OK first off for those that no matter what is asked say no need for higher amp alternator I am not asking that so save your typing and my time, any search on alternators finds plenty of that and I am looking for help not more of that. I am looking for help and input and to learn more about my car and cars in general.

I am not saying I need to go to a higher amp alternator, I am asking because mine is a 61amp but more so because someone spliced and cut wires before and I will replace those but if upgrading wires helps and then I don't need an alternator that's stronger great, if not then what do I need to do?

I have a 61amp alternator right now with a car that has auto, air conditioning, and otherwise standard 1972 corvette electrical system for a 350 engine.

I am putting in a DeWitts radiator with SPAL 640 dual electric fans so that will draw more amps, in fact has two 30 amp fuses although it will draw less than that.

In the future I plan to upgrade the headlights so I can see at night.

With all that in mind I went trough my wiring and several wiring diagrams and the first picture is what I have with out the splices in the wires and ends falling off Just what I see as related to the charging system. So that's my starting point.

The second picture is ideas, I keep reading upgrade the wiring so the yellow spots are where I think people are talking about, but that brings up the question of to what gauge and which ones. The large yellow spot is what I am thinking, put in a juntion block and then run the fans, headlights what ever off of it so it is not using the original wiring harness for those higher draw items.

IF the fusible links need replaced as I put larger wire what do I do, increase the fusible link the same amount or will that risk damage to the original wiring and systems oe use fuses or circuit breakers again increasing the size or do I keep the original size and just increase the wiring size?

I kind of think the most important would be the alternator to the horn relay and then to the junction block and leave the rest the same size?

Is the 61 amp alternator enough??? Seems like I will be drawing at least 30 to 40 amps with both fans on (is that correct?) and if I add headlights (100watt) even more and if I turn on the A/C, etc... No I am not thinking I need 140 amps by any stretch but maybe go to 80 or 100 maximum.

OK so any thoughts?? Input?? Obvious errors?

Now to try and post those pictures, here goes nothing.

 

dbelectrical.com has every kind of alternator you can think of and the have awesome customerervice. I tried the 140 amp alt. from summit and it works but the idle voltage in the summer with everything on drags it down to 10v.
I have a little more electronics then you with the CFI I have to run the fuel pump, injectors,ECM and dual electric fans but it does work without killing the battery! Not that I would leave my car idling for an hour but I think it would be a problem on a hot day.

 

Usually, fusible links are 4 numbers 'smaller' (ie: a 10 gauge wire needs a 14 gauge fusible link) than the circuit it protects. Some swear by links, others use Maxi fuses. I would do more studying on the circuits. My situation is similar to yours and I ended up with a 100A alternator and rewired using 8 gauge and Maxi fuses.

 

Will look into maxi fuses.

When you say rewiring using 8 guage what wires exactly, that's the part I am trying to figure out. I have to replace the alternator to horn relay wire, it was spliced for something and what ever it was they just cut the wire leaving the splice. After that what else woudl need it? With most of the red wire now 10GA the I would put a 14amp maxi fuse versus a fusible link

Thanks!!

 

Looked at their alternators and was thinking of 100amp but want the wiring right first because it was spliced for something at one time.

Where did you run all your electronics from, the horn relay or did you put a junction block like I am thinking just to keep it all separate?

 

The stock alternator will not be enough with electric fans. The stock alternator is enough to run your stock system but the alternators never seemed to have much extra capacity on the older cars so once you added new loads they quickly end up under sized.

I'd say a CS130 or CS144 would be the way to go. Besides a higher output, these alternators were specifically engineered to produce more current at idle. They will work much better then a modified 10SI which was never engineered to produce 100A let alone 140A.

You can get adapter plugs to go from the original alternator plug to the CS plug. I believe the one you would want is the one with a resistor.

I don't believe the black/white going to the alternator goes to the wire from the ammeter but otherwise your diagram is correct.

I would upgrade the wire from the alternator to the horn relay and horn relay to the solenoid. The wires used on the newer cars is metric but the closest size is 6 gauge. That would mean use 10 gauge fusible links. It would also mean your ammeter would no longer display the correct current, but it would still work to display charging or discharging.

I would likely also get rid of some of the junctions on the right of your drawing. Ideally, I'd put a fusible link on the wire at the solenoid and run it right to the horn relay and change the ammeter to a voltmeter.

Alternatively, bring it up to the firewall to where the ammeter wire connects and terminate it at a junction post there. You know the insulated stud type. Then, continue the wire to the horn relay or another terminal block by the horn relay. This second terminal block or horn relay is where the other ammeter wire connects and also serves as the spot to run new accessory power from. There should also be a main wire feeding the fuse block that connects to this point. If you use a terminal block then just put a jumper wire to the horn relay so the horns have power. Then, go from either of those points to the alternator.

