Everything You Need To Know About F-150 Exhaust Systems

The exhaust system on your F-150 is comprised of several different parts including:

•    The headers
•    Mid-pipe
•    Cat-back
•    Axle-back
•    Downpipe (EcoBoost Only)
•    Catalytic Converters
•    O2 plugs

The exhaust system on your F-150 is solely responsible for taking all of the cycled gases from your engine and expelling them out in a way that doesn’t (overly) pollute the environment, all while still getting good performance and gas mileage. The exhaust system impacts your acceleration, fuel economy, weight of the vehicle (very minimally, but nonetheless), and of course the sound/audio profile of your truck.

The headers are the first part of the exhaust system on your F-150 and are attached directly to the engine block (with a gasket in between the two to make a tight/secure connection). The headers collect all of the exhaust gases and channel them down into one condensed pipe which connects to the rest of your exhaust system. V8 and V6 F-150s use a set of headers (2) with one for each bank of cylinders.

The headers will have the most impact in your sound and performance as they are easily the biggest choke point in your exhaust system (due to how they take four cylinders plus worth of exhaust gases and consolidate them into one pipe). For aftermarket options, you can go one of a few ways. First, you will have to decide if you want to go long tube or shorty style headers.

For an in-depth answer on the differences between shorty and long tube F-150 headers, be sure to check out our guide on them. To give you the simple rundown, shorty headers use a short amount of exhaust piping before merging all of the pipes into one (the design the factory headers use), while long tube headers use about 2-3x the amount of exhaust piping before merging. Long tube headers offer more power and a deeper, louder sound than shorty headers, but they can come with a tough install. Shorty headers tend to net you at max 25 HP (which is a little generous), while long tube headers can net you up to 45-50 HP at max. If you are looking for power and sound, then long tube F-150 headers are the way to go.

Mid-pipes are the mid-point connector of the exhaust system, connecting the front (the headers) to the back (the cat-back/over-axle pipes and axle-back). For F-150s, there are a few mid-pipe options that will come down to what engine size you have. The names of the mid-pipe styles are reflective of their design (X, H, and Y), meaning they are in the shape of the letter they are named after.

X & H pipes are pretty much exclusive to V8 F-150s as they are designed to support and enhance a dual exhaust setup, with pipes coming out the passenger and driver side of the pickup. X-pipes tend to be more raspy and high-pitched, while H-pipes tend to have a lower, bass exhaust note.

Y-pipes can be found on EcoBoosts, V6s, and V8s, and are designed to connect the two sides of exhaust pipes into one. Y-pipes will typically channel your exhaust either out to a side exit or rear exit exhaust setup (more on them later).

Picking a mid-pipe for your F-150 is going to come down to what your truck can support, which is determined by A.) the engine size and B.) the rest of your exhaust system. Regardless of which design you go with, replacing the mid-pipe on your F-150 can net you anywhere from 5-20 extra HP/TQ, while drastically changing the sound of your truck for the better, making it louder and more noticeable.

The cat-back is the part of the exhaust system that runs from the catalytic converter to the back of the truck. Hooking into the mid-pipe, the cat-back has a large impact on your exhaust sound and performance as a decent chunk of the whole exhaust system is made up of the cat-back.

Also referred to as over-axle pipes, replacing the factory setup with an aftermarket F-150 cat-back exhaust setup is a common mod and for good reason. Replacing the cat-back can net you anywhere from 10-20 HP/TQ and give your pickup a much louder and deeper exhaust note. While cat-backs can be on the pricier side of exhaust components (anywhere from $500-$1,500), they give you a good bang for your buck and also include the muffler, which means you don’t have to replace the axle-back unless you want to go for a custom sound.

The axle-back is the very last part of the exhaust system as it goes from the rear-axle back (hence the name). The axle-back is mainly a sound upgrade for your truck as it isn’t a large choke point for the exhaust gases since the exit the vehicle complete after the axle-back.

Axle-backs are a great upgrade for any F-150, regards of the other modifications made to it. At the most, you may pick up an extra 5-10 HP, but the main purpose of F-150 axle-backs is to give your truck a louder, more intimidating exhaust note.

The downpipe is a section of piping the runs from the headers/exhaust manifold to/through the catalytic converter and hooks into the turbo. Downpipes are a newer component to the Ford F-150 aftermarket parts scene, but are integral to the design and performance of turbo systems, especially those found in EcoBoost F-150s.

The downpipe can be one of, if not the biggest limiting factors to your EcoBoost F-150’s power and performance as the stock one is somewhat restrictive. Replacing the downpipe on your EcoBoost F-150 will not only make it significantly louder, but it will also help it pick up anywhere from 15-75 HP.

When you do buy a downpipe, you will have to decide if you want to go with an off-road version (no catalytic converters) or a street legal version (catalytic converters included). Catted downpipes will not make as much power or be as loud as off-road downpipes, but they will keep you street legal.

Catalytic converters are designed to filter out the gross majority of pollutants coming out of your exhaust. Catalytic converters use a precious metal such as platinum, or more commonly palladium or rhodium that is arranged in a webbed like structure to filter the gases.

Replacing the catalytic converters can be an upgrade or a maintenance item for your build. Aftermarket F-150 hi-flow cats will be much less restrictive than stock, allowing you to have more power, performance and sound. If your catalytic converter fails, you can replace it with an OEM style one to keeps things factory. Some headers and most downpipes will force you to choose whether you want to keep your catalytic converter(s) or if you want to remove them.

Arguably the least exciting part of your F-150’s exhaust system is the O2 sensors. The O2 sensors plug right into your exhaust system and relay information to your F-150’s computer and can trigger a check engine light should something be off. O2 sensors monitor the flow of exhaust gases through the system and can notify you via a check engine light if you are running too rich, too lean, or if there is a general issue with your catalytic converter and too much carbon dioxide is passing through the system.

The only time you really need to think about replacing the O2 sensors is if you upgrade to a set of long tube headers for your F-150 (causing you to need two extensions to reach the port), remove your catalytic converters, or if the stock ones develop a fault/failure. If you do remove your catalytic converters you can plug up the hole for the sensor and tune out the check engine light, but this is not a street legal setup.

By in large, most exhaust systems will be crafted from either 409 or 304 stainless steel. 409 stainless steel is not as durable or long-lasting as 304, but it is cheaper and holds up fairly well over time. However, when it comes to top quality, 304 stainless steel should always be your go to choice for exhaust materials and is something you will want to consider before buying an exhaust system.

With that said, don’t let the fact that a system is constructed from 409 stainless steel turn you off from purchasing it as it is still a suitable material for any build. You will want to read reviews and forum posts no matter what to see what other people’s experiences have been with the different grades of steel/exhaust systems.

When it comes to F-150 headers, you may also have the option for buying a coated header. This means that once the header is crafted from whatever metal is used, it is treated or mixed with another material in order to improve performance. The most common instance of this is ceramic coatings (typically seen on headers that use 409 stainless steel), as ceramic coatings help to dissipate heat in the exhaust system.

When you upgrade the exhaust system on your F-150, you will want to ensure you are getting the most out of it. Since replacing exhaust components frees up the flow of exhaust gases, you may need to recalibrate your truck to account for this change.

When you replacing the following exhaust system components on your F-150 you will need to tune your truck:

•    Headers
•    Downpipe
•    Removing the catalytic converters

If you replace the cat-back, axle-back, O2 sensors, or mid-pipe you will not need to retune your F-150. However, retuning your F-150 is never a bad idea after any upgrade.