TedH

When just out cruising with the wife, I tend to loaf along in my C3 with the 700R4 OD engaged anywhere from 45mph or higher. The other day, the car nearly died at a stop and I suspect that the discount alternator that I installed, although considered a 'high amp' alternator, has to be turning steady above 2000rpm to really charge the battery.

I've noticed such vendors as 'Mr Amp' and others in Chevy High Performance that appear to offer 'low rpm/high amp' alternators.

Worth a try?


[Modified by TedH, 4:47 PM 3/23/2004]

gkull

Ted - i bought my power master polished 100 amp out of Summit. PWM-27294

It works great. I pulled the small chrome pulley that cam with mine and used my larger pulley to make it turn even less rpm

dsagers

These guys built my high amp alternator, very good quality.
http://www.rushpowersystems.com

page62

Nope. My instincts tell me you're treating symptoms and not finding a cure. (Not that I have the answer...)

BTW: Don't lug that 700R4 too much. It's the #1 cause of premature failure. I keep my tranny in 3rd except when on the freeway.

427V8

MSD just brought out a killer Altenator, take at look at it...

shoptek

TedH,

69'er (Joe from New Jersey) e mailed me a great alternator companys site.
Unfortunately......I have that e mail on my computer that is currently down.

You might want to IM him.

stickboy

I got the powermaster 140 amp from summit. I believe the card that came with it said tested with 80 amps at idle.

mrvette

The one you want is factory rated at 108 amps, comes from a '79 Seville with window defogger.....and is slightly larger than stock....same hookups...and runs fine at idle....called a 17SI, maybe SI17, whichever.....

about 80 bux at AZ/etc.....

GENE

jetmech

What about a smaller pulley to turn the alternator faster at idle?

:cheers:

TedH

Good question. The pulley on it is fairly small. How much smaller can it go? I'll try to measure the diameter of the pulley (both inner surface and outer edges since I don't know which is the relevant factor).

dogboy

I had the same problem, low lights, radio cut out,almost stalling, I put in a pwr master 100 amp that was actually rated at 70 amp idle & 106 amp max. $120 & it fixed all of that. Looks great in chrome also.

TedH

What's the Supplier/Part Number for that $120 alternator?

gkull

I gave you the part number from summit

TedH

ack. Was wondering of dogboy had purchased one from elsewhere. Also, the alternator from Summit appears to be 'old style' that has to be converted to one-wire. Is that correct?

Larry B.

Ok ...Here's what I found over the years of owning several C3s. Corvettes have a smaller crankshaft pulley than say a full sized Chevy or even a Camaro. They also used a Corvette specific aternator with different spec's. It puts out more AMPS at lower RPM. Most aftermarket builders just group them all together into sorta 1 size fits all category. (it's clocked this way so it fits theses cars)So Everything is OKat 1000rpm but at idle you have no reserve power. I went through this at Auto zone a few years ago. The alternators were fine except at idle. Of course they exchanged a couple to no avail. I did some research and found out the difference and of couse expaining that to the guys at Atuo zone was like talking to a cinder block. All they could say was "the book says you have the correct unit... theres nothing wrong with the alternator. There must be something wrong with your car. Set your idle up to 1000 in D...... RIGHT!!!!.... (Nothing wrong with a 30 amp discharge with the lights and A/C running) Anyway, while I was at the counter a guy from on of the old precision tune shops overheard the conversation (wich was quickly turning into a shouting match) He came to my rescue and said that a guy with an 82 spent $800 trying to figure out why his car would stall at a light with the A/C on. Turned out that he had put a rebuilt alternator on and of course it was a standard unit and the electronics shut down due to low voltage.. When They replaced it with a new Delco corvette specific unit.... Problem solved. I found A Delco unit listed as different unit for Corvettes so I tried it and it work fine. After I show the guys At Auto zone the results they refunded my money and we all agreed that we had learned something over that. I understand that some of the 5.0 mustang have a similar problem. I don't know if that's your problem but that's what I learned. :rant:


[Modified by bluevetteman, 2:26 PM 3/24/2004]

TedH

Very valuable information. Much appreciated :thumbs:

Fevre

$89.99

http://store.summitracing.com/partde...t=SUM%2D811001


$119.88



http://store.summitracing.com/partde...57#largerimage


Black one works great for me, it plugs right it with no re-wiring. :thumbs:

TedH

This eBay seller is offering a Delco 10SI alternator rebuild kit for $25. It has the feature that allows power generation at lower rpm.
http://cgi.ebay.com/ebaymotors/ws/eB...category=33573

I am going check my alternator and make inquiries with this vendor regarding compatability.

Not bad for $25 if it is a good solution. Don't see much sense in completely abandoning the alternator if just needing to replace some internals. Will advise...


[Modified by TedH, 2:35 PM 3/24/2004]

SteveG75

http://www.alternatorparts.com

I rebuilt my 42 amp unit as an 85 amp for $24.95. They even have a 200+ unit available.