Subaru WRX (FA20DIT) Turbo Upgrade Guide

The 2015–2021 Subaru WRX (VA) was one of the best modern tuner cars on the market. It responds great to both bolt-on upgrades and E85 fueling, and makes good power at a relatively low price point. Much of this is due to the potent FA20DIT inside the WRX. The FA20 is a turbocharged 2.0 liter, direct injection, flat-four engine, producing 268 horsepower and 258 lb-ft of torque from the factory. It was one of the few cars still available with a six-speed manual transmission, and is highly respected by many auto enthusiasts. 

Enthusiasts love modifying the WRX, and one of the most popular mods is a WRX turbo upgrade: And we’ve got you covered. A WRX turbo upgrade is great for those looking to broaden their power band and push their WRX to the next level. In this guide, we’ll discuss all things turbo on your WRX, and then we’ll look at the top turbo kits available on the market.Make sure to check out our other FA20 WRX content including our: WRX intercooler upgrade guide, WRX exhaust upgrade guide, WRX vs STI Guide, WRX intake upgrade guide, WRX coilovers guide, Top WRX Mods guide, Common FA20 engine problems guide, WRX Reliability guide, WRX Racing Seats guide, FA20 vs EJ257 Guide, and our WRX FAQ.

2015+ WRX Turbo Upgrade Basics

The stock turbo on the 2015–2021 Subaru WRX is a Garrett MGT2259 journal bearing, twin-scroll turbo. It is oil cooled with a 50.3 mm compressor wheel and is internally wastegated. With full bolt-on mods and E85 fueling, the GT2259 can make approximately 375 horsepower before it starts to fall off and run out of steam. On just pump gas it runs out after closer to 350 horsepower.

Upgrading to a “big turbo” on the WRX is a relatively common upgrade that has been standard since the WRX came out in the 1990s. Not only will a larger turbo give you better peak power, but the entire power band will be much improved over stock, too. The stock turbo starts to fall off hard past 5,800 rpm, and upgrading to a larger unit will allow you to keep making power well past 6,000 rpm without massive amounts of advanced ignition timing. 

However, the stock turbo will also usually have a little less lag than a bigger turbo, and can be more responsive at lower loads. The WRX’s turbo runs 16 PSI on the stock setup, though it does allow for brief periods of overboost that spike as high as 22 PSI. Most tuners will run the stock turbo at a consistent 19–20 PSI on staged tunes. With larger turbos, they generally increase that by at least 3–4 PSI.

How much power can the FA20 take?

An important question when upgrading the WRX’s turbo is to determine how much power the FA20 can hold before the internals start to let go. It’s not an exact science, but most people will say the weak part of the engine is the connecting rods. In the early days of the FA20, tuners were blowing connecting rods on engines left and right due to pushing too much torque too early in the power band. This gave them somewhat of an unfair reputation for being overly weak, but they are the most common failure point on the motor. 

Generally, it’s accepted that ~350 wheel-torque is the limit for the stock FA20 connecting rods. Past that, most tuners would argue that you are living on borrowed time with your engine. Usually, the pistons and block will be fine well past 400 wheel-horsepower, though it makes sense to put in a set of forged pistons if you are upgrading the connecting rods. ARP head studs are another common upgrade when going with forged internals. 

It’s important to note that ~350 wheel-horsepower is far from a definitive number, and many WRXs have failed at those power levels or lower. A lot of it has to do with making sure you are using reputable and respected Subaru tuners, like Phat Botti and Bren Tuning. 

Yet, as you can probably tell, an upgraded turbo is pushing past the reliability limits of the FA20. You can install a WRX turbo upgrade on a stock motor, but it’s highly recommended to upgrade to forged internals before doing so.

Twin-Scroll Turbo Basics

The stock WRX MGT2259 turbo is a twin-scroll turbocharger, and so are all of the upgraded turbo kits for the WRX (VA). A twin-scroll turbo is similar to a traditional turbo, but it cleans up some of its inefficiencies. Also referred to as “divided” turbos, twin-scrolls are relatively new to the OEM turbo industry. The difference between the WRX’s twin-scroll turbo and a traditional single-scroll turbo is how the exhaust pulses are routed.

