Power Draw - Smaller Alternator
Joined: Jan 2005
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From: St.Peters,Mo
All s2k alternators are rated for 105 amps @ 13.8 volts, if you want to reduce drag on the engine find a larger pulley or a smaller alternator it's a old drag racing trick to gain HP. I used to shut my alternator off when I came out of the waterbox and went down the track on the battery, made the car more consistant
Joined: Sep 2004
Posts: 735
Likes: 2
From: Mentor, OH
Adding a larger pulley also reduces drag when the alternator is not charging. If you are constantly at higher rpm's, the alternator will still charge the battery. Say the alternator can supply enough at 2000 rpms for your needs now, you average 6000 rpms racing, so you can triple the size of the pulley and reduce the speed of the alternator 3 times also. Another alternative would be to buy the small racing alternator. You could remove windings. I would work, but it is not worth it in my opinion.
Joined: Sep 2004
Posts: 735
Likes: 2
From: Mentor, OH
Originally Posted by hecash,Sep 7 2005, 01:46 AM
If you had a 6" crank pulley and 4" alternator pulley, it takes about 890 rpm to hold a 2000 rpm charging floor at the altenator. To move that floor to 6000 rpm at the crank, you would need to increase the size of the alterantor pulley to roughly 10.4 inches or 2.6 times the original size.
--------------Crank-----------------Alternator
Diameter....6..............................10.392
Radius.......3.0000........................5.196
Pi..............3.1416.......................3.141 6
Lineal/Rev..28.2743.....................84.8180
RPM...........6,000..........................2,000
Lineal/Min.................................169,636
--------------Crank-----------------Alternator
Diameter....6..............................10.392
Radius.......3.0000........................5.196
Pi..............3.1416.......................3.141 6
Lineal/Rev..28.2743.....................84.8180
RPM...........6,000..........................2,000
Lineal/Min.................................169,636
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