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Straight Pipe Aluminized Cat-to-Axle H-Pipe Kit (11-14 GT)

AmericanMuscle no longer carries the Straight Pipe Aluminized Cat-to-Axle H-Pipe Kit (11-14 GT). Please check out 2010-2014 Mustang H-Pipes for an updated selection.

Features & Details

  • Improves Exhaust Flow for More Power
  • Muscle Car Rumble
  • Aluminized Steel Construction
  • Clamp-On Design
  • Reuses Stock Catalytic Converters
  • Uses O.E. or Aftermarket Axle-Back
  • Fits 2011-2014 GT Mustangs
Better Flow, More Power. Ford actually did a decent job on the Mustangs catalytic converters, but the factory piping can be restrictive. That's where the Heartthrob Straight Pipe Cat-to-Axle H-Pipe Kit comes into play. Featuring a H crossover and 3" free-flowing mandrel-bent piping, this Heartthrob Mid Pipe will dramatically improve exhaust flow for more power and sound that you can feel.

Muscle Car Rumble. This free flowing Heartthrob Cat-to-Axle H-Pipe Kit for the 2011-2013+ GT Mustang's not only increases power, but it also adds a deep muscle car rumble to the sound of your exhaust with its classic "H" crossover pipe design.

Reuses Stock Cats. The installation of the Heartthrob Exhaust cat to axle system requires removing the stock exhaust piping from the catalytic converters back to the axle-back, and reuses the factory catalytic converters saving you money. Clamps and instructions are provided.

Versatile Design. The unique design of the Heartthrob Cat-to-Axle exhaust kit allows you to install the axle-back of your choice. You can keep the factory mufflers for a mild sound or go with a set of muffler deletes for a wild sound. The choice is up to you.

Durable Construction. Heartthrob uses free-flowing 3" diameter CNC mandrel bent aluminized tubing with a H style crossover and a high flow straight pipe design to improve exhaust flow to provide a significant increase in power and sound.

Application. This Heartthrob Straight Pipe H-Pipe Kit is designed to fit the 2011-2014 GT Mustangs with either the factory exhaust manifolds or aftermarket shorty style headers installed.

Fitment: 2011 2012 2013 2014 Details

CA Residents: WARNING: Cancer and Reproductive Harm -

What's in the Box
  • (1) H-pipe
  • (2) Over axle pipes
Installation Info
Tech Specs
Mid Pipe Specifications
Style Mid Pipe: "H" Type Headers Required: Shorty or Stock Manifolds
Piping Material: Aluminized Steel Piping Size: 3"
Catalytic Converter: Reuses stock Catalytic Converters Fitment: 2011-2014 GT Mustangs
Will it fit my Mustang?

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        Customer Reviews (14) Write a Review

        Overall Rating 3.7

        out of 5 stars

        Installation Time:Full Day

        Installation Cost:$100-$250

        • Loudness / Volume 4.461538 4.5
        • Exhaust Note 4.230769 4.2
        • Fit & Finish 2.153846 2.2
        • Bang For Your Buck 3.538461 3.5

        • 1/5

          Installation Time: Less than 1 Hour

          February 19, 2019

          Terrible fitment.

          Decided to give this system a try knowing that there were already some mixed reviews. Install was done on a 2 post lift with a buddy helping me, after about 4 hours of wrestling and reinstalling we finally gave up and put back the original exhaust. Everything was fine except the ota extensions, its as if they were made to long. No matter how hard you beat the pipes into one another they would still hit under the car. We gave it the best shot we could but just would not work. AM was totally understanding and let me return the system with no questions asked.


          Year: 2012 Submodel: GT

          Helpful (0)

        • 4/5

          Installation Time: Full Day

          November 01, 2018

          Worth the noise but take to muffler shop

          I bought these expecting it to be an easy install because exhaust work is pretty basic if you ask me, but I ended up under my car for about 8 hours trying to get it into place with a friend of mine who knows welding pretty well. Turns out the pipes were to long and the S pipe was to long as well to fit with the Roush mufflers i have. Him and I gave up at 3 in the morning and i took it to a muffler shop where they did custom work cutting the pipes and welding them on. Overall the exhaust is worth it my car is the loudest thing around for blocks, it has a really nice rumble to it as well i just wasnt happy trying to do the install. YOU NEED A LIFT TO DO THIS AS WELL WELDING THE PIPES!!! Totally worth the product but install different story


          Year: 2012 Submodel: GT

          Helpful (1)

        • 5/5

          Installation Time: Less than 1 Hour

          May 07, 2017

          The thunder

          Fit,finish,performance and sound is great with this product.


          Year: 2012 Submodel: GT

          Helpful (6)

        • 4/5

          Installation Time: Afternoon

          October 01, 2013

          Works well for the money.

