Sonu Atwal had been a long-time 034Motorsport customer when he picked up his latest project, a B5 Audi S4 Sedan that had been modified by the previous owner. The car already came with another company's full RS4 K04 turbocharger upgrade kit and tuning, as well as full downpipes and exhaust. Despite the existing modifications, he wasn't satisfied with how his new ride was performing.
B5 Audi S4 2.7T Stage 3 K04
At first, Sonu's plans were simple: install a water-methanol injection kit, and have us calibrate it on our dyno. Even with the newly installed WMI kit, his car wasn't making the power that it could be. The lack of power and other issues with the S4's idle and part-throttle drivability sent him looking for other options. Sonu was already familiar with 034Motorsport's tuning prowess, as we had spent some time tuning his 034EFI Stage IIc equipped big turbo B5 Audi A4 1.8TQM a while back. Convinced that our tuning could get his S4's performance to his expectations with the current hardware, Sonu considered getting another 034EFI Stage IIc Standalone ECU for his new toy, but we offered to optimize the tuning on the stock ECU. We both agreed this would be a great option for the project.
B5 Audi S4 2.7T Stage 3 K04 Engine Bay
Luckily for him, we had been tuning factory Motronic ECUs for years, and his car was the perfect candidate for our ME7.1chip tuning. With only a few minor changes, including our 85mm Billet MAF housing, Silicone RS4 MAF Hose, stock fuel pressure regulator, and larger Bosch 550cc EV14 Fuel Injectors, we were ready to start the tuning process. We also added our Bosch 044 Drop-In Fuel Pump Upgrade for safe measure, to ensure that no drops in fuel pressure would occur and cause the engine to run lean.
After a few hours on the dyno, Sonu's car was tuned to perfection. In addition to having a butter-smooth idle and perfect drivability, our tuning also picked up over 100 ft-lbs of torque and 78 horsepower at the wheels! Sonu was ecstatic with the results, and couldn't wait to drive his reborn S4.
This Stage 3 B5 Audi S4 2.7T is the perfect German sports-sedan, comfortably delivering 500 horsepower of driving bliss with uncompromised drivability and reliability. Keep an eye out for Sonu and his S4 in the greater Bay Area... You probably won't see anything except for a silver blur unless he's stuck in traffic or stopped at a red light, but if you're lucky enough to keep up, you'll be able to recognize him by his permanent horsepower-induced grin and full-034Motorsport shwag.
B5 Audi S4 2.7T Stage 3 K04 Tuning: AWE vs. 034

Sonu's Stage 3 B5 Audi S4 2.7T:

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B5 Audi S4 2.7T Stage 3 K04 034 Tuned Dyno

B5 Audi S4 2.7T Stage 3 K04 91 Octane + Water Meth Dyno