Table of Contents
The Audi RS3’s 2.5-liter five-cylinder engine has earned a reputation as one of the most tunable powerplants in the modern era. While the stock turbocharger delivers satisfying punch from the factory, enthusiasts seeking serious four-digit-whp potential eventually look to larger hybrid or full-frame options. The TTE700 turbocharger represents one of the most popular intermediate steps—offering substantial gains without requiring a complete engine rebuild or custom fabrication. This guide covers everything from installation details to realistic power expectations, helping you plan a reliable, high-output build.
What Makes the TTE700 Different
The TTE700 is a hybrid turbocharger built on the core of the factory IHI IS38 or the larger RS3 OE turbo. It features a larger compressor wheel and a machined turbine housing that flows significantly more air than the stock unit. Key design characteristics include:
- A billet 67 mm compressor wheel (up from roughly 58 mm stock)
- A ported shroud housing to reduce surge at high boost
- A 10-blade turbine wheel with improved aerodynamics
- A reinforced center section to handle higher thrust loads
These changes allow the TTE700 to support up to 700 wheel horsepower on a properly fueled and tuned RS3. That figure is approximately 200–250 hp more than the stock turbo can reliably produce, while still spooling quickly enough for daily driving.
Installation: Planning and Preparation
Installing a TTE700 isn’t a simple bolt-on job. The process requires removing the entire exhaust system, the downpipe, the intake, and several coolant lines. A lift and transmission jack are highly recommended for access. Below we break down the critical stages.
Required Tools and Consumables
- Standard metric socket set (8–19 mm) with extensions
- Torque wrench (10–150 N·m range)
- Breaker bar and impact gun for stubborn bolts
- New exhaust manifold gaskets, turbo-to-downpipe gasket, and copper washers
- High-temp anti-seize compound for exhaust hardware
- Coolant and oil for refilling after installation
- Intercooler inlet couplers (if upgrading piping)
- Boost leak tester (to verify after installation)
Step-by-Step Turbo Removal
- Disconnect the battery – prevent accidental airbag or sensor damage.
- Drain coolant at the block drain plug and the radiator petcock; remove the intercooler and charge pipes.
- Remove the intake system – airbox, MAF sensor, and turbo inlet pipe.
- Unbolt the exhaust manifold heat shield and the oxygen sensors.
- Separate the downpipe from the turbo and the exhaust system (rear oxygen sensor may need removal).
- Unbolt the turbo from the exhaust manifold (four nuts on the TTE700 flange) and then from the oil and coolant lines.
- Lift the old turbo out – careful not to damage the firewall or wiring harness.
Installing the TTE700
- Clean the mounting faces of the exhaust manifold and oil return flanges.
- Install new gaskets and apply anti‑seize to the manifold studs.
- Position the TTE700 onto the manifold and tighten the four nuts to 30 N·m (22 ft‑lb).
- Connect the oil feed (banjo bolt with new copper washers) and then the coolant lines (rubber hoses with spring clamps).
- Attach the downpipe with a new gasket; use the OE spring bolts or aftermarket V‑band clamp.
- Reinstall the charge pipes, intercooler, intake, and all sensors.
- Refill coolant and oil; check for any leaks.
- Reconnect the battery and prime the oil system by pulling the fuel pump fuse and cranking the engine for 10 seconds (without starting).
Power Expectations with the TTE700
Real-world dyno results on 93-octane pump gas typically land between 570 and 620 wheel horsepower. On E85 (or ethanol blend), with upgraded fuel pumps and injectors, the TTE700 can safely produce 650–700 whp. Torque peaks are equally impressive: 550–600 N·m (405–442 lb‑ft) on stock fueling, climbing to 650 N·m (480 lb‑ft) with auxiliary injection.
The powerband remains broad. Boost threshold is only about 300–400 RPM later than the stock turbo, reaching full spool around 3700–4000 RPM. This retains excellent drivability while giving a genuine teeth‑clenching surge in the mid‑range.
Supporting Modifications
The TTE700 alone cannot reach its potential without a properly upgraded supporting system. Below are the most critical components.
