Tristan Symington owns a 1999 Audi A4 with a turbocharged 1.8 L inline-four that made 148 hp (110 kW) and 155 lb-ft (210 Nm) of torque from the factory. He turned to his best friend Hunter Inman and his experience building engines to find more power. It’s taken over two months to create what they are calling the Budget Big Turbo Audi (BBT).
The budget for the project would need to stay small since both recently graduated high school. This meant the project would involve more research and elbow grease.
Hunter pulled the engine apart and started rebuilding it with Wieseco flat top pistons, Eagle forged crank and forged H-beam rods. He built a custom engine girdle from a sheet of aluminum. For added insurance he installed a set of Clevite main and rod bearings and increased the oil pressure by adding tension to the oil pump relief spring.
Hunter spent over a week working on the 20v head. He ported and polished every port along with the intake runners and throttle body. He added more tension to the valve springs by installing washers under them.
With the engine ready Hunter added the missing piece, a Garret GT3071R turbocharger with an external waste gate set to 33 psi. The result was 555 horsepower and 432 lb-ft of torque to the wheels.
Hunter replaced the factory transmission with one from a 1999 A4 V6 model. The V6 transmission has longer gears allowing the engine to stay in boost longer. The transmission also received a lightweight flywheel (8 lb vs factory 24 lb) and SPEC 6 puck clutch.