Full-Race’s Answer to the Naturally Aspirated FA20  (2023)

“Bounce on the devil put the pedal to the floor.” Unfortunately, a bone-stock FR-S/BRZ would most definitely leave Jay-Z with 99 problems, power being each and every of them. Nearly four years after its introduction, an overwhelming majority of enthusiasts continue to agree that the only thing missing from the otherwise nimble and fun FR-S/BRZ is a turbocharger. With its all-wheel- drive cousin, the WRX, featuring a turbocharged variant of the FA20 engine, we begged Toyobaru to stuff some boost into the modern day hachi-roku. As expected, they didn’t listen. Fortunately, the aftermarket now offers a plethora of supercharging and turbocharging solutions to increase the power output of the FA20. The latest of these kits comes from Full-Race Motorsports, a company synonymous with three things: turbochargers, impeccable craftsmanship and high horsepower.

Text by Jun Chen // Photos by Sami Sharaf, Jun Chen & Cameron Parsons

DSPORT Issue #166

Full-Race’s Answer to the Naturally Aspirated FA20 (1)With over twenty turbocharger kits already available for the FR-S/BRZ, Full-Race’s approach to forced induction for the FA20 wasn’t to be the first to market. Instead, they designed and engineered the kit based on a principle shared across all of its turbo kit offerings: turbocharged engines work best when optimized for maximum efficiency on the exhaust side.

The foundation of the kit centers around Full-Race’s signature turbo manifold. Constructed from high- grade stainless steel tubing, the manifold features a hand fabricated collector and robotically TIG-welded runners. Full-Race chose low-angle merge collectors combined with long runners to ensure quick spool and minimal pressure drop from the boxer engine. To complement the manifold is a plethora of BorgWarner EFR turbocharger options to meet the power goals of any enthusiast. Turbocharger options range from an ultra-responsive 300whp EFR6758 setup to the larger EFR7163 that can easily support 550whp and beyond on a fully-fortified mill with E85 or race gas.

Full-Race’s Answer to the Naturally Aspirated FA20 (2)(1) The proven BorgWarner EFR turbocharger features an all-in-one design. The internal wastegate, built-in recirculation valve and turbo-mounted boost solenoid all contribute to minimizing the overall footprint of the turbocharger’s ancillary components. (2) To keep the charge air as cool as possible, Full-Race stuffed in a large front-mount intercooler which mounts to the included replacement bumper beam. (3) Long runners paired with the low-angle merge collectors allows for good spool and plenty of top-end power. (4) The included 3-inch front pipe, overpipe and downpipe help route exhaust gasses as quick as possible to allow the turbocharger to breathe efficiently.

Included Parts List

– Full-Race EFR Turbo Manifold
– BorgWarner EFR 7163 Turbo (0.85 A/R, IWG, T25) – Full-Race 3-Inch Downpipe
– Full-Race Intercooler with Mounting Beam
– Full-Race Charge Piping, Couplers and Clamps
– Full-Race Belt and Pulley Engine Shield
– Slim LHS Radiator Fan
– Full-Race Hardware Kit

Additional Parts Needed

– Oil Drain Fitting for oil pan
– Air Intake and air filter
– Catch Can Solution

(Video) How To Make More Power with an NA Engine (HUGE INCREASE!)

Additional Parts Recommended

– 3-Inch exhaust system
– High-Performance Clutch
– Engine-Management System
– Fuel Pump (Minimum of 255lph)
– Fuel Injectors (Minimum of 750cc/min)
– Spark Plugs (2 Steps Colder)
– Heat management solution

For the D’Garage FR-S, we stepped up to the EFR7163 option for a variety of reasons. First, our FR-S had already made over 300-wheel horsepower on the Innovate supercharger setup with E85. Secondly, we’re building another FA20 engine with forged internals to handle the higher boost levels without issue. However, regardless of the turbo selected, the entire EFR lineup shares the same underlying technologies.

