(approx) 2 Hours
Light to Moderate mechanical skill required.
Hey guys, Stephanie with AmericanMuscle.com here with my review of the Kooks shorty catted H-pipe available for Kooks long tube header equipped 2012 to 2013 Boss Mustangs. This one's pretty easy as far as who it's going to be for. This shorty H-pipe is going to be for the Boss Mustang owners that plan on using Kooks long tube headers and want to keep their side pipes. Whenever you go from a shorty or factory header setup to a long tube, you're going to need to change your midpipe to a shorty midpipe. There really aren't too many options out there when it comes to the Boss Mustang, but Kooks has you covered with this H-pipe. Long tubes and a shorty midpipe go hand in hand since you need one to install the other. Usually those installing long tubes are looking for power gains. Speaking of gains, let's break some numbers down first before we get into the midpipe here. We already ran a baseline run and got some numbers in the books. We're going to run the car again with the Kooks long tubes and Boss midpipe installed. We did pair these mods with a VMP X4 tune because you will need a tune when you switch over to running long tubes. A tune here will not only help you get everything out of these expensive mods, but one of the main purposes of the tune with long tubes is to turn off the rear O2 sensors so you won't be getting a check engine light. Our baseline run with the 2013 Boss gave us numbers of 398 horsepower and 337 foot-pounds of torque at the rear wheels. After installing the long tubes and midpipe and throwing the tune on the car, it made 417 horsepower and 353 foot-pounds of torque. That means a peak gain of 19 horsepower and 16 foot-pounds of torque, which are solid numbers considering the gains that you usually see from long tubes. Throughout the curve we're seeing gains of 23 horsepower at 6400 RPM which is what we expected to see, top end gains with the long tube headers. We also saw 26 foot-pounds of torque at 3500 RPM which is a nice torque jump in the lower RPMs. I always like to see low end torque gains because they're going to make a big difference in the driving experience. Overall, I'd say that these are solid curve gains that anyone should be happy with. These are on the higher end of numbers that people can expect from adding a catless long tube and midpipe setup. A lot of these gains are from the long tubes and the tune, not necessarily the midpipe, but you can't run long tubes without the midpipe. Now that we have the numbers out of the way, we can look more at the midpipe itself. We're looking at a three inch to two and three-quarter inch step down here to work with the Kooks headers. The H-pipe is mandrel bent 304 stainless steel as well. This is a catted H-pipe, like I just said. Normally an H-pipe's going to give more of a deeper sound as opposed to the raspier note of an X-pipe. We are talking about a Boss here. This midpipe does retain the side exhaust, so you'll still have that distinctive quad exhaust out back. The side pipes are unbaffled. The H crossover does create a deep note. The cats are high flow race cats so they're going to flow more than the factory cats would for sure. We're going to give you guys a sound clip in a minute so you can hear what this setup sounds like, so hang tight. This is a different kind of H-pipe that is catted. It's made by Kooks, which is one of the top quality contenders. We all know that if you want a quality product you're going to have to pay for it. This midpipe is no different. It's going to cost right around $750. I will point out that this is one of the only midpipe options that keeps the side pipes for the Boss. Keep in mind that catted midpipes or catted pieces of exhaust in general are going to cost more than an off road version will. Also, keep in mind that you won't be running this midpipe without a set of Kooks long tubes, so you can factor those into the price of this shorty H-pipe. These items go hand-in-hand since you can't install one without the other, which is another reason why long tube headers are an investment. With all of that said, the quality of the Kooks option is going to be top notch. I mean this in terms of materials, fabrication, fit, and performance. We are going to be installing this midpipe with a set of Kooks headers. I can speak more about the fitment and the install in a minute. We all know that Kooks has a solid reputation, and the proof is in the pudding. Just take a look at all the serious race cars that are running Kooks. You may not necessarily be installing long tubes and a shorty midpipe for sound, but you are going to get a huge change in sound. The long tubes alone are going to change the sound of your exhaust, and when you combine that with changing the midpipe you can expect a pretty big difference in sound here. You're looking at a brand new sounding pony when you're done. We did grab some sound clips so you can hear what the long tubes will sound like with both a factory catback as well as with an aftermarket catback, so take a listen.At the end of the day you're looking at both power and sound gains here. You saw the gains from the Dyno. Keep in mind those will change depending on your setup and tune, but you have a pretty good idea of what you can expect here. In addition to that, you're also going to get an awesome change to your exhaust tone.Install of the H-pipe alone is not difficult at all. It's just a basic midpipe swap that doesn't involve removing any other items or any cutting. Since you'll most likely be installing this along with the Kooks long tube headers, you can expect a project here. Because of the combo install you can expect a full three out of three wrenches on this one and a full day in the garage if you do decide to tackle this yourself. If you don't have a helping hand or you don't have much experience in this area, it might be better just to take the car to a shop for the install. If you do tackle this yourself, just know that you can do it on a jack and stands, but a lift will make it easier for sure. Like I said before, the midpipe is easy enough to install. The difficult part will be installing the headers. You're going to need your toolbox for the install along with an assortment of different sockets, wrenches and extensions. You're looking at things like disconnecting the steering shaft, removing the motor mounts, and dropping the cross member for the header portion of the install. A lot of this install obviously requires working in some pretty tight areas. While everything is straightforward, getting access and maneuverability in these areas is actually tricky. Having a helping hand in this case is really going to benefit you, but at the end of the day I think this is really worth it. As far as the midpipe, it comes in three pieces. You can start by loosely installing the cat portion of the pipe first. Disconnect the side pipe portion of the factory midpipe and install it on the Kooks H-pipe before you get it on the car. You can do this the other way around as well. Then it's just a matter of lining up the exhaust and tightening everything down and getting your O2s ready to go. To wrap this up here, the Kooks shorty H-pipe is going to be a must-have for anyone with a Boss Mustang that's looking at running Kooks long tube headers. It's a full length stainless steel H-pipe that comes with high flow race cats. It keeps the side exit exhaust for the Boss which makes for a very unique sound. As always, you guys can check this midpipe out some more online for yourself. I'm Stephanie, and for all things Mustang keep it right here at AmericanMuscle.com.
