The tendency in the USA is that a big engine means big power, but when the EcoBoost Mustang came out in 2015, it brought with it a “small” 2.3L turbocharged inline-four. This specific engine was designed to give the iconic car enough power to still have the pony car spirit, yet be able to be imported to countries with tariffs based on engine sizes (such as China) or where gas is relatively expensive and a V8 doesn’t make sense.

Developed at the Ford Performance Dunton Technical Center in the UK, the EcoBoost engine shares its name with a range of engines. These range from the current 1.5L Dragon three-cylinder turbo engine in the Mk VIII Fiesta ST (not sold in North America), to the massive 3.5L Cyclone V6 that is used in some F-150’s and even in some Police Interceptor models because of how much power can be tuned out of it.

Turbocharging was chosen over supercharging as well, because the parasitic loss from engine power is reduced, and when you’re under the boost power point, while the turbo is still compressing some air, it doesn’t drink as much gas.

Still, Ford had their hands full when the EcoBoost Mustang came out, as many visitors to MustangSpecs know—since the V8 is still “the only engine for the Mustang” in the hearts and minds of purists. Yet, with a turbo I4 and a naturally aspirated V6, the Mustang does, indeed, have engines for all budgets, and all of them produce decent power.

The 2.3L EcoBoost, for example, is stock at 310 HP, and was developed intelligently to be able to accept a lot of modification and tuning, to the point that some EcoBoost Mustangs can produce over 500 HP using strengthened internals and race-grade petrol.

However, this list is more about the budget-conscious tuner, the speed demon that wants to improve their Mustang’s performance without needing to rip the engine out, bore and port the cylinders, and whack on a Garrett T50 with an anti-lag system. Basically, for most if not all of these mods, all you need is the radio on in the garage, some wrenches, and the willingness to dive under the hood and crawl under the car to literally bolt them on.

1: Power Commander Unit with a Dyno Tune

COBB AccessPort V3 for the 2015 EcoBoost Mustang
COBB Access Port kit for the EcoBoost Mustang. via COBB

Okay, so it’s not so much a bolt-on as a solder-on, but getting a power commander ECU intercept unit like a Cobb Access Port or a Burger Motorsports JB4, and having it professionally programmed by a tuning shop with a dynamometer is probably the easiest way to give your engine a little extra grunt.

No need to really even muck about with the engine as a physical thing, and depending on the type of tune you’re going for, you can even massively improve your fuel mileage as the horsepower and torque start to creep skyward.

This is also probably one of the most cost-to-HP-gain-efficient mods you can do, as you can get a Cobb Access Port for the 2.3L Mustang for $595 as a kit that includes multiple mounting options, the access cable, faceplates, power connector, and the like.

The cost of a dyno tune varies wildly from shop to shop and state to state, but on average, you can expect to be paying between $150 to $300 for a simple tune, ranging upwards from there if you want a more detailed tune to maximize every rev your engine makes.

The biggest impact getting a professional tune does is level off the massive power drop that hits the 2.3L EcoBoost around 5,500 RPM before the redline of 6,500 RPM. As I4 engines often develop most of their power at high revs, this leveling-off of the power keeps more grunt going to the wheels.

You won’t see that much overall extra horsepower as a net gain, often in the range of going from 310 to 325 to 330 HP, but the biggest part is that the power is consistent instead of dropping off.

2: Performance Intake Filters and/or Replacement Intakes

K&N Air Intake for Ford Mustang
K&N Air Intake for Ford Mustang. Via K&N.

Remember, the intake that comes on the Mustang EcoBoost is meant to provide the stock engine (with the stock tune, stock filter and stock everything else) with enough air to efficiently give the engine the torque grunt that almost all turbocharged engines get when they’re a thousand RPM above warm idle. It is not meant to whack in a great volume of cold air, nor is it meant to flow that air nearly directly to the compressor blades of the turbo.

