[DeTomaso] upgrading to high output alternator

[B. Seib]

I think this has all been said before, but...

The main advantage of the newer, high powered integral regulator alternators
is NOT the large amp ratings they have at high RPM. It is the large amount
of current they produce at idle and low RPM to balance the loads on the
system. The original 61A stock alternators didn't make that until 3-4000
engine RPM. At idle, they were pretty pathetic.

I've installed the following 130A Ford 3G alternator from DB electric:

AFD0032
20-234-30-1

3G Series IR/IF Alternator for Ford 130 Amp, 12 Volt, wo/ pulley

Used On:
(2000-94) Ford Mustang 3.8L
(1995-94) Ford Mustang 5.0L
(1997-94) Ford Thunderbird 3.8L
(1997-94) Mercury Cougar 3.8L

Replaces:
Ford F4PZ-10346-B

I used a C5AF-10344F 77mm single V-belt pulley. I added a new #8 or #6 wire
from the alternator output to a power stud supplying a relay bank in my
front trunk. These relays power the fans, AC, etc., etc. in my car.(like the
Mosley kit)  I also have the stock wiring from the LOAD side of the ammeter
to this power stud supplying the relays in the front trunk. So, there is
parallel wiring to the heavy loads from the larger alternator output
terminal. There is NOT any addition or change to the BATTERY side of the
ammeter, which is all stock.

I'm very happy with the performance at idle and up. It's great. It makes
about 60-70 amps at 800-1000 RPM idle, which is more than enough to balance
loads. The stock cable from the battery to the ammeter cannot handle 130A
sustained, but there is no reason to ever have more than this stock cable
can handle going into the battery.

A fused link (or breaker) in the alternator output wires would be insurance
against a large, unforeseen shot-circuit fault (shorted battery plates or
cables?) or a totally dead battery and an operator that didn't have the
common sense to let the engine idle for a few minutes before revving the
engine and driving away. You should never boost another while the engine is
running in any car anyway, so that shouldn't be an issue, and even if they
did, the amperage at idle would be limited to 60-80 amps on the 130A
version. If you want insurance against all foolish acts, you need the fused
link (or breaker).

Sorry for the long winded story.


Barry