K04-001XL E05 50mm Billet Hybrid Turbo Upgrade
VW Golf GTI MK4 | Jetta 1.8T | New Beetle 1.8T | Audi TT 180HP
Upgrade beyond an ordinary K03 replacement. The XS-POWER K04-001XL combines an enlarged 50mm billet compressor design with a compact K04-style turbocharger configuration for enthusiasts seeking stronger airflow potential, responsive boost and serious Volkswagen/Audi 1.8T performance.
Performance Highlights
Upgraded E05-style compressor configuration.
Compact performance upgrade for compatible 1.8T applications.
Customer-reported result; not a guaranteed output.
Select transverse 1.8T engine configurations.
Why Upgrade Your VW 1.8T Turbo?
The Volkswagen and Audi 1.8T 20-valve turbo engine has long been a favorite among European performance enthusiasts. Whether you are upgrading a MK4 Golf GTI, building a modified Jetta 1.8T or improving the performance of an Audi TT 180HP, turbocharger selection is one of the most important decisions in the build.
A basic K03 replacement is generally intended to restore original turbocharger operation. The XS-POWER K04-001XL is designed for a different purpose: providing an upgraded compressor configuration for customers seeking greater airflow potential and improved performance when matched with appropriate tuning and supporting modifications.
- Enlarged billet compressor: 50mm E05-style upgrade for performance-oriented airflow capability.
- Compact hybrid configuration: Designed for enthusiasts seeking an alternative to a much larger custom turbo installation.
- Responsive street performance: Turbo sizing is intended to balance airflow and boost response.
- Performance upgrade path: Suitable for properly planned 1.8T builds with compatible hardware and engine management.
- Customer dyno documentation: Real-world results are available for buyers researching the upgrade.
K03 Replacement vs. XS-POWER K04-001XL
| Feature | Stock-Style K03 | XS-POWER K04-001XL |
|---|---|---|
| Primary purpose | Factory-style replacement | Performance upgrade |
| Compressor configuration | Original-style sizing | Upgraded 50mm billet design |
| Power potential | Primarily OEM-oriented | Greater upgrade potential with supporting modifications |
| Tuning | Depends on application | Performance calibration recommended |
| Fitment | Application-specific | Verify engine code, housing and inlet configuration |
Real-World Customer Dyno Results
XS-POWER has received customer-submitted performance information documenting the K04-001 billet turbocharger on a modified 1.8T application.
One reported result reached 266 wheel horsepower. The original product documentation also describes comparative dyno testing against a factory-style K03 and a Frankenturbo F21 configuration, including testing at approximately 8,600 feet of elevation using locally available 89-octane fuel.
These examples demonstrate why turbocharger performance should be evaluated through complete vehicle testing, including boost response, tuning, fuel quality, supporting components and environmental conditions.
View the product image gallery for the available dyno charts and turbocharger housing photographs.
Volkswagen and Audi 1.8T Application Guide
This turbocharger is intended for selected Volkswagen and Audi 1.8T applications with compatible K03/K04-001-style turbo mounting arrangements. The vehicles below are application references, not an unconditional bolt-on guarantee.
| Vehicle | Engine | Fitment Guidance |
|---|---|---|
| VW Golf MK4 / GTI | 1.8T 20V | Verify AWD, AWW or AWP engine and existing turbo configuration. |
| VW Jetta MK4 | 1.8T 20V | Verify engine code, inlet pipe and exhaust housing. |
| VW New Beetle | 1.8T | Selected applications; confirm existing turbo hardware. |
| Audi TT MK1 180HP | 1.8T | Selected compatible configurations; inlet upgrade may be required. |
Common VW engine-code references: AWD, AWW and AWP. These are references for fitment verification and do not establish compatibility by themselves.
- Compare the exhaust-side housing and mounting arrangement with the product photographs before ordering.
- Some Audi TT 180HP applications, including ATC configurations, may require a larger turbo inlet pipe.
- Not intended as a direct bolt-on replacement for the factory Audi TT 225HP K04 twin-intercooler turbo configuration.
- Longitudinal Audi A4 and VW Passat applications may use different turbocharger housings and connections. Do not assume direct compatibility.
- Contact XS-POWER with your model year, engine code and existing turbocharger identification if fitment is uncertain.
Turbocharger Specifications
| Brand | XS-POWER |
| Product type | Performance hybrid turbocharger |
| Model | K04-001XL / K04-001XLB |
| Compressor | E05-style billet compressor |
| Advertised compressor size | 50mm |
| Engine platform | Selected VW / Audi 1.8T 20V |
| Inlet pipe | Not included |
| Installation | Professional installation and appropriate tuning recommended |
What Is Included?
- 1 XS-POWER K04-001XL E05 billet turbocharger
- Supplied turbocharger gaskets
Not included: Larger turbo inlet pipe, tuning, fuel-system upgrades, intercooler upgrades or other supporting modifications unless specifically stated in the selected purchase option.
Recommended Installation and Supporting Upgrades
A properly planned K04 hybrid turbo upgrade involves more than replacing the turbocharger. Engine calibration, fuel delivery, charge-air temperatures and exhaust flow can all affect reliability and performance.
- ECU tuning calibrated for the installed turbocharger and hardware.
