Choosing the Right Blouch Turbo for Your Subaru
Upgrading the turbo on your WRX or STI is one of the single biggest power modifications you can make — and Blouch Performance Turbo has been the go-to choice for Subaru owners for over two decades. But the Blouch range has grown significantly, and choosing between a DOM 1.5, 2.5, 3.0, the XT-R series, and the newer G2R series can be genuinely confusing. This guide breaks down every Blouch turbo in the current WRX/STI lineup, explains the real-world differences, and helps you pick the right one for your power goals, fuel type, and driving style.
Every turbo in this guide is a direct bolt-on replacement for the factory unit — same oil, coolant, and exhaust connections. No custom fabrication needed. That's the beauty of the Blouch platform.
The Complete Blouch WRX/STI Turbo Lineup
Entry Level — TD05H XT Series
If you're stepping up from the factory VF turbo but want to keep things simple and affordable, the TD05H XT series is where you start. These turbos use Blouch's CNC billet compressor wheels on the proven TD05H platform.
TD05H-16G-XT — The smallest upgrade in the range. A noticeable improvement over the factory VF with faster spool and more airflow. A good choice if you want a bit more power without changing anything else on the car. Capacity: ~300bhp.
TD05H-18G-XT — Steps up the compressor size for more mid-range and top-end. Still spools quickly but delivers noticeably more power than the 16G. Capacity: ~350bhp.
TD05H-20G-XT — The largest of the TD05H series. Pushes more air for builds targeting 350–380bhp. You'll want supporting fuel modifications at this level. Capacity: ~380bhp.
Mid-Range — XT-R Series (Ball Bearing)
The XT-R series is where Blouch really separates itself. These turbos use ceramic ball bearing centre sections instead of journal bearings, which means dramatically faster spool, lower friction, and better durability. The "R" in XT-R stands for the XT-R billet compressor wheel — Blouch's fully machined, closed-die forged compressor with optimised aerodynamics.
16G-XT-R — Ball bearing version of the 16G-XT. Noticeably faster spool than the journal bearing version with the same airflow. Great for stock-engine WRX builds that want more response. Capacity: ~320bhp.
18G-XT-R — The sweet spot in the XT-R range. Fast spool, strong mid-range, and enough headroom for a well-tuned EJ25 on pump fuel. Capacity: ~370bhp.
20G-XT-R — The biggest of the non-Dominator XT-R turbos. Pushes more air at the top end while still spooling faster than the journal bearing 20G-XT. Capacity: ~400bhp.
Dominator XT-R Series — The Street/Track Sweet Spot
The Dominator series is what made Blouch famous. These are larger-frame turbos that use custom turbine housings, custom compressor covers, and the full XT-R billet compressor wheel technology. They're designed to make serious power while still fitting in the factory turbo location.
DOM 1.5 XT-R — Custom 56.5mm turbine wheel, Blouch 71mm XT-R compressor wheel supporting 49 lb/min airflow, ceramic ball bearing CHRA. The fastest-spooling Dominator. Originally developed for 2.0L EJ20 engines in the UK where mid-range response matters more than peak power. On an EJ25, it delivers an incredibly broad powerband with quick spool and strong pull all the way to redline. Available in 8cm² and 10cm² turbine housings. This is the turbo for daily-driven WRX and STI builds that want serious power without sacrificing drivability. Capacity: 480bhp.
DOM 2.5 XT-R — Custom 60mm turbine wheel, Blouch 71mm XT-R compressor wheel supporting 49 lb/min airflow, ceramic ball bearing CHRA. The original "Polka Pickle". The full 60mm turbine delivers slightly more top-end power than the 1.5 at the cost of marginally slower spool. This is the turbo that built Blouch's reputation — thousands of these have been fitted to WRX and STI builds around the world. Available in 8cm² and 10cm² housings. Adjustable wastegate actuator is pre-calibrated to 15 PSI. The go-to for builds targeting 350–400whp on pump fuel or 400–450whp on E85. Capacity: 490bhp.
Dominator G2R Series — Latest Generation
The G2R series is Blouch's newest technology. The "G2" refers to the second-generation compressor wheel design with improved aerodynamics that flows more air than the XT-R wheel at the same physical size. This means you get a higher power ceiling without increasing spool time.
