Alternator Problems

[andrewb_80]

I just have a one wire alternator in my mustang. As we all know they do not charge well below 1500 RPM. This is causing me a huge problem bc at idle the battery is not charging and i am continously having to recharge my battery. The alt and battery both tested fine and the system charges great at higher RPM's. I was wondering if anybody knew of a way to get a smaller pulley to get the RPM's in the alt. higher so it spins and charges faster. Thanks!

 

[HISSIN50]

Does it act the same way at all times or is there an issue with getting the alternator to initially excite?

The critical speed for most 3G type alts is ~15000 RPM. Choose your overdrive pulley accordingly, if that's the route you go. Note that an OD pulley often voids warranties.

Have you talked to the alt manufacturer yet?

Good luck.

 

[andrewb_80]

Does it act the same way at all times or is there an issue with getting the alternator to initially excite?

The critical speed for most 3G type alts is ~16000 RPM. Choose your overdrive pulley accordingly, if that's the route you go. Note that an OD pulley often voids warranties.

Have you talked to the alt manufacturer yet?

Good luck.

No I have not talked to the manufacturer yet. It is made by Tuff Stuff. Once the engine RPM's are up the alt is fine, just at idle it doesnt charge at all.

How may I purhase an OD pulley and what size do I need?

 

[HISSIN50]

To know what size OD pulley you need, knowing the critical speed of your exact alternator is helpful.

Formula: (Engine RPM x crank pulley diameter)/alt pulley diameter.

March, ASP and others make overdrive alternator pulleys. Summit and most big parts sites sell them.

Absent that, I still might talk to the manufacturer and get their input. Either there's an issue with your particular alternator or they might know what a fix is that has worked for others.

Good luck.

 

[superhuaman]

You should switch to a 6G or 3G...the one-wire units do not put out any more amps at idle than the stock 2G alternator. however, this should not make a problem as bad as you have. some crown vics at the junkyard have smaller alternator pulleys (like smaller than 2") but i dont have the part number anymore.