1-734-237-8442 sales@usalternators.com

High Output Alternators

We sell NEW alternators, not RE-MANUFACTURED alternators like many of our competitors.

We offer various sizes of alternators in both our small and large case hairpin lines. We also offer a budget line of slot-wound alternators that fit select GM and Ford vehicles. Our slot-wound units are made here in the USA. When idle is important, we will always recommend a large case option if possible.


US Alternators only advertises a HOT, realistic ratings that you will see while driving every day.  When comparing to other brands, please make sure that you’re comparing hot ratings. Many competitors advertise a cold rating at a tempting price to lure in buyers. Most engine bays run around 200 degrees, not 70 degrees. Don’t be fooled by competitors’ cold output ratings!


All prices are subject to change at any time. Cost can vary by vehicle
Slot-Wound Alternator Line
(select GM and Ford vehicles)
160A HOT “185A”
90A HOT @ idle

110A COLD @ idle

130A HOT @ 2500 Alternator RPM


200A HOT “240A”
100A HOT @ idle

130A COLD @ idle

160A HOT @ 2500 Alternator RPM


240A HOT “285A”
100A HOT @ idle

130A COLD @ idle

180A HOT @ 2500 Alternator RPM


Small Case Hairpin Line
160A HOT “180A”
110A HOT @ idle

125A COLD @ idle

140A HOT @ 2500 Alternator RPM


240A HOT “250A”

120A HOT @ idle

140A COLD @ idle

160A HOT @ 2500 Alternator RPM

320A HOT “330A”

100A HOT @ idle

120A COLD @ idle

170A HOT @ 2500 Alternator RPM


Large Case Hairpin Line

250A HOT “285A”

170A HOT @ idle

190A COLD @ idle

220A HOT @ 2500 Alternator RPM


390A HOT “410A”
120A HOT @ idle

140A COLD @ idle

240A HOT @ 2500 Alternator RPM


All HOT max ratings are measured at 6,000 alternator RPM, which is roughly 2,000 engine RPM depending on the vehicle's pulley ratio.

All HOT idle ratings are measured at 1,800 alternator RPM, which is roughly 600 engine RPM depending on the vehicle's pulley ratio. This idle rating covers 99% of vehicles made and more than likely, you will see higher ratings than we have posted.

Most pulley ratios are around 3:1 (6" diameter crankshaft and 2" diameter pulley).

To find your vehicle specific pulley ratio and rough estimate of how much power your alternator is making at a given engine speed, use the following formula:

Crankshaft Pulley Diameter / Alternator Pulley Diameter = Pulley Ratio

Pulley Ratio * Engine RPM = Alternator RPM

***These ratings are much lower than our competitors who rate their alternators at an idle speed of 2,500 alternator RPM and a peak speed of 8,000 alternator RPM. Many of their tests equal 833 idle engine RPM and 2,667 engine RPM. ***

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