I installed the alternator Friday evening with no trouble. Only had to make 2 changes: 1) The bolt holes in the CS-144 are larger (3/8") than the bolts and bolt holes in the original Bosch alternator (8mm (approx.5/16")), I cut and formed 2 sleeves from a piece of copper water pipe to make the 8mm bolts fit snugly in the 3/8" holes. 2) I could have used a larger v-belt, but; didn't have one on hand, so; I lengthened the slot in the adjustable mounting bar (to the left of the alternator in the photos) by about 1.5 or 2 inches. The bar had very little room for adjustment to begin with - only about 2 inches. I drew a line across the bar at the original mounting point for the Bosch alternator so you can see the difference between the Bosch and CS-144 mounting points when using the original Porsche spec v-belt. That can be better seen in the second photo.
For wiring, I made 3 connections: 1) the red battery wire 2) a ground wire from the engine to the alternator housing (used the 3/8" threaded hole at the upper-rear of the alternator nearest to the engine block) (The Bosch alternator had a ground wire here since all the mounts are cushioned with rubber.) The old wire can be reused if the original v-belt is used. If a longer v-belt is used, that will probably move the ground wire attachment points too far apart, but; it's a good idea to replace the old ground wire anyway. They're made of bare braided copper and most have probably gained some resistance over 20 years of exposure. 3) The car has a battery light that lights with the ignition on and the engine not running. I took a voltage reading from the final small gauge wire attached to the Bosch alternator. It read approx. 1.4 volts. I connected this to the "L" wire on the CS-144 with a single wire plug (can be seen running alongside the red wire to the right of the alternator in both photos). That's all.
The Bosch was a 75 amp alternator. Voltage readings taken from the cigarette lighter port gave approx 12.9V with the engine running at idle and no lights, interior fans, audio, wipers, horn, nothing turned on. With the radio turned on, the voltage would drop by .65V to approx 12.25V. Then with lights and windshield wipers and ventilation fan running, that took it down below 12V. Not good... With the CS-144, I get approx 14V with the engine idling and nothing electrical turned on. It still drops by .65V when I turn the radio on (to 13.35V). Then with all the usual nighttime electrics on - radio, headlights, ventilation fan it shows approx 12.8V. One time I saw a reading of approx 12.3V. That was on my first time driving it after the CS-144 was installed. I had driven about 10 miles and it had been idling for a few minutes when I looked at the meter and saw 12.3V. The lowest reading I've seen since then is approx 12.8V.
There is no higher output alternator available from Porsche or Bosch or the Porsche parts suppliers that I use (Automotion, Tweeks, PAR, Zims). Automotion sells the Bosch 75amp (rebuilt) for $199.98. The 924 turbo and 924 models 1976-1982 all can use the same alternator. I actually had a Bosch AL-109X which is listed in the Automotion catalog as being for the 1976-1979 924 in my car. For the 1980-82 924 and 924 Turbo, they show a Bosch AL-23X. Both the AL-23X and AL-109X are 75 Amp and $199.98. The highest output Bosch alternators shown in the Automotion catalog are an AL-170X for later 944 and 928's and the 968 at 115 Amp ($279.98 rebuilt) and the AL-176X for 911 Carrera and Turbo's also at 115 Amp ($238.98).
Jim M. for the inspiration for innovation
Click here for the CS-144 Alternator order page