73-87chevytrucks.com

73-87 Chevy _ GMC Trucks => Electrical => Topic started by: rich weyand on April 03, 2014, 07:59:36 PM

Title: Stupid-simple alternator upgrade -- 55A to 94A
Post by: rich weyand on April 03, 2014, 07:59:36 PM
OK, so I got carried away.  First there was the powered subwoofer.  300W, or 25 amps peak draw.  Then there were the Hella 7" round replacement glass with Philips Xtreme Power bulbs.  11 amps.  Then the replacement bumper with the integral fog lamps.  9 amps.  Finally the Flexalite Syclone electric fan.  18 amps run and maybe 30 amps on start-up.

I have been waiting for the 10SI 55 amp alternator to die, and it did.  Lost a diode, I think.  Anyway, it won't lock in at idle any more if even just the headlights are on.  So, time for a replacement, which means time for an upgrade.    ;)

Yes, you can grind brackets and change wiring and change pulleys or go serpentine, and then run the 105 amp CS130.  Or you can just buy a 12SI 94 amp alternator, and swap it out with no other changes.

The one I got is from O'Reilly's.  It's their part number ULT 01-0266.  They stock these all over as they were ubiquitous.  $70 plus a $15 core until you bring the old one in.  It lists as for a 1984 Chevy Camaro with the 305 G-code engine as one example.

One change I did make.  I did not hook up the stock charge wire to the BAT connection on the back of the alternator.  That 12 AWG wire down to the starter is not stout enough for 94 amps.  I cut the connector off the end and put some shrink wrap over the end to keep it out of trouble.  Then I ran a 6 AWG wire from the BAT post on the alternator directly to the battery POS terminal.  I loomed it with the negative battery cable so it's not obtrusive.

Works great.  No more problems keeping voltage lock, even when I am running lots of lights and loud stereo and the cooling fan kicks on.   8)

Here's a good resource on the 10SI and 12SI alternators.
http://www.madelectrical.com/electricaltech/delcoremy.shtml
Title: Re: Stupid-simple alternator upgrade -- 55A to 94A
Post by: bake74 on April 03, 2014, 08:39:56 PM
     Thanks Rich for the post, this is one that is going into the saved file under alternator upgrades.  Great job.
Title: Re: Stupid-simple alternator upgrade -- 55A to 94A
Post by: rich weyand on April 03, 2014, 10:52:41 PM
Thanks!  Any time I look into an upgrade or change, and I don't see all the info in one post, or have to scrounge info from all over the net, I figure it's time for a post.  I tend to do quality upgrades that don't require lots of changes, use common parts, and run parts and wiring well within their design envelopes to avoid problems later on.

So I try to write the post I wish I could have found myself, with complete description of the goals, the methods, the part numbers, things to watch out for (like that too-small charge wire), and some reference material -- basically everything you need to go "Hey, I'll just do that" and you can print it out and drag it around with you to the parts store and what-not.

Thanks for the note.  It's nice to get feedback on these posts so I know it's worthwhile to write them!
Title: Re: Stupid-simple alternator upgrade -- 55A to 94A
Post by: dvdswan on April 04, 2014, 12:38:29 AM
that's awesome.  Thanks for doing the leg work.  I was wondering about an alt upgrade just haven't looked yet.
Title: Re: Stupid-simple alternator upgrade -- 55A to 94A
Post by: rich weyand on April 05, 2014, 02:54:52 PM
BTW, getting rid of the stock charging wire (BAT on alternator to starter) and replacing it with a 6AWG wire from alternator BAT direct to the battery is a good idea if you are running a lot of electrical equipment on your truck.

If you pull 50 amps through five feet of 12 AWG, you get .4 volts of loss, and heat that wire with 20 watts.  If you pull 75 amps though five feet of 12 AWG, you get .6 volts of loss, and heat that wire with 45 watts!

