SharkSkin

I probably should have gone with the CS130, but I listened to all the stories about the more robust bearings, the better regulator, the better low RPM amperage.... Bah.

toofast928

Dave I have to measure the crank pulley. My crank pulley is from 928Motorsports, replacement of the stock unit, it is one piece aluminum with the additional blower drive pulley.

I can tell you the alternator pulley diam is whatever size OEM was. The only change is Carl converted to V type belt.
Sorry to hear this alternator project is given you a hard time. It should almost bolt right in. My guess is somthing is still wrong with that CS-130d. See if you can get your $ back and pick one up from Auto Zone. DON"T GIVE UP... the Delco is the the best, single, quick mod I've done.

Tony
This help? http://www.alternatorparts.com/pulley_size.htm

SharkSkin

Thanks Tony -- the smallest pulley(vee type) I would be able to lay my hands on would be 2.1", which would bring the rotor to just over 1650RPM -- still not enough. Please do check the crank pulley on your setup. Maybe there is another pulley that I can put in there, but I can't tell from any of the info available to me.

Airflite40

I am gonna go with the cs130 when I do this in the next two weeks. Dave, would the shroud that you sourced for the 130d fit the 130?

Lorenfb

Most alternators require a minimum of 100 to 250ma to start which then
requires a 50 to 100 ohm resistor. The use of a 500 ohm resistor is too
large especially for cold weather alt. starts. Remember, power = V X V / R
or 12 X 12 / 100 = 2 watts or 3 watts for the 50 ohms. That's the worst case
only when the key is "on" without the engine running.

Again, as mentioned on another 928 thread, the key for improved
idle charging is greater alternator shaft RPM and NOT a greater
capacity alternator. All the early 928 alts. (SEV Marchel, Bosch,
and the '82/'83 Paris-Rhone) are adequate alternators for the
early cars, but as with most alternators it's the shaft RPM that's
very critical.

SharkSkin

Borys, it wouldn't fit. Not without some modification, anyway. The 130 has more of a flat back end, larger in diameter. I may just hang on to the shroud and the nifty 1.5" ducting I found, in case someone has a use for it later on.

I had fun doing this and wish it could have worked out. This unit would be ideal in a car with a larger pulley on the crank; it really kicks *** once it's spinning. Attached is an example of a motor that would have come with this alternator in a new car, a 2001-2002 LS1. Note the large crank pulley. Anyway, I told them it had to work at 1400RPM -- they assured me it would -- and it doesn't. Over 2000 RPM at the rotor, you could probably use the thing to weld railroad track. I don't see any suggestions on alternate crank pulleys, so I guess this unit goes back tomorrow.

I considered the 130 but just don't like the idea of tying the B+ into the regulator full-time, since that is known to reduce the life of the regulator. I hope you have better luck with the 130.... Be sure to compare notes on crank pulley size with the guys that have had some success.

Lorenfb

"I considered the 130 but just don't like the idea of tying the B+ into the regulator full-time, since that is known to reduce the life of the regulator."

Not true. The 911s have B+ always on the regulator without a degraded life.
Sounds like another "old wife's tale".

SharkSkin

Loren, I posted earlier about how I have been experimenting with different resistors. This latest iteration of the regulator worked with the bulb only, bulb+68Ω, and bulb+560Ω (all in parallel). It really was the perfect regulator for the task, would have worked on any shark, resistor or no. I have to say the alternator I have in hand works perfectly -- in it's RPM range.

Lorenfb

"I posted earlier about how I have been experimenting with different resistors"

The key is what works under the worst case conditions which isn't always
solved by simple tests.

SharkSkin

That's a Delco regulator?

SharkSkin

Your point? None of them provided proper operation at idle. As in no charge current whatsoever. That's about as "worst case" as it gets. All of them provided proper operation just off-idle.

That's poorly worded, because clearly the problem isn't with the lamp circuit or resistor. Anyway, if you have anything helpful to add feel free to type away....

Lorenfb

All the early 928 alternators (SEV Marchel, Bosch, & Paris-Rhone) always start
with a minimum of 250ma at 300-500 RPMs. This is basically the same for most
all other alternators. The key is NOT the resistor used but the actual field current
excluding the regulator current and saturation voltage of the regulator which
reduces the field current given the bulb/resistor used.

Basic no-start problems:

1. regulator sat too high
2. field current too low
3. alternator not designed for low RPMs, e.g. the 917 alt
4. pulley ratios WAY off
5. regulator sense circuitry sinking too much field current

Typical GM alt not like the Bosch setup requiring a field current
via a bulb/resistor, but just a +12 ignition voltage to "full field"
which turns on the switching regulator resulting in 12 volts / 3 ohms
equals 4 amps for very low RPMs to start.

Bottomline: One must know how the alt is used in ITS proper application.

SharkSkin

I strongly suspect it's #3 of your list, as I've already stated. This particular regulator provides field current itself, the lamp circuit is supposed to be non-critical. It has connections P-L-I-S, no direct field connection. Just for giggles, I'll try running straight 12V to the lamp circuit(no resistor), to see if that changes anything. That will address point #2 that you mentioned. I'm not sure that will preserve the light function but I'll look into that if it works. The one other thing I might be able to try is the "one wire hookup" regulator, which requires NO connections -- only the B+.

The fact remains, the few pics I've been able to dredge up of how this alt is normally used indicate pulley ratios in excess of 3:1. This fits well with my observation that the alternator performs satisfactorily at a rotor speed of ~2K RPM. This is point #4 on your list. I have no control over #1 or #5.

Thanks for the input, it did draw my attention to one thing I might try with the setup I have. If that helps and I can get it to charge with the rotor at 1400RPM then I'll know the alternator is capable of doing the job and I will go for the one wire hookup.

BC

I think I could be interested in this alternator from you Dave if you end up not usuing it. I will have to check and see if Tim Murphy's pulley makes anything spin faster, because I think that may help me work around your problem.

The other 130 - is that a better solution? Is it even smaller too?

There is a 130A Bosch on ebay alot - same model as is what is in 85+ cars but that doesn't help you does it....

SharkSkin

Brendan, I've tried hooking it direct(no resistor). The 130 is a tad heavier than the 130D, I believe. Please decide quickly, as I am about to take it back on my way to work.