Outwardly, the EFR resembles no other turbocharger currently on the market. Whether you love or hate the aesthetic, the forward-thinking design of the EFR makes it one of the most lightweight, compact and versatile turbochargers currently available. The engineers at BorgWarner took the modern turbocharger back to the drawing board with the EFR series.

Full-Race’s Answer to the Naturally Aspirated FA20 (3)

The overall footprint of the turbocharger system is drastically reduced by using an EFR turbo that incorporates a wastegate, boost solenoid and recirculation valve.

Full-Race’s Answer to the Naturally Aspirated FA20 (4)One of the most obvious features of the EFR is its internal wastegate design. Since most high boost applications rely on an external wastegate setup, the EFR team realized the need for an internal wastegate capable of handling the flow requirements of high performance applications. These 36mm or 42mm valves (depending on turbo size) feature a design optimized for airflow, allowing for up to 40-percent of airflow passing through the wastegate at maximum power. BorgWarner offers three actuators for the EFR, one for low, medium and high boost. Once the actuator is chosen, it can be easily tuned using the integrated rod-swivel joint.

(Video) How to make power with your FA20D powered BRZ or GT86

In addition to the high-flow internal wastegate, the EFR continues the all-in-one (AIO) approach to the remainder of ancillary turbo components by squeezing a boost solenoid, recirculation valve and turbo speed sensor port on the compressor cover. These integrated features eliminate the need for an external blow-off valve, boost solenoid or drilling into the compressor housing to mount a speed sensor. Incorporating all of these components directly onto the turbocharger reduces the need for lengthy vacuum lines and minimizes the overall complexity of the turbo system.

At its center, the EFR’s center hub rotating assembly (CHRA) utilizes a dual-row ceramic ball bearing system and water cooling for minimal parasitic loss, quick spool and improved thrust capacity. Out back, the EFR features its proprietary Gamma-Ti turbine wheel. This material, neither a metal nor a ceramic, weighs just half that of a typical turbine wheel while maintaining a very high temperature capacity. Likewise, the compressor side of the equation also receives an upgraded CNC-machined “Forged Milled Wheel” compressor wheel.

Full-Race fabricates each and every one of its turbo kits right here in the USA. Based in Phoenix, Arizona, the manufacturing process begins with cutting the required tubes to length, shape and size. Then, a highly-skilled welder will tack and weld a flange and the appropriate tubes together to form the merge collector. Once complete, the collector will join a set of robotically TIG-welded runners to form a manifold. Intercoolers and all associated piping are also fabricated in-house.

By using a combination of robotic welders and several finish welders, Full-Race ensures full penetration of all its welds while a watchful eye of a skilled finish welder carries out the intricate welds not possible by the robotic welder.

(Video) TURBO BRZ VS. WRX FA20 Engine Comparison

Making the move to E85 and a larger turbocharger like the 7163 requires a fuel system capable of handling significantly increased fuel demands. To provide additional fueling capacity, we turned to Fuel Injector Clinic for a set of 880 cc/min injectors (p/n IS144-0880H) and plug-n-play pigtail adapters (p/n PADPJtoD4). Fuel Injector Clinic claims that its data match technology provides some of the most complete flow matching and latency value information on the market. Feeding those four high-flow injectors is an E85-compatible AEM 320LPH in-tank fuel pump (p/n 50-1220). Designed to work with ethanol fuels up to E100 and all types of gasoline, this pump will sufficiently meet our fueling needs at our desired power levels in a compact package that fits inside the factory FR-S/BRZ fuel pump basket.

Full-Race’s Answer to the Naturally Aspirated FA20 (8)

Big boost often translates into increased oil blow-by, a case of fuel, air and moisture seeping past the piston rings and into the crankcase. The blow-by cocktail is then released by the crankcase vents back into the intake pipe, reducing horsepower. To help protect against this phenomenon, we installed the Mishimoto FR-S/BRZ baffled oil catch can (p/n MMBCC-BRZ-13P). This catch can features billet 6061 construction, a bolt-on application-specific bracket and a 50 micron bronze filter to keep blow-by at bay.

