The stock MAF was replaced...
The stock MAF was replaced with this 73mm unit from C&L. The C&L meter was run with a K&N cone filter to replace the factory airbox and panel filter. The new MAF offered consistent power gains and will pave the way for the additional mods we have planned for our bird of prey.
After freeing up the inlet...
After freeing up the inlet system, we once again turned to increasing the boost pressure. On the 3.8L V-6, the Eaton supercharger is driven by an idler pulley system that is in turn driven by the crank pulley. Altering the size of the idler pulley will change the speed of the supercharger. Super Coupe Performance supplied a 5 percent idler overdrive pulley to increase the boost pressure by roughly 1.5 psi. Equipped with the new idler pulley, the peak power numbers checked in at 216 hp and 327 lb-ft of torque.
SC Performance's 5 Percentage...
SC Performance's 5 Percentage Idler Pulley
Since we had such good luck with increasing the blower speed in Test 2, we decided it was worth another look. Super Coupe Performance supplied one of its 5 percent overdrive idlers (the supercharger is actually run off an idler pulley that is itself driven by the crank) pulley. The increase in blower speed once again increased the boost pressure and the power right along with it. Note that the increased blower speed added more power down low than up top. Was this a sign there was a flow restriction elsewhere in the system?
With the blower now making more boost, we turned our attention to the inlet system. After we had such good success with the K&N filter, we looked at the small factory mass airflow meter (MAF). A call to C&L netted us a 73mm meter along with a free-flowing cone filter. Being a true bolt-on performance piece, installation was easy, and we were up and running in no time. The C&L improved the peak power output to 211 hp at 4,100 rpm and torque production was now up to 315 lb-ft at 2,800 rpm. The larger MAF added power throughout the rev range, but was most effective near the top (where the additional airflow would be most useful). With plenty of inlet flow available to the supercharged motor, we once again stepped up the blower speed. This time we employed a 5 percent overdrive idler pulley, as the Super Coupe motors rely on a secondary idler (driven off the crank) to provide drive to the blower. Increasing the blower speed via the revised idler resulted in a jump in peak power to 216 hp, but the torque gains were as high as 12-15 lb-ft through most of the curve. The extra 1.5 psi of boost was especially beneficial from 2,000 rpm to 3,600 rpm, where the 3.8L pumped out more than 300 lb-ft of torque.
Flowmaster After-Cat And Resonator...
Flowmaster After-Cat And Resonator
The final modification was to swap out the factory exhaust for a Flowmaster system. In addition to the after-cat setup, Flowmaster also supplied a resonator upgrade. The combination of the after-cat and the resonator improved the power output significantly, especially at the top of the rev range. The boost gauge was now showing a peak of 14.6 psi, and we had exceeded 230 rwhp and 330 lb-ft of torque.
The final modification was...
The final modification was to replace the factory exhaust system.
Flowmaster supplied an after-cat...
Flowmaster supplied an after-cat exhaust complete with new intermediate resonator. The system offered impressive sound quality and upped the peak power numbers to 230 hp and 332 lb-ft of torque.
With the motor now producing 216 hp and 327 lb-ft of torque, we took one final shot at our bird of prey with a Flowmaster after-cat exhaust. In addition to the free-flowing exhaust system, Flowmaster also supplied a new resonator. The combination proved to be quite effective as it improved peak power output to 230 hp and 332 lb-ft of torque. Unlike the previous mods, the majority of the power gains occurred higher in the rev range, though the Flowmaster exhaust system did offer additional power as low as 2,300 rpm. While we're still not near our goal of 300 hp, we're making gains, and perhaps we'll continue the hunt in future issues.