Increasing alternator efficiency can, and will, measurably reduce fuel costs. High efficiency alternators translate to less engine horsepower requirements, resulting in substantial fuel savings to the customer. Remy recognized the opportunity for this fuel savings and made significant improvements in alternator efficiency with the Delco Remy heavy-duty alternator product offering. The Delco Remy 28SI™, 36SI™, and 40SI™ alternators operate with industry-high efficiency ratings from 68% up to 70%. Typical alternator efficiencies are in the 54%-60% range.