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Features, Description, Reviews, Q&A, Specs & Installation
Fitment: 2012 2013 Details
CA Residents: WARNING: Cancer and Reproductive Harm - www.P65Warnings.ca.gov
November 11, 2017
Kooks = Smiles
My car sounds amazing after installing this h-pipe along with Kooks' 1 3/4 long tubes. I paired this h-pipe up with QTP Boss 302 electronic cutouts and did run into fitment issues, but only on the passenger side (side pipe mounting point did not line up with the mounting hole in the chassis). Driver side fit perfectly. So I'm currently running without the side pipes installed. I don't believe the h-pipe is to blame for the issue. I think it may be a product of tolerance stack-ups in my particular combo along with addition of the electronic cutouts. One other note: I ended up removing the locking clips on the 4 bolts at the header collector to h-pipe joint as it cause false knock issues for me.Helpful (10)
June 10, 2017
boss sounds like a BOSS
After putting on the kooks long tube and H pipe it now sounds like the boss should have sounded from the factory. MEANHelpful (10)
September 09, 2014
Great Boss 302 Upgrade.....Kooks LT + Kooks Catted Boss H-Pipe
Great compliment for the Kooks LT. My Boss really sound different especially with my Track Key. Boss owners will definitely love this upgrade.Helpful (10)
August 17, 2012
This pipe coupled with the headers and unbaffled sidepipes make the Boss sound like a Boss. At times it sounds like a Ford Stockcar.Helpful (13)
Will this Kooks catted H pipe fit my 2011 Mustang GT now that have purchased a set of Kooks long tube headers . Haven't installed them yet but intend too soon. My stang has a Roush stage 3 supercharger on it now. Thanks for any helpful info ~
No, this will not fit GT models.
Fitment I'm curious why it states it only fits 2012-13 boss. If there is a 11-13 boss h-pipe with side exhaust, would this not fit a 2011 gt? Would it fit with long tube headers? I really want it!!!
This does fit the GT as long as you have the Long tube Headers I installed them on my 2011 GT with KOOKS Side pipes. Kooks makes side pipes that are the same shape as the NASCAR Nationwide series exhaust pipes and they are crazy Loud easily that loudest exhaust I have heard. You will get tickets with this set up..It is also too loud for some road coarses if you track your car, but its soo worth it lol and sounds so sweet at the Drag strip. Bad thing is the side pipes dont come with any hardware so a $10 trip to your local auto shop for some bushings; washers and bolts will do the trick. There is also a company called Quick Time Performance that makes electronic cut outs so you can turn them on and off with the flip of a switch or a remote from a key chain...and Yes I passed inspection with them turned off!!!!
Is this CARB legal?
The Kooks Catted H-Pipe has not been tested or approved by the California Air Resource Board (CARB) meaning this is not legal for use upon highway in the state of California.
Can this H-pipe work with other companies besides kooks?
This H-pipe is designed for use only with Kooks long tube headers. As far as exhaust, this is a turn-down setup where the piping goes from 3" to 2.75" to accommodate the stock or even other aftermarket exhaust systems.
Can I get this mid pipe without the step down to 2.5 inchs. Can I get this H pipe as a full 3 inch unit with no step down?
The Kooks GREEN Catted H-Pipe - 3 in. to 2.75 in. (11-14 GT w/ Long Tube Headers) is the only Kooks H-pipe we have to offer.
you should always use an aftermarket tune. installing the new headers will change the way the exhaust flows. without a tune your engine won't understand how to handle the new set up.
(approx) 2 Hours
Light to Moderate mechanical skill required.
What's in the Box
|Style Mid Pipe:||Shorty "H"||Type Headers Required:||Kooks Long Tube|
|Piping Material:||304 Stainless Steel||Piping Size:||3" to 2.75"|
|Catalytic Converter:||"Yes"||Fitment:||2012-2014 BOSS 302|
Fits 2012-2013 BOSS Mustangs Only!