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Guest Message by DevFuse

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Another GM ALT swap

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9 replies to this topic

#1 Flow


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Posted 24 April 2004 - 03:38 PM

I used a CS-130 GM ALT off a '91 3/4 ton truck. A more expensive alt than the late 70's model that most people are using but this one was free and it puts out 105 amps. Don't laugh at my welds. We all gotta start somewhere. :rolleyes: Seems sturdy tho, I jumped up and down on it. The bracket makes it tight but there is still enough room to get to the spark plug. Everything was left stock so I can throw a Hitatchi back on. Since the Alt only had 2 wires, 1 to the battery and one to the guage, that left one unused on the subaru harness. Should I run this to the battery as well? This alt seems really sensitive to low RPM's too, could that be the reason?

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#2 baccaruda



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Posted 24 April 2004 - 05:09 PM

sometimes a higher output alternator will be "geared" higher; this may be why it's weaker at low RPMs.

#3 Flow


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Posted 24 April 2004 - 05:39 PM

So a smaller pulley then?

#4 78TurboBrat


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Posted 24 April 2004 - 06:15 PM

I used the same alternator on my tbird and i had to use a smaller pulley to spin the alternator faster, so my light and gauge wouldnt reflect not charging at an idle of only 450 RPM's. I went to an alternator shop and they had on that worked for like 5 bucks. I did the swap to compensate the power accessories i had in the car. along with two batteries.

#5 LostWater


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Posted 27 April 2004 - 11:04 AM

I also have the 105 amp conversion done. When cruising along in 4th gear, my guage also does not show any charging happening below like 1500. I haven't had any problems recently, but if all one does is drive around city streets, they likely won't keep their battery charged and will definitely have to put a smaller pully on there.

Another thing, make sure your belt is TIGHT as the 105 amp alt is a harder beast to turn and the belt could slip more than when stock was on. Mine did, until I tightened it up.


#6 rallyruss


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Posted 27 April 2004 - 01:50 PM

I know the higher amperage is a enticing draw to these alternators but I will issue a little warning. the bearings are rather small and tend to go kaput on this style of alternator as well as some other heat/durablity issues. GM has moved on from that design due to the problems with it.

the ND alt. is a rather durable unit in comparison.

#7 Flow


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Posted 27 April 2004 - 05:02 PM

the ND alt. is a rather durable unit in comparison.

By ND do you mean Nippon Denso? I'm not too concerned about the durabilty because it was free. I've got 5 bucks in bolts and about 2 1/2 hours invested so far. I might think about rebuiling this one when it craps out, to get a few more miles out of my bracket but I'm not married to the idea. I'm happy except for the weakness at idle. My main concern was to keep everything stock i.e Belt and wiring harness. I'm gonna look into a smaller pulley and then start adding some lights. Driving, Fog and Reverse.:D

#8 Partsman


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Posted 27 April 2004 - 09:40 PM

GM has moved on from that design due to the problems with it.

And parts remanufacturers rejoiced - the next generation (Delphi) alternator has GOT to be the highest failure rate alternator on the market. :grin:

#9 oddcomp


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Posted 28 April 2004 - 03:42 PM

i think for alts either go with a older bigger gm unit since they almost never seem to die mine came off a car that has been sitting since 95 i think
shh don't tell my grandma...

or with "gasp" a newer ford high amp unit

#10 MorganM


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Posted 28 April 2004 - 06:13 PM

that's so custom. the fact you did all that yourself far out weighs any thoughts of ugly welds :D

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