I have been using a dual belt alt pulley from racing beat and am happy with it for the most part. I am running an e-fan and at idle the alternator cannot put out enough juice to keep the system running good. I have also done emissions removal stuff too.

So the idea: Raise the idle when the fan kicks on and not by the use of your right foot.

So there is this AWS solenoid that just sits on the UIM now. Just sitting dormant. My idea is to rig this AWS solenoid up to the high speed of the fan so when the fan kicks on, the AWS solenoid will allow more air to pass, thus raising the idle, but it raises the idle *too* high. I am thinking of just squeezing some RTV in the one rubber tube and then drilling a hole through the silicone with a much smaller diameter bit than the rubber tube. In theory, it should work. My goal is to achieve a 1500rpm when the high speed fan kicks on. That seems to be the sweet spot for the alternator to kick in.

Has anyone tried this? How about one of the smaller vacuum solenoids from the rats nest? Would that possible be the right size for a 1500rpm idle?

 

Have you tried reinstalling your BAC valve?

 

The BAC is not emissions. It stayed on. I'm not having a problem with the idle dropping, just the volts. It's not a bad alt, it just doesn't spin fast enough to do anything at idle. Just for the info of the readers, the alternator is unable to have a high enough power output at 800rpm when using a dual belt alt pulley because 99% of them are underdrive pullys. So the volts drop to 11.5 and fall when the rpms are not up enough and the high speed fan is on. At 1500rpm the volts are fine and dandy at 13.7 with fan on.

 

Didn't I hear somewhere that there is a GM alt. that will replace the Mazda alt.? If that would turn out more volts, then I would be more than happy to move it where my A/C and PS used to be for a bette fit.

 

FD alt?

 

Don't most alternators have a minimum speed requirement to produce useful amps? Do the GM and FD alts require less input speed to produce enough volts?

I have a graph of the power output of my alternator from when I bought it. The curve starts at 900rpm at zero amps and goes up to 60 amps at 2000 rpm. Now that in conjuntion with 800rpm idle and pulley.....


Alternator info sheet:

"Turn on speed: 1296 rpm"
"Rated: 70 Amps"
"Max output under full load: 89 amps"

 

Have you ever been in a car that needed 1500rpm just to run the e-fan? Didn't think so...

If you have idle problems with the e-fan on then something is wrong and needs to be fixed. Getting rid of the underdrive alternator pulley would be a good start.

 

underdrive pulleys were originally designed for actual race cars to reduce waterpump cavitation and such from continuous high RPM use. they're just marketed cleverly with names like AEM Tru-Power, as if the real potential of your motor will only be unleashed if you spin all your accessories too slowly for street driving.