Once the exhaust was in place, it was run in for a week or two when the snow finally melted, and then it was back to the RCTS dyno for the big test. The best of three dyno runs demonstrated solid results, with peak values of 383.6 whp and 274.4 lb-ft of torque, up a significant 13.3 whp and 9.9 lb-ft; this was equivalent to the manufacturer’s claim within a reasonable scientific error. So the Akrapovic Full Evolution exhaust system truly makes power. The graph shows the Sport mode comparison with the baseline run plotted in blue and the final dyno run in red. These results show a healthy curve with 10-13 whp and 15-30 lb-ft gains on the low end, a minor dip in power and torque from 2950 to 4300 rpm (not as pronounced in “Normal,” i.e., non-Sport, mode), and excellent 10-20 whp and 10-15 lb-ft gains upwards to the 8500-rpm redline. Be aware that the results are likely to be even better when the vehicle is run on the street or track with full cooling and airflow.
The added power is certainly noticeable from the seat of the pants, and most welcome. However, the deeper, much more mechanical and racy soundtrack, and the amazing weight savings is what slams home the true value of this system’s high price of admission (MSRP $12,495). Where the stock GT3 exhaust note is civilized and muted by comparison, the Akrapovic Full Evolution system allows the full motorsport bandwidth of the GT3’s flat-six to blow through the spectacular upsized titanium exhaust tips. In Normal mode below 4200 rpm all three mufflers are utilized, so your neighbors aren’t going to be too upset with you. But pressing the Sport button, you can choose to cause audio mayhem, depending on how much right foot is applied. Thus, the new system gives a true Jekyll-and-Hyde effect—it can be borderline conservative, or just plain wild and nasty.
One minor downside to this installation is the occurrence of an engine check light signaling the malfunction codes for inefficient catalytic converters on both cylinder banks. Such is the price of replacing the OEM cats with the power-enhancing 100-CPI race units. A software remap for the ECU is the only remedy for this issue. Akrapovic is currently making corporate alliances with performance software vendors to help streamline solutions for their customers.
Next time, we’ll get back on track with our GPS lap testing and add some suspension tricks to tweak the already excellent handling.
First, remove the rear bumper shell and inner bumper heat shielding on both sides. Then, remove the aluminum bumper and additional heat shield off the rear of the car. Next, the rear muffler can be unbolted by first loosening the plates on each side. All four O2 sensors are then removed from the exhaust piping and tucked out of the way, leaving them wired up. Working on each side, remove both side mufflers and associated bypass pipes, then release the rear muffler by removing the mounting straps. Finally, unbolt each header/cat assembly from the engine block. The install is the reverse of this process; be sure to use plenty of sealant and thread anti-seize paste per Akrapovic’s instructions. Note that you will have to reroute the O2 sensor wiring slightly. —DN