View Full Version : Alternator question about wiring
LuckyWinner
09-21-2013, 08:31 PM
Is the wiring that comes with the full kit (Ron Frances) made for a 3 wire or 1 wire Alternator?
Boz1911
09-22-2013, 04:55 AM
The harness for my 33 (which is basically the same) gave directions for either style alternator. I'm using a one wire alternator and was able to eliminate quite a bit of that portion of the harness.
Jeff Kleiner
09-22-2013, 07:15 AM
The Ron Francis harness is set up for a Ford 2G alternator. Pick one up for a 1990 Mustang GT and it'll be plug & play.
Jeff
LuckyWinner
09-22-2013, 04:33 PM
will this work? Summit Racing® Alternators SUM-810300
Walker Frank
09-23-2013, 03:51 AM
The wire to excite the charge circuit should be ignition power and run through a bulb in the dash. This circuit provides 2 uses. First is to send power with the ignition on and once it is all running, if there is a fault, the voltage regulator will ground the wire as it does when the alternator is not turning to indicate a problem.
rich grsc
09-24-2013, 07:16 PM
Why go to Summit to purchase a part that any auto parts store will have, and for less money? As Jeff said, an alternator from an 89 to 92 Mustang.
If you want to upgrade to 3G, then here is a small case 95amp at a great price.
http://www.dbelectrical.com/p-4024-new-ford-aerostar-alternator-30l-92-93-94.aspx
GT Trooper
09-25-2013, 04:50 PM
Is the Ron Francis harness plug and play for the 3G alternator too?
with the one wire, you end up cutting wires out of the harness and hooking up just the main red one. Very easy and clean. My one wire starts working right at startup.
Jeff Kleiner
09-25-2013, 08:15 PM
Is the Ron Francis harness plug and play for the 3G alternator too?
No.
Jeff
tirod
09-26-2013, 09:34 AM
One wire setups were invented for ag use for tractors. They ran steady state rpms all day, and the self exciter rpm was just under the typical one used in the fields.
Using a one wire setup on a hot rod is not a "better" electrical choice, it's an aesthetic one, no production car ever used it. They were three wire to get the alternator to run according to demand - not rpm. Cars have increasingly higher power demands, EFI for one consumes 40-60 amps alone, add power everything and it's common these days to see a 120 amp alternator standard on a four cylinder economy sedan.
Many post they have no problem with them, some post they do - the one wire is prone to just run down the battery cruising around all day. It never gets to it's rpm to start working. The worst case situation is one set up with underdrive pulleys, which make the rpm "excite" point even higher, and a glass mat battery with high reserve capacity.
Here's a link: http://www.madelectrical.com/electricaltech/onewire-threewire.shtml and as the title suggests, you be the judge. It's going to be the way you want regardless, making an informed decision will prevent the difficulties some experience, along with the expense of converting back to a street system for a street car driven on the street.
The 3G was Ford's answer to the problem the Mustang had with low output at idle rpms, and on the protouring forums, even the GM owners are converting to it. If you don't have the need for a lot of amps, great, but having a system that won't charge the battery unless you keep the rpms up isn't all that.