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Everything You Need To Know About S550 Mustang Fuel Systems

Written By: Zach Wright

The 2015+ Mustang’s powertrain is a fine-tuned instrument that is balanced in a way that provides a performance, decent fuel economy, and world-class driveability. However, when you start upgrading your Mustang, tweaking the powertrain as you go, this balance gets thrown out of whack; an integral component to maintaining an ideal balance is the fuel system. This guide will give you a rundown of your S550 Mustang’s fuel system, providing you with everything you need to know and how to upgrade it.

What is an S550 Fuel System & How Does it Work?

Your S550 Mustang’s fuel system is made up of several parts, which include:

  • Fuel injectors
  • Fuel pump
  • Fuel rails
  • Fuel filter
  • The tune

Together, all of these parts flow gasoline into your engine and helping it pump out power smoothly and in big numbers.

S550 Mustang Fuel Injectors Explained

Fuel injectors deliver the fuel from the lines into your engine and are what many consider to be the main part of your fuel system. Fuel injectors are rated and distinguished by the rate at which they flow fuel, which is usually rated in either cc’s (cubic centimeters) or pounds, measured over time (i.e. 39 lb/hr).

Going with a bigger fuel injector on your S550 will allow your Mustang to make more power. Making power can be boiled down to how much fuel and air you can mix together (this is an oversimplification, but holds true nonetheless), which is why a larger fuel injector will give you more power.

Fuel Injectors

Stock S550 Mustang Fuel Injector Sizes

  • S550 Mustang GT – 34 lbs/hr
  • S550 Mustang V6 – 29 lbs/hr
  • S550 Mustang EcoBoost – 24 lbs/hr

2015+ Mustang Fuel Pumps Explained

All S550 Mustangs use an electric fuel pump to push the fuel from your tank to your engine. The fuel pump goes inside of the gas tank and creates a positive pressure to send fuel from the tank, through the lines, up to the injectors, and into the engine.

Fuel pumps are rated by PSI and GPH (gallons per hour). The more PSI, the more GPH, and the more power you can make. Going with a high PSI fuel pump is a necessity for boosted application as you will need more fuel to get your ride ripping, and also avoid serious engine issues due to lack of fuel.

Unfortunately, there are not a whole lot of fuel pump options available for the S550 Mustang, but there are a few designs in the works. You can also go with a custom fabricated fuel pump or one that is modified to work with the S550, but you have to be careful about quality and overall performance. Stick to your major manufacturers.

Fuel Pump Voltage Booster

What are S550 Mustang Fuel Rails & What Do They Do?

S550 Mustang fuel rails are the connecting point between your fuel line and your fuel injectors. The line feeds into the rails, which then distribute the fuel evenly to all of the injectors. The fuel rails can be a choking point for fuel systems, as the stock rails can’t fulfill the needs of a high horsepower build, even if you have an upgraded pump and/or injectors.

Replacing the fuel rails on your 2015 Mustang will allow you to flow more fuel into your engine by using a larger diameter design. Upgrading the fuel rails on an S550 Mustang is really only needed if you are starting to push above 600 HP, otherwise you may actually incur a negative effect on your performance (mainly the car will run too rich).

S550 Mustang Fuel Filters Explained

Fuel filters go in somewhere in between your tank and your fuel rails, as part of the line assembly and filter out any harmful pollutants in your fuel. Fuel filters ensure the fuel going into your engine is as clean as possible and will deliver you the most performance possible.

As you upgrade the fuel pump and injectors, you will want to also upgrade the filter to one that can handle the increased demand/pressure. Fuel filters, like fuel pumps, are measured in GPH and PSI. Mustang fuel filters typically need to be replaced as part of routine maintenance as they will rob you of power over time, the dirtier they get.

Fuel Filter

Tuning for an Upgraded 2015+ Mustang Fuel System

As soon as you start to upgrade the fuel system on your 2015 Mustang you will need to upgrade the tune. A major change up like a fuel system upgrade requires your tune to account for the difference in pressure/incoming fuel in order to optimize its performance.

To guesstimate how much power you may pick up from upgrading your fuel system and tuning it is almost impossible. It comes down to what parts you upgrade it with along with who you use for a tuner and how aggressive of a tune you go for. You can pick up anywhere from 30 HP – 100 HP depending upon a litany of factors.


How Much Power Will I Get From Upgrading My Fuel System

As mentioned above, it is really difficult to accurately say how much power you can pick up from upgrading your fuel system. How much power you make will depend upon your other modifications, how “big” of a system you are running, the tune you have on your Mustang, and the type of fuel you use (which varies station to station).

On a naturally aspirated car you can pick up anywhere from 10-50 HP and on a boosted application you can pick up anywhere from 10-100 HP.  It’s really anyone’s guess and comes down to a case-by-case basis.

When Should I Upgrade My S550 Mustang’s Fuel System?

Upgrading your fuel system is dependent upon your goals for your build. If you are a daily driver with minor bolt on mods, you shouldn’t consider doing much more than upgrading your injectors and your tune. If your S550 Mustang is a dedicated track car, you may want to upgrade the rails and the pump as well. If you have a fully built or boosted build, you will want to upgrade every aspect of your fuel system to support the amount of power you are shooting to put down. This will require a bit of reading and research on your end, but it will leave you with a car that is driveable and lives up to its full potential.

Fitment includes: 2015, 2016, 2017, 2018, 2019, GT, V6, EcoBoost, ShelbyGT350