Fuel System Upgrades
- High‑pressure fuel pump (HPFP) – at minimum a 4‑piston unit (e.g., RS3 high‑flow HPFP).
- Larger injectors – 1000 cc or larger for ethanol fuels.
- Low‑pressure fuel pump (in‑tank) – upgrade to a 525 lph unit for consistent volume.
- Ethanol content sensor – if running flex fuel, integrate this for tuning safety.
Intake and Exhaust Flow
- High‑flow intake (such as Eventuri, Unitronic, or 034Motorsport) – reduces restriction before the turbo.
- Turbo‑inlet pipe – a larger diameter silicone or aluminum piece eliminates the OE bottleneck.
- Upgraded intercooler – a bar‑and‑plate design (e.g., Wagner or CSF) lowers intake air temps by 30–50°F under sustained load.
- Free‑flowing downpipe – 3‑inch or 3.5‑inch with a high‑flow catalytic converter or catless option.
- Full exhaust system – 3‑inch cat‑back reduces backpressure.
Engine Management and Tuning
A proper tune is non‑negotiable. The factory ECU will not adapt to the increased airflow and fuel demands. Use a known tuner specializing in RS3 2.5T platforms (e.g., Unitronic, IE, United Motorsport, or Dyno Spectrum). Expect to pay for a custom dyno or remote tune session.
Boost Leak Prevention and Post‑Installation Checks
After any turbo upgrade, boost leaks are the most common cause of reduced performance, high exhaust gas temperatures, and lean conditions. Use a smoke machine or a pressure tester at the intake snorkel. Pay extra attention to:
- The charge pipe couplers – tighten T‑bolt clamps to 8–10 N·m
- Turbo inlet pipe connections
- Intercooler end‑tank O‑rings
- Boost reference line to the blow‑off valve or wastegate
Maintenance Considerations
The TTE700’s hybrid bearing system (journal or ball bearing depending on version) requires diligent oil change intervals. Use a high‑quality 5W‑40 synthetic oil and change every 5,000 miles (8,000 km) regardless of manufacturer claims. Let the turbo cool by idling for 30–60 seconds after hard driving before shutting down. Install a turbo blanket to reduce under‑hood temperatures and protect the stock heat shield.
Pros and Cons of the TTE700 Upgrade
Advantages
- Direct bolt‑on for RS3 (no custom fabrication)
- Up to 700 whp potential with supporting mods
- Spools nearly as fast as stock, preserving daily usability
- Proven reliability with proper tuning
Disadvantages
- Requires extensive supporting modifications (fuel, intake, exhaust)
- Not suitable for stock internals past ~650 whp (consider forged rods/pistons)
- Installation is labor‑intensive (8–12 hours for a DIY mechanic)
- Higher operating temperature demands excellent intercooling
Comparing the TTE700 to Other RS3 Turbo Options
| Turbo Model | Max WHP (E85) | Spool RPM | Relative Cost |
|---|---|---|---|
| Stock IS38 | ~480 | 2900 | – |
| TTE700 | ~680 | 3700 | $$ |
| TTE850 | ~820 | 4500 | $$$ |
| Full-frame (e.g., Precision 6466) | 900+ | 5000+ | $$$$ |
For most street‑driven RS3 builds, the TTE700 offers the best balance of power, spool, and budget. If you plan to track the car regularly, consider the slightly larger TTE850 or a full‑frame kit with a low‑mount manifold.
Real‑World Driving Impressions
Owners frequently report that the TTE700 transforms the RS3 into a genuine supercar slayer. Fourth‑gear highway pulls feel like low‑orbit launches. The torque surge from 4500 RPM to redline is addictive, and the engine note remains undeniably five‑cylinder. On E85, the car will outrun many built V8s while returning nearly 30 mpg on the highway (when driven conservatively).
Final Thoughts
The TTE700 is an excellent upgrade path for the Audi RS3 owner who wants serious power without losing daily drivability. Plan for a complete fuel system and a professional tune before you ever turn the first bolt. With careful installation and proper maintenance, the TTE700 will provide years of reliable, electrifying performance.
For further reading, check TTE‑series turbo technical details or join the Audi RS3 Owners Club for build logs and dyno sheets.