Clean Stock MAF Element
The first thing we noticed after installing Project RSC on the chassis dyno was that the air/fuel mixture was excessively lean, despite running with all stock components. The high-mileage (just under 200,000) car was serviced regularly and seemed to be in good condition. We aborted the first run due to the air/fuel mixture exceeding 15.5:1. The culprit turned out to be a dirty MAF element (the hot wire). Cleaning with brake cleaner cured the issue, and the result was just over 195 wheel horsepower with the typical decreasing air/fuel ratio.
Stock MAF/Air Filter and Inlet vS. C&L
First up was a C&L MAF and aluminum intake tube to replace the factory components. Though the C&L MAF (with factory electronics) and matching intake tube (from the MAF to the throttle body) outflowed the factory components, the dyno indicated that the stock components were more than able to support the airflow needs of the anemic engine. The C&L components did lean out the mixture slightly (13.3:1 versus 13.0:1) but the stock components actually produced the best power curve up to 3,800 rpm. Past 5,000 rpm, the C&L components may have been worth a few ponies, but the difference was negligible. We know from prior testing that the C&L inlet system will pay larger dividends once we have modified the motor with cams, ported heads, and a new intake.
Stock Throttle Body and Inlet Elbow vS. C&L
One of the most popular performance upgrades for the 4.6 engine has to be the throttle body and inlet elbow (often called an upper intake). Some of the popularity has to do with the ease of installation, but testing has shown that upgrading the stock components with aftermarket systems can be worth significant power gains on modified motors. Unfortunately, the flow needs of our stock non-PI motor did not exceed those of the stock throttle body and elbow, as upgrading the stock components with a C&L elbow and Accufab 75mm throttle body showed virtually no gains in peak power. The additional airflow did make itself known by adding as much as 6-7 hp at near 5,500 rpm.
Stock vs. BBK UnderDrive Pulleys
Underdrive pulley systems have been a mainstay of the aftermarket since the introduction of the serpentine belt. This power absorbed by the accessories is power not produced for acceleration. Underdrive pulleys are used to decrease the speed of the accessories, thereby decreasing the amount of power required to drive them. We installed a set of pulleys from BBK. The kit included a smaller crank pulley (which decreases the speed of all of the remaining accessories) as well as larger water pump and alternator pulleys. The combination of these parts allowed us to retain the factory belt size. As we have come to expect, the power gains offered by the BBK underdrive pulleys increased with engine speed. Though the peak power was up only 2 hp, past 4,500 rpm the BBK pulleys offered as much as 6-7 hp.
Stock vs. PowerTrain Custom Chip
Using Chip Master Revolution software, Steve Rideout from Powertrain Dynamics dialed in our fuel and timing curves to maximize (pump gas) power. His years of experience tuning Mustangs showed as he nailed the tune for Project RSC on the first attempt. Using the Powertrain Dynamics chip, we were able to produce 209 hp at the wheels and 286 lb-ft of torque.