With a dire need to get the car running so the kids could eat, Jim D'Amore of JDM Engineering took on the task of seeing what we could do to try and rectify the problem. Our original thought, while confusing to us, was that the car needed either an upgraded fuel pump like the one found in the GT500, or a set of Ford GT injectors. In the end, neither a part nor a piece was needed. D'Amore strapped Project MILF to the dyno, uploaded a tune that had as much fuel as possible going into the engine, and cranked up the Three-Valve. Through the scan tool he was using, he noticed during startup that the charging system for the car was pumping out only 12 volts. After running through a few diagnostic checks, it was determined that the alternator was not working. With the alternator not putting out the usual 14 volts, the fuel system-especially the fuel pump-was seeing only the 12 volts produced by the battery. "The alternator wasn't operating at full capacity," D'Amore explains, "so the car is obviously going to run lean. With the system down on voltage, the signals will be weak to the computer, as well as the injectors."
The voltage got below 11.99 volts at one point, causing the battery light to come on. "The ideal setting, since the alternator is computer controlled, is that at 0 degrees ambient air temperature, the charging system will see 14.6 volts," D'Amore says. "At 90 degrees, you will get 14.1 volts, and at 170 degrees, 13.3. With the bad alternator, the car was seeing 12.8 volts at an idle."
We swapped out the bad alternator, and things got better as quickly as a Top Fuel car making it down the 1,320. With the charging system finally registering 14 volts, D'Amore played with the tune, eventually getting the car to rip off 385 rwhp and 368 rwtq. "I still have the tune a bit soft," he says. "I went with a conservative timing curve. If I had a full day with the car, I could get the power closer to 400 rwhp just by getting the timing perfected." If D'Amore is correct, Project MILF should be able to sneak into the 11-second zone with the revised tune. Not bad for a daily-driven grocery-getter.
Even so, with the tune itself, the car picked up 50 rwhp and 60 lb-ft of torque. To say that's a lot would be an understatement. The result at the track was noticeable. After spinning hard on our first few rips with the stock wheels and tires, we borrowed a set of Mickey Thompson 275/40/17 drag radials, which were mounted on a pair of 17x9 Cobra rims. Once we bolted on the drag radials, Project MILF roared to a 12.200 e.t. with a trap speed a tick under 115 mph. Our 60-foot time dropped to a 1.746, which is awesome considering the car weighs 3,650 pounds without a fat-cat MM&FF editor behind the wheel. As a matter of interest, cruising rpm was raised only 500. Before the gear change, the tach registered 1,750 rpm at 60 mph. With the 4.10s, the tach needle moved up to 2,250.
While Project MILF may have had us in the doghouse for a few days, not only did we get out of it, but we decided to stop at a jewelry store along the way and pick up a make-up present in the form on an intercooler. That should bring a smile from the wife for sure.
With the ring gear set and...
With the ring gear set and ready to go, Knell went back under the car and, using a few taps from a rubber mallet, removed the stock pinion gear.
We tried to remove the stock...
We tried to remove the stock bearing and reuse it on the new 4.10 gearset's pinion gear, but the bearing broke as we did so. A phone call to a local parts store yielded a new bearing, which was promptly pressed on the new pinion gear.
With the bearing on and set,...
With the bearing on and set, Knell installed the new pinion gear through the back of the housing. Once the pinion was in, he put the yoke back on.
Knell then installed the differential...
Knell then installed the differential that was bolted to the new ring gear. Once the assembly was in place, he reinstalled the main caps and torqued them down. He spun the rear around, checking for excessive backlash. Not finding any, he double-checked the backlash with a dial indicator, which came in at 0.010 inch. The backlash should come in between 0.008 and 0.011 inch.
Time to start putting everything...
Time to start putting everything back together. Knell pushed the axles back into the differential and kept them in place by reinstalling the C-clips and the cross pin.
With the rear reassembled,...
With the rear reassembled, it was time to button it up with the FRPP girdle. Knell spread black RTV sealer around the perimeter of the girdle before bolting it to the housing and wrenching it down. He then tightened down the adjustment bolts on the girdle to where they were just snug against the main caps. You don't want to overtighten the adjustment bolts on the girdle as doing so can crack the main caps.
The brakes were reinstalled,...
The brakes were reinstalled, followed by the wheels. Last but not least, the sway and Panhard bars were put back in their previous positions.
Before we took Project MILF...
Before we took Project MILF around the block to check for any unruly noises coming from the rear, Knell filled the housing with two quarts of Royal Purple gear lube through the filler hole in the FRPP girdle.
To recalibrate the computer...
To recalibrate the computer for the new gears, we first had to take the tuner supplied with the FRPP Super Pack and use it to remove the supercharger-specific tune, replacing it with the stock tune. To do so, plug the tuner into the serial port under the dash and move the switch to the left. The tuner will display a yellow light until it has reflashed the computer with the stock tune. You will know when the task has been completed because the green light will illuminate. Once the stock tune is back in, you can custom tune the car like you normally would with an aftermarket tuner.