Review on BBK 15550 Underdrive Performance Pulley Kit - High-Quality CNC Machined Aluminum 8-Rib for Ford F Series Truck, Expedition 4.6L, 5.4L - Complete 3-Piece Set by Steven Brouillard

Fits 2000 EB Expedition with 5.4 liter engine. The installation didn't cause any problems. Special tools are required for the crank pulley. The hardest part for me was loosening the crankshaft pulley. I didn't have an impact wrench and it was a bit difficult to find one that would fit the gap between the screw and the radiator. One snag in my application is that the water pump pulley is large enough to partially block one of the bolts holding the nut. Generator. They can still come out, but you have to be careful not to damage the threads. Also, you have to remove it with a wrench, not a socket, so it takes longer. It also affects the performance of your alternator. Example: The gear ratio of the crankshaft pulley to the alternator pulley was approximately 3:1. The alternator pulley was 58mm in diameter and the crankshaft pulley was about 6.9in in diameter. Thus, the generator idle speed (600 rpm) was about 1815.15 rpm. Referring to my alternator dyno sheet, I could see an output of 94 amps at 1800 rpm. After installing the underdrive kit, your crank pulley is now 5.25" and the alternator pulley will not change. Their ratio is now 2.3:1. At 600 RPM your alternator is now 1381.58. Looking back at the dyno sheet we can now only support about 30 amp load with the generator. Have you noticed your headlights dim at a traffic light? I have made. These output values also refer to my 200 ampere secondary generator. Not the standard 130 for my car. Well, if you don't have a lot of accessories, you should be fine. You can notice it here and there at low rpm, but not much, and you never notice it at higher rpm. As long as the generator can keep the output voltage at 13 and 14, everything is fine. However, I have a lot of accessories and was planning to switch to electric fans. Long story short, I have an overdrive pulley for the alternator to get a 3:1 gear ratio, as well as a 200 amp alternator to handle higher loads. Of course, this negates some of the effects of the underdrive pulleys, but I needed more power. Basically the kit is very good. It keeps what it promises and is made of high-quality materials. Since installing my kit I have contacted BBK Performance and Powermaster to get the numbers above. Both companies were very polite and helped to the best of their ability. Think before you buy and you won't be disappointed.