DOM 1.5 G2R — Custom 56.5mm turbine wheel, Blouch 71mm G2 compressor wheel supporting 52 lb/min airflow, ceramic ball bearing CHRA. Same fast-spooling turbine as the 1.5 XT-R but the G2 compressor pushes 3 lb/min more air. The result is quicker spool than the 2.5 with a higher power ceiling than the 1.5 XT-R. Available in 8cm² and 10cm² housings. The best all-round choice for new builds. Capacity: 520bhp.
DOM 2.5 G2R — Custom 60mm turbine wheel, Blouch 71mm G2 compressor wheel supporting 55 lb/min airflow, ceramic ball bearing CHRA. The "Polka Pickle" upgraded. The G2 compressor on the full 60mm turbine pushes significantly more air than the 2.5 XT-R while maintaining similar spool characteristics. Ideal for builds pushing past 400whp where you want headroom for future power increases. Available in 8cm² and 10cm² housings. Capacity: 550bhp.
DOM 3.0 G2R — Custom 60mm turbine wheel, 57mm/76mm G2 compressor wheel supporting 60 lb/min airflow, ceramic ball bearing CHRA. The biggest bolt-on Dominator. Built for serious high-horsepower EJ builds running E85 or race fuel with full supporting modifications. The larger compressor wheel pushes substantially more air than the 2.5 G2R for significantly higher peak power. Available in 8cm² and 10cm² housings. This is a track and drag turbo — if you're building a 450whp+ street car and want it to still spool like a factory turbo, look at the 1.5 or 2.5 instead. Capacity: 600bhp.
High Power — DOM 4.0 and 5.0 XT-R
DOM 4.0 XT-R — Full ball bearing, larger compressor wheel than the 3.0. For builds targeting 550+bhp. Requires full supporting modifications including front-mount intercooler, uprated fuel system, and E85 or race fuel. Capacity: ~580bhp.
DOM 5.0 XT-R — Full ball bearing, 65 lb/min compressor wheel, 3" inlet. The biggest bolt-on Blouch turbo available. Built for maximum power builds on built EJ engines. Requires a 3" inlet which means aftermarket intake piping. Capacity: 650bhp.
XT-R vs G2R — Which Series Should You Choose?
This is the most common question buyers have, so let's address it directly.
The XT-R series uses Blouch's 71mm XT-R billet compressor wheel with 49 lb/min maximum airflow. It's a proven design that's been in production for years with an enormous track record of reliability and performance.
The G2R series uses Blouch's 71mm G2 compressor wheel with improved aerodynamics and higher maximum airflow — 52 lb/min on the 1.5, 55 lb/min on the 2.5, and 60 lb/min on the 3.0. The G2 wheel pushes more air at the same physical size, which means you get a higher power ceiling without sacrificing spool.
In practical terms: if you're building a new setup today and the budget allows, the G2R is the better choice. It gives you more headroom for future power increases. If you're on a tighter budget or you find a good deal on an XT-R, you're not missing out — the XT-R is still an excellent turbo and thousands of fast Subarus are running them.
8cm vs 10cm Turbine Housing — Which One?
Most Dominator turbos are available with either an 8cm² or 10cm² turbine housing. The turbine housing size affects how quickly exhaust gases reach the turbine wheel and how freely they exit.
8cm² housing: Smaller volume means exhaust gases reach the turbine faster. Quicker spool, earlier boost onset. Better for street cars, lower boost targets (under 20 PSI), and smaller displacement engines (EJ20). The trade-off is slightly higher backpressure at high RPM which limits peak power.
10cm² housing: Larger volume means better exhaust flow at high RPM. Lower backpressure, lower exhaust gas temperatures, and more top-end power. Better for track cars, higher boost targets (20+ PSI), larger displacement engines (EJ25), and E85 builds where you're pushing more fuel and air through the engine. Slightly slower spool than the 8cm.
For most Australian WRX/STI builds running an EJ25 on pump fuel or E85, the 10cm housing is the right choice. The spool difference between 8cm and 10cm is marginal on a 2.5L engine, and the reduced backpressure gives your tuner more room to make safe, reliable power. The 8cm housing makes more sense on EJ20 builds or applications where absolute spool speed is the priority.
Which Blouch Turbo for Your Power Goal?
250–320whp — Daily Driver, Minimal Mods
The TD05H-16G-XT or 16G-XT-R is your turbo. Quick spool, easy installation, and enough power to make the car noticeably faster without needing a full supporting modification list. You'll want an ECU tune and quality exhaust but can likely run stock injectors and fuel pump.