          I went with the H kit for 3 reasons: The X went off of clearance HeartThrob claims more power with the H than the X I prefer rumble to scream NOTE: As I found other places online, I needed to cut almost 2 inches off of the H section to make it fit. Other than that, the kit fits pretty well, but I do get the occasional bump from the exhaust over dips in the road. Possibly install error. I managed to install this in a garage using 2 regular Jacks stands and 2 tall jack stands. I had just enough clearance to pull the old exhaust without cutting. Install would have taken about 2 hours if I would have been able to figure out how to remove the clamps from the stock cats. I still haven't figured out how everyone else does it... The bolts are up toward the body with essentially no access for any type of wrench. Eventually, in a 2 person effort with vise grips on the bottom of the bolt and a slim ratchet on the top, we got them off. Install was much easier and I finished it in under 45 minutes time. Recommendation: start from the mufflers and work forward. If you try to do the mufflers or H to axle after everything else is connected, it's a pain. Sound: the car is definitely louder. I have a pair of Dynomax axle backs and it sounds very good. The car is dead silent at a cruise at any speed. On throttle, the noise is good and present, but not quite as loud as I'd like. I had my friend drive it around for me on an autocross course. The car sounds great from behind, but is very quiet from the front or side. The note is just about perfect. NO RHASP! My only issues is that it seems like the seams aren't perfect or the clamps aren't tight enough... I hear a little exhaust leakage. I'll get back under the car in a few weeks to clamp everything down some more.


          Year: 2011 Submodel: GT Indianapolis, IN, USA

          Helpful (8)

        • 4/5

          Installation Time: Afternoon

          September 25, 2013

          Overall good product

          I have a 2012 Roush Stage 1 5.0. I already have the Roush square tip axle back on as well. Sound wise it's great!! I didn't want to touch the cats yet but I wanted a better sound out of my exhaust. This is perfect. Awesome low end rumble when cruising and driving around town and when I really get on it she screams!! Fit and finish could have been better. Not awful by any means but do yourself a favor and take it to a well known exhaust shop unless your pretty handy. The job isn hard but the fit isn't great so some custom work was needed. However for the clearance price this was a great buy!!


          Year: 2012 Submodel: Other Chicago, IL

          Helpful (4)

        • 5/5

          Installation Time: Weekend

          June 03, 2013

          Gained 20+ RWHP and 25 ft-lbs of torque (tuned).

          Short story: I installed the exhaust by myself with no help using car ramps in front and jack stands in the rear. It was a long and tedious process to get the stock exhaust out without cutting and to get the new pipes to fit and line up just right. With my Flowmaster American Thunder exhaust, the sound is great and not overbearing. You can definitely feel the power. I had the car re-tuned by Bama Tuning and did not add any other modifications. On the same dyno as last year, the results area gain of 20 RWHP and 25 ft-lbs of torque! At 93 degrees, the temperature was 20-30 degrees warmer than when I last ran, so the results could possibly be even more. Long story: Without a lift, trying to get out the stock exhaust without cutting is a waste of time. It took me hours of changing the height of my car and repositioning my jack stands to get the s-pipes out. By removing my rear springs and shocks, I was just barely able to remove the stock exhaust without cutting it. Once I had everything loosely installed, I realized at the pipes were hanging very low and I had to rotate the pipes that connect the H-pipe to the cats using a pipe wrench and a 3 pound mallet - I was determined not to take anything apart. After I got the exhaust tight to the body, I had difficulty trying to get the pipes to go in as far as they could into their sleeves - it was causing the axle to bump into the exhaust. Pounding on the parts with a rubber mallet didn't work and I ended up putting some dents into the piping from hitting so hard. I was able to solve the problem by wrapping a tow rope around the pipes and attaching them to a come along. Using my truck as an anchor, I pulled everything forward 5/8" (pulled from two different points, each about 5/16") which was just enough to clear the axle. My next problem was that the S pipe kept banging into the underside of my car on hard bumps. I solved this by taking 2 3/4" thick rubber blocks and shoving them between my exhaust and the bottom of the car and held them in with metal screws. Even with all the trial and error, the outcome is great. The extra power and torque are very good for the price paid and the sound is amazing. It has been said by various people that the sound is just right when combined with my Flowmaster American Thunder mufflers. You can keep a conversation at a relatively normal volume and you don't have to be blasting your music to hear it over the exhaust. If you are looking for a good modification to get you more power and you have a good mechanical ability, get this. Drive by video here:


          Year: 2011 Submodel: GT New Jersey, USA

          Helpful (6)

        • 5/5

          Installation Time: Shop Install

          Installation Cost: $100-$250

          November 29, 2012


          Had this installed at a local shop for $120. They had to weld due to exhaust leak. I have Pypes pipe bomb along with this set up. Sounds awesome. It has that deep throaty sound and then SCREAMS when you get on it.


