Ultimate High Output Bosch Alternator fits 1985-1995
12-06-2016, 11:47 AM
#16
Looks fantastic Greg, job well done.
12-06-2016, 12:37 PM
#17
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Greg,
That looks fantastic with the satin finish. Good job getting a clutched alternator out there. Its perfect for those running heavy load items with the multi-rib belts. Supercharged guys without a dedicated belt drive should take notice!
That looks fantastic with the satin finish. Good job getting a clutched alternator out there. Its perfect for those running heavy load items with the multi-rib belts. Supercharged guys without a dedicated belt drive should take notice!
12-06-2016, 02:24 PM
#18
That was my thinking exactly.
12-06-2016, 02:36 PM
#19
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The primary circuit from the alternator lug to the jump post, and the power post on the driver side aren't the problem. Neither is the primary from the batt + to the starter. The starter line only gets a hot shot for a few seconds while starting, although that generates plenty of heat which I've felt several times. No, the problem, as I said is the various current paths leading away from the primary circuits which add up to a lot of paths. You mentioned a couple big ones, and those are often the culprit. Anytime we see burnt CE fuse or relay connections, and semi-melted harness ends this is an indication of latent resistance chewing up current along it's path to the ultimate delivery point(fan, motor, lights, etc).
I do agree that at idle, with many circuits running like the AC on high, wipers, rad fans(part of HVAC), and some lights you are at the limit of the alternator supply. However, if all the wiring that served these various loads were cleaned up, and renewed as I've seen done before, a larger alternator isn't needed. Porsche specced the alt for a given load factor, and put in a modest reserve. The reserve they allocated is most often chewed up in the supply wiring to the ultimate end load. Sure, if a guy puts in a big stereo amp, that can affect the ampacity as well. But one would be better served to replace those old rad fan motors, clean every high amp circuit from end to end, and clean all the grounds, as well as replacing the batt ground which is another indicator of high resistance in the load paths.
But, it is a very nice looking alt, and having the free-wheel clutch is a bonus on decel.
I do agree that at idle, with many circuits running like the AC on high, wipers, rad fans(part of HVAC), and some lights you are at the limit of the alternator supply. However, if all the wiring that served these various loads were cleaned up, and renewed as I've seen done before, a larger alternator isn't needed. Porsche specced the alt for a given load factor, and put in a modest reserve. The reserve they allocated is most often chewed up in the supply wiring to the ultimate end load. Sure, if a guy puts in a big stereo amp, that can affect the ampacity as well. But one would be better served to replace those old rad fan motors, clean every high amp circuit from end to end, and clean all the grounds, as well as replacing the batt ground which is another indicator of high resistance in the load paths.
But, it is a very nice looking alt, and having the free-wheel clutch is a bonus on decel.
And having worked on these cars since they were new, They did a really good job.
However, over the years, the parameters have changed.
The majority of the people that own these cars today, use them in a far different manner.
When these cars were new, most were daily drivers. That is no longer true.
The majority of the cars I see sit for weeks, slowly draining the battery. When they are used, they are generally working on a very low battery....sometimes jumped to even start the cars.....or charged only enough to start the car.
The alternator is then expected to both run the car and bring the battery up to full charge....very rarely occurring. It's not uncommon to see 12.5 volts (or lower on a hot summer day with the A/C running.) Headlights are dim, sunroofs barely function, windows work slow, and the injection system on the late cars is VERY dependent on good voltage.....sometimes resulting in misfires.
Rarely, the battery achieves full charge before the cars are parked...starting the cycle all over again.
These cars respond much better, when they can make over 13.5 volts while running and still have enough capacity to charge the battery.
Everything works better......all of the electric motors love the proper voltage and the correct operating speeds.
In reality, every single one of these cars will benefit from a high output alternator.
__________________
greg brown
714 879 9072
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Semi-retired, as of Feb 1, 2023.
The days of free technical advice are over.
Free consultations will no longer be available.
Will still be in the shop, isolated and exclusively working on project cars, developmental work and products, engines and transmissions.
Have fun with your 928's people!
greg brown
714 879 9072
GregBBRD@aol.com
Semi-retired, as of Feb 1, 2023.
The days of free technical advice are over.
Free consultations will no longer be available.
Will still be in the shop, isolated and exclusively working on project cars, developmental work and products, engines and transmissions.
Have fun with your 928's people!
12-06-2016, 02:57 PM
#20
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Without your help, this would have never happened!
Thank you, very much!
(Hans drew up the housing and made it possible to be machined on an CNC mill.....he's got a serious amount of talent.)
12-06-2016, 03:23 PM
#21
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12-06-2016, 04:13 PM
#22
12-06-2016, 04:56 PM
#23
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I have a little question. My Alt on my 81 has a V style pulley on the alternator. Would getting this alternator require getting a new crank pulley from a later car to get it to work?
Same goes for all the other pulley widths Porsche used over the years to drive the alternator.
Same goes for all the other pulley widths Porsche used over the years to drive the alternator.
12-06-2016, 05:03 PM
#24
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Yes, new crank pulley. Though I think Jake Myers has retrofitted his '81 with the whole alternator/PS pump cassette from the S3+ cars, to run a polyrib- belt alternator. Perhaps he can chime in.
12-06-2016, 05:28 PM
#25
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I'm a firm believer that Porsche knew what they were doing, given the parameters of their goal.
And having worked on these cars since they were new, They did a really good job.
However, over the years, the parameters have changed.
The majority of the people that own these cars today, use them in a far different manner.
When these cars were new, most were daily drivers. That is no longer true.
The majority of the cars I see sit for weeks, slowly draining the battery. When they are used, they are generally working on a very low battery....sometimes jumped to even start the cars.....or charged only enough to start the car.
The alternator is then expected to both run the car and bring the battery up to full charge....very rarely occurring.
And having worked on these cars since they were new, They did a really good job.
However, over the years, the parameters have changed.
The majority of the people that own these cars today, use them in a far different manner.
When these cars were new, most were daily drivers. That is no longer true.
The majority of the cars I see sit for weeks, slowly draining the battery. When they are used, they are generally working on a very low battery....sometimes jumped to even start the cars.....or charged only enough to start the car.
The alternator is then expected to both run the car and bring the battery up to full charge....very rarely occurring.
12-06-2016, 05:29 PM
#26
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I have a little question. My Alt on my 81 has a V style pulley on the alternator. Would getting this alternator require getting a new crank pulley from a later car to get it to work?
Same goes for all the other pulley widths Porsche used over the years to drive the alternator.
Same goes for all the other pulley widths Porsche used over the years to drive the alternator.
12-06-2016, 05:52 PM
#28
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Bottom of post #1, $795 for the next month, $995 thereafter. I know enough about this project to know that between the parts cost, machine time, and the sweat equity, this is more or less a zero sum game for Greg and Hans.
I had the pleasure of testing one of these on my GTS. Here it is at warm idle, A/C on recirc, front fan on high, rear fan on three, highbeams and fogs on, Stereo on with the sharkwoofer thumping. 13.93V at the jump post:
Stock brackets, easy fitment. We had it installed in about 20 minutes.
I had the pleasure of testing one of these on my GTS. Here it is at warm idle, A/C on recirc, front fan on high, rear fan on three, highbeams and fogs on, Stereo on with the sharkwoofer thumping. 13.93V at the jump post:
Stock brackets, easy fitment. We had it installed in about 20 minutes.
12-06-2016, 06:22 PM
#30
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714-879-9072. Operator is standing by.