320–380whp — Strong Street Car
The 18G-XT-R or 20G-XT-R gets you here. You'll need larger injectors, an uprated fuel pump, a quality turbo-back exhaust, and a professional tune. This is the sweet spot for a fast daily driver that you occasionally track.
380–450whp — Serious Street/Track Build
This is DOM 1.5 XT-R or DOM 2.5 XT-R territory. The 1.5 if you prioritise response; the 2.5 if you want more top-end. At this power level you need the full supporting mod list: larger injectors (ID1050x or ID1300x), uprated fuel pump, turbo-back exhaust, front-mount intercooler, uprated clutch, and a professional tune. If you're running E85, plan for a Radium fuel pressure regulator or surge tank.
450–550whp — Built Engine / Track Weapon
The DOM 1.5 G2R, 2.5 G2R, or 3.0 G2R depending on where in that range you want to sit. At this level you should be on a built engine (forged internals), running E85 or race fuel, with every supporting modification in place. The G2R series gives you the headroom to grow into this power level without changing turbos.
550whp+ — Drag / Time Attack
The DOM 4.0 XT-R or 5.0 XT-R. Full race builds with built engines, E85 or methanol, and professional tuning. These turbos sacrifice some low-end response for massive top-end power.
Supporting Modifications Checklist
A turbo upgrade without supporting modifications is money wasted — and potentially engine damage. Here's what you need at each level:
Every Blouch Turbo (Minimum)
• Professional ECU tune (mandatory — the turbo will not perform correctly on the factory map)
- Quality turbo-back exhaust — KORSH Performance stainless steel or titanium systems are designed specifically for Subaru platforms
- Uprated brake pads — DIXCEL Z-type or RE-type compounds for spirited street and track driving
DOM 1.5 XT-R and Above (Add These)
• Larger fuel injectors — Injector Dynamics ID1050x for pump fuel builds, ID1300x for E85
- Uprated fuel pump — the factory pump runs out of capacity around 300whp
- Front-mount intercooler — recommended for DOM 2.5 and above, essential for 3.0 G2R
- Uprated clutch and flywheel — the factory clutch will not hold the increased torque
- Boost controller — electronic boost controller for precise and repeatable boost targeting
E85 Builds (Add These)
• E85-compatible fuel system throughout — Radium Engineering fuel pressure regulator, surge tank, and fuel rails ensure consistent fuel delivery under all conditions
- Flex fuel sensor and tune — allows your ECU to adjust for varying ethanol content at the pump
- Larger fuel lines — the factory fuel lines are marginal for E85 flow rates above 400whp
High Power Builds — 450whp+ (Add These)
• Built engine with forged internals — the factory cast pistons and rods have a hard limit around 400whp on an EJ25
- Uprated oil pump — factory oil pump struggles to maintain pressure at high RPM under sustained load
- AOS or catch can — Radium Air Oil Separator keeps blow-by out of your intake, especially important on built engines making boost
Fitment Notes
All Blouch WRX/STI turbos are direct bolt-on replacements for the factory turbo. They ship complete with braided stainless steel oil feed line, oil feed restrictor, oil drain tube, coolant pipes, banjo bolts, copper washers, turbo mounting gaskets, and a pre-calibrated adjustable wastegate actuator (set to 15 PSI unless specified otherwise).
2002–2007 WRX / 2004–2021 STI: Direct fit, no modifications required.
2008–2014 WRX / 2008–2013 Forester XT / 2007–2009 Legacy GT: These models use a different intercooler hose routing. Installing a Blouch Dominator requires an aftermarket front-mount intercooler with a traditional STI-style hot-side intercooler hose. The turbo bolts on, but the intercooler plumbing needs to change.
DOM 5.0 XT-R: Uses a 3" inlet compressor housing due to the size of the 65 lb/min compressor wheel. Requires aftermarket 3" intake piping.
Browse the full Blouch range at Chicane Australia: Blouch Performance Turbo. Supporting mods for your build: Injector Dynamics · Radium Fuel Systems · KORSH Exhausts · DIXCEL Brakes WRX/STI · Hardrace Suspension
Need help choosing the right Blouch turbo for your build? Contact us or email sales@chicaneaustralia.com.au — we can help you spec the right turbo and supporting modifications for your power goals.
