APR announces the Stage III+ kit, the ultimate turbo system upgrade for the 00-2001 A4 1.8T. This kit is capable of 333 horsepower and 322 foot-pounds of torque at the flywheel on 93 octane gas, while retaining stock-like drivability. The highlights of the kit include the following:
- APR Investment Cast Inconel Exhaust Manifold
- Honeywell/Garrett Ballistic Series Ball-Bearing Turbocharger
- Larger APR designed Mass Airflow Sensor Housing
- APR Custom Cast Silicone Intake Hoses
- APR High Flow Fuel Injectors
- All Associate Plumbing and Hardware

Components

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. What this means to the end user is the ultimate in performance and reliability.

Custom Silicone Inlet Hoses: These CAD designed hoses are designed to replace the factory hoses between the airbox and turbocharger, and the turbocharger to the factory cross-over pipe. APR both designs and makes the tooling for these items in house, using a combination of our CMM tool, SLA machine, and CNC machine.

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.

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. APR 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.

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.

APR Fuel Injectors: APR sent many hard hours with a major OEM manufacturer to develop a fuel injector that has the same spray pattern as a stock injector, but with a very high flow output.