Full-Race’s Answer to the Naturally Aspirated FA20 (9)

Due to the addition of a very hot turbo to the front of the engine, we put together a heat management plan. Full-Race recommends that various lines and hoses be wrapped in a gold foil to protect against radiant heat. To this end, we chose DEI’s Reflect-A-GOLD heat reflective tape to wrap the turbo coolant lines, lower radiator hose and slim fan motor assembly. The metalized polyamide polymer laminated glass cloth handles continual temperatures up to 850°F. In addition to the heat created by the turbo, we wanted to minimize any heat created by the manifold. By wrapping the manifold with DEI’s Titanium Exhaust Wrap, the exhaust gas heat stays hotter, thereby improving exhaust gas velocity and also radiating less heat into the engine bay.Full-Race’s Answer to the Naturally Aspirated FA20 (10)

Even though the AEM Brute Force Dryflow Air Filters are mainly designed for off-road applications, we opted for a 21-2039BF conical filter due to its tremendous amount of media surface area which bumps up filtration capability. The filter we selected measured a massive 9.25-inches in height and it allowed us to use a full 3-inch intake pipe all the way from the turbocharger to the filter inlet.

Full-Race’s Answer to the Naturally Aspirated FA20 (11)

Given the nature of turbocharger installations, this top mount kit is actually pretty straightforward. The charge pipe setup requires some trimming of the non-structural headlight support and a -10AN fitting must be welded to the oil pan for the oil drain. Full- Race includes detailed step-by-step installation instructions on its website, complete with pictures and tips for a smooth install. We took our time to ensure proper installation of all components and didn’t encounter any major setbacks.

Full-Race’s Answer to the Naturally Aspirated FA20 (12)

With the kit installed and ready for a tuning session on the DSPORT Dynojet all-wheel- drive dynamometer, we turned to our resident EcuTek pro tuner Bill Knose from Delicious Tuning. Already equipped with the flex-fuel kit from Delicious Tuning, our D’Garage FR-S hit the dyno for a tuning session on both 91 octane and E85. Beginning with ACN 91 octane at about 10 PSI of boost, we were able to reach 308.43 wheel horsepower and 247 lb-ft. of torque. Bill added in a throttle boost control for the ACN 91 octane because the boost creeped significantly at high RPMs and the only way to control it was with throttle control. The flat torque and subsequent linear power curve makes for a “this is what it should have felt like” experience.

(Video) The 2022 Subaru BRZ Doesn't Need A Turbo - 2.4L Boxer Engine Explained

Full-Race’s Answer to the Naturally Aspirated FA20 (13)

On 91 octane, the FA20 pumped out 308.43 whp and 247 lb-ft of torque.

Although the 91 octane results were impressive, we quickly drained the fuel and poured in a few gallons of fresh E85 to see where the 7163 could take our stock-block FA20. Once back on the dyno, Bill slowly increased the boost up to about 15 PSI. At this boost level, the D’Garage FR-S put down 411.17 wheel horsepower and 332.13 lb-ft. of torque. Unfortunately, the connecting rods on the FA20 are known to let go around this torque range so we wouldn’t recommend going above 330 lb-ft of torque. While the 7163 turbocharger definitely had more power left in it, we decided not to push our limits. Even though the factory engine left the dyno in one piece, we think we might be dangerously close to the threshold of what’s sustainable. We’ll see how long this setup lasts and anticipate going to more power at higher boost levels for the fully-built engine we’re putting together at Club DSPORT.

Full-Race’s Answer to the Naturally Aspirated FA20 (14)On E85, the FA20 generated 411.17 whp and 332.13 lb-ft of torque.

Full-Race’s Answer to the Naturally Aspirated FA20 (15)

(Video) Blown Subaru BRZ / Scion FRS FA20 Boxer Engine Teardown. A $3,000 + Whoopsie.


What is the most powerful FA20? ›

FA20 World Record - 811whp/499tq @ 40psi.