Three feet of 6 AWG wire from BAT on the alternator to the battery only loses .02 volts at 50 amps, and .03 volts at 75 amps.
Title: Re: Stupid-simple alternator upgrade -- 55A to 94A
Post by: DnStClr on April 15, 2014, 07:19:03 PM
Thanks for the info, Rich. After reading all that, I feel alternated... :P
Title: Re: Stupid-simple alternator upgrade -- 55A to 94A
Post by: JustinV on July 09, 2014, 10:38:09 PM
Just thought that I'd throw another part number in here, I got mine from Napa and their p/n is 13-4356. Direct bolt in, and I believe the old timer behind the counter looked up a '85 buick century with a 3.8. Rated for 94 amps, but the one I got said it tested 110 amps @ 6000 rpm. At idle it spits out 64 amps per the test sheet. 
Title: Re: Stupid-simple alternator upgrade -- 55A to 94A
Post by: bake74 on July 10, 2014, 09:06:51 PM
Just thought that I'd throw another part number in here, I got mine from Napa and their p/n is 13-4356. Direct bolt in, and I believe the old timer behind the counter looked up a '85 buick century with a 3.8. Rated for 94 amps, but the one I got said it tested 110 amps @ 6000 rpm. At idle it spits out 64 amps per the test sheet.

     Perfect, we need more post like this one on the exact subject matters of the threads.  So we can have options, nice contribution.
Title: Re: Stupid-simple alternator upgrade -- 55A to 94A
Post by: Tilt on July 30, 2014, 10:35:47 AM
This is definitely going in the to do file.  Thanks
Title: Re: Stupid-simple alternator upgrade -- 55A to 94A
Post by: roundhouse on August 28, 2014, 07:03:52 AM
Nice.   
Title: Re: Stupid-simple alternator upgrade -- 55A to 94A
Post by: fitz on August 28, 2014, 01:42:17 PM
Great write up, thanks
Title: Re: Stupid-simple alternator upgrade -- 55A to 94A
Post by: 75_chevy on November 17, 2014, 12:33:07 AM
Rich, I am having trouble with my electrical system. I am trying to power two big subs and at night when I have my headlights on and the stereo, the headlights dim drastically.  then when the subs go to hit it draws so much power that the amp shuts off and turns back on. do you think this 94 amp alternator would solve my problem? thanks for your time


Sent from my iPhone using Tapatalk
Title: Re: Stupid-simple alternator upgrade -- 55A to 94A
Post by: rich weyand on November 17, 2014, 09:44:37 AM
If every thing works individually, and then when you have them all on you get problems, yeah, you're running out of juice.  I had the same thing, and this solved it.
Title: Re: Stupid-simple alternator upgrade -- 55A to 94A
Post by: 75_chevy on November 17, 2014, 11:56:38 AM
yup. sweet thanks rich! I'll probably be picking one up today


Sent from my iPhone using Tapatalk
Title: Re: Stupid-simple alternator upgrade -- 55A to 94A
Post by: FlatBlack77 on November 17, 2014, 07:43:52 PM
Rich, I am having trouble with my electrical system. I am trying to power two big subs and at night when I have my headlights on and the stereo, the headlights dim drastically.  then when the subs go to hit it draws so much power that the amp shuts off and turns back on. do you think this 94 amp alternator would solve my problem? thanks for your time


Sent from my iPhone using Tapatalk

what size amp are you running and are you running a capacitor?
Title: Re: Stupid-simple alternator upgrade -- 55A to 94A
Post by: Engineer on November 17, 2014, 09:51:32 PM
If you are wanting to run a CS130 alternator order one for a 1988~1995 GM C/K truck with a 454 engine.

The mounting ears on the 454 CS130 are exactly identical as the 10SI/12SI, and you don't need to modify any brackets.

