Third Generation Challenger Mid-Pipes: Bridging the Gap

Whether OEM or aftermarket, every Challenger exhaust has a mid-pipe. In simple terms, a mid-pipe is where the exhaust gases continue on to after passing through the headers or stock manifold before reaching the mufflers and tailpipes (cat-back).

• System that connects the headers to cat-back
• Contains your car’s catalytic converter

The mid-pipe is also home to the catalytic converter, which comes equipped to every car sold off of the showroom floor. Catalytic converters—also known as “cats” —are designed to remove contaminants, but are also restrictive and rob horsepower. That said, some aftermarket mid-pipes lack a cat in order to maximize outright performance.

With three different mid-pipe designs available, choosing one for our Challenger can get complicated. Each offer their own sound and power characteristics, so choose wisely.

H-Pipe: In comparison to the other two designs, an H-pipe is best at efficiently balancing sound waves. The result? A deep growl reminiscent of the classic muscle car era of the 60s and 70s; surely worth a head turn. That said, however, the H-pipe promotes smooth exhaust gas flow, but not as smoothly as an X-pipe—ultimately limiting power near redline. Instead, this design is beneficial when searching for torque gains early in the powerband.

X-Pipe: X-pipes are built with a shape just as their name sounds. This design features a crossover, or “X", which is built to balance and improve the flow of gases as they travel through the rest of the system. Typically, X-pipes give off a raspier note than other designs and offer more horsepower gain near redline.

Y-Pipe: The most common aftermarket mid-pipe choice for Challengers are those with Y-pipe designs. This design is balanced in the sense that it will offer performance gains in all areas of the powerband. Like an X-pipe, these will produce more of a raspier sound characteristic than that of the H-pipe.

Okay, let’s clear this one up right away. In your search of aftermarket mid-pipes, you may have come across a few sets marked with “off-road use only”. No, these aren’t special pieces designed to handle dirty conditions, rocks, or summiting mountains. Use a truck for that.

Instead, an “off-road” designation means the mid-pipes lack a catalytic converter, which then makes them illegal for use on public roads in most states. That said, put them to use on a closed racetrack! By skipping the use of cats, your mid-pipes will offer improved flow of exhaust gases, which will boost performance even further.

No, not exactly. Even with catalytic converters, some aftermarket mid-pipes are not legal for use in various states—most notably California. The golden state has adopted strict emission standards called CARB, which some aftermarket exhaust systems struggle to pass. The thing is, it’s not just California either. More and more states have been adopting the CARB standards as well. Before purchasing a set of mid-pipes—equipped with a set of cats or not—do homework on your state's emission standards.

Now, let’s dive into what exhaust pressure is and how it can affect the performance of your ride. First things first, exhaust pressure (or exhaust back pressure) refers to the atmospheric pressure opposing the flow of exhaust gases in your car’s pipes, caused by the restriction of your exhaust system. Too much back pressure from a very restrictive exhaust system means that the exhaust gases velocity will be shot out too quickly, robbing horsepower. On the contrary, an exhaust system with very low back pressure or restriction forces the exhaust gases to travel a lower velocity, also hurting performance. The ideal situation is somewhere in between.

Analyzing the exhaust pressure measurement on your suped up Challenger is important in the case you want to extract out the most performance possible. It can also help solve performance issues you might be having. For example, usual symptoms of too much back pressure are poor fuel economy, low horsepower, and high or overheating engine temperatures. 

When looking at back pressure measurements, you’re going to be reading them in terms of PSI. Typically, stock exhaust systems will produce about 1.5-2.5 PSI at idle, about 3 PSI at 2,000 rpm and 4-8 PSI (dependent on the vehicle) at about 4,000 rpm. If you see readings much higher than these, it should tell you that there is some sort of restriction—most likely limiting your power and spiking emission readings.

Something to consider when shopping around for mid-pipes is does your Challenger have an SRT engine? If so and if you fall into the 2011 and newer range, your ride will have exhaust pressure sensors (EPS). These sensors plug into your mid-pipes after the catalytic converters. If you're gung-ho about a set of pipes that don't have the adapter for your sensors, you'll have to have your local shop weld the adapters in. For ease of installation, keep an eye out for mid-pipes that come with the EPS adapters.