I installed underdrive pulleys, but not an overdrive on the alternator...... so the alternator is running at 80% normal output.
Also, I'm running two 16" E fans.

I noticed that at idle the a/c fan runs a bit slower than at driving speeds, and you can hear the fan speed increase as you accelerate from a stop.

I checked the temp at the center vent at idle with a thermometer inserted, after the a/c was good and cool....... then watched the thermometer drop about 8 - 10 degrees after I ran it up to 1800 rpm for 20 - 30 seconds: dropped fast.

Is my alternator maxed out, and not providing enough amps for the fan at low engine rpm's?

Should I cut to the chase and just get an overdrive pulley for the alternator?

 

Yes!

 

+1

 

Hi. Yes, or you can invest in a custom tuner and get the idle speed bumped up.

That's what I did ( same effective setup as you) - MT raised the idle speed to 725 rpm in my 9100 custom tunes. Works great. My headlights used to dim at idle before this was done.

Cheers
Grog

 

Thanx all,

MGD- I have an xc2 on the way - MT will probably make the same adjustment.
I don't mind changing the pulley ..... probably do it any way....

 

Hi ONELOWF;

Congrats on the X2 purchase!

Yeah, if you indicated on your CPW's that you had underdrives, MT automatically adjusts the idle speed to compensate. His underdrive kit is a 2 piece only - crank and water pump.

If you also change the alternator pulley, you should let him know - the adjustment may be different.

Cheers
Grog

 

alternator pulley swap are pointless they dont drag at all unless they are trying to charge the battery and when they need to charge the batter why under drive it?? u will just be hindering the spark that your coils can discharge and other problems. so puttin a UD pulley on ur alternator takes more power then it would actually generate"in theory" and if u are to get UD pulleys at all get light weight aluminum ones... heavy steel ones dont show u much gain due to the larger pulley being heavier then stock... so there is paracitic loss from the added weight... its like puttin 20's on ur truck which originally had 17's while yes top speed will be imporved u put down less power to the wheels and takes longer to get up to speed from all the extra weight u have to spin

 

Well faster if you noticed he wanted to put and overdrive pulley on not an under drive pulley, to get the alternator back to factory specs from the underdrive pullies he has on his crank and water pump, so unless you want to spend the money to get the tuner yes get on overdrive pulley to put you back to specs