The single groove pulley bolts right on in place of the 6-groove serpentine pulley, but you will need the CS130 specific electrical connector.
Title: Re: Stupid-simple alternator upgrade -- 55A to 94A
Post by: 75_chevy on November 18, 2014, 01:21:05 AM
flat: 1600 watt hifonics brutus fused with a 60amp fuse. not running a capacitor yet but I was gonna get one off my bus for 20 bucks.
engineer: I don't know what a cs130 alternator is. I don't need anything too crazy, just enough to keep everything running smooth when the lights are on


Sent from my iPhone using Tapatalk
Title: Re: Stupid-simple alternator upgrade -- 55A to 94A
Post by: 75_chevy on November 18, 2014, 01:21:46 AM
bud*


Sent from my iPhone using Tapatalk
Title: Re: Stupid-simple alternator upgrade -- 55A to 94A
Post by: 75_chevy on November 18, 2014, 02:09:50 PM
rich thank you so much for the post. alternator bolted right up looks good and truly
performs! couldn't be happier!


Sent from my iPhone using Tapatalk
Title: Re: Stupid-simple alternator upgrade -- 55A to 94A
Post by: rich weyand on November 18, 2014, 02:49:31 PM
Excellent.  Thanks for letting me know.

You can switch to a CS130 style alternator, but there's no need.  You can get aftermarket 12SI alternators that bolt right up, same electrical connection, up to 240 amps.
Title: Re: Stupid-simple alternator upgrade -- 55A to 94A
Post by: 75_chevy on November 18, 2014, 08:23:06 PM
yea just an fyi for anyone else the price has gone up to 89 with 15 core charge.

Rich what is the difference between a cs and an si alternator?

also here is a pic for the heck of it. I'll probably throw some black loom over the deal sometime soon(http://tapatalk.imageshack.com/v2/14/11/18/6c6ed6b1f1b63437104f0e798aec1e1c.jpg)


Sent from my iPhone using Tapatalk
Title: Re: Stupid-simple alternator upgrade -- 55A to 94A
Post by: FlatBlack77 on November 18, 2014, 10:52:03 PM
so i could get this alternator(possibly have to swap pulleys), bolt it on, and just run a 6awg wire directly to the battery?
http://shop.advanceautoparts.com/p/toughone-alternator-remanufactured-94-amps-p7294-3/5210283-P?navigationPath=L1*14920|L2*14999|L3*15587#

this sounds like a good upgrade seeing as how my alternator is taking a crap. at least it seems to be because driving around is fine but when it comes to an idle the voltage drops down and wont stay consistent.
Title: Re: Stupid-simple alternator upgrade -- 55A to 94A
Post by: rich weyand on November 19, 2014, 07:09:34 AM
so i could get this alternator(possibly have to swap pulleys), bolt it on, and just run a 6awg wire directly to the battery?
http://shop.advanceautoparts.com/p/toughone-alternator-remanufactured-94-amps-p7294-3/5210283-P?navigationPath=L1*14920|L2*14999|L3*15587#

this sounds like a good upgrade seeing as how my alternator is taking a crap. at least it seems to be because driving around is fine but when it comes to an idle the voltage drops down and wont stay consistent.


Yup.  Direct replacement.

Difference between 10SI/12SI and CS alternatorrs?  10SI/12SI is what came on the trucks, and there are no bracket/pulley/wiring changes.
Title: Re: Stupid-simple alternator upgrade -- 55A to 94A
Post by: Engineer on November 19, 2014, 07:30:40 AM
so i could get this alternator(possibly have to swap pulleys), bolt it on, and just run a 6awg wire directly to the battery?
http://shop.advanceautoparts.com/p/toughone-alternator-remanufactured-94-amps-p7294-3/5210283-P?navigationPath=L1*14920|L2*14999|L3*15587#

this sounds like a good upgrade seeing as how my alternator is taking a crap. at least it seems to be because driving around is fine but when it comes to an idle the voltage drops down and wont stay consistent.


That is a 12si alternator but if you bought that particular model you would still have to change the pulley over to a single V groove pulley if your truck doesn't have a serpentine belt.

Installing a CS130 is not anymore difficult if using the 180 mount. If you can run the heavier cable to your bat+ terminal you can change the exciter wiring harness just as easily.
Title: Re: Stupid-simple alternator upgrade -- 55A to 94A
Post by: rich weyand on November 19, 2014, 01:10:30 PM
That is a 12si alternator but if you bought that particular model you would still have to change the pulley over to a single V groove pulley if your truck doesn't have a serpentine belt.