What is the difference between the FA20 and the FA20F? ›

The FA20D (often referred to simply as the FA20) is the 200-flywheel horsepower naturally-aspirated version found in the BRZ, FR-S and 86; while the FA20F (mistakenly referred to as the FA20T, since it is turbocharged) delivers nearly 270-flywheel horsepower.

Is FA20 naturally aspirated? ›

The FA20 builds on the base of the next-generation boxer engine's design concept to develop a new normally aspirated engine, which aims for higher output and environmental performance as well as an even lower center of gravity.

How much HP can FA20 handle? ›

You can safely make up to 300whp/360bhp on an OEM FA20 short block with proper maintenance and a solid tune.

How much power can a FA20 WRX handle? ›

The OEM FA20DIT fuel system is capable of around 450 HP before secondary port injection should be considered.

How much HP can a built FA20 make? ›

Other than that, you'll be set for a 350-700 HP BRZ/FR-S/GT86! The stock FA20 block it self can handle pretty much 500-700 HP if you upgrade the internals. The only reason people blow engines or make holes in their blocks is because a rod or piston breaks and launches into your block at 8000 RPM!

What is the top speed of a FA20 WRX? ›

2018 Subaru WRX 0-60, Top Speed and Quarter-Mile
Trim Name0-60 MPHTop Speed
4dr Sedan AWD (2.0L 4cyl Turbo 6M) Premium 4dr Sedan AWD (2.0L 4cyl Turbo CVT) Limited 4dr Sedan AWD (2.0L 4cyl Turbo CVT) Limited 4dr Sedan AWD (2.0L 4cyl Turbo 6M) +2 More5.2 sec160 mph
Premium 4dr Sedan AWD (2.0L 4cyl Turbo 6M)5.5 sec160 mph

What size turbo is stock on FA20? ›

The FA20 Blue™ turbocharger for the 2015+ Subaru WRX features the 73mm HTZ™ compressor wheel with a stock fitment, stock appearing cover coupled to the 10cm2 turbine section.

How can I make my FA20 stronger? ›

FA20 Turbo Upgrades

The more air you can get into an engine, the more fuel it can burn and uprating the induction with a turbocharger upgrade makes superb power gains. When the engine is fitted with a turbocharger upgrades are more reliable and you will discover turbo charged engines are built with uprated components.

Does the FA20 have forged internals? ›

JE FA20 and FA20DIT pistons are of a forged side relief design (FSR).

How long do FA20 Motors last? ›

It will last 100,002 miles.

What fuel pressure for FA20? ›

The HPFP needs a constant supply of fuel pressure (around 4 bar) at its inlet in order to avoid cavitation.

Is the FA20 crankshaft forged? ›

HKS FA20 2.1L Capacity Upgrade Kit (Low Comp)

HKS has developed a highly durable low compression piston required to move onto the next tuning level. The crankshaft is made from forged materials.

Is the FA20 a short block? ›


Short block built with FA20 2.2L LOW COMP KIT essential for high power turbo engine. Closed deck design significantly improved strength from open deck. Piston coated by two-layer molybdenum for less friction.

How much HP is a Stage 2 WRX? ›

Stage 2 vs Stock

This included the same fuel from our stage 1. We removed the 2nd restrictor pill and added a Grimmspeed J-pipe and Intake. This stage made 232.0HP and 252.1FtLb TQ on our dyno.

What happens if you put 87 in a WRX? ›

For the WRX model, the Owner's Manual states: “The engine is designed to operate using unleaded gasoline with an octane rating of 91 or higher.” However, fuel with an octane rating of 87 or higher can be used with no detriment to engine durability.

Does WRX have more power than STI? ›

Overall, the key difference between the Subaru WRX and WRX STI is performance. The Subaru STI is the more powerful and performance-oriented of the two. It comes with a bigger engine, stiffer springs, thicker tires, more powerful brakes, and more. By comparison, the WRX isn't something to sleep on.

How much HP does a FA20 WRX have? ›

FA20 DIT engine uses twin scroll Garrett MGT2259S turbocharger. The maximum boost pressure is 15.9 psi (1.1 bar), and power is 272 HP at 5,600 rpm, torque 350 Nm at 2,000-5,200 rpm.

