alternator upgrade

[richard c bieber]

Hi , I am just gathering info for now and have been to various sites for alternators. I currently have a 120 amp alternator which is fine . But i am upgrading to some electric dual fans that are rate at 40-50 amps depending on which ones i pick. I also am using a PWM to control them so they will not be using full out put at start up but soft start. Just in case i need more amps what would be a good choice. I am more worried about idle in traffic for the fans if they are at full capacity with the ac on. I was thinking i could get away with 170 -175 as long as the idle amps are around 100 amp or better. I already have upgraded the wires to 4ga for the alternator and bigger wires from the custombatterycables so i am prepared for a bigger load if needed. I keep seeing massive 250 and higher but feel this is ridiculous. I know the wire can handle more just was hoping to find one at about 200-220 even though i will never use it. The regulator will only call for what is needed anyway. thanks for any input.
1995 dodge ram 1500 408 stroker, msd ignition.

 

[Fast69Mopar]

Hi , I am just gathering info for now and have been to various sites for alternators. I currently have a 120 amp alternator which is fine . But i am upgrading to some electric dual fans that are rate at 40-50 amps depending on which ones i pick. I also am using a PWM to control them so they will not be using full out put at start up but soft start. Just in case i need more amps what would be a good choice. I am more worried about idle in traffic for the fans if they are at full capacity with the ac on. I was thinking i could get away with 170 -175 as long as the idle amps are around 100 amp or better. I already have upgraded the wires to 4ga for the alternator and bigger wires from the custombatterycables so i am prepared for a bigger load if needed. I keep seeing massive 250 and higher but feel this is ridiculous. I know the wire can handle more just was hoping to find one at about 200-220 even though i will never use it. The regulator will only call for what is needed anyway. thanks for any input.
1995 dodge ram 1500 408 stroker, msd ignition.

If you are planning to run a pair of fans that pull 40-50A at 100% duty cycle then I would go with something in the 200A range. If you could find some fans that pull about 30A at 100% duty cycle then you could go with a 175A alternator and be just find.

 

[richard c bieber]

I went with a dual fan setup from TCPperformance and a PWM setup to control the fans from autocoolguy. The whole setup is great the fans never really come up to full speed ever. I am guessing but the most by the sound is about 40 -50 percent. I barely hear them on except the high pitch sound when the truck turns off and there is a one minute cool down phase. I have a over ride switch so i can tell the difference between full on and what it sounds like all the time. Well worth the money for the autocool set PWM . the alternator i wound up was a power master 170/110 amp from fourwheelparts. plenty of power.