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View Full Version : Which alternator?

NotUrAvgStangGrl
10-01-2006, 09:53 PM
I have a system in my car thats draining power.. It dims my headlights everytime it hits..

What amp alternator would be suitable for an 04 3.9L?
I was told a 6g 130 amp?
phatpharmacist
10-01-2006, 10:26 PM
Hmmm, a nice aftermarket altenator might help you out. But, How many watts you running? May want to think about a capacitor or something.
311-420
10-01-2006, 11:26 PM
i have seen Mean Green Alternators in Dallas Mustang seasonal mags. I thought about getting one because of my system too but 300+ seemed a little high.
Bulldog Stang
10-02-2006, 02:41 AM
Capacitors .. try that 1st .... try running 2 .. they are cheaper than an alternator
white35th
10-02-2006, 10:33 AM
The alternator size has nothing to do with your problem. The alt is only the prob if your battery gradually runs down while driving. you need a big storage capacitor or secondary battery mounted close to your bass amp to solve this problem, also unless it just bugs the heck out of you it does not hurt anything. :shane:
NotUrAvgStangGrl
10-02-2006, 10:58 AM
And another thing.. when I roll down my window and hold the button my rpm's drop? I was told it was my alternator...?
2k4mk1
10-02-2006, 11:06 AM
A capictor is always good for the amp keeps the voltage to the amp constant.
However if you are having these other issues (window lights etc) You maybe drawing close to what is your alts max when all these are running at the same time.IE nite driving thumping system rolling dwnn windows all while at idle. A larger alt wont hurt but it isnt most likely the cause
NotUrAvgStangGrl
10-02-2006, 11:08 AM
My rpms would drop when i rolled down the window even before the system. Thats what Im confused about..
white35th
10-02-2006, 11:44 AM
My rpms would drop when i rolled down the window even before the system. Thats what Im confused about..

It is a mater of physics, when you ask for electrical power for any load it requires a input of power from the alternator to replace what is being drawn from the battery( think of the batery as a big capaciter) this requires an equal input of power to the alternator from the motor. It takes a few seconds for the computer to notice and tell the motor to bring the rpm back up so the motor rpm drops. This is normal. :shane: