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Author Topic:   Some quick questions on alternators
Cowboy Carson
Dirt Roller

Total posts: 10
posted April 27, 2005 08:45 AM  
Hope someone can help me with a couple of questions on alternators.

1) What size pulley shold one use? 4.5", 5", or what? Looking at putting one on a car that may turn up 6,000 to 7,200 rpms (@ the crank, not the alternator). My guess is use the same size pulley as the one on the power steering pump, but I don't want to assume.
2) What vehicle would have an alt bracket for my application (350 with Vortec heads, short water pump)?
3) I'm planning on using a single wire alternator. Do you connect the wire to the battery side of the solenoid or where?
4) And about what gauge wire should one use?

Appreciate any help one would lend.

[This message has been edited by Cowboy Carson (edited April 27, 2005).]

Dirt Maniac

Total posts: 116
posted April 27, 2005 06:00 PM  
A while ago I was relocating a delco alternater. I had to make my own drive for it. This being for a street driven car I wanted to make sure I spun the alt. fast enough to work and charge, but no faster then nessacary. A local auto- electric shop told me the the typical Delco alt. reaches max capacity at between 5000-6000 shaft RPM. Output is a near straight line with RPM... As to what size pulley to use, You need to compare it with your crank pulley. A example would be.... 5in. diameter crank pulley and 5in alt. pulley. 1:1 ratio. 6000 engine rpm, 6000 alternater rpm. To figure for different size crank and alt. pulleys just do this..... divide crank pulley dia. by alt. pulley, then multiply by rpm. So 5in crank pulley divided by 3 alt. pulley gives you 1.666 then you multiply by engine speed. Say 7000 rpm = 11666 alternater RPM.

Yes you would run the wire to the bat. side of the solenoid.

You can run a good quality 10ga(fine stranded stuff) with up to about 45 amps. After that you should probably head to 8 gauge.

Hope this helps...

[This message has been edited by eenfield (edited April 27, 2005).]

Cowboy Carson
Dirt Roller

Total posts: 10
posted April 27, 2005 08:03 PM  
Yes, it did. Thank you very much.

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