Technical Alternator issues

Hi
i want to use one of the small nippon denso style alternators - partly for size/neatness on my 32.

I have a powermaster race alternator here on the shelf, but am told that at idle they only give 7 amps. I can’t get detail on what rev range the full charge is supplied.

does anyone have experience of running what is basically a circle track alternator in a road car? The car doesn’t have much loading beyond MSD and a fan.

Thanks guys

 

There are many densi alternators out there from 25 - 50 amp versions .

try finding one for a Japanese import car you will pay less then getting a “ race prepped” version.

7 amps sounds real low at idle , should be at full potential at just over 1000 rpm

 

Check the amp load on that electric fan. They often pull a lot of amps requiring a little better or more powerful alternator. I agree that 25 seems a bit low.

 

Any 80's or 90's Toyota alternators will work good and are so easy to mount.

 

"Idle" isn't really a good data point, as one engine may idle fine at 600rpm, while another may be kept at 1200 and yet other engines in race trim may have such lousy low rpm performance it has to stay above 2000rpm just to keep the spark plugs clear. On top of that, different size belt pulleys give a different ratio between engine rpm and alternator rpm, and it's the alternator rpm that's the important bit.

I googled "powermaster race alternator and found this:
Race Alternator Specs (powermastermotorsports.com)

"For alternators, these tags show the output at idle, and the output at highway speed. (Technically, the tag shows 2400 alternator RPM and 6000 alternator RPM, or typically 800 engine RPM and 2000 engine RPM with a standard 3:1 pulley ratio)."

 

There is also the '03/'04 Mustang 3.8 6G 95A alternators. Smaller case than the earlier '94-00 130A 3G cases and uses the Ford mounting.
65A @ idle
100A @ 1700rpm
120A @ 3000 rpm

 

Yep. 3 of them, on Circle track Dart SBC that sees 7000 rpm, a 302 GMC that’s used on the street and the 302 in my LSR roadster which sees 6000, All single wire that connect on the starter solenoid lug. The SBC photo will get thrown off. The CT race cars turn crank speed and the streeter probably 2x’s like a normal engine and the LSR about 1-1/4 speed.

 

You may not want to cut into your framerail like I did but this was my answer so I could use the Ford Motorsports alternator I chose.
The decision was made only after trying the two possible mounting points on the alternator housing and the direct to block mounting (with one small spacer) and related pulley spacing.

 

If your Denso permanet magnet unit output is RPM sensitive made for one RPM applications