Installing Carrera alternator in SC- Easy?

I took apart my alternator yesterday, and one of the brushes is kind of pitted. I think my multi amp stereo might be too much for the 55 amp alt, so I would like to install the 90 Amp Paris-Rhone, as used in the 84-89 Carrera. Automotion offers a kit for this purpose, has anyone here ever done this? Happy with the results?

Serge:

This is what was done on my '78 sc by the PO, and as far as I can tell the job performed on my car was a straight shoe-in, without need of resistor across the Alt light (if I remember the "conversion" literature correctly).

There is a thread I saved on this subject:

Subject: "Upgrading" alternator and voltage regulator on a 911SC

"I posted a question earlier about replacing my alternator in my 911SC. Now I have a new question. A few people have mentioned upgrading one or both of them to the Carrera spec parts. Can anyone give me details on why and/or exactly what parts I need ?
Thanks again in advance,
"


"Here are the parts you will need to update your car to an alternator
with an internal voltage regulator...
911 603 1204 04 Alt w/regulator built in
911 106 033 05 Air duct (although with a little cutting you can use
yours)
911 603 428 01 Cover for shaft of alt

There is a connector and diode you will need to make the conversion, however
you can make these parts for your local Radio Shack...Other wise you can
order through the dealer 111 971 511/911 641 981 00

You simply remove the old alternator, cut the DF wire (black) then remove the voltage regulator use the red, two browns and the field wire (blue on the appropriate markings on the new alt..red=B= Brown=D- and blue=61 The air duct will have to be notched to clear the internal voltage regulator. Start the car and see if the alt light goes out . If not then continue on. Remove the gauge in the dash and pull the indicator for the alt. Place the resistor, 91ohms 5 watts, across the terminals and hook it back up. That's
it! Hope this helps

A response to my question about why the Alt light stayed on even AFTER I put in a rebuilt alternator:

John,
The warning light is connected between the battery positive and the
regulator of the alternator, the doodad in charge of controlling the output
voltage. When you switch on the ignition, current flows from the battery
through the light into the regulator and to ground. It lights up because of
this current. When you installed the rebuilt alternator, and ran it, the
output volts on the alternator would be several volts higher than the
battery voltage, especially if the battery was not fully charged. In this
situation, these few volts difference will send a current from the
alternator to the battery and make the light glow a little. This could explain what you observed.



Hope this helps,
Jw

Jw-

Thanks for your reply- I think I saw something similar on rennlist, it might have been from you. I tried to order these parts today, with no luck. Pelican couldn't help me, Automotion has discontinued the kit, and the guy at Vertex was insisting that I would have to change the fan housing to put in the Carrera alternator! It seems you have a 78 911SC with the original fan and housing so it seems to work, but I don't know where to go from here. Thanks for your input.