Rick Carter

On the way back from SITM my alternaor gave up 85 miles from home. I turned off all accessories except AC with fan on 0 and made it to within 10 miles of home; I flat bedded it to my office and charged the battery and will drive it 5 miles home where I can garage it. I know the early MR often "update" to a Delco unit but in searching I haven't seen in options for my 85. Caul has higher output units but they are rather pricey. It looks like stock rebuilts can be had for about 180 plus a 100 core charge. Something else I saw on Pirtles' email keeper list was adjustable voltage regulator but the link is gone. I did see a Volvo site LINK and it looks like I could get one from them if I know the right Bosch part number. I haven't yet looked for a local rebuilder.

RyanPerrella

couple options, none of them budget busters

Rebuilt the original. As you said <$200.00 not bad

Go with the Delco and consider it an upgrade, and probably save 10lbs as well. I think its pretty well documented here on Rennlist also.

Sorry, but isnt Carl's just another domestic alternator except that its $700

EDIT: honestly, i thought i was being sarcastic at the $700 price i mentioned, but i was just $5.00 off. CHRIST!

The Delco can be had from Autozone for less than $130 and comes with a lifetime warranty.

Or for a factory rebuild try Ebay. I bought a starter from a guy in Van Nuys CA and paid almost nothing for it, works great 18 months in. No complaints! I think ive seen stock rebuilds in the $130 range there also. If i was replacing mine i would really consider the delco. You can eliminate the cooling ducts the OE one requires, and it weighs half as much. I am a pretty strong guy, but that damn alternator is so heavy, it can be a PITA to remove and put back on.

ROG100

I sell the Bosch remanufactured unit for $199.95 plus core charge - in stock and ready to ship.

Rick Carter

When i search I see Delco for older MY but not for the later models. What is the part number? Roger, I'll certaintly keep your offer in mind. Louie O had posted about a rebuilder in Ohio that upgraded the amp output. I'm in Ohio but not close to them.

Landseer

Rick, you're right, no documentation on post-84 alt conversion.

Like you, I can confirm that particular delco won't fit an 86, but does fit the 84 and prior. Tried to convert it early am Friday before leaving for SITM.

Son got creative though, and pulled the Bosch off his 85.5 944 and we used it on the 86 --- they share a part number.

I think an adapter bracket could be created fairly easily, though, to achieve the conversion. I won't get to it anytime soon, but will keep it in mind as a project.

Carl Fausett

No, it is not just another Delco alternator - we have them puprose-built for us, and we include a welded steel adapter bracket so it slides into place on the 928 engine without mods.

Your garden-variety Delco alternator will not do that.

Our alternators are also available up to 200 Amp in size.

SharkSkin

Carl, what do the alternators that you offer for early cars put out at idle, say 1500 RPM rotor speed in a heat-soaked condition?

Carl Fausett

Dave,

Your question has two issues: temp and input RPM.

As to heat: alternators will produce significantly less AMPS as they get warmer, and so the SAE (Society of Automotive Engineers) developed the standard that all alternators are measured on the bench, not in the car. In this way they can control the ambient temperature aropund the altrernator when they measure output, in the engine bay, they cannot.

Our alternators are SAE rated. That means a 200 amp alternator will produce 200 amps on the bench at the designed input RPM. In my experience, deduct 25 amps for a hot engine bay and you would be darn close to the in-car amp output. An estimate is the best I can give you from this distance.

So our 200 Amp alternator probably produces about 175 Amps in-car, our 175 Amp alternator produces about 150 in-car. These are both significant improvements to the stock 95 and 115 amp (also SAE numbers from Porsche) that were OEM (with 60 amp and 85 amp outputs, respectivly)

As to spindle speed: the early 78/79 alternators like yours with a v-belt have the largest pulleys, and there for the slowest input speeds. They did not charge at idle as a result.

Porsche changed idle speeds (up) and alternator pulleys (down) to keep the voltmeter out of the red at idle as the years wore on. You should see the size of the 1984/85 alternator pulley! Its tiny!

Suggestions: raise your idle a little, install a smaller alternator pulley, or try one of our alternators. Our customers tell us that even at slow idle, they do produce enough amps to charge.

Rick Carter

I'm buying a unit from these guys:
LINKOhio Generator
134 N. Chapel St
Louisville, Ohio 44641
Business Hours: M-F: 8AM - 4:30PM
Phone: 330-875-6677
Fax: 330-875-6688
Dealer Inquiries Welcome!
E-mail Address: info@ohiogen.com

They are mentioned in a post by Louie Ott when I did an alternator search in the 928 forum.

They have a direct high amp bolt in with an adujustable voltage regulator. I won't mention the price because I think it may be against the rules. If you have a license to resell as an automotive or audio shop the price will be lower. I did leave in the part where Dealer's Inquiries are welcome in case a sponsor wants to contact them.

RyanPerrella

thanks for the info Rick

How much power can they get out of the alternator with this bolt in?

Rick Carter

It is comparable to other high amp units discussed. They gave me the details but I was multi-tasking when they called and don't rember the exact specifics. Each unit does come with a graphed ouput. After installation I'll post my impressions; hopefully in less than two weeks.

SharkSkin

Thanks Carl, I know they are inter-related, which is why I asked the way I did. I've already moved the idle near the top of the spec, and couldn't find a smaller pulley. The idle is a bit lumpy now compared to the silky-smooth idle it had before. I'd like to be able to get that smooth growl back and still have charging capacity to spare.

ROG100

Ohio Generator seem like an excellent compay.
They also know there S**t.

Basically they take a stock Bosch (or other make) alternator and rebuild it to produce the desired output which in our case is up to 225 amps.
So what you get is identical to what is fitted to the car but with a higher output. Simple bolt on as stock and takes the standard cooling shroud.
My selling price will be in the region of $550 to $650.

Rick,
I would be very interested in your experiance and if you could update us on your findings that would be invaluable?
Roger

Rick Carter

It will probably be close to two weeks before I can install, I'll post my impressions.

KenRudd

Rick,

I've got an 88 S4 that is heading for a new alternator as well, so I am looking forward to hearing your impressions on the install.

-Ken Rudd