Greedspeed Audi A4
Two different engines are offered in the Audi A4 for the North American market: a 1.8-liter turbocharged gas engine and a 2.8-liter gas engine--both with five-valve heads. The 1.8-liter turbocharged engine (1781cc) follows Audi's traditional under-square design and has an 80mm bore and an 86.4mm stroke. Under-square engines are noted for putting big torque in smaller packages, all at a lower engine rpm.
Greedspeed's Audi A4 is built around the GS4 turbocharged engine program. Audi uses a relatively small KKK K03 model turbocharger and it's the small size of the turbocharger that doesn't deliver quite enough air for high-horsepower use. Greedspeed used a custom turbocharger built by Turbonetics in Moorpark, Calif., instead of the stock version. Turbonetics built a T3/T4 hybrid unit with ceramic ball bearings. The compressor housing section and back plate are from a Garret Air Research T4 model turbocharger while the turbine section is from a T3 model wit a stage 2 turbine. According to Turbonetics, the exduser diameter is one of the important parameters determining how much exhaust can enter the turbine housing. This hybrid unit is said to flow about 40 lb of air per minute up to 400 hp. The stock KKK charger is good only up to 220 hp but by then it's spinning at a fast speed. The charger can't be bolted up to the stock exhaust manifold, so Greedspeed had a custom tubular header/manifold made by Turbonetics. They supplied a high-flow external wastegate and Neuspeed a billet blow-off valve to control boost levels. The stock compressor bypass valve remains to vent pressure during low-boost shifts, while the larger Neuspeed valves take care of the high boost. Greedspeed also provided the intake tube, catalytic converter, exhaust downpipe, oil and water lines. The tri-flow exhaust system from the cat back is provided by B&B Fabrication in Glendale, Ariz.
There is a Vortech Super FMU that works with the standard fuel pressure regulator to increase fuel pressure based on boost level. The engine management system is outfitted with Neuspeed's "Extreme" P-Chip programmed for the large turbo and Neuspeed's high-performance fuel injectors, lightened flywheel, performance clutch and Ram air-flow panel filter. All of this adds up to 300 hp when using 14 psi boost and a larger intercooler.
The car was tested at 12 psi and had an 80 hp gain with the stock intercooler, which implied 230 hp at the flywheel. The Vericom was used instead of the Dynojet because the car was a Quattro. Compared to a stock A4, the larger turbo hurt bottom end but helped the top end. Some turbochargers will start out flat and spike but the Greedspeed A4 makes more power the higher it revs. It was running the quarter in 14.0 sec at 99 mph (at 3,000 ft above sea level).
Greedspeed used D2 Autosport's A!Avant Garde body kit, which included a front spoiler, rear valence and side skirts. Another addition was Kamei's metal mesh front insert. APS, related to Neuspeed, provided the European headlamp assemblies, In-Pro smoked tali lamps, smoked side indicators and European side indicator lamps.
Handling was improved by exchanging the stock 7x15 or 7x16 wheels for 8x17 TSW MAK wheels with Nitto NT 501 tires, sized 225/40 ZR17. Neuspeed provided front and rear Neuspeed/Koni threaded body shocks, race lowering springs and anti-roll bars (27mm in the front and 22mm in the rear).
Boston Acoustic fitted the car with a direct-fit component speaker system, a PP PC15 subwoofer and a PPI PC650 amplifier. This is controlled by an Alpine model CDA7832 and a Scosche Audi installation kit and Scosche EFX wiring. Tying it all together is a Neuspeed HD 170-amp alternator.