Oops.  Missed that.  Yeah, you definitely can get the one with the right pulley on it already.
Title: Re: Stupid-simple alternator upgrade -- 55A to 94A
Post by: FlatBlack77 on November 19, 2014, 03:10:03 PM
that is the one i found just from a quick search. a buddy of mine has a camaro the same year and his is not serpentine so i guess some are some arent. it doesnt say the pulley will need changed just might. it would be no problem to change the pulley.

thanks guys this is a very informative thread
Title: Re: Stupid-simple alternator upgrade -- 55A to 94A
Post by: rich weyand on November 19, 2014, 03:20:38 PM
But of course you can buy one with the correct pulley....
Title: Re: Stupid-simple alternator upgrade -- 55A to 94A
Post by: FlatBlack77 on November 19, 2014, 10:11:14 PM
I plan on it
Title: Re: Stupid-simple alternator upgrade -- 55A to 94A
Post by: Engineer on November 20, 2014, 07:30:21 AM
When I first bought my '77 it came with a 10SI alternator. About 20 years ago I upgraded to the 12SI for the extra amps.
 
The problem with the 12SI is the same problem many people have with their 10SI, just as Rich alluded to in his first post. The diode trio is notorious for blowing the diodes when overworked. Usually you will blow the diodes when you are jump starting your buddy's Ford, or Dodge. When unhooking the jumper cables one should always turn on the headlights. This gives a path for the alternator's current to take so it doesn't damage the diodes. The 12SI uses the same diode trio, and rectifier bridge as the 10SI.
 
The main reason I went to the CS130 is to avoid the issues with the diode trio. It has a few more amps, and it is more "modern". Lol.

This is the connector that you replace. It splices into the wire from the 10SI/12SI that is switched from the key.

(https://lh4.googleusercontent.com/-NAMF6cZ4TaM/VG0xaz_z4tI/AAAAAAAAAms/Wuw2DEkp3zY/s512/Things%2520010.JPG)

Here is my CS130 from a 88~95 TBI 454 with a deep groove racing pulley installed in place of the 6 groove serpentine pulley:

(https://lh3.googleusercontent.com/-AS35evNm6HE/VG0mfIa1ngI/AAAAAAAAAmc/q-HnQG05y0E/s512/CS130.jpg)

It is a direct bolt in to the older v-groove engine brackets.

When I get my '77 back together it will have a serpentine belt assembly so I'll be going back to the 6-groove. I may also go to a "one wire" regulator so the wiring change won't be necessary.

This above alternator works in place of the 10SI/12SI because it is from a 454. The 350 TBI had a different mounting ear arrangement so the 350 types won't work with the standard v-belt brackets.

Of course if you have a 454 that you are converting to a serpentine drive, and have a CS130 meant for a 350, you can replace the smog pump with the extra alternator for a cool dual alternator set up. Which is something I'm considering as well.

(https://lh3.googleusercontent.com/-mqMaND3yTz0/VG0xgAGRYKI/AAAAAAAAAm0/YBc0KFqA5SE/s512/engine%2520002.JPG)


Sorry Rich for jacking your thread.
Title: Re: Stupid-simple alternator upgrade -- 55A to 94A
Post by: rich weyand on November 20, 2014, 09:11:28 AM
... Sorry Rich for jacking your thread.

Not a problem at all!  The whole point is to make it easy for people to upgrade their alternators to handle all the extra crap we put on the trucks, like extra lights, and more powerful headlights, and heavy-duty stereos, and electric fans, and whatever.  Adding to that discussion is excellent.
Title: Re: Stupid-simple alternator upgrade -- 55A to 94A
Post by: TRAZOII on June 01, 2018, 05:27:42 AM
i dont know if this helps. But I upgraded my alternator to a 120 amp out of an 85 Caprice with a 350. Slight modification to the bottom bracket and it works fine. put in my 85 k10 Sub Silverado.