Part One: Single car multi-chip dyno test
As previously mentioned, we did not get the large turnout originally expected for this shootout. Some tuners felt they had nothing to gain by participating, while others had other time commitments that same weekend. In the end, it was GIAC and REVO for the chip-only test.
In order to establish baseline performance we did initial runs with the S4 completely stock. The car was driven onto the dyno and strapped down into testing position. Once the baseline data had been collected it was time to cut its chastity belt so new tuning programs could be deployed. GIAC went first.
At this point a second, new ECU was installed into the stock car and the GIAC programming
was flashed onto it. After the GIAC runs the ECU was flashed back to stock
programming and then George Osmun from REVO flashed their code
into the stock car.
Again, from a consistency standpoint, we were meticulous about timing between runs of the same program. We used a stopwatch and allowed a 3 minute cool down period with the engine idling between each run. Dyno cooling fans were left running to help the vehicle cool off between each dyno run.
Interestingly, for both the GIAC and REVO chips the strongest runs came on the third and final attempt. Two potential conclusions can be made. First, the B6 S4 might just like to run "hot" and be more willing to get up and go when the engine is warmed up. Second, the ECU, during the course of the runs, would be adjusting many variables on the fly as it always does. It is possible that the car was learning to perform better on each subsequent run.
When it came time to go from one tuning program to the next the ECU was re-flashed through the diagnostic port. This entire process lasted at least 20-25 minutes, providing ample cool down time for the engine before the next set of runs began.
The dyno sheets below show very close numbers with the GIAC chip pulling ever-so-slightly ahead with .1 HP over the REVO chip and 2.2 ft-lbs of additional torque.
