high output alternator,chrome alternator,Odyssey battery,high torque starter,high amp replacement alternators


 Free Ground shipping in the continental US for orders over $200 


Pulley Ratio Chart

Alternator Pulley Diameter Crankshaft Pulley Diameter
5.0" 5.25" 5.5" 5.75" 6.0" 6.25" 6.5" 6.75" 7.0" 7.5" 8.0"
1.9" 2.63 2.76 2.89 3.03 3.16 3.29 3.42 3.55 3.68 3.95 4.21
2.0" 2.50 2.63 2.75 2.88 3.00 3.13 3.25 3.38 3.50 3.75 4.00
2.2" 2.27 2.39 2.50 2.61 2.73 2.84 2.95 3.07 3.18 3.41 3.64
2.4" 2.08 2.19 2.29 2.40 2.50 2.60 2.71 2.81 2.92 3.13 3.33
2.5" 2.00 2.10 2.20 2.30 2.40 2.50 2.60 2.70 2.80 3.00 3.20
2.75" 1.82 1.91 2.00 2.09 2.18 2.27 2.36 2.45 2.55 2.73 2.91
3.0" 1.67 1.75 1.83 1.92 2.00 2.08 2.17 2.25 2.33 2.50 2.67
3.25" 1.54 1.62 1.69 1.77 1.85 1.92 2.00 2.08 2.15 2.31 2.46
3.5" 1.43 1.50 1.57 1.64 1.71 1.79 1.86 1.93 2.00 2.14 2.29
4.0" 1.25 1.31 1.38 1.44 1.50 1.56 1.63 1.69 1.75 1.88 2.00

 

The pulley ratio is the diameter of the crankshaft pulley divided by the diameter of the alternator pulley.

Multiply that number times the engine RPM to get the alternator RPM.

 

For example, a 6 inch crankshaft pulley and a 2 inch alternator pulley equals a pulley ratio of 3:1.

Three times an engine speed of 800 RPM equals 2,400 alternator RPM.