket 3" catback as well as the factory or an aftermarket 2.25" catback exhaust with the use of the included 3" to 2.25" step-down adapter. This adapter allows you to upgrade your EcoBoost Mustang in stages saving you money.

      Application. This Mishimoto Catted Down Pipe is designed to fit both automatic and manual 2015-2023 EcoBoost Mustang models equipped with the turbocharged 2.3L in-line 4-cylinder engine.

      Technical Note: This Mishimoto product is intended for off road use, and is not legal for use in emission restrictive states.




      Mishimoto MMDP-MUS4-15CAT

      CA Residents: WARNING: Cancer and Reproductive Harm -

      Installation & What's in the Box

      Installation Info

      What's in the Box

      • (1) 2-Piece Downpipe
      • (1) High-Flow Catalytic Converter
      • (1) 3.0" Slip Joint Clamp
      • (1) 3.0" V-Band Clamp
      • (1) 3.0" to 2.25" Exhaust Adapter

      Tech Specs

      Down Pipe Specifications
      Piping Material:304 Stainless SteelPiping Size:3" (includes 2.25" step down adapter)
      Catalytic Converter:"Yes" - Intended for off-road use onlyType Cat-Back Required:Stock, 2.25" or 3" aftermarket 
      Tune Required YesFitment:2015-2021 EcoBoost

      Customer Reviews (36)

        Questions & Answers

        10 More Questions

        Will It Fit My Mustang

        • EcoBoost - 15, 16, 17, 18, 19, 20, 21, 22, 23
        • GT - 23
        • Mach 1 - 23

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