How much horsepower does a WRX have compared to a BRZ? ›

Engine and Power

The Subaru WRX carries a 2.4-liter DOHC turbocharged engine. It can deliver up to an estimated 271 horsepower and 258 pound-feet of torque. The Subaru BRZ is packed with a 2.4-liter DOHC engine and is able to produce up to approximately 228 horsepower and 184 pound-feet of torque.

What model WRX is fastest? ›

2013 Subaru WRX Special Edition

The 2013 Subaru WRX Special Edition was capable of doing 0-60 MPH sprint in 4.7 seconds and reaching a top speed of 142 MPH.

Which engine is better EJ or FA? ›

While the EJ motors remain sensitive to knock conditions and tuners do everything in their power to prevent detonation, the FA motors are even more sensitive and the challenges of direct injection have made avoiding knock much harder.

Is the WRX FA20 reliable? ›

Currently, owners have given them an average reliability rating of just two out of five. Like the EJ series engines, the FA20 engines in the fourth-gen WRX and WRX STI models are experiencing connecting rod failures. But most of these failures are coming due to modifications like aftermarket tunes and additional power.

Can you replace a stock turbo with a bigger turbo? ›

If you're looking to maximise the power and performance of your vehicle, then changing your stock turbocharger for a bigger or better model can be an effective part of the process.

What is the stock fa20 compression ratio? ›

Compression ratio for the turbo engine falls to 10.6:1 from 12.5:1 for the FA20D.

How much HP can a 2017 WRX handle? ›

Skim through the Subaru forums and you'll find the question on so many STI owners' minds, “how much horsepower can my EJ257 handle?” The answer is different for everyone, but the general consensus is that the 400-450whp range is when you might want to clear out the garage and get ready to pull a motor.

What is the difference between FA20 and fa24? ›

The FA24F was introduced in 2018 initially for the 2019 model year Subaru Ascent. The bore is increased compared to prior FA20 engines, increasing displacement to 2.4 L (2,387 cm3). The engine has an all aluminum head and block in order to keep weight and warm-up times low.

Which Subaru has the most power? ›

1. 2021 Subaru WRX STI
2021 Subaru WRX STISpecs
Powertrain2.5L Turbo Inline-4
Horsepower305 hp
Torque295 lb-ft
Transmission6-speed manual
3 more rows
May 15, 2023

What size is the stock turbo on the FA20? ›

The FA20 Blue™ turbocharger for the 2015+ Subaru WRX features the 73mm HTZ™ compressor wheel with a stock fitment, stock appearing cover coupled to the 10cm2 turbine section.

Is the WRX or STI faster? ›

The Subaru STI is the more powerful and performance-oriented of the two. It comes with a bigger engine, stiffer springs, thicker tires, more powerful brakes, and more.

What is Subaru's fastest car? ›

The answer is a resounding yes! The 2019 Subaru STI S209 reaches the 60 MPH mark in only 4.5 seconds, and it can go 155 MPH. So expect to have some fun when you get out on a track with the Subaru STI S209. If you want a speedy Subaru, this vehicle is going to get you there.

Why is Subaru so powerful? ›

Unlike Petelgeuse who called the power the "Unseen Hand," Subaru chose to call his version of the Authority "Invisible Providence." Invisible Providence was a power that allowed Subaru to summon invisible hand-like appendages from his chest that he could move and extend telekinetically.


1. Stock FRS vs Supercharged BRZ
(Gears and Gasoline)
2. 7 Cheap Engine Mods your 86/BRZ NEEDS in 2021!
(Angus Outram)
3. Subaru BRZ w/ Ethanol & Bolt-Ons - One Take
4. Subaru FA 20 engine internal modifications tips and traps with turbo and supercharger
(MRT Performance)
5. The 12,000rpm Subaru called Betty 😲 | Built by GotitRex
6. Building a Time Attack FRS in 10 minutes!
(Kevin Vo)


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