This page focuses on the items that are included with the Stage III for the 225 TT. Because this kit is so extensive, it would be impossible to highlight all of the items that are included with it. This page highlights some of the major components of the kit.

Exhaust Manifold

The Stage III exhaust manifold is investment cast out of Inconel, a high-temperature nickel alloy. The manifold was designed in CAD and optimized using computational fluid dynamics (CFD) software. The manifold is then machined in-house on our Fadal CNC machine. What this means to the end user is the ultimate in performance and reliability.

MAF Housing

The mass air flow sensor (or MAF sensor) measures the amount of incoming air and sends an analog signal to the engine computer representing the amount of air flowing into the engine. The MAF sensor is mounted in a cylindrical housing that is sized according to engine displacement and maximum power output. We replace the stock MAF housing with a cast aluminum unit to allow the proper metering of the additional airflow and to minimize pressure losses. The cast aluminum housing is CNC machined to exacting tolerances and powder-coated to inhibit corrosion.

Flow Straightener

The correct flow straightener was sourced to ensure laminar air flow through the mass air flow sensor. This is important for proper air flow metering at all flow levels. The flow straightener is sandwiched between the MAF meter and the air horn and is held in place by a retaining clip.

MAF Silicone Hose

After the passing through the APR MAF Housing, air goes through this custom designed silicone hose to the turbo compressor inlet plumbing. This hose has all of the needed bungs for the N75 valve and the factory oil recirculation valve.

Turbo Compressor Inlet Plumbing

From the Silicone MAF Hose, air is sucked into the turbocharger through this custom designed stainless steel pipe and silicone compressor inlet hose. The compressor inlet hose has wire reinforcement to prevent collapsing. This entire assembly is then wrapped in a heat shield.

Intake Heat Shielding

A custom heat shield is included with the kit to reduce the effect of radiant heat from the exhaust manifold being absorbed into the intake stream.

Honeywell/Garrett Turbocharger

Representing the latest in turbocharger technology, a Garrett Ballistic series turbocharger is the only choice for a premium turbocharger system. APR is unique in that we deal directly with Garrett turbochargers rather than buying turbochargers through turbocharger supply houses. Our engineering-house distributor status with Garrett turbochargers means that we receive assistance from the manufacturer on technical issues and work with Garrett engineers on specifying the optimal turbocharger for each application.

Compressor Outlet Hose

Once the air is pressurized by the turbocharger, it travels through this heat protected silicone hose. This hose also has a bung to directly connect the diverter valve to the compressor inlet plumbing.

Intercooler

Pressurized air then flows through the included APR Z-Flow Intercooler. The APR Intercooler features such technologies as a top-bottom feed core, custom mandrel bent plumbing, and innovative cast endtanks with internal vaning.

APR Fuel Injectors

The TT Stage III requires larger injectors, which are supplied with the kit. They are capable of over 500cc at the 4bar fuel pressure the kit runs.

APR Quattro Downturn

Because of such tight clearances on the Haldex quattro drivetrain, APR felt that it was necessary to manufacture a cast exhaust downturn so that the kit would fit perfectly every time. The downturn has a flex section and a short 3" section of pipe added as well.

APR Boost Pressure Sensor

In order to properly tune the TT Stage III kit, APR has changed the boost pressure sensor. This allows us to measure higher boost pressures more accurately. It also, with the correct changes to the engine managemnt, properly extends the range of boost pressure that the ECU can see.

Supplemental Fuel Pump

To maintain the correct fuel pressure for the outputs that this kit is capable of, APR has added an supplemental fuel pump. This pump mounts where the stock fuel filter is located in the car. It also has a decibel sock to keep pump noise to a minimum.

Fuel Filter Relocation Kit

With the supplemental fuel pump in the fuel filters stock location, the fuel filter is changed and relocated to the engine bay of the car. With the supplied bracket, it mounts neatly in front of the stock coolant reservoir.