I spent the last week or so chasing and correcting some issues so I figured it was a good time for an update to the build thread.
When I originally swapped in the electric cooling fans about 10 years ago, I also upgraded to a CS-144 style 140 amp alternator which I hung off of March Underdrive pulleys and brackets. It took a bit of work to get the larger alternator case to work with the bracket and turnbuckle and several tries on belt length until I got it "right". It all worked pretty well until about 3 years ago when that alternator failed (right after moving to Phoenix and of course a couple of days before my first race event here). A friend loaned me a Alternator out of a 90 Caprice which is basically the same as what I had and I've been running it since.
When I swapped in the EFI last year, I discovered that the alternator didn't put out enough amps at idle to run a heavy load of accessories. By the time the AC blower was full blast and engine cooling fans were on high, the charging system was down around 12 volts. We remedied that by building a table into the EFI software that bumped the idle up as the volts dropped below where they needed to be...and that worked well as well.
For the last year I've been limping along a 9 year old Optima Red Top that would only charge to about 12.2-12.3 volts even with the big Optima charger. It was fine as well as long as I kept up on it. Well, until Tuesday that is. This is the day I finally took my wife for a second ride in the car since the EFI install. The first time was when it was 110 degrees out and the ECU freaked out when the volts dropped too low and we barely made it home. This time I dropper her off at Target for a bit then went for a cruise to see how Andrew's latest tune was...when I noticed the care was having trouble idling. When I looked...the volts were down in the 10s... Even a cruise up the highway wouldn't cure it so I called her, told her I'd come back in the truck to get her as I had to get the car home. I pulled into the driveway with it at 9.5 volts and yes, it was dead as soon as I turned it off.
My first thought was the battery finally died. It would hold 12.1v but as soon as I turned key on and fuel pump would prime it would drop into the 9s...so I put a new battery in it. During the next test drive, all was good, volts were fine, it idled great...all good... Until the engine warmed up enough to turn fans on when the volts dropped down to 12.0 once again. Even revving the engine to 3,000 RPMS wouldn't spin the Alternator fast enough to make enough amps to run the fans. So I started the chase for a new alternator knowing full well I had about 3 days before a race and then another 5 days or so before a 2 day race event at Good Guys.
Making wholesale changes to the charging system was a dream, but reality was I needed it to be fixed that day. I found a place that rebuilt alternators here in town, so I loaded both of mine up and headed there. They gave me several options but the most favorable wouldn't be ready for 8-10 days (270 amp alt that would bolt right on). So I bought a rebuilt CS-144 with a stock smaller pulley for about $100 and headed home. I knew I'd need a shorter belt but I forgot that I'd need to work around the turnbuckle that would only move the alternator so far before it would interfere one way or the other. A 42" belt was great with the larger March pulley. A 41" looked to be about right with the smaller stock sized pulley, but O'Reillys only had a 40" in stock. Of course it moved the alternator so close to the water pump the turnbuckle was too long. I thought about cutting it down or searching for a shorter one...then decided to try AutoZone to see if they had a 41" belt, which they did. I had to fiddle with the turnbuckle just a bit to get it so it would tighten the belt up but in the end everything ended up in just about the right spot. Next time I have it off I'll space the turnbuckle out from the Alt just a bit for a bit more room to turn the lock nut but for now, it's ready to race.
What is really sweet is it now holds 14.3v at idle with the cooling fans on. And with every accessory and light on full blast it holds about 12.8v at idle...so the smaller pulley and the fresh alternator cured the charging issue I've had for a LONG time. I've got the car all cleaned up, all autocross gear loaded up and it's ready to head out at the butt crack of dawn tomorrow for Arizona Region Fall 2020 Event 3.