Getting the Right Sound, Plus Some Extra Power: How to Choose the Right Aftermarket Exhaust For Your Bronco
There’s a reason why we refer to that singular sound emanating from our car’s tailpipes as an exhaust “note” and not merely an exhaust “sound,” “noise” or some other variation. To the overwhelming majority of true automotive aficionados — especially those of us focused on aftermarket upgrades — that very sound is music to our ears. It plays a big part in defining a vehicle’s character.
The right aftermarket exhaust system can bring out the best of that vehicular music, whether the goal is rumbling, high decibel domination, or a deep growl that serves notice of our arrival. But an exhaust system can also do plenty more than that. So it’s worth putting in some time carefully considering both your goals and options when choosing the right aftermarket exhaust for your Bronco.
In addition to making your vehicle sing — figuratively, of course — a well-designed and well-fitted aftermarket exhaust system can provide tangible gains in performance. By creating a more efficient and less obstructed path leading out from your car’s engine to its tailpipes, your Bronco will breathe easier as the spent air/fuel mixture leaves its engine. The result? Better performance and often better fuel economy, as well. And of course, there’s no minimizing the impact of equipping your Bronco with just the right exhaust note.
Since even many well-regarded vehicles leave the assembly line with less than optimal exhaust systems on board, this is an area where substantial improvements can be made. In addition to providing just the right sound to serve notice of your vehicle’s arrival — that auditory goal may not necessarily be about sheer volume, but rather about sheer resonance and distinction — the right aftermarket exhaust remedies those mechanical shortcomings that keep your ride from reaching its full performance potential.
Let’s Take a Look at Exhaust System Construction
Not all exhaust systems are created equal where construction is concerned, but since you’re obviously pondering the addition of an upgraded system, you may already know that. Even to this day, a large percentage of production vehicles roll off the assembly line equipped with exhaust systems made of mild steel. As far as appearance is concerned, these exhaust systems will certainly pass muster — they’re new, and haven’t been exposed to the elements, after all — but it’s a good bet that they will deteriorate consistently over time.
Taking a step up the quality ladder, the addition of aluminized steel to exhaust components will help with longevity to a degree, but this means of construction also stops far short of conferring exhaust system immortality.
Stainless steel exhaust systems are at the top of the quality “heap”. This means of construction is so durable that many such systems will last nearly as long as the vehicle they service.
As far as automotive performance enhancements are concerned, we tend to equate those that are more extreme with also yielding bigger results, but where pipe diameter is concerned, this isn’t always the case. Sure, the size of certain exhaust system components will play a big part in shaping your car’s exhaust note and a modest increase in exhaust pipe diameter will almost always yield benefits. But it’s also possible to take this aspect too far. On nearly every vehicle, save for those sporting thoroughly enhanced powerplants, there comes a point where too much exhaust pipe diameter will actually HURT performance.
Because both the 4-cylinder and 6-cylinder Ford Bronco Ecoboost engines are equipped with turbochargers, they will benefit from more robust exhaust diameters — but they also have their limits.
With their larger, more aggressive exhaust tips and polished mufflers, aftermarket exhaust systems will certainly add an element of eye candy to any ride, but this improved level of aesthetics doesn’t necessarily equate to improved performance. Sure, there’s an implied correlation between the two — most of us prefer upgrades that are both functional and aesthetically pleasing, after all — but there are plenty of aftermarket exhaust systems that look essentially stock or very close to it, and yet are capable of providing substantial performance gains.
Crush Bent vs. Mandrel Bent Exhaust Systems
Largely due to production time constraints and economic factors, a big percentage of production vehicles are equipped with “crush bent” exhaust systems. This is a less expensive way of shaping an exhaust system to allow it to be properly fitted to a given vehicle and, for the most part, it does get the job done — just not optimally. This technique creates wrinkles in the interior of the exhaust pipes, along with subtle decreases in diameter at various points, that can restrict airflow and cut into performance potential.
By contrast, though more time consuming to produce, mandrel-bent exhaust tubing features a smoother, more consistent interior surface. This is achieved by inserting a properly fitted steel rod or tube into the section of piping to be bent, in order to provide extra support that will allow it to resist wrinkling. This absence of wrinkling translates to more efficient airflow and therefore, better performance.
This very brief video shows the mandrel bending process in action.
Keeping this information in mind, it’s also easy to see why a straighter exhaust system, free of any unnecessary twists and curves, will generally provide improved performance, with all other factors being equal.
A Few Words About Catalytic Converters
Sure, you’ll often hear performance enthusiasts bemoan catalytic converters, but they no doubt serve a substantial purpose. While they may cut into your car achieving its full performance potential, there’s no doubt that their invention and eventual requirement in most parts of the country has produced tangible results in improving the level of automotive pollution levels over time. Those of a certain age can tell you just how much clearer the view is when descending into a basin in virtually any major metropolis, as compared to a number of decades earlier.
And, of course, the inclusion of a catalytic converter is really the only failsafe way to make sure a post-1975, gasoline-powered vehicle is truly 50-state compliant.
So, you might wonder, just what does a catalytic converter do in order to achieve these results?
A few things, actually. The front half of a catalytic converter is equipped with a combination of platinum and rhodium that serves to remove nitrogen oxide — which is a harmful by-product of high temperature petroleum combustion — from your car’s exhaust. As the exhaust continues its journey to the second half of the catalytic converter, a big portion of the carbon monoxide and hydrocarbon output is burnt off. As a result, by the time exhaust leaves the converter entirely, about 90% of the damaging gases that would otherwise be released will never reach the sky.