Turbochargers work by using exhaust gas pulses to power a turbine which spins a compressor. The compressor draws in and compresses ambient air before sending it to the engine, allowing it to make more power. To harness these exhaust gasses, turbochargers are mounted directly onto exhaust manifolds themselves. The area where the turbocharger and the manifold meet is known as the turbine inlet housing. This is where the difference between single and twin-scrolls comes into play.

On a single-scroll turbo, there is one volute (passage) that travels from the turbine inlet to the turbine housing. On a twin-scroll, the turbine inlet is divided to have two volutes running to the compressor. The twin-scroll setup ends up being more efficient, because engines produce their exhaust gasses in pulses due to not every cylinder firing at the same exact time. In a single-scroll, these different pulses can interfere with each other, leading to reversion (when exhaust gasses become trapped in the combustion chamber) and poor scavenging.

However, on a divided inlet on a twin-scroll, the exhaust gas pulses do not interfere with each other as much. This means no kinetic energy is lost, allowing the turbo to work more efficiently and ultimately produce higher and more consistent levels of boost.

How much power can I make with a turbo upgrade on my WRX?

With the increased boost and cfm from a larger turbo, users can see anywhere from moderate to massive gains with a WRX turbo upgrade. The stock turbo maxes out at about 350 wheel-horsepower, and most turbo upgrades start in that neighborhood. While maintaining the stock location, the FA20 can make about 450–500 wheel-horsepower. 

The problem with using too big of a turbo on the FA20 is both the OEM location and lack of fueling. Due to the low-mount turbo on the WRX, it’s hard to keep fitting larger turbos, and eventually you will need to relocate – which isn’t easy due to the design. In addition, the stock fueling on the FA20 is not powerful enough to keep up with builds past 500 wheel-horsepower. 

The FA20 uses only direct injection and does not have any port fuel injectors. The stock injectors are capable of about 500 wheel-horsepower, but fall off quickly after – especially on ethanol. In order to truly run past 500 wheel-horsepower reliably, you will need to upgrade with supplemental port fuel injection. There are a few kits for the WRX, but they are expensive and you will need new engine management to control them. 

FA20 Turbo Upgrade Supporting Mods

Before looking into a WRX turbo upgrade, it is important to make sure you are going to be safe and reliable. The main things that you should look at when upgrading are the intake/exhaust, cooling, fueling, boost control, and tuning. Turbos are far from the first upgrade you should be looking at for your WRX. Below we will look at supporting mods you will want and need before going big turbo on the Rex.

Upgrading the Intake/Exhaust

If you are looking to put a bigger turbo on your WRX, you absolutely need to have an upgraded exhaust and intake. Exhaust-wise, you will need a full turbo-back exhaust with 3” diameter piping. We have a guide on WRX downpipes/j-pipes, so take a look at what suits your build best. The stock exhaust is only 2.5” and is not capable of enough flow for a larger turbo, and will quickly choke out any gains.

You will also need an upgraded intake. The stock intake will be maxed out around 350 horsepower, and for any turbo upgrade you definitely need something freer flowing. Not all intakes will fit all turbo kits, so make sure you confirm fitment before purchasing. Most units do not fit the stock unit anyways, necessitating an upgrade. 

Improving Cooling

Upgrading your intercooler is also a must on your WRX before getting a larger turbo. The stock intercooler is capable of only handling stock power levels, and anything bigger needs aftermarket help. Check out our guide on intercooler upgrades for the WRX to see which one is right for your build. It is also a good idea to upgrade your charge pipe, which connects the intercooler to the turbo. The stock charge pipe is pretty restrictive past 350 horsepower, but make sure you get one that fits your intercooler.

