The CTS Turbo BOSS800 is a high-performance hybrid turbo upgrade for the Audi/Porsche EA839 3.0T platform. This turbo is a direct replacement with OEM-like fit and drivability, but with significantly increased airflow, improved boost efficiency, and strong top-end power. The BOSS800 maintains quick response at low rpm and pulls strongly all the way to the rev limit.
The turbo uses an upgraded compressor and turbine configuration and supports a wide range of fuels, from pump gasoline to ethanol blends . Power gains scale predictably with ethanol content, with strong mid-range torque and stable boost control. This is a completely new unit (no core required) and compatible with many off-the-shelf Stage 3 software .
Note: A 66mm turbo inlet required for installation. The original diverter valve and boost pressure relief valve will be transferred.
Advantages
• Direct OEM fit hybrid turbo upgrade
• Fast spool with strong top-end power
• Pulls through to redline
• Suitable for pump fuel and ethanol blends
• All-new unit, no core needed
• Compatible with many Stage 3 tuning
• Suitable for street and track builds
• VSR balanced for reliability
Turbo specifications
• Turbo inlet: 66mm (required)
• Compressor wheel: 66mm 7+7 billet
• Turbine wheel: 63mm 9-blade high-flow
• Exhaust housing: Stainless steel, tuned for increased flow
• Bearings: Heavy-duty bearings and thrust washers
• Balancing: VSR balanced
• Compatibility: All exhausts, charge pipes and 66mm inlets
• OEM parts to transfer:
– Diverter valve
– Boost pressure relief valve (06M133554A)
Asset Results (Logic Street Performance)
(same car & hardware, only fuel changed)
• 92 Octane: 561 hp / ~532 lb-ft
• E50: 640 hp / ~643 lb-ft
• E55: 658 hp / ~654 lb-ft
• E60: 671 hp / ~663 lb-ft
Results achieved with full bolt-ons and upgraded fueling (RS6 injectors, HPFP, LPFP, 4BAR MAP sensors) and Stage 3 tuning. Results may vary.
Parts required for assembly (not included)
• 2× 06M253039G – exhaust manifold gasket
• 1× 059253232C – exhaust ring gasket
• 1× WHT006901A – oil feed O-ring
• 3× WHT007689 – oil/coolant O-ring
• 4× WHT004982 – barrel nut
• 4× N91130801 – exhaust nut
• 1× WHT007923 – connecting pipe O-ring
• 2× 8K0253115K – exhaust gasket
• 1× N0138441 – boost pressure relief valve seal
Compatibility
EA839 3.0T engines (check software at tuner):
• Audi S4 B9/B9.5 (2018–2023)
• Audi S5 B9/B9.5 (2018–2023)
• Audi SQ5 B9/B9.5 (2018–2023)
• Audi Q7 4M 3.0T (2020–2022)
• Audi Q8 4M 3.0T (2019–2022)
• Audi A6 C8 3.0T (2019–2022)
• Audi A7 C8 3.0T (2019–2022)
• Audi Allroad C8 3.0T (2020–2024)
• Audi A8 D5 3.0T (2019–2023)
• Porsche Macan S 3.0T (2019–2021)
• Porsche Cayenne 3.0T (2019–2023)
Contents
• CTS Turbo BOSS800 hybrid turbocharger
Frequently Asked Questions
1. Is this turbo suitable for everyday use?
Yes, thanks to its smooth boost response and OEM-like drivability.
2. Do I need additional fuel upgrades?
For maximum performance and ethanol blends, upgraded injectors and HPFP/LPFP are recommended.
3. Is tuning required?
Yes, Stage 3 software is necessary to utilize its potential.
