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Discussion Starter #1
Thinking I'm going to need a new alternator soon and will be headed to a Pick&Pull early next week; was thinking of a bigger more modern alternator for my 89 Grad (even though I'm very impressed by the nifty red band around the present one).
Any suggestions on donner vehicles?
Thanks
Paul
89 Graduate
 

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There was a post a while back about replacing the original Bosch unit with a higher output unit from (I think) a Subaru. you might want to do some past post research and see if you can find it. It was about 6 months ago. Maybe you will get a new post in response to this one from someone who has this information.

Robert
 

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Thinking I'm going to need a new alternator soon and will be headed to a Pick&Pull early next week; was thinking of a bigger more modern alternator for my 89 Grad
azALFAowl:

As I always ask in these situations, what is wrong with your existing alternator? Do you think it is wearing out? Battery not charging? Headlights dim? Have you added a lot of power-hungry accessories?

See what Papajam and I wrote in posts #6 and 7 in that 2012 thread which you cited. Unless you need more current, a larger capacity alternator won't buy you anything.

While spica-era Alfas did have pretty wimpy alternators, I think that by 1989 Alfa had upgraded the capacity, as well as transitioned to internal, solid-state regulation (can anyone confirm this?). So while I can certainly understand converting a '69 to a bigger/later alternator, I'm puzzled why someone with an '89 would need to.

If your alternator seems to be wearing out, and if it is the type with the one-piece brush/regulator assembly, just replacing that part may solve your problem.

But hey, if you want a "science fair project", adapting a 120 amp Suburu alternator to your '89 Alfa could be an interesting challenge. Just don't expect any benefits beyond bragging rights.
 

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i got one form a subi,95 amps,smaller than the bosch unit, and easy fit, just change the pulley , and a longer arm..pm me for any questions
 

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Discussion Starter #6
Thanks to all.
I've checked the output at the alternator terminal and main junction box and the are both 14.5V...so it looks like the alternator is OK. But I was thinking if I was going to replace it, I might as well go bigger...but now I understand , the extra capacity would be excess...but I was thinking, if I'm going junk yarding, might as well consider my options...as junk yards consider all alternators as equals!!
So now we know that the alt is putting out 14.5V, why is the dash gauge saying 11V or less?
Oh, so now that I've looked at mine it's a 55A with internal regulator...see how smart you guys have made me!!!! WooHooo
Thanks All
Paul 89 Grad
 

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So now we know that the alt is putting out 14.5V, why is the dash gauge saying 11V or less?
That's a good question. I don't know the answer, but here are two ideas:

- The dash gauge might not be that accurate. It would be interesting to apply the same voltmeter that measured 14.5v at the alternator to the terminals on the gauge.

- Obviously the engine was running when you measured that 14.5v at the alternator. So there were some loads on the electrical system (ignition, fuel pump, EFI computer at a minimum). Those loads may have pulled down the voltage at the point where the gauge connects (though that 3.5v difference seems like a lot).
 

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When I checked on my car, a lot of the voltage drop on the switched circuits (which includes the gauge) was in the ignition switch itself.
 

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《snip》

But hey, if you want a "science fair project", adapting a 120 amp Suburu alternator to your '89 Alfa could be an interesting challenge. Just don't expect any benefits beyond bragging rights.
Saving $200 is a benefit. I even bragged about it, win-win! Hehe. Pulled a reman Bosch from a 3 series bmw for $25. It did take about 90 seconds to figure out the 3 wires...

But that original post by breastroke that was referenced is very informative!
 

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So now we know that the alt is putting out 14.5V, why is the dash gauge saying 11V or less?
Either the dash gauge is inaccurate or there is some significant voltage drop in the circuit. 0.5V over the length of a circuit is usually not worth chasing down. But if your gauge is correct then you are losing some significant electrons. Corroded connections, broken wire strands, etc, could easily account for the loss.

My brother is into old Jeeps but he has written some info about voltage drop testing. See: Chasing Sparks. Note that an ohm meter will likely not tell you where the problems lie.
 

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Richard Jemison
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Higher amp alternators

The Bosch 65 amp alternator can be built with different internals to produce 95 amps. Below are two units built by M&D who is a commercial Alternator rebuild facility here. ( The local Deep South AROC members have met Ron,the owner, here as his turbocharged Datsun 510 has flared fenders from a GTV6 I gave him)

The First unit is a new one still in the box. The 2nd one was originally fitted to the montreal but no room for it in the setback chassis in the "coupe". It was on it on the test stand, during run-in but replaced with a tiny rearward facing Japanese forklift alt in the car.

The new one with air scoop is $150.00 and the one with the big pulley (which will be replaced with a stock pulley) is $100.00
Usable upgrades for Alfa`s with AC and power window lifts etc.
 

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But Mad North-Northwest
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True, but if he's really got 14.5V in the engine bay and really 11.5V on the switched circuit, the amps aren't the problem and even a 95A alternator won't help.

Paul, you should spend some time with a voltmeter before proceeding. Figure out if the gauge is accurate, and if so where you're losing the volts. Like I said, first place to check would be in the ignition switch itself.
 
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