powertrain
Turbocharger Upgrade Guide: Garrett Gtx2860r on S5 3.0t, Power Gains & Installation Costs
Table of Contents
What Is the Garrett GTX2860R and Why Upgrade Your S5 3.0T?
The Audi S5 3.0T, equipped with the supercharged 3.0-liter V6 (EA837), is already a strong performer from the factory. However, for enthusiasts seeking genuine big-power gains, a turbocharger conversion—particularly with the Garrett GTX2860R—has become one of the most effective paths. The GTX2860R is a dual-ball-bearing, billet-wheel turbo that bridges the gap between quick spool and top-end flow. It’s designed for engines in the 250–400 horsepower range, making it an ideal match for the 3.0T’s displacement and aftermarket tuning support.
Unlike the factory supercharger, which provides linear boost but becomes heat-soaked under sustained load, a properly matched turbo like the GTX2860R can deliver higher peak boost with lower intake temperatures, especially when combined with an upgraded intercooler. The result is a dramatic improvement in both horsepower and torque across the rev range.
For a deeper look at Garrett’s GTX series technology, visit the Garrett Motion GTX Gen II page.
Turbocharger Specifications and Compatibility
- Compressor wheel: 54mm inducer / 71mm exducer, billet aluminum GTX Gen II design
- Turbine wheel: 54mm inducer / 50mm exducer, Inconel with 9-blade design
- Housing options: T25 or T3 turbine inlet; 0.64 or 0.86 A/R for turbine, 0.60 A/R compressor
- Bearing system: Dual ball bearing with oil and water cooling
For the S5 3.0T, the most common configuration uses a T3 0.64 A/R turbine housing to balance spool and top-end flow. The turbo is typically mounted using a custom or kit-based manifold that replaces the factory supercharger assembly.
Expected Power Gains With the GTX2860R on the S5 3.0T
The GTX2860R is capable of supporting up to 400–420 wheel horsepower on the 3.0T with proper supporting mods and ethanol-blended fuels. On pump gas (93 octane), realistic peak numbers sit closer to 380–400 wheel horsepower. Torque production often exceeds 400 lb-ft, with peak torque arriving as early as 3,800–4,200 RPM depending on tuning.
Here’s a typical gain breakdown compared to a stock supercharged S5:
- Stock (supercharged, stage 1 tune): ~340–360 whp, ~330–350 lb-ft
- GTX2860R + 93 octane tune: ~380–400 whp, ~400–420 lb-ft
- GTX2860R + E50 ethanol blend: ~410–430 whp, ~430–450 lb-ft
These gains are not just peak numbers—the mid-range torque curve is significantly thicker than the supercharged setup, making the car feel faster both on the street and the track. However, it’s important to note that reaching these numbers requires a comprehensive supporting mod package, which we’ll cover in detail.
Dyno Results and Real-World Expectations
While every build varies, several documented S5 3.0T builds with the GTX2860R have shown consistent results. On a dynojet, a car with the turbo, catless downpipes, a front-mount intercooler, and a proper custom tune often lands between 390–410 whp on 93 pump gas. With ethanol, the same car can exceed 430 whp, though fuel system limitations (injectors and low-pressure pump) often need upgrading beyond that point.
For a verified S5 turbo build thread, check out this Audizine forum discussion showing real dyno graphs.
Installation Process — A Step-by-Step Guide
Converting the S5 3.0T from supercharged to turbocharged is a major undertaking. It requires removing the supercharger, intake manifold, and many ancillary components. Below is the general workflow for a shop-level installation.
Step 1: Prepare the Vehicle and Gather Parts
- Drain coolant and oil; disconnect battery
- Remove the front bumper, radiator support, and intercooler for access
- Collect all gaskets, o-rings, and new fasteners (turbo hardware kit, V-band clamps, copper nuts)
Step 2: Remove the Factory Supercharger and Manifold
Unbolt the supercharger from the intake manifold (6 bolts), disconnect the bypass valve and charge air cooler lines. Remove the intake manifold (12 bolts) and the lower intake runners. The factory supercharger system weighs around 35 pounds and its removal frees up significant space.
Step 3: Install the Turbo Manifold and GTX2860R
- Mount the aftermarket turbo manifold (usually a T3 flanged header) to the cylinder heads using new gaskets
- Bolt the GTX2860R to the manifold, torquing the V-band clamp to spec
- Connect oil feed line (from the engine block) and drain line to the oil pan (needs an additional bung welded or an existing plug)
- Connect coolant feed and return lines from the factory coolant pipe or an auxiliary setup
Step 4: Fabricate Intake and Charge Air Piping
A custom intake pipe with a cone filter and MAF housing is needed. The compressor outlet (2.5” or 3”) must connect to the intercooler, then from the intercooler to the throttle body. Many kits use a silicone coupler and aluminum pipe solution.
Step 5: Install Exhaust and Wastegate
The turbo downpipe can be 3” with a V-band to the turbine outlet. A wastegate (typically a Tial 38mm or 44mm) must be welded into the downpipe or a dedicated dump tube. The factory exhaust can be adapted, but a catless or high-flow setup is recommended for performance.
Step 6: Wire the Boost Control Solenoid and Tune
Install a 3-port or 4-port MAC solenoid for electronic boost control. Connect wiring to the ECU harness. A custom ECU tune is mandatory—either through a handheld device (like Cobb Accessport or Eurodyne) or a remote tuner. The tune must account for the new fuel map, boost curve, and timing.
For a detailed parts list and wiring diagrams, consult EuroParts SD’s GTX2860R kit overview.
Installation Costs — Budgeting Your Turbo Upgrade
Costs vary widely based on whether you source the turbo alone or a full kit, and whether you DIY or use a shop. The following estimates assume a complete installation with all new components.