Since this apparatus doesn’t work properly unless the exhaust gases reach a threshold temperature, auto manufacturers have to mount them as close to the vehicle’s exhaust manifold as possible to best capture engine heat before it dissipates on its way to the tailpipes.
After leaving the catalytic converter, the exhaust then travels on to the resonators and mufflers, which work to tame your vehicle’s sound. The nature and extent to which this taming occurs naturally will vary with the components you select. Those of us who seek the most dominant exhaust note possible might at first take issue with nearly any level of reduction in sound output. But where exhaust volume is concerned, there are, of course, limits to just how “aggressive” you’d want an exhaust note to be for practical (and legal) purposes.
Anyone who has run an engine without mufflers knows that being behind the wheel of a vehicle in this state would get tiring (as well as deafening) pretty quickly, let alone the annoyance it would cause to surrounding motorists.
Even leaving emissions regulations aside, in your quest to get your exhaust system to its free-flowing best on a modern vehicle — like the Ford Bronco — you can’t simply remove the catalytic converter, replace it with a straight pipe and call it a day.
This modification, though it may seem appealing, would drastically increase the level of hydrocarbons, carbon dioxide and carbon dioxide being released. These increased levels would be picked up pretty quickly by your car’s ECU, resulting in a persistent check engine light. Your car would, in most cases, run fine without the converter, but the legal ramifications would be substantial — removing a catalytic converter carries some pretty hefty fines in most states.
Cat-back vs. Axle-back Exhaust Systems
Some of us may have privately believed that the term “cat-back” exhaust refers to the intrinsic curves in an automotive exhaust system, which at various points may resemble the shape of an agitated cat’s back, but the terminology is simpler and more direct than that.
A cat-back exhaust simply refers to the collection of exhaust components positioned behind the catalytic converter, leading all the way to the tailpipes. This would include the intermediate pipe, which runs directly out of the catalytic converter, as well as the muffler and tailpipe. Since the installation of a cat-back exhaust system would imply that the catalytic converter remains intact, this is a system that should be street legal in any of the 50 states. And because aftermarket cat-back systems will generally improve on the more restrictive areas of a stock exhaust, they’re capable of helping to maximize your Bronco’s power potential while maintain this compliance.
An axle-back system refers to the components positioned behind the rear axle. Again, a literal term. This would include the muffler and piping leading out to the exhaust tips. Since an axle-back system includes only this limited array of components, obviously there’s less equipment involved, so an upgraded axle-back exhaust will tend to not only be a less expensive purchase than an entire cat-back system, but will also be an easier installation.
At the same time, if you’re going for an improved exhaust note —which, as we’ve discussed, may not necessarily be louder — and you’re seeking reduced backpressure in the name of improved performance, this option can deliver it.
Since both exhaust systems have their upsides, let’s look at an option in each category:
MagnaFlow Overland Series Cat-Back Exhaust W/Single Straight Driver Exit for the Ford Bronco
Magnaflow’s Overland Series Exhaust system provides a great balance of improved performance with an enhanced exhaust note that gives off a decidedly aftermarket sound without being so dominant that it becomes too much to take for longer drives. They’re tuned to bring out your Bronco’s audio character, but they won’t wear your ears out.
Once you find yourself off the asphalt, the Overland Series sports a markedly higher clearance design that really can come in very handy when navigating rough or uneven terrain.
And, as we noted a little earlier, its stainless-steel construction equates to a much longer service life, so this is an exhaust system that will be around for the long haul.
MagnaFlow Ford Bronco Street Series Axle-Back Performance Exhaust System
If bringing out the best in your Bronco’s exhaust note is high on your list, then this MagnaFlow Street Series Axle-Back system is definitely an option to consider.
Dyno-tested to back its design, it’ll give you enhanced performance for highways and trails alike, and enhance your Bronco’s exhaust sound, but in a tasteful way. Its 2.5” main piping channels are mandrel-bent, so exhaust restriction is minimized, and as exhaust gases make their way to the back, they’ll enter a straight-through muffler for maximum flow before heading out to this system’s dual 4” black powder-coated tips. As a result of this well-designed system, you get the benefits of a tastefully deep and aggressive exhaust note, while also keeping the decibels in check within the confines of the cockpit.
Whether you’re just logging the miles during your daily commute, or veering off the asphalt for some spirited off-roading, you’ll come to appreciate the sonic balance this system offers. And, because it’s been meticulously manufactured using CNC precision and state-of-the-art 3D scanning techniques, it’ll be a direct-fit for any 2021 Ford Bronco equipped with either Ford’s factory 2.3L turbo I-4 or 2.7L twin-turbo V6.
For those of you who might be pondering an exhaust upgrade and are looking for a solution that checks a few very specific boxes, the MBRP High Clearance Cat-back exhaust system just might be the right choice for you.
Not only does it offer the 50-state compliance of a cat-back system (assuming you don't take any liberties with the catalytic converter, of course), but plenty of versatility as well. Its high clearance design makes it well suited for everyday driving, off-roading and even and the track -- just in case you're looking for a setting to get in some more "spirited" driving.
Sonically speaking, this system strikes a great middle ground. Step into the throttle and you'll get plenty of that aggressive, resonant awesomeness you're looking for, and yet in more conventional, everyday settings, this set-up isn't going to wear your ears out during long drives.
Constructed of high-grade T304 Aluminized Steel, the MBRP High Clearance system offers increased longevity over most factory setups and yet comes in at a price point that's literally a fraction of many of its stainless-steel counterparts, so that's another box checked, too.