Audi RS4 K04-025 / K04-026 Turbo Kit
Stage 3 Upgrade for B5 S4 • C5 A6 2.7T • Allroad 2.7T • Tiptronic Compatible
Proven On Real Stage 3 Cars
These are the latest generation XS-POWER LARGE cast K04-025 / K04-026 turbochargers that have now been successfully installed on multiple Stage 3 builds, including a proven Tiptronic-equipped vehicle with over 30,000 miles of reliable operation.
Built for enthusiasts who demand OEM-style fitment with upgraded durability and proven power capability.
Product Overview
These brand-new cast K04 turbochargers are direct replacements for the factory BorgWarner K04-025 and K04-026 turbos used on the Audi RS4 2.7T and are designed to fit B5 S4, C5 A6 and Allroad 2.7T applications without modification.
Each turbo features an upgraded compressor housing machined to accept a larger CHRA, oversized wastegate ports to eliminate boost creep, adjustable wastegates preset to approximately 9 PSI, and an upgraded 360° thrust bearing for maximum reliability under repeated high-boost conditions.
These turbochargers have been dyno proven to support approximately 500+ horsepower on E85 with the proper supporting modifications and tuning.
Features
- Latest Generation Cast K04-025 & K04-026 Turbochargers
- Direct Bolt-On Replacement
- No Vehicle Modification Required
- Fits Manual & Tiptronic Applications
- 360° Heavy Duty Thrust Bearing
- Ceramic Coated Compressor Housings
- Modified Compressor Housing Accepts Larger CHRA
- Oversized Wastegate Ports & Flappers
- Helps Eliminate Boost Creep
- Adjustable Wastegates Preset Around 9 PSI
- High Temperature Components Throughout
- Designed For High Boost Reliability
- Dyno Proven 500+ HP Capability On E85
Package Includes
- 1 Pair Cast K04-025 / K04-026 Turbochargers
- 1 Pair Silver Turbo Inlet Pipes
- 6 Bosch 550cc Fuel Injectors
- Injector Electrical Connectors
- Complete Installation Gaskets
- Turbo Hardware
- Washers
- Oil & Coolant Fittings
- Everything Shown For Installation
Optional Upgrades
| Upgrade | Additional Cost |
|---|---|
| 630cc Fuel Injectors | +$30 |
| Aluminum Bipipes | +$140 |
| Braided Flex Downpipes (B5 S4 / A6 / Allroad / Tiptronic) | +$315 |
| Pair Stainless Steel Exhaust Manifolds | +$200 |
| Hitachi Aluminum MAF Housing | +$100 |
| Custom Stage 3 ECU Tune | +$350 |
Vehicle Fitment
- 2000-2001 Audi RS4 2.7T V6
- Audi B5 S4 2.7T
- Audi C5 A6 2.7T
- Audi Allroad 2.7T
- Manual Transmission
- Tiptronic Transmission
Factory Reference Numbers:
- 078 145 705 HP
- 078 145 706 HP
Performance Benefits
- Supports 500+ Horsepower With Proper Supporting Mods
- Excellent Street & Track Reliability
- Improved Turbo Response
- Higher Airflow Capacity Than Stock
- Reduced Chance Of Boost Creep
- Designed For Repeated High Boost Operation
- OEM Style Installation
Why Choose XS-POWER?
Unlike many generic replacement turbochargers, these units have been installed and tested on multiple real-world Stage 3 vehicles, including long-term Tiptronic applications. Every turbo incorporates upgraded internal components, enlarged wastegate ports, ceramic-coated compressor housings and heavy-duty thrust bearings for exceptional durability and consistent performance.
XS-POWER Performance Turbo Systems
Trusted Worldwide By Audi Performance Enthusiasts
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THESE HAVE NOW BEEN INSTALLED ON SEVERAL CARS ALL ON STAGE 3 BUILDS Brand New -cast K04-025 & 026 Turbo Chargers Direct replacement (with no modification)- Audi RS4 2.7T V6 (00-01) Have this available for tiptronic as well with a known working tiptronic k04 car over 30k miles. This means k04's for allroad, a6 and b5 s4 tiptronic trans. Audi factory parts number for reference: 078 145 706 HP & 078 145 705 HP ONE PAIR CAST K04S ONE SET OF SILVER INLETS INCLUDES 6 BOSCH 550CC INJECTORS WITH CONNECTORS. ADD 30 FOR 630CC Add Bipipes for 140 Add SET OF BRAIDED FLEX DOWNPIPES FOR ALLROAD,A6 OR B5 S4 or Tiptronic for 315 Add ONE PAIR OF STAINLESS STEEL MANIFOLDS for 200 ADD MAF HOUSING ALUMNIUM HOUSING FOR HITACHI MAF for 100 ADD CUSTOM TUNE FOR 350 COMES WITH ALL NECESSARY GASKETS, HARDWARE WASHERS AND FITTINGS FOR INSTALL AS SHOWN. Wastegate openings are ported larger than stock. Compressor housing has been ceramic coated and modified to.accept larger chra. We use a 360deg. Thrust bearing to aid in longevity with repeated HIGH BOOST situations. Its the best of the best! Adjustable Wastegates - These are preset to aprox 9psi. Oversized & Ported Wastegate Holes/Flappers for longevity and no chance of boost creep! These will handle~500+hp on e85 dyno proven
