The sun had set an hour ago as brothers Raffi and Vic Kazanjian at Euro Sport Accessories in Anaheim, CA wiped the sweat from their brows. For the last 12 hours, they'd been working on our `03 Audi A4 1.8T quattro. Introduced in et 12/08, the car came to us as a real POS with 120k on the odometer, worn parts and check engine lights. But thanks to Euro Sport and several suppliers, we've breathed new life into Project B6.
The chassis saw improvements first. Goodbye to a raggedy set of lowering springs and blown struts. We now had H&R Street Performance coilovers along with adjustable sway bars to grant our Audi supreme handling. The coilovers' height adjustment would allow the car to sit just above the new wheels - a set of TSW Jarama five-spokes. The 19x8.5" rims were a huge aesthetic improvement from the rattle-canned 17" stock rims. Mounted on the wheels would be 235/35-19 Toyo T1R tires designed with solid shoulders to enhance cornering power and wide center tread for grip and stability. The stock brakes required attention as well and Euro Sport easily fitted StopTech's stage 2 kit, which included Powerslot rotors, pads, lines and fluid.
Now to the fun part - power-adders! We started with a stainless steel Techtonics Tuning cat-back exhaust to give the 1.8T a deeper rumble, although it remained relatively quiet. We also fitted Forge Motorsport's turbo inlet pipe along with an ITG drop-in filter from Euro Sport.
You can find the step-by-step instructions in the et 5/09 issue or on the Tech pages at www.eurotuner.com But a couple of months later, we're back to finish the job with Unitronic software and some dyno graphs.
Unitronic Tuned
It was the little engine that could. The 1.8T was found in a plethora of vehicles from Golfs and New Beetles to our own Audi A4. Introduced overseas in '96, the models sported a K03 turbo and intercooled 20v inline-four. The factory rated horsepower at 150-225hp depending on the year, make and model, but our B6 boasted 170hp.Considering the A4 weighed around 3400 lb and suffered quattro drivetrain losses, it fell short of expectations.
Aaron Cohen of DC Performance...
Aaron Cohen of DC Performance uploading Unitronic software
So we decided to upgrade the software. Because our A4 had a Techtonics exhaust, Forge inlet pipe and drop-in filter, we contacted Unitronic Chipped for the best software upgrade to account for the mods we had.
To understand the dynamics behind what a software upgrade does, we sat down with Michel Szmiegel of Unitronic. "We follow the path of Bosch engineers," he began. "We don't just increase gas and boost. Good software doesn't work unless you understand why you're changing the parameters. We spend a few months studying the Bosch documentation, or we open the ECU and reverse-engineer it to find the different maps - there are over 2000 maps that interlink."
To understand this concept better, we asked Michel to give an example. You may not know it but there are different maps for nearly every road condition - for example when it rains. "Let's say your catalytic converter gets wet after you drive over a pothole. Water will cool the cat and the 02 sensor records the drop in temperature. The engine then automatically retards the ignition to heat the cat. Once we have a good understanding, we're in full control and determine how we need to go about tuning the ECU."
The engineers at Unitronic first raise the boost to see how the fuel map reacts. They then adjust more parameters including fuel and timing to optimize the program. And there are hundreds of maps to correct. For example, if you go over a specified torque level, a certain map limits the output, so Unitronic has to raise that as well...