You might also consider upgrading your radiator too, especially if you are in hotter climates, like Arizona or Texas. The higher power levels you push the greater heat the engine will ultimately produce, so on bigger builds coolant temperatures can be an issue after sustained runs.

Upgrading the Fueling

As we mentioned, the FA20DIT utilizes direct injection fueling. As of now, there are not proven and reliable injectors upgrades on the market, but like we stated, the true upgrade would be to add supplemental port fueling.

To get the best bang for your buck out of your turbo upgrade, users should seriously consider going the E85 and flex-fuel route on their WRX. Adding ethanol will allow tuners to run leaner air-to-fuel ratios with more ignition and camshaft timing without running into detonation problems. This means serious upgrades in horsepower and torque. 

The stock turbo with no other modifications can make 300 wheel-horsepower on an ethanol blend, making the possibilities with an aftermarket turbo pretty staggering. The WRX is capable of running ethanol levels up to E60 without any modifications. Though, most people opt for a flex-fuel kit so they can monitor ethanol levels. 

FA20 Boost Control

Boost control is another important aspect of your turbo upgrade. Nearly every tuner will require clients to upgrade from the stock 2-port system to an electronic 3-port system. The Electronic Boost Control System with 3 ports will do a much more precise and accurate job of controlling boost over the factory system. It is even recommended by most tuners when using the stock turbo, let alone with any turbo upgrades.

Subaru WRX Turbo Tuning

Tuning is probably the most important aspect of your WRX turbo upgrade build. You 100% need a tuning solution before installing a turbo kit on your FA20. Ideally, an arrangement with a tuner should be finalized before your new turbo is installed, not after. Some tuners require specific mods when updating to a particular turbo, so make sure you plan ahead.

There are multiple options for tuning Subarus, both online through E-tuning and in-person on the dyno. The Cobb Accessport is a standard device for tuners, and one of the most popular and reputable on the market. Make sure you work with a reputable and quality tuner who is willing to work with you and answer your questions. Phat Botti tuning and Bren Tuning are two of the most popular options. 

Data logging is also an important part of keeping your car safe, so make sure you are data logging even after your tune is finished to ensure everything is still okay. Monitoring your air-to-fuel ratio, knock sensors, and boost, is paramount to making sure your car stays healthy. Ask your tuner what you should be looking for. 

Best 2015+ Subaru WRX Turbo Kits

Now that we have looked at what it takes for a safe and reliable WRX turbo upgrade, let’s check out the top turbo kits on the market for the FA20 WRX. There are plenty of turbo kits available, and these are our top four recommendations of the countless available today. These give a great balance of performance, precision, quality, and price.

• Extreme Turbo Systems
• Forced Performance
• SteamSpeed
• SoCal Performance compressor upgrade

1) Extreme Turbo Systems 2015+ WRX Turbo Kits

Price: $6,545.00+

Expected Power: 350–1,2000 wheel-horsepower

The first entry on our list is the Extreme Turbo Systems (ETS) 2015-2021 Subaru WRX Turbo Kit. The ETS Kit was one of the first on the market and has stood up to the test of time. ETS offers six different sizing options for their turbo kit. All of them are made by Precision Turbos. They offer the 5858, 5558 Gen 2, 5862 Gen 2, 6062 Gen 2, 6266 Gen 2, and 6466 Gen 2 turbo options.

The ETS kits all feature dual dump tubes, dual wastegates, headers, and a downpipe. Some of the most iconic FA20 builds have utilized the ETS kit, and with the larger PT turbos and proper supporting mods and ethanol fueling, this kit is capable of as much as 1200 wheel-horsepower. 

This kit is by far the most expensive, but it includes all of the parts necessary for an entire turbo build, including the downpipe and headers. However, it is also the most proven, and can deliver by far the most power – depending on the turbo chosen.

2) Forced Performance FA20DIT Turbo Kits

Price: $3,099.00+

Expected Power: 440–475 wheel-horsepower

The next on our list are the Forced Performance FA20 Blue Turbo Kits. FP has established themselves as reputable turbo manufacturers for both WRXs and Evos, and their FA20 line does not disappoint. They offer two options, both of them are FP Blues, and they come with either internal or external wastegates and optional coated turbine housings.