- Compatible turbo inlet piping and intake connections.
- Fuel injectors and fuel delivery components sized for the intended power level.
- Appropriate intercooler capacity and boost-leak-free charge piping.
- Compatible downpipe, exhaust and turbo oil/coolant connections.
- Inspection of oil supply, oil return and cooling connections during installation.
Do not assume that a factory ECU calibration, stock fuel system or existing intake plumbing will support an upgraded hybrid turbocharger at its full performance potential.
Complete Your VW / Audi 1.8T Performance Build
Explore additional XS-POWER products for your turbocharged Volkswagen or Audi:
- Shop Volkswagen Turbochargers and K04 Upgrades
- Compare the XS-POWER K04-001XLB Billet Turbo Listing
- K04-001 Turbo Package With Diverter Valve and Boost Controller
Frequently Asked Questions
Is the K04-001XL better than a stock K03 turbo?
The XS-POWER K04-001XL features an upgraded 50mm billet compressor and is intended for performance builds. A stock-style K03 replacement is primarily designed to restore factory operation. Actual performance depends on the complete vehicle setup.
Will this fit my Volkswagen Golf GTI MK4 1.8T?
It is intended for selected MK4 Golf GTI 1.8T configurations, including applications with AWD, AWW and AWP engine-code references. Verify the existing turbocharger housing, exhaust mounting arrangement and inlet connections before ordering.
Does this turbo fit the Audi TT 180HP?
Selected MK1 Audi TT 180HP configurations may be compatible. Some require a larger inlet pipe. Confirm the engine code and turbocharger hardware before purchasing. The TT 225HP configuration is not a direct replacement application.
Can this turbo make 266 wheel horsepower?
A customer-reported dyno example documented 266 WHP. That is an individual result, not a guaranteed rating. Horsepower varies with tuning, fuel, engine condition, boost pressure and supporting hardware.
Is the K04-001XL equivalent to a Garrett GT28RS?
The K04-001XL is marketed as a compact performance hybrid in a similar enthusiast upgrade category. It is not represented as mechanically identical to a Garrett GT28RS. Direct performance comparisons require controlled testing.
Do I need ECU tuning?
Appropriate ECU tuning is strongly recommended for an upgraded hybrid turbocharger. Fuel delivery and boost control must also be matched to the intended setup.
Does the turbocharger include an inlet pipe?
No. The package includes the turbocharger and supplied gaskets. The inlet pipe is not included.
Can I install this on an Audi A4 or Volkswagen Passat 1.8T?
Do not assume direct compatibility. Many longitudinal 1.8T applications use different turbocharger configurations. Contact XS-POWER to confirm the correct upgrade for your engine and existing hardware.
Build Your 1.8T Around the Right Turbo
From MK4 Golf GTI and Jetta builds to selected Audi TT 180HP applications, the XS-POWER K04-001XL E05 billet turbocharger offers a performance-focused alternative to ordinary stock-style replacements.
XS-POWER Performance Parts | Volkswagen and Audi Turbo Upgrades | International Customers Welcome
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EO5 50mm BILLET COMPRESSOR
At sea level and 91 octane we expect a 25% increase just based on atmospheric pressures and fuel. This potentially means 320+whp!!!!
KO4-OO1XL Upgraded Model - HUGE Compressor -
THIS TURBO IS gt28RS territory...slightly smaller.
EXHAUST SIDE PICS TO MAKE SURE IT WILL FIT
AWW ENGINE CODE,
Turbo, with gaskets, no inlet -
Don't get stuck with a KO3 replacement that is less power then your OEM model
Don't get fooled by the Blades - check our blade count out - true EO5 spooling power
FOR example , if you have a 2000 + Audi TT coupe, fwd 180 HP with ATC Engine -you will need to get the larger INLET pipe. Please contact us for further help and details.
2000 - 2001 Audi TT - NON-Quattro with ATC engine1998 - 2004 Volkswagen Beetle - 1.8T2000 Volkswagen Golf - 1.8T2000 Volkswagen Jetta - 1.8T
00-04 Audi Mk400-05 Volkswagen Golf Mk4 GTI/ GLS00-05 Volkswagen Jetta Mk4 GL/ GLI/ GLS00-06 Audi TT Mk1 Typ 8N (Does Not Fit with TT 225 PS)99-05 Volkswagen Beetle 1.8T
There are 2 posted sets of graphs:
1 shows this turbo at 266whp
The second set of graphs show it against some known competitors after a retune.
In the last picture shown you will see e dyno.graphs. These are posted on my facebook pages as well along with a full review from a customer from Columbia. This dyno shows stock vs frankenturbo f21 vs my billet k04-001. The first graph also shows that my turbo has no lag just like the stock k03 and does not lag like the frank unit.
This is real numbers done by a customer at 8600ft above sea level on 89 octane gas...the only available gas in his country.
2000 Golf/Jetta: AWD awd,
2001 Golf/Jetta: AWW aww,
2002+ Golf/Jetta: AWP 1997-1999 Passat: AEB and awp
1999-2001 Passat: ATW
2002 A4: AMB 2000-2001 TT 180hp: ATC,AJQ,APX,APP,ARY,AUQ
2001-2004 TT 180hp: AWP
