BBK stepped up with a three-piece underdrive pulley system to replace the crank, water pump, and alternator pulleys, while we relied on Steve Rideout from Powertrain Dynamics to custom tune the finished combination.
The first order of business was to test the 200,000-mile wonder on the chassis dyno to see if it was still in decent working order. Project RSC was strapped to the Dynojet, and we anxiously awaited the power numbers. Unfortunately, we had to abort the initial run as the air/fuel meter indicated the WOT mixture was excessively lean (over 15.0:1). Knowing the motor had plenty of miles, Rideout checked the MAF element and found it to be dirty (a common problem). Some brake cleaner cured the problem, and we were back in business.
The first dyno runs on the...
The first dyno runs on the DynoJet indicated that the air/fuel mixture on the stock non-PI motor was dangerously lean. The culprit turned out to be a dirty MAF element.
The stock engine was run once again, and we were quite surprised when we saw it produce 195 rwhp. The air/fuel curve started out at 13.5:1 at 2,000 rpm and tapered down below 12.0:1 at 5,500 rpm. There would obviously be some power to be had from tuning the air/fuel curve, but that would have to wait until the remainder of the bolt-ons were run.
With backup runs confirming our stock power output, we installed the C&L MAF, air filter, and aluminum intake tube. Though we have had success testing the C&L components in the past, the stock motor simply did not respond to the airflow and minor air/fuel changes-fairly typical of other '96 4.6s MM&FF has tested. The C&L components seemed to offer a few horsepower past 5,000 rpm, but 1-2 hp can simply be the difference experienced run to run.
Next up was the C&L upper intake (elbow) and Accufab 75mm throttle body. In terms of ease of installation, the throttle body and elbow ranked right near the top. Unfortunately, the peak-to-peak power gains were only minimal (2 hp), but out near redline (past 5,000 rpm) the induction upgrade improved the power output by as much as 7 hp. It should be noted that we removed the C&L MAF and intake tube and replaced them with the factory components before continuing. All subsequent runs were made with the stock MAF and inlet components.
The BBK underdrive pulleys reduced the parasitic losses associated with driving the accessories by reducing the speed of all the accessories with a smaller crank pulley. The gains offered by the system were further improved by increasing the size of the alternator and water pump pulleys. Equipped with the BBK underdrive pulleys, we managed to exceed 200-wheel horsepower while the power gains increased with engine speed. Near 5,500 rpm, the BBK underdrive pulleys offered 6-7 extra horsepower.
The final modification was to have Powertrain Dynamics burn a custom chip. By altering the timing and fuel curves (that is really all there is to tuning), Rideout was able to up the power output of Project RSC by as much as 6-7 hp and 14-15 lb-ft of torque. We left the dyno producing 209 hp and 286 lb-ft of torque.
The factory MAF electronics...
The factory MAF electronics were removed for use in the new C&L meter.
The wimpy stock motor just...
The wimpy stock motor just couldn't take advantage of the extra airflow offered by the C&L MAF and aluminum inlet tube. We will put these to better use after a few more serious modifications.
Once the new chip was cleaned,...
Once the new chip was cleaned, we plugged it in and were rewarded with as much as 7-8 hp and 14-15 lb-ft of torque.