[Photoman]

I was asked a question about the rpm’s that the larger case 130/150 amp alternators would turn at with the stock pulley being used. The short answer is I don’t know. The larger case alternator comes with a ribbed pulley and the stock pulley is a grooved pulley. Crudely the stock pulley is larger than the ribbed pulley. This is meaningless though since the diameter of the drive (crank) pulley on the Tundra /Sequoia is not known. So to know whether the new large case alternator is spinning faster or slower would depend on the two drive/driven ratios; the ribbed one from the Tundra/Sequoia, and the grooved one from the stock 80. As a further complication in my estimation it would depend on the age of the belts and/or the condition of the pulleys. One worn groove pulley either the drive (crank) or the driven (alternator) and the ratio and rpm’s would change. One possible test could be if someone had a running Sequoia and an IR tach, the engine rpm’s could be recorded with the alternator pulley rpm’s; then the same thing could be done on a stock 80.That way at say 700 engine rpm’s on each vehicle the alternator rpm’s could be compared.

Bill