Even something as simple as replacing the stock paper filter with a washable high-flow filter will improve fuel efficiency, as there is more air available to be compressed, meaning less fuel needs to be injected to achieve optimal performance. All of the EcoBoost Mustangs have a variable ECU that talks with the mass airflow sensor, the engine itself, and even the turbocharger to vary spark timings, air-fuel mixtures, and the like.

That’s because Ford wants to sell the same Mustang to someone in Colorado, thousands of feet in the air, as they do to someone in California, a few feet above sea level. The performance gain will barely be noticeable (literally the same as those windows stickers on Japanese imports stating “this sticker adds 0.5 HP,”), but where you will notice a difference is in how long your tank of gas will last.

Taking that a step further, a replacement intake, often called a cold air intake or a direct air intake, can actually give you a few more horses under the hood. You should know what these look like: a whacking huge tube with a cone-type air filter on the end that you move and position to get as much air as possible, with the least heat in it as possible.

It takes an afternoon of unbolting the stock intake, unplugging a few sensors, plugging those sensors onto the new high flow intake, and bolting that intake on, but you can expect to see anywhere from 3 to 10 BHP added, depending on altitude, and probably only 2-5 WHP.

An intake replacement is also one of the cheaper bolt-on mods you can do. As a popular choice, the K&N Air Intake Kit for the EcoBoost Mustang is only about $330, with the intake pipe, an air dam, and the cone filter included.

3 & 4: Upgraded Downpipe & Exhaust

Mishimoto downpipe with half-exhaust kit for EcoBoost engine
Mishimoto downpipe kit with first half of exhaust. Via Mishimoto.

Getting into the more complicated bolt-ons, the stock downpipe on the 2.3L EcoBoost is designed to create back pressure, boosting fuel efficiency at the cost of some horsepower loss. You will also hear the terms catted and catless exhausts, and it really falls to what the emissions regulations in your State allow. Good luck going catless in California—but in places like Idaho, it’s barely even mentioned in the State regulations.

The best all-around option is to get a high-flow “sport catted” exhaust, even though it adds cost. The catalytic converter in the exhaust will flow nearly as much air as a catless exhaust, but also let you install it in California and other highly regulated States. What replacing the downpipe and exhaust will do is decrease back pressure to allow the turbo to spool faster, compressing more air quicker, and also adding a deeper, louder sound to the exhaust.

Expected performance gains are anywhere from 10 WHP for a sport catted exhaust to over 20 WHP for a “full flow” catless downpipe and exhaust. Costs also vary wildly, but for a sport catted downpipe and exhaust, expect to spend anywhere from $300 for a budget option, up to $1,000 for a top name system.

5: Upgraded Intercooler & Charge Pipes (Optional)

COBB Sport Mustang Front Intercooler Kit with Charge Pipe replacements
via COBB.

Since many Mustang fanatics are all about the V8, intercoolers are not something they tend to think about much. Like the radiator it sits in front of, an intercooler is there to cool something down—except that in this case, it’s compressed air.

Sitting between the output pipe of a turbocharger and the air intake of the engine, the intercooler is there to suck out the heat generated through the compression of air, and the intercooler should therefore be restrictive enough to keep the hot air in it long enough for the cooling air passing through it to wick away that heat. However, it also needs to be free-flowing enough that it doesn’t “choke” the pressurized side of the forced induction loop.

This balance can be a difficult dance, and the stock intercooler veers more towards the restrictive side of the equation. By changing out just the stock intercooler to a sport intercooler (less restrictive), you can expect to see some immediate horsepower gains, up to maybe 10 HP.

Combine the sport intercooler with a charge pipe kit, and you could probably get over 10 to maybe 20 HP gain at the wheels. You may hear terms such as pressurized piping, charge pipes, or high-pressure pipes, but in general, anything between the output of the turbo to the intake of the engine is considered as turbocharged, so the most common term is “charge pipe.”

This is getting into the deeper pockets side of things, however. A middle-of-the-road sport intercooler with piping kit, such as the Cobb Sport Mustang Front Intercooler Kit for $875, starts high and generally, the higher quality you go, the more it will cost.

