Yesterday I finally got around to swapping out the bad alternator on my van. It charged fine, but the mounting hole had worn out so the alternator rattled like crazy when I drove. I replaced the alternator with an original conmdition 1975 vintage 50 amp alternator I had in my garage. When I took the old alternator off I noticed that one of the three diode terminals was missing on the back.

Anyway, the new alternator is not only quieter (I thought I had a couple collapsed hydraulic lifters, but it was the alternator), but it puts out 14 volts at idle ( ) and the van has a very noticeable increase in power. I was able to zoom in and out of traffic on the highway and pass people with ease. even in this 4500 pound van!

Would increasing the primary ignition voltage really make a big difference in performance?

It certainly could, depending on how low it was before.

_________________
David Kight
'62 Valiant Signet, White
'98 Dodge Dakota
'06 Jeep Liberty

Growing older is unavoidable but growing up is strictly optional.

Weird, now my van is putting out a lower than normal voltage. TIme to investigate the voltage regulator.

It takes power to make power, you can't fabricate it out of thin air. Alternator takes mechanical energy from the belt and turns it into electrical. If you take an inefficient alternator (bad bearings, shorted windings/diodes) and replace it with a more efficient one, it'll rob less mechanical energy to put out the same/more electrical energy then the old one.

A quick way to test this - remove the field wires from an alternator and you'll hear the engine rpms rise one or two hundred.

If you want to notice an even bigger difference try swapping to a modern nippondenso alternator.