Subaru WRX FA20 Turbo Upgrade Guide - Best WRX Turbo Kits
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Subaru WRX (FA20DIT) Turbo Upgrade Guide

Chandler Stark

Meet Chandler

Chandler is an automotive expert with over a decade of experience working on and modifying cars. A couple of his favorites were his heavily modded 2016 Subaru WRX and his current 2020 VW Golf GTI. He’s also a big fan of American Muscle and automotive history. Chandler’s passion and knowledge of the automotive industry help him deliver high-quality, insightful content to TuningPro readers.

The 2015–2021 Subaru WRX was one of the best modern tuner cars on the market. This makes it ripe for turbo upgrades, but unfortunately this isn’t a simple plug-and-play modification on the WRX. The factory internals can only handle about 350whp, and the factory turbo can hit these power levels, so if you want to upgrade the turbo and push more power there are some serious considerations.

In this guide we’re going to discuss engine power limits, stock turbo limits, and the supporting modifications you’ll need to run an upgraded turbo. Lastly, we’ll cover a few kits on the market that will help you achieve various power levels, from a modest 400whp to over 1,000whp.

Stock Engine Power Limits

The WRX’s power is more so limited by torque, rather than horsepower. ~350wtq is the limit for the stock FA20 connecting rods. Past that you are living on borrowed time with your engine. Usually, the pistons and block will be fine well past 400whp, 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. 

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.

Factory Turbo Limits

The factory turbo can make around 375whp with E85 fueling and full-bolt on mods. The biggest limitation to the stock turbo is its location. It is bottom-mounted in a tight space in the engine meaning you can’t really fit a larger turbo down there. On the stock location you can get a turbo upgrade that can handle 450-500whp. Anything above 500whp and you will need to go with a top mount turbo.

WRX Turbo Supporting Mods

This is all of the mods that we recommend before you upgrade your turbo. All of the basics are in there like tuning, cooling, and exhaust upgrades, but the most important thing is the internal upgrades. You will need forged rods, pistons, and ideally a head stud kit before you try pushing too far beyond 350whp. This makes a turbo upgrade significantly more expensive and adds a huge barrier to entry.

Fueling is also capped. You’ll need to run ethanol blends to max out the stock turbo and to run beyond 500whp you will have to add supplemental port injection alongside ethanol fueling.

Subaru WRX Turbo Upgrade Kits

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

1) Extreme Turbo Systems

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

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 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.

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