Also, make sure you get or borrow a decent crimp tool and use the proper crimp on wire lugs so that the terminations are good. When upgrading, that's the most likely point where failures would occur due to not properly terminating the wire. If you have to solder, put the joint together and then heat it on the outside until the solder melts or wicks into the wire/lug. Make sure the joint remains stationary until the solder has hardened.

 

i ran a 100 amp alternator and ran a 10 gauge wire in addition to the stock wire to the starter lug. i have added 340 watts of headlights thru 12 ga wire and relays with no issues . if i should decide to run electric fans i would probably upgrade the alternator again. the stock unit is marginal and if you don't have the load the alternator doesn't work as hard. i also recommend an a.g.m battery. i bought one of the new ones from Interstate and it is great.

 

So more like this? And if I use a maxi fuse instead of a fusible link then I am thinking 20-25% below max output of alternator is that right?

 

OP, feel free to PM me over this honestly I am too tired to read this entire thread.....


BUT I know more than anyone on this forum about electricals on older cars....


and updates too, been there and done that....

 

No, that's not at all what I described. Try reading the second last paragraph again.

There must be a piece of wire that charges the battery between the 2 wires from the alternator or it won't read any current.

I personally wouldn't use a fuse, but if I did it'd be rated well above the alternator current so I wasn't worrying about blowing it.

The one inconsistancy you'll find in any recommendations is due to the cars with ammeters or without. Without an ammeter you can just parallel the charging wire or do other changes since the meter is not there. If you want that meter to show something, then you have to somewhat mimic the original wiring.


Ya, keep telling yourself that and then it might be true in your mind. Much better to share the upgrade ideas openly and let others benefit.

 

OK no fuse.

The rest I am just trying to picture as I read it as two different alternatives, the first upgrade the wire from the alternator to horn relay and horn relay to solenoid which is what I thought I put together in the drawing but took the connection from between the two circuits doing it. The second was solenoid to the firewall and a junction point where the ammeter terminates and then from that junction a wire to the horn replay or a term block and the other wire to the ammeter connects there and that junction block is where I would also connect my new electrical accessories?? And from there power the horn relay and the main power to the fuse box?? And then connect the alternator directly there?/

Then this part sounds real easy "I would likely also get rid of some of the junctions on the right of your drawing. Ideally, I'd put a fusible link on the wire at the solenoid and run it right to the horn relay and change the ammeter to a voltmeter."

Sounds like a fusible link at the solenoid and wire straight to the horn relay and just swap in a voltmeter but then were do new electrical devices connect, at the horn relay (or a junction block from it)??

Using something like this??
http://www.mamotorworks.com/corvette...-1974-642085-1



Thanks

 

You've pretty much got it all correct. That voltmeter would work well and then ideally you get rid of those 2 ammeter wires in the engine compartment completely and re-wire under the dash to apply voltage to the meter instead.

In the second option, yes, you would use the horn relay or a terminal block in the same area for the extra accessories, connecting the alternator, connecting power to the fuse block, etc, etc. It'd be the point where all the power branches off from.

I'm just saying to use a terminal block because it'd be easier to connect more wires to it. The horn relay has 2 smaller screws and is really only suitable to connect 2 wires on each. You could use a 1/4" or larger stud instead and be able to solidly connect many more wires onto it.

 

Getting closer I think, my understanding to swap out the ammeter to a volt meter was connect the two ammeter wires together and hook to one side of the volt meter and connect the other side to ground.

You say get rid of both wires (cleaner) and pick up power under the dash, from what sources??

Using 6GA wire and the 4 number raise for fusible link it would be a 10GA fusible link? Is 6GA good or 8GA (little more flexible but will it be large enough?

Found the terminal block at MAD Electrical PN CN-1 for a single post, and fusible link kits for the solenoid connection but only have 12-18GA on their site so will keep looking but will 12GA work or be to big (just using the add 4 formula) the part number is FL-12. Of course other places do have 10GA just wondering on size more than source.

 

Sounds like you've got it pretty good from what I can see,
I'll put this up, I'm in mid-process of converting to a CS-144 for mostly the reasons you've mentioned but mainly the amps delivered at idle since I end up in crawl speed frequently.

72 LS5, auto, no air. Dual Spal fans, headlight relays, stereo with a single amp and a few other items here and there
CS144 out of a loaded Buick, 140A, looked like crap but tested very good.

One thing to keep in mind on a CS144 is they are physically larger than the others, changes to the brackets is needed.




All (most) information distilled from many, many posts here and on DC and a few others. including those from L-Hutz, D_B, MrVette, Z-Man, KaiserBud etc.etc.etc.

