Got my Tenney 300 amp alternator today! She sure is purdy!

[Chriszle 10+ year member]

My truck (NBS GM) has a stupid feature that cuts the alt to save gas. When it does this the volts drop to 13.5 or so. I am sure it will still do this when I put the tenney in. If I am not happy with the performance I will add the external reg. Just su cks that the bat light will be on all the time with the external alt. Little things like that (bat light always on) will get on my nerves so I am going to try without the ext reg. When I am at shows I will be competing and demoing right after I turn the truck on and at that time it is always above 14.4 volts.

I am a little confused. If your alternator is already internally regulated, what will be the point of getting an external regulator. Is there a way to override the internal one?

 

[sbarber82 10+ year member]

Yea the external reg bypasses the internal one

I am a little confused. If your alternator is already internally regulated, what will be the point of getting an external regulator. Is there a way to override the internal one?

 

[NASTY08IMPALA 5,000+ posts]

I am a little confused. If your alternator is already internally regulated, what will be the point of getting an external regulator. Is there a way to override the internal one?

yes u wire up a relay and overrides it from the sensing wire and doesnt let the trucks computer shut down the voltage

 

[Chriszle 10+ year member]

Good to know. Never had an external reg.

 

[NASTY08IMPALA 5,000+ posts]

Good to know. Never had an external reg.

it really helps out us gm guys who have bs fuel saver modes which kills voltage

 

[Thumpersplbassx 10+ year member]

This is a 300 amp alt from Tenney alternators. I had it powder coated matte black. She is very very heavy and just beautiful! Will be installing this tomorrow!

That's a very nice looking alt you have there!

 

[awefald]

Newb question: Is there a standard RPM I should get my alt measured at? I also have a Tenney alt and my mechanic said it was doing 254 amps, 15.6 volts, but didn't specify at what RPM. When I bought it he said it would be a 270 amp alt and in another phone conversation mentioned 300 amps. It was $300. I had some issues getting my alt. I was initially sent an alt that was faulty - the bushings were rubbing against the case. I sent it back and he repaired it and sent it back again to me. It's now in and working though.