2022+ Subaru WRX Turbo Shootout: 8 Turbos Tested at the Same Boost

Have you ever wondered which turbo is actually the best for your 2022+ Subaru WRX? So did we. So we tested EIGHT of them.

Dyno sheets from different shops, different cars and different boost levels only tell you so much. We wanted real answers, so we bolted the factory FA24F turbo and seven of the most popular bolt-on upgrades onto the same WRX, strapped it to the same Dynojet 424x, filled it with the same E60 fuel and tuned every single turbo to hold the exact same boost. One car. One dyno. One variable: the turbo. And nobody paid us to do it. We either bought these turbos ourselves or had them on loan.

Want to skip straight to the data? The full interactive results are at the bottom of the page, where you can compare every turbo at every boost level yourself.

Not Your Average Dyno Day

This was no seat-of-the-pants shootout. Our WRX shop car is wired with more than 12 pressure and temperature sensors from the intake to the exhaust, logged on a MoTeC dash and synced with the COBB Accessport data from every pull. That means we’re not guessing at what each turbo is doing. We’re measuring it: compressor efficiency, pressure ratio, backpressure, turbine drive pressure, intercooler efficiency, intake pressure drop and more. It also let us confirm air-fuel ratio and timing stayed consistent, so no turbo got a better tune than the next.

The contenders: the Blouch 5056XT and 5356XT, Equilibrium EQT-660 and EQT-770, Tomioka Racing VB670, Boost Lab BL54XR and PLM P660, with the factory VB turbo as the baseline. Each one ran flat 14, 16, 18 and 20 psi, then 20 psi climbing to 22, 24, 25 or 26 psi up top, all on a stock engine. Every turbo breathed through the same AMS hardware: our front mount intercooler and intake, plus a few parts you can’t buy yet, including our upcoming catted downpipe, our upcoming turbo inlet pipe with adapters to fit each turbo’s inlet, and a prototype AMS cat-back. More on those soon.

Here’s how the turbos stack up on paper, using each maker’s published specs. Wheel sizes are in millimeters (inducer / exducer).

Percentages compare inducer diameter to the factory turbo. Boost Lab doesn’t publish exducer or turbine wheel sizes. Ratings are shown as each maker publishes them (crank hp, wheel hp or airflow), so they aren’t a direct comparison.

How We Tested

This was not a max-power contest. Every turbo ran the same boost targets on a matched tune, held within about 0.3 psi of target and within 0.5 psi of each other, so we could isolate what each one does to the engine: backpressure, spool and response. A customer tune would give each turbo its own boost curve and timing, so these peaks aren’t where every turbo tops out. What no tune can change is how hard the engine has to push its exhaust out, and how fast the turbo comes up to boost.

To protect the stock engine, we capped torque at about 420 lb-ft and tuned for a flat torque curve wherever we could. On the climbing profiles, boost ramps in as rpm rises to hold that torque all the way to our 6,500 rpm rev limit. Some turbos could keep up. Some of the smaller ones couldn’t do it efficiently, which is why the climbing profiles top out at different boost levels: the 5056XT stops at a flat 20 psi, the 5356XT at 20 → 22 and only the EQT-770 made it to 20 → 26. We raised the rev limit to 6,500 rpm for testing, above the factory 6,100 rpm redline, and some tuners go as high as 7,200 rpm on the stock engine for high-horsepower builds. The higher you rev, the more a low-backpressure turbo like the 770 pays off.

You won’t see every run we made, either. Once a turbo hit the point of diminishing returns, we stopped and left that data out. Forcing the wastegate shut to squeeze more boost from a turbo running well outside its efficiency range nets almost no power, but backpressure shoots up. When an extra 1 psi of boost costs 5 psi of exhaust backpressure, that turbo is done.

All power figures are uncorrected Dynojet wheel horsepower. SAE and STD corrections are a click away in the tool, though they exaggerate weather differences on boosted cars. Runs spanned about 45 to 94 °F, so call a few horsepower a tie. Heat slows spool too, about 30 rpm per 10 °F, so the EQT-660, EQT-770 and Boost Lab, tested on 89 to 96 °F days, are each a bit quicker than shown. And because the tune ramps boost to full by about 2,350 rpm, the quickest turbos, the factory unit and the 5056XT, may be quicker still.

Why Backpressure Matters

A turbo is driven by exhaust, so its turbine is always a restriction the engine has to push through. The pressure that stacks up in front of it, shown in the tool as engine ΔP (exhaust manifold pressure minus boost), is one of the clearest measures of how hard a turbo makes the engine work. It shows up three ways:

• Lost power. Every psi of backpressure is work the pistons spend pushing exhaust out instead of turning the crank. On the FA24 that’s about 1.1 hp per psi at 6,000 rpm, before anything else goes wrong.
• Hotter cylinders and more knock. When exhaust pressure outweighs boost, more hot exhaust gas stays trapped in the cylinder for the next cycle. That raises combustion temperatures and makes the engine more prone to knock, so the ECU pulls timing and power drops further, especially on pump gas.
• More heat and stress. Exhaust that can’t get out carries its heat into the exhaust valves, cylinder head and turbo, which is load you don’t want on a stock engine.

