Overdrive Alternator Pulley... anyone used a capacitor

AnthonyR23

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Sep 8, 2006
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Anyone know what number my chargine should be at... sits at about 13... I'm guessing it should be 14.. but is 13 a little too low or should that be ok... I just ordered a overdrive pulley so hopefully that helps.. Car starts up but just don't want to get stuck somewhere... I have a battery charger so I throw that on once in awhile, especially when the car just sits... anyone ever used a capacitor?

3G 130amp Alt., Mark 8 fan, Underdrive Pulleys, Cold Air Intake, A/C eliminated, BBK equal length headers, on mainly stock 88 mustang gtc with speed density.

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How do I add cars info in the tag so I don't have to write it every time?
Click on the "User CP" link near the top[ of your page and add a signature.


anyone ever used a capacitor?
A capacitor won't help. Capacitor help mostly in holding a charge for WELL UNDER 1 second. In some very low power applications, big capacitors ("ultra/super capacitors) may hold a charge for 2-60 secs.

Get an overdrive pulley. With your lights, AC, rear windows defogger off, your car battery should be above 14V. But, the stock gauge is NOT accurate. You need a digital volt meter - $15 from Walmart, etc.

Under-drive pulley are horrible for charging systems. You really need to put an overdrive pulley on the alternator when you have an under-drive crank pulley.
 
I'm with Stang&2Birds on this one.

Your battery is as close to a capacitor as you're going to get for this application. :p
Good advice about measuring actual voltage (with a real gauge/meter). Between gauge hysteresis and voltage drops in these 20 year old cars, you can't really know what's going-on otherwise.

Monte Smith has some info on overdrive pulley sizes on his alternator page.
A 3G's critical speed is about 15K RPM, so be mindful of that when crunching ratios to decide upon the best size.

Good luck.
 
Anything over 12V is charging your battery, so 13V is still fine, it's not low.

If you are reading 13V at idle then it's good enough, when you drive and engine rpm's climb, the increased revs will put out more voltage, around 14.4V