Another thing that is often left out of the consideration with a replacement intercooler is that a dyno tune is almost mandatory, as you are now affecting airflow to the point where you can over-boost the engine if it is not ready to handle the higher flow of pressurized air. In extreme situations, this can even cause dieseling or detonation inside the cylinders, both very very bad things for turbocharged engines to experience.

6: Upgraded Turbocharger

Precision NX2 Turbo Kit for EcoBoost engine
via Precision Turbochargers.

We have now left the cheap and cheerful part of bolt-ons and are now entering the “oh, we’re being serious about performance now” part of the list. This is because on top of the cost of a new, higher performing turbocharger, you are also looking at an almost mandatory upgrade of the intake, charge pipes, intercooler, downpipe and exhaust, on top of needing to have the ECU or an access port professionally tuned on a dynamometer.

You can get everything from a “Drop-in” turbo kit, which replaces the stock turbo with one of similar size but higher compression, such as the Turbonetics EcoBoost Mustang kit for $2,099 or the Precision NX2 Turbo Kit for $1,995. You can also get a performance turbocharger from companies like Garrett or BorgWarner where the turbo itself is several thousands of dollars along, without a kit filled with the flanges, gaskets, or mounting plates needed.

However, this is where you will also see the most performance gained on stock internals. With a custom tune and the supporting hardware as mentioned above, the Precision NX2 kit can get you to a little over 500 HP, which is on the very top end of what the stock internals of the engine can handle. These are rivaling Mustang GT numbers with the 5.0L Coyote V8—however, the costs involved (unless you can get things at or nearly at cost), are negligible to just buying a Mustang GT.

Keep in mind as well that by running high boost on stock internals, you are running the risk of accelerated wear and tear on the engine. Some EcoBoost engines, like the 1.6L Sigma engine in the Fiesta ST and Fusion Turbo, were developed to be able to handle high boost for long durations because of the “overboost” functionality built into the ECU for those cars when it detects wide open throttle. Others are oriented more towards a wider fuel octane range, like the 2.3L Mustang EcoBoost, which can run anything from 87 octane to 98 octane—the highest octane gas you can get in most European countries.

Your mileage may vary, but if you are planning on turbocharging beyond 450 HP, it’s definitely something you’ll want to consult a tuning expert for. That will help you get the absolute correct turbo for your car, which will run on the stock internals without overboosting them. You’ll also want to have your tuner do the custom tune.

7: Sport Manifold Spacers

Boomba Racing EB intake manifold spacers for the 2.3L EcoBoost Mustang engine
via Boomba Racing.

Bordering on getting into engine modding, manifold spacers are the last line to cross before replacing full intake manifolds and engine parts. Specifically useful for forced induction engines, manifold spacers do exactly what they say they do on the box. They introduce anywhere from ¼ inch to a full inch of extra air space between the throttle body and the actual intake to the cylinders.

While this may not sound like much, that extra volume can be enough to allow for more compression in the charging intake, which in effect means that the turbo can start building up charge lower down in the rev range. This has a knock-on effect of improving your fuel mileage without necessarily needing an ECU tune.

In fact, for spec racing series where you have to use most of the original engine, intake spacers are a go-to solution, which is why you will often find road-legal spacers manufactured by racing specialists. One example is Boomba Racing with their EB intake manifold and throttle body  spacer at $271.00.

Another thing that these spacers, if properly installed, can do is give a sharper throttle response. One of the few downsides to a turbocharger is the unavoidable turbo lag. While the turbo is almost always compressing air, by giving the charge pipes that little bit extra room, when the turbo starts to significantly build boost just under 2,700 RPM (because it has those few square inches of extra volume), counter-pressure against the compressor blades is reduced, so the compressor will spin up much faster.

The horsepower gains are negligible, probably in the 1 or 2 BHP range, but where things are improved is torque. Without a tune, you’d probably see 5 to 10 more lbs-ft of torque at the wheels—however, if you combine these spacers with a few or all of the previously mentioned mods as well as an ECU access port tune, you can gain upwards of 50 or more lbs-ft of torque, on stock internals.