Enhancing The Modern Mustang GT Soundtrack With JBA Exhaust

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Since the advent of hot rodding, upgrading the exhaust system of a new vehicle has been a nearly obligatory alteration. It’s one of the easiest, most gratifying ways to modify an otherwise factory stock car for improved performance, and a more authoritative engine note.

While this was a pretty straightforward proposition back in the day—bolting on freer-flowing exhaust parts to get more power and additional sound to your ride—the situation is a bit trickier with modern hardware. Not only are the OEMs getting better at dialing in their factory-installed systems to provide maximum efficiency, it can be tough to modify your car’s exhaust system without running afoul of the law–particularly in California.


The sixth-generation Mustang offers great performance right off the showroom floor, but most enthusiasts will agree that the factory exhaust system lacks some personality. Roger and Martha Baker are among that contingent, so they’re upgrading their 2016 GT with a set of emissions-compliant Shorty headers and a cat-back exhaust system. Along with a more aggressive exhaust note, they should see more horsepower and torque, improved fuel economy, and a better throttle response–all while staying compliant with the smog laws in all 50 states.

Here in SoCal, the California Air Resource Board regulates which aftermarket parts can be used with modern vehicles while remaining compliant with the state’s smog laws. CARB compliance is required when bolting on aftermarket parts to vehicles that require smog checks. Without it, not only are you polluting the environment; you won’t be able to smog (and thus register) your car in this state.

JBA Performance Exhaust is one of the few exhaust companies that has worked closely with CARB to ensure various parts that they offer work within the guidelines set by regulators. “One of the things that we’ve done really well is work directly with the California Air Resource Board to gain compliance on our JBA components all the way up to our 2017 units,” Greg Raymond of JBA told us at this year’s SEMA show. “We’re one of the only manufacturers that has CARB E.O. numbers that go that far up, and that’s included on the ’15-plus Mustang GT, the ’17 Camaro, the latest Dodge cars, and Toyotas.”

Before even turning over the motor, some of the benefits of JBA's Shorty headers and cat-back exhaust system are obvious. Also available in silver and titanium finishes, the ceramic coating on these shorty headers not only keeps them looking good in the engine bay, it also keeps the under-hood temperatures down. The tips of the JBA cat-back are double-walled stainless steel, which means they'll look great for the lifetime of the car.

With that in mind, we’re taking Roger and Martha Baker’s otherwise factory stock, automatic equipped 2016 Mustang GT to the next level in terms of both performance and sound with JBA’s Silver Ceramic Cat4ward Shorty headers (PN 6689SJS), as well as a 3-inch, dual-rear-exit, stainless steel exhaust system (PN 40-2646).

CARB Approved Performance

When it comes to developing headers for modern vehicles, aftermarket companies have their work cut out for them within the tight confines of modern engine bays. Designing around emissions regulations (when applicable) further complicates the situation. “When we decide to design an emissions-legal header, we are constrained by the configuration of the placement of the catalytic converter as it is originally positioned by the manufacturer,” Don Lindfors, of JBA Performance Exhaust, explained.

While installation of the cat-back system is pretty straightforward and can easily be done in a home garage, JBA recommends a lift for the installation of the headers—as it's a significantly more involved operation. You'll be removing the stock manifolds and installing the headers from underneath the car, and you'll need to be able to lift the motor up within the chassis using a tall screw jack in order to provide enough clearance to make the swap.

An engine is an air pump. If you increase the flow into the motor with, say a better intake, larger cam, or forced induction, then naturally, you need to increase the flow potential on the exhaust side as well.—Don Lindfors, JBA Performance Exhaust

“We cannot move that position at all. Other emissions components that are attached to the exhaust manifold, if any, like EGR valves or AIR Injection have to be taken into account as well. On top of that the available room within the engine compartment is usually quite restricted as well. Taking all that into account, we then have to figure out how we can best fit four tubes, with as much length as possible and a collector within those parameters. On top of that, tube diameter plays a role in whether or not the new header increases emissions (which is not allowed) and still allows for an increase in power. Some of this comes from previous experience and some from testing different designs,” Don said.

Because of those constraints, many companies opt to simply not design their parts for compliance, offering them for off-road and competition use only. But in states where modern vehicles must conform to emissions laws, using these non-compliant parts on street-driven cars is not only illegal; it creates a hassle for owners who will need to regularly swap out exhaust parts when it comes time to smog their cars if they want to continue being able to register their shady whips.


A look at the visual differences between the JBA cat-back exhaust (foreground) and the stock system. Aside from its higher quality construction using 409-grade stainless steel tubing, the JBA system is less bulky overall and features 4-inch polished exhaust tips. All components in the JBA system use factory-style exhaust hangers for ease of installation.

“The process for obtaining a CARB certificate on for new parts is both extensive and expensive,” Don said. “First, we have to apply for a CARB application detailing what we are planning to get an E.O. (Executive Order, the exemption) for. They then look for the worst case scenario of that car model. We then install the headers on the car, and take it to a CARB approved lab for testing. The testing is pretty extensive–and more involved than people understand. The test protocol that we have to meet is not the same as when you have your smog test done; we have to pass emissions tests that are the same as when the manufacturer certified the car new. Even though we must test cars that have at least 3,000 miles on them–and have already started to deteriorate emissions wise. This process can take anywhere from six weeks to four months, and that is if you pass on the first test.”


