Is there a consensus on how fast the alternator should be allowed to spin ?

I know there are larger pulleys for the alternator.

Anyone ever have an alternator balanced ????

Powermaster racing alternators are rated to 21,000 rpm

Only needs to spin fast enough to maintain 13.5 - 14V or so. Why use the power and tear it up by zinging it up?

We used stock pulleys on the alternator with a small pulley on the crank. Worked fine. 13+ volts at less than 3K.

Andy thanks much for bringing that Powermaster to my attention.

I might be slowly putting a new plan together.

McAllister, I need to read more about this, I suspect there is some kind of
trade-off for the useful RPM range of the alternator. While I'm planning
I should get to know what kind of electrical loads I'll realistically need.

Race car I assume.

We ran two batteries. Car was light to begin with, had mounts for two, just made sense. Not having to charge the batteries at the track (usually) was a nice side benefit to running an alternator. I did charge them up to 100% between weekends.

The main reason I ran an alternator was to keep the voltage consistent run to run, hoping that anything with a wire attached to it would also be consistent - ignition, timers, solenoids, etc.. Wasn't concerned about whether it was 13.7 or 14.7, just that it was the same every pass.

If its a small alternator you'll need to spin it to get any kind of charging at low rpm. My East Coast mini is at nearly 3-1 pulley ratio. The motor goes thru thru the lights at 7200-7300. Still struggles with both fans on driving in the pits.
Doug

I used a one wire Delcotron. Not small, bit it worked. Carried parts for it and fixed it at the track as well on the rare occasion a diode trio or something failed.

I like stuff that works and is servicable in the field.

We have a GM style one wire onthe Vette and the engine sees 10,000 plus rpm every pass. We use a serpentine belt for the Alt and Vaccum pump

Couple nutdrivers and a straw from a can of Brakleen and you can rebuild the whole thing at the track.