APR T3100021 Stage III+ Turbo Kit for 2001 Audi B5 A4

APR announces the Stage III+ kit, the ultimate turbo system upgrade for the 2001 B5 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. APR has worked long and hard to bring you the finest B5 A4 1.8T upgrade available. This kit is made with the best materials and engineering available, from the exhaust manifold to the hose clamps. APR's Stage III+ kit consists of the following components:

• APR Investment Cast Inconel Exhaust Manifold
• Garrett/Allied Signal Ballistic Series Ball-Bearing Turbocharger
• Larger APR designed Mass Airflow Sensor Housing
• APR Custom Cast Urethane and Silicone Intake Hoses
• APR High Flow Fuel Injectors
• All Associated Plumbing and Hardware

The most important part of the Stage III+ kit is the exhaust manifold. APR has spent enormous time and resources developing the turbo manifold. The exhaust manifold has been designed in Pro/Engineer 20, a 3-D modeling package and validated extensively on the computer using Exa Powerflow, a CFD analysis program. By performing a computational fluid dynamics analysis, they were able to study exhaust flow, pressure drops, and fluid flow through the exhaust manifold. Multiple computer simulations were done to prove the design before they even had a physical manifold in their hands.

Once the manifold was fully passed on the computer APR had the exhaust manifold CAD file transferred to a rapid prototyping machine. A polycarbonate exhaust manifold was cast from the prototyping machine. With this plastic manifold APR was able to mock everything up in the test vehicle before proceeding to the next process.

From the polycarbonate piece APR was able to cast a metal piece for prototyping. The metal used for the prototype and the production manifold is Inconel 625. Inconel is a very high quality (yet expensive and difficult to machine) metal that is used extensively in the racing and aeronautical industry (Audi Sport sells an Inconel exhaust manifold for $10,000). Inconel has excellent heat retention characteristics that work to enhance turbo response by keeping exhaust velocities high. APR guarantees that this manifold will never crack. Furthermore, the production manifold is cast using a lost-wax process versus a traditional sand-casting process. This process is more expensive but gives a much higher quality part with better tolerances, no parting lines, and a smoother surface finish (the internal surfaces feel like they have been Extrude Honed).

The exhaust manifold is mated to a Garrett turbocharger that replaces the stock Triple K K03 turbocharger. APR choses to use a Garrett turbocharger in lieu of a Triple K unit for several reasons. First of all, the new Garrett GT-Series is a more efficient design than the old Triple K K-24 turbocharger used by one of our competitors (the K-24's design dates back to the mid 70's). The Garrett turbocharger we have selected is a 1990's design. Also, Garrett turbochargers are available in a wider variety of configurations than the Triple K line, which allowed APR to find a more exact match. The stock injectors are maxed out at power levels much over 220HP and consequently the fuel injectors have been replaced by larger units. Dialing in the injectors required many hours on the chassis dynamometer to achieve the proper fuel mixture throughout the entire rpm range.

Note:
An exhaust system with a downpipe (sold separately) is required with the Stage III+ upgrade.

The power increase with the APR Stage III+ kit for the A4 1.8T is substantial. It is highly recommended that brake and suspension upgrades are done to safely use the potential of this upgrade.

Free shipping on this item (if advertised) only applies inside the continental US.