Stock vs Unitronic Programming

There's good ideology behind Unitronic's software. "It's not all about boost," continued Michel. "Peak power is only a small element. Most cars are faster not because of how much boost they push, but how they introduce the boost and maintain it. If you have a lot of boost that comes in quickly, the turbo will spool fast and get really hot. After 4500rpm, it's going to be hot and won't be productive anymore, the power will die off. With our software, we bring the turbo in slowly but smoothly. We keep the boost as long as we can for a strong power band versus a peaky power band."

When all is said and done, Unitronic touches more than ten major parameters to retune the software, and it's different for every car, as our Audi highlighted. Our software was optimized for our power-adders. However, our output would be limited because of the fuel injectors. "The stock injectors are at their limit," Michel told us. "They lean out at the top-end. To take full advantage of the car with a stock turbo, it's best to fit the 380cc injectors from the 225hp Audi TT, whereas the stock injectors are 280cc. We would then be able to push the car more without damaging the engine."

The Final Word
So we made our way to partners DC Performance and Abbott Automotive in Los Angeles, CA. DC is one of Unitronic's California dealers and would be able to flashload our A4 with the new software in minutes. Unlike most facilities, DC uses a Dynapack chassis system to measure the power directly at the wheel hubs via hydraulic pumps. This should give us a more accurate measurement of engine power without estimating wheelspin loss.

So before we installed the new software, we put our quattro on the dyno for a baseline test. The first graph shows the difference between the stock ECU against the Unitronic stage 1+ software. During both tests, we should note that temperature remained relatively the same at 72F. Both tests were done with the aforementioned bolt-on modifications fitted to the car.

On stock software, the dyno showed 126whp and 150 lb-ft of torque. After the dyno runs our motor kept pulling ignition timing. Fortunately, DC was able to help diagnose the problem and Unitronic engineered a stage 1+ file to account for the modifications and the characteristics of our high-mileage California-driven 1.8T. The custom-tuned file displayed an impressive 158whp at 5000rpm and 197 lb-ft at 3000rpm.

Comparing both horsepower curves, we noticed a large increase across from 2500rpm to redline. The difference equates to approximately 30whp more than stock. The torque curves show an even larger increase between 2500-4500rpm, where more than 40 lb-ft was realized.Unfortunately, the torque dies quickly after 4500rpm, which is explained by the lack of fuel from the stock injectors.

We also looked at boost levels. Although it's not the only factor Unitornic modified, we were curious to compare stock and chipped boost levels.

Under stock programming, boost peaked at 11psi at 2500rpm, leveling out to 6psi at redline. However, Unitronic's program meant that boost pressure remained at a constant 16.5psi from 2200-4200rpm. It then slowly dropped to 9psi at redline.

Our dynamometer test showed a tremendous improvement in power with the Unitronic stage 1+ software, but there's more power to be realized once fueling is addressed. Plagued by California's 91-octane gas and stock injectors, we've reached a safe limit on our 1.8T.

Sprint Booster
For drive-by-wire cars such as our A4, there can be a minor delay in throttle response whenever you step on the gas pedal. The Sprint Booster is a module that installs behind the gas pedal and eliminates the pause by altering throttle response.

We decided to give it a shot after hearing discussion about the product among enthusiasts. Best of all, if it didn't work or we don't like it, we could simply unplug it without damaging the car.