The difference in the visual presentation of the ceramic coated JBA Shorty headers versus the factory manifolds is obvious, and that coating will keep the heat insulted, resulting in lower engine bay temperatures and a longer-lasting header. Also, while they won’t change the volume of the engine note, headers typically add another level of texture to the sound, too. JBA’s Shorty headers feature 3/8-inch thick laser-cut one piece flanges and mandrel-bent 1 3/4-inch stainless steel tubing.

Fortunately for enthusiasts like Roger and Martha Baker, JBA has gone through this arduous process; which means their new exhaust system will provide the benefits of the company’s efforts to improve their Mustang’s performance, and sound while also being compliant with those smog laws.


Made from stainless steel and ceramic coated to improve under-hood appearance and engine bay temperatures, JBA’s Cat4ward Shorty headers offer not only increased horsepower and torque throughout rpm range—but improved throttle response, increases in fuel economy, and a more rich engine note.

Folks who live in states which do not have smog laws can use JBA's off-road mid-pipe, which features high flow catalytic converters. However, here in California that's verboten, so the new Shorty headers and cat-back exhaust needed to be merged with the factory mid-pipe to make the system emissions compliant. Doing so requires a bit of cutting and welding, but nothing beyond the work that an exhaust shop typically sees on a daily basis. Here the catted mid-pipe is being freed from the stock manifold (left) and then welded to the new headers (right).

Off-Road and Motorsport Parts

Along with their CARB-approved offerings, JBA also makes exhaust components that are designed to provide the most performance possible without the constraints of emissions compliance. Here are some of the features and benefits of these competition-only parts.

JBA Long tube headers:

  • Large diameter mandrel-bent stainless steel primary tubes
  • 3/8-inch thick CNC laser-cut flanges
  • O2 sensor provisions

JBA Mid-Pipes

  • Superior flow and efficiency
  • Easy installation
  • Factory-style hangers
Along with their 3-inch stainless dual exhaust system, this setup will not only provide the aforementioned benefits in terms of sound and performance, but it also creates a foundation for future mods down the road. With the JBA parts installed, the Bakers’ Mustang will respond to future upgrades with increased output due to the less restrictive exhaust system.”An engine is an air pump,” Don noted. “If you increase the flow into the motor with, say a better intake, larger cam, or forced induction, then naturally, you need to increase the flow potential on the exhaust side as well.Headers and free flow exhaust will definitely help increase the power potential of other modifications to the engine. The parts will work together to make a complete package in the quest for more power.”And when it comes to the modern 5.0-liter Mustang, the difference is especially notable on all fronts. From a sonic perspective, new owners will note that the sixth generation GT’s roar is particularly subdued from the factory. Part of the reason for this is because the Mustang is now sold in Europe, where exhaust volume regulations are stricter than they are here in America. This is less of an issue for vehicles that have active exhaust systems, where the exhaust volume can change based on throttle position or the mode selected–like the Mustang GT350 and GT350R. But the GT does not use this active system, so the stock GT exhaust had to be tuned to be quiet in order to comply with those European standards.

The Bakers' Mustang GT is a daily driver, so getting an emissions-compliant system was mandatory for these Southern Californians. Roger and Martha reported that they love the new sound of their GT and that they can’t wait to throw some more modifications on it to really wake it up at the drag strip.



Headers and free flow exhaust will definitely help increase the power potential of other modifications to the engine, the parts will work together to make a complete package in the quest for more power.—Don Lindfors, JBA

There’s a lot of performance left on the table here as well. “With many of the modern muscle cars, the performance is far above what the classic muscle car era was,” Don points out. “Due to the flow characteristics of the short headers (or stock manifolds) and the cats, these cars can handle larger exhaust diameters than would be optimum for older design engines and long tube headers.

“The Coyote four-valve motors in particular move a lot of air. For that reason, JBA’s 3-inch diameter exhaust system has a functional purpose beyond just looking cool and sounding good. Exhaust system diameters can influence overall power if too large or too small,” Don told us.

“Too small can be restrictive, creating excessive back pressure and will hurt power output, especially in higher rpm. Too large can slow down the velocity of the exhaust, and will hurt lower rpm torque more than anything.” Looking to upgrade the exhaust system in your late model street driven muscle car for more performance and a more aggressive soundtrack?

While peak gains came in at only 2.07 horsepower (and a loss of 8.17 lb-ft of torque), under the curve on this Mustang shows a different story.

Comparing both the baseline and post installation dyno graph, you can see that power under the curve is slightly more advantageous at just 2,700 rpm. With a custom tune, there's no doubt in our minds that this Mustang could pick up some additional horsepower from the new JBA exhaust.

Comparing both the baseline and post installation dyno graph, you can see that at 2,700 rpm the GT is up 9hp and nearly 6 lb-ft. With a custom tune, there’s no doubt in our minds that this Mustang could pick up some additional horsepower from the new JBA exhaust.

Whether you’re in California or elsewhere, JBA Performance Exhaust can set you up with a system that will fit your needs and give your machine an extra dose of performance while remaining compliant with the smog laws in all 50 states. We’ll be checking out a set of long-tubes in another installment for even more gains. Stay tuned!

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About the author

Bradley Iger

Lover of noisy cars, noisy music, and noisy bulldogs, Brad can often be found flogging something expensive along the twisting tarmac of the Angeles Forest.
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