New alternator, new voltage problems

[ahole-ic]

The ecm knows the speed of the crank sensor only so how will changing a pulley that the ecm does not see change anything?

On 1 wire alts you'd be right. On anything else I think you need to check your facts.

Also, I'm not sticking up for mechman. I have literally never heard anything good about his products. I've bought from him and had bad results and so have my friends. I'm just stating that if you've got all this experience, you should know a bit more than you do.

 

[sexy 10+ year member]

On 1 wire alts you'd be right. On anything else I think you need to check your facts.
Also, I'm not sticking up for mechman. I have literally never heard anything good about his products. I've bought from him and had bad results and so have my friends. I'm just stating that if you've got all this experience, you should know a bit more than you do.

I was asking you to explain your comment not picking on you at all but if you are going to challenge me I could make you look silly.

 

[basshead442]

I had the same issue with a HO alt I had rebuilt but by another company. It is the pulley and the reason you need a smaller one is because when they made the alt to have alot of amperage output it makes it to where you have to spin the alternator faster to get the proper output because there are so many more windings than a stock alt and to spin the alternator faster at idle rpm you need a smaller pulley to make it spin faster and charge at idle.

 

[MECHMAN 10+ year member]

Could you explain that a little please? I have worked on alternators for 20 years and that’s a new one for me. What is there to adjust inside of an alternator?

Changing the stator wire diameter or the resistance of the rotor will effect the turn-on speed of the alternator. The Denso Hairpin alternators have at least 4 wire diameter or thickness, whichever you prefer. This in combination with the proper rotor resistance and proper connection of the stator will produce the desired output curve. If the rotor resistance is too low it can raise the turn-on speed above where the car idles.

The turn on speed is monitored by the ecm of the car. Once the alternator is up to speed, it is safe to draw current from it. THAT is what he means by turn on speed. This can be remedied with a smaller pulley.

Often it is that simple, but no, we can't go smaller on the pulley in this application.

The ability to produce current is based on the rotor speed, not the crankshaft speed. The PCM only watches the engine speed, the rotor speed is assumed based on the factory pulley ratio.