          Year: 2011 Submodel: GT Washington state

          Helpful (5)

        • 3/5

          Installation Time: Full Day

          August 21, 2012

          Still Issues with this Kit

          I've bought several Heartthrob exhausts in the past and had no problems with them. I understand they're a budget kit and I did not expect the quality/fit/finish of a $1000 exhaust system. However, this kit is really bad. -The H pipe had pinholes in the welds that I had to reweld -The S-Pipes had incomplete ball flange forms that would not seal even installing the S-pipes by themselves and creeping up on overtorquing the specs until the pipes themselves deformed and made the leak worse. I had to bring them to a muffler shop to reform the ends. -The H-pipe is STILL too long, something noted in October 2011. I had to take 1.3" out with a cutoff saw to get the exhaust system to go together. -They cut the pipes to length while full of oil, so be prepared to spend a lot of time with rags and poles to clean the tubes of chips and debris before you even think of putting things together. I talked to Mike at Heartthrob and he offered to send me a replacement H-pipe and S-pipes, but I had already done what I had to to get the kit on the car over the weekend. I was told he would look at the kit fitment on a car. If you buy this kit, be prepared to make cuts and take a few trips to your local muffler shop. A buddy who can weld is a good precaution, too.


          Year: 2012 Submodel: GT Connecticut

          Helpful (5)

        • 2/5

          Installation Time: Shop Install

          March 26, 2012

          Heartthrob Heartache

          The Heartthrob system did infact improve the exhaust flow, with a power bump I could feel. The sound was also louder. Unfortunatly there are so many other negatives with this kit that if I had to do it again I would go with another product. The welds were of poor quality and rusty. The system is about 2" too long and will have to be cut. This is NOT a true bolt on system. I'm not the only one who had issues, it was not an isolated case. Leaks at the cat side flanges. Again others have had the same problem, but it's not to hard to fix. If you use this with an axle back like the Roush it will me much louder and raspy. Not a good sound I had to add some resonators to try and tone it down. In the end I had to spend an extra 300 on top of the kit cost just to get it right (200 for aero resonators) and a good portion of my day with the car at the shop. With this kit the old saying "you get what you pay for" rings true, there is a reason it's cheaply priced. Too bad as it has potential to be a bang for the buck bargan with a few changes. Untill then I suggest you look for a higher quality product.


          Year: 2012 Submodel: GT

          Helpful (9)

          • Response from AmericanMuscle

            Heartthrob does offer another kit similar to this one called the Flowpack Cat-to-Axle H-pipe Kit, SKU 53803, that it a mid-muffler design, which may have helped tone down the loudness with your Roush Axle-back. I'm sorry you were unhappy with the sound after installing prior to adding the resonators. I am forwarding all this feedback to Heartthrob R&D as we speak to ensure they produce the highest quality systems they can. Thank you for sharing your experience with us and hope you're enjoying your new performance gains!

            Lisa, Content Specialist

        • 4/5

          Installation Time: Afternoon

          March 15, 2012

          Sounds great!!

          Tight fit had to do a little tweeking to get it to fit right. But great sound and great performance. I'm running Flowmaster axle backs on a Super charged 5.0.


          Year: 2012 Submodel: GT Kyle tx

          Helpful (5)

        • 5/5

          Installation Time: Afternoon

          January 06, 2012

          Great sound

          This system lets you feel the noise, just just hear it, underneath the floor boards. If you don't want that, this isn't for you. Took a lot of adjusting and work the the coaxing tool (rubber mallet) but not too bad of an install overall. Combined the Flowmaster American Thunder.


          Year: 2012 Submodel: GT Indiana

          Helpful (5)

        • 1/5

          Installation Time: Afternoon

          December 07, 2011

          Save your money and buy a quality system

          Fit & finish was very poor, just skip it and save up for a higher quality system.


          Year: 2012 Submodel: GT Louisiana

          Helpful (9)

        • 4/5

          Installation Time: Afternoon

          October 18, 2011

          Big difference!!

          I added this to MRT's Interceptor axleback which I had installed about 1 month prior. I've done plenty of exhaust on late model mustangs but I can honestly say this was one gave the most trouble. Hearthrob's info says it will work with the stock or it's own axle back. After trying to rearrange the pipes for about 2 hours I finally just cut almost 2" from the back of the H-pipe which worked great with plenty of clearance. Maybe using this kit with the MRT axleback makes a difference in which case it's not the kit's fault but either ways its on now. That said it sounds great!! A big difference over just the axleback, fuller and smoother sounding in a way, and also a bit louder. Can't say much about power because I did this install with an SCT custom tune and a drop in K&N at the same time. The car rocks out now, just don't know how much I can attribute to just the exhaust. Thanks!


          Year: 2012 Submodel: GT MD

          Helpful (7)

        • 5/5

          July 05, 2011

          heartthrob straight pipe cat to axle h-pipe kit

          I put this kit on my 2012 mustang gt. the sound is amazing. I also added the flowmaster american thunder axleback mufflers. This combination sounds awesome. I highly recommend it. The install was fairly easy. The only trouble i had was removing the stock exhaust where it goes overtop the axle. Highly recommend for you to use a lift, or have a muffler shop install it. I jacked my car up and could not get the pipes that go over the axle off. Ended up having to cut the exhaust off.


          Year: 2012 Submodel: GT

          Helpful (4)

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