The Results

Here’s what roughly 180 dyno pulls told us.

• Every upgrade beats stock at the same boost. At 14 psi, every upgrade topped the factory turbo’s 349 whp, making 356 to 371 whp on the same tune. The stock turbine is the bottleneck, as the backpressure table below shows: more of its power goes to pushing exhaust instead of turning the wheels.
• Lowest backpressure: Equilibrium EQT-770. Lowest backpressure and highest turbo efficiency at every boost level, thanks to the biggest compressor in the test and one of the two biggest turbines. That free-flowing exhaust is why it made the most peak power at matched boost from 16 psi up, topping out at 490 whp on 20 → 26 psi.
• Quickest spool: Blouch 5056XT. It hit 90% of target boost at about 2,400 rpm at every flat boost level. At 20 psi, that matches the factory turbo’s 19 psi run almost exactly. The catch is its small compressor: it runs out of breath around 20 psi and topped out at 415 whp, the lowest power ceiling of any upgrade.
• The sweet spot: Equilibrium EQT-660. Second-lowest backpressure and second-highest efficiency at every boost level, and still at full boost before 3,000 rpm.
• Spool versus backpressure is the tradeoff. Bigger turbines let exhaust out more easily but take more energy to spin up: at a flat 20 psi, the EQT-770 was still at 14.2 psi at 3,000 rpm while the rest were near 20. Size isn’t everything, though. The PLM P660’s turbine is about as big, yet it ran more backpressure, so housing and wheel design matter too.
• The midrange is tight. Once on boost, the field ran within about 25 whp at 5,000 rpm.

Backpressure vs. the Factory Turbo

At 6,000 rpm, here’s how much exhaust pressure each turbo stacked up over boost, in psi, lowest first. The EQT-770 and EQT-660 ran the lowest at every boost level. Ask the factory turbo for 19 psi and it climbs past 20 psi of backpressure while boost fades to 16, burning about 22 hp just pushing exhaust out. Below about 3,800 rpm, every turbo runs negative backpressure, so the exhaust side is actually helping the engine breathe. The Engine ΔP chart in the tool below shows the full curves.

*Factory turbo’s 19 psi reference run, where boost faded to 16 psi by 6,000 rpm. **The 5056XT was only holding about 17.5 and 19.5 psi at 6,000 rpm on these runs, which flatters its backpressure figures.

Spool vs. the Factory Turbo

Here’s how quickly each turbo reached 90% of target boost at every flat boost level. At 14 psi, the Blouch pair basically keeps factory response, while the EQT-770 trades the most spool for the lowest backpressure. Ask for more boost and the gaps grow. From 14 to 20 psi, every upgrade except the 5056XT spooled 100 to 300 rpm later. Against the factory turbo’s 19 psi run, that puts the middle four roughly 380 to 460 rpm behind stock and the EQT-770 about 770 rpm behind.

*The factory turbo ran 14 psi plus a 19 psi reference run, so its 20 psi figure comes from that 19 psi run.
Treat small spool gaps as a tie. Runs were spread across days with different air temperatures and barometric pressure, and even exhaust manifold temperature can nudge spool a little. We kept conditions as consistent as we could, but some run-to-run variance is part of real-world testing.

So, Which Turbo Should You Buy?

• Quick spool for the street: Blouch 5356XT. Second only to the 5056XT for spool at every boost level, landing about 90 to 250 rpm behind the factory turbo from 14 to 20 psi for near-stock response. Plan on topping out around 450 whp. It gives up a little spool to the 5056XT as boost climbs but brings far more power on tap, so there’s no reason to run the smaller Blouch. It also reuses your factory lines, which keeps the install simple.
• Best balance: Equilibrium EQT-660. More room to grow than the quick-spool options without giving up much response. It’s our pick for E85 and flex fuel builds on the stock engine, where its quicker spool pays off and the engine itself becomes the limit before the turbo does. We expect it to make around 500 whp on E85 with a stock engine. Equilibrium also ships the best-quality lines of the group.
• Most headroom: Equilibrium EQT-770. A great option if you’re staying on pump gas or plan to build the engine and want to maximize horsepower. Its low backpressure makes the engine less prone to knock, so we think it runs better, and safer, on pump gas. It made 490 whp in our controlled test, and we expect well over that with a built engine and supporting modifications, likely 600+, once it’s tuned to its full potential. The tradeoff is spool, with full boost arriving around 3,000 to 3,200 rpm.

Dig Into the Data Yourself

The SnailWorks Engineering Team packed every pull into the interactive shootout below. Pick a boost level, toggle turbos on and off, overlay dyno curves and compare spool, backpressure and efficiency head to head. Want to nerd out? The Metrics tab breaks down exactly what every number means and where it comes from.

Want an AMS Turbo for Your WRX?

We’ve measured every turbo in this shootout down to the last psi of backpressure, and we’ve got ideas. Quick spool, big top end and the data to prove it, engineered by the SnailWorks Engineering Team to bolt right onto your VB WRX. If you want us to build the ultimate bolt-in turbo, let us know. Make enough noise and we’ll make it happen.