The difference between the two of them is the center housing rotating assembly (CHRA). One has a journal bearing and the other has a Xona Rotor Ball Bearing. The Xona Rotor is another $1,100 on top of the journal ball bearing, but gives decreased spool time and better durability. Both turbos flow 57 lbs/min and can produce upwards of 475 wheel-horsepower on E85. This turbo was designed specifically for the FA20, and offers a very favorable power curve.

3) SteamSpeed FA20 Turbo Kits

Price: $1,799.00+

Expected Power: 350–500 wheel-horsepower

SteamSpeed offers two different turbo kits for the WRX. One features a GEN2 67R+ Ball Bearing Turbo, and the other features a GEN2 71R Ball Bearing Turbo. Both of them are bolt on replacements for the OEM turbo, and bolt up perfectly with standard “Stage 2” kits.

The 67R+ is the smaller turbo of the two. It can make 350–400 wheel-horsepower on pump gas, and reach up to 425 wheel-horsepower on E85. It is a combination of their previous 67R turbo with the ball bearing of the 71R. The 71R is capable of making as much as 500 wheel-horsepower with E85 fueling, and flows an incredible 59 lbs/min. It is also a direct OEM replacement and fits in the stock location and most “Stage 2” kits.

The SteamSpeeds are not quite as reliable as either the FP or ETS kits, but it is a great budget option capable of decent power. They likely won’t be as consistent as the FP or ETS kits, but they are also cheaper and have been proven to make good power.

4) SoCal Performance V4 GT2259 Upgrade 

Price: $1,005.00+

Expected Power: 500–560 wheel-horsepower.

The final entry on our list is not a turbo kit but an upgrade for the stock GT2259 turbo. SoCal porting is a relatively new company on the WRX market, but they have a solid reputation already. Instead of offering a new turbo, SoCal offers to upgrade the compressor wheel and turbine shaft of the OEM turbo. Their full kit also includes machining, re-contouring, clipping, rebuilding, and full porting and polishing of the OEM turbo.

You send them your FA20DIT stock turbo and they make the upgrades in house before sending it back. This is their fourth-generation design of the compressor wheel, and offers their best flow yet. It also retains all of the stock housings for complete retainment of OEM fitment. Power gains are substantial on the stock turbo, and users can make as much as 560 wheel-horsepower with full bolt-ons and E85 fueling.

However, it is important to remember that the stock turbo will likely not dissipate heat as well as a larger aftermarket turbo. This means that not only will longevity be compromised, but EGTs will also rise. However, it is also the lowest price option and will offer the best fitment.

2015+ WRX Turbo Upgrade Summary

Upgrading the turbo on your WRX is a great modification for getting a larger powerband with increased peak performance. With supporting mods, the sky truly is the limit when adding a new turbo to your WRX (VA). There are options for all levels of builds, from moderate (350-400 wheel-horsepower) all the way to some of the fastest cars in the world (1,200+ wheel-horsepower).

Our recommended turbo kits all prioritize reliability, performance, and cost. The ETS kit is by far the most expensive, but it is also the most proven and includes other supporting exhaust mods. The FP Blue turbos have been a standard among the WRX and Evo community for years, and their FA20 line is exceptional. The SteamSpeed kit is a good budget option that can produce great numbers, but with questionably longevity. Finally, the SoCal porting V4 upgrade for the OEM turbo is another solid option for those looking to retain their stock hardware but still get a good power bump.

All kits are designed to fit the 2015–2021 WRX, the real question becomes what size turbo you need? The bigger the turbo the more power, but eventually going too big will diminish the mid-range at the expense of peak top-end power. It all depends on your build priorities.

What’s your experience with Subaru WRX (VA) turbo upgrades? Are you considering one?

Leave a comment and let us know!

2015+ WRX Turbo Upgrade FAQ