8g run from the alt to the starter lug with a 12g fusible link near the starter end. (most seem to run a 14g FL)

8g run from the alt to the horn relay terminal replacing existing 10g

8g ground run from alt to rad-support replacing existing 12g

New 4g wire run from starter lug up to a 4-fuse distribution block on the driver’s inner fender by the rad-support for the 2 spal fan relays and 2 (high and low) headlight relays. One extra circuit available for ??? if needed later on.






The VAK6986CS conversion harness I got from LL has only a single brown wire on the “F”. Bought another "correct" one from NAPA and it was also wrong, a search on the net shows that apparently there was a shipment of these miss-boxed and I've ended up with on.

I'll add a 180ohm - 1/2w resistor between the “L” terminal and the original black w/stripe wire and the original brown straight to the “F”
When the harness is back together and in I’ll have to check the resistance on the line (35ohms or less use a resistor, 35-350ohms (or 35 -500ohms) are the numbers’ I’ve come across.

Headlamp relays were wired with the stock harness to the relays for trigger and 10g (I might need to check as I wrote in pencil 12g on my notes) for the actual supply wiring to the relays and then 12g to the lights.





I've got the parts to change the gage over to a volt's one from a 77 vette which is similar to the stock (If I could have got the one you listed I would have gone that way)

Not sure if this helps, hinders or otherwise mucks things up
M

 

Everything helps, I am learning a lot, get tired of the "do a search", or negative comments "don't need it", "don't do it" and no reason, no explanation, no help at all.

It is the information like you and others give that make coming to the forum worthwhile, I have the AIM, I have DOC Rebuilds diagrams, I have a 72 service manual but it is only good if you don't change anything and if it is correct it is the personal experiences that help the most.

 

I will do my best to explain how I did my '72, I too have Dual Spal fans, and the previous discussion is just about right on, one suggestion is to eliminate that wire from the alt out stud that on my car went directly to the horn relay....I had a rough idle some years ago, and under that red insulating cap the wire just broke off and sent power surges out that burnt up the computer, long story.....but if you work on other cars, the way Pontiac did it is much better, I took a 8 ga wire from the alt out stud, down the intake mani to back of block, joined other wires in a corrugated harness across the firewall, to the fender, then forward to the horn relay.....I never upgraded my lights, and so my wiring is stock in that respect.....I run ALL of my accessories off that horn relay, EXCEPT the Spal fans.....now I don't even have tunes in the car, so no amps/etc to worry over, the main power amp would go to the battery post on the starter if it was me, and the control head would turn the main amp on/off and so wired through a filter to the horn relay, or switched orange off the ign. sw.....

I took my Spals forward right off the alternator, with a 10 ga wire and a slight/short fuse link all left over from some tear out or other, the fans are grounded on the cross support that the lower A arms attach to....My FI computer controls the fans/relay, the fans are their own setup, right off the alternator, my alt is a 17SI rated at 108 amps from factory....try a '79 Seville with window defroster....it's a plug in for your stock alternator....just slightly larger in diameter, should not be an issue.....

now if you want to get involved with the regulator wiring, send me a note, and I have to refresh my memory on my car, no biggie.....

as for a voltmeter, look at older chebby pickups in the junkyard, and you will find a voltmeter that is a direct plug in fit something out of the 80's as I recall..... and yes, dump the amp meter wiring or just tie it off secure....and run a wire from the orange switched wire, no need to run the VM with ign off......

As for my comment last night, I was just tired and in a grumpy mood got some health issues.....sorry to bug anyone....

 

I ran an 8 ga wire from the back of the alternator to an external fuse block. From there I powered the fan relay. A little extra protection because the alt post is always hot.

 

A autowiz, do you know anyone making a smaller V belt pulley? I've used the ribbed belt pulley many times with good results but I had to make my own V belt pulley on a lathe. Worked out pretty good but my bit couldn't get in far enough to make a perfect V groove. So the belt is showing signs of wear after 10,000 miles but nothing serious.....

 

The 2 black wires run though the firewall bulkhead connector and then continue on to the middle cluster where they connect to the ammeter. They are live all the time. You need a switched 12V source for the voltmeter so I'd suspect the instructions will say you cut the wires under the dash and reconnect them to ground and 12V power wires. Once that is done, the wires that connect under the hood are no longer used so they should be disconnected.

8awg wire would also be OK to use. I'm just saying, the newer cars running the CS130 alternators use 6awg.

Here's a neat trick. The CS144 alternators have a terminal in the plug called "S". This is the voltage sensing terminal. If you connect this, the alternator will regulate the connection point to 14.2V. Here's how it works. First run the main charging wire to a terminal block which will be used as the power source to run your fans and new lights - the new high current draw accessories. Also use this terminal block to run a wire to the starter solenoid, hi-speed fan for the AC and the firewall bulkhead connector. Now, also connect the S terminal to this terminal block. The alternator will maintain 14.2V at this terminal block with your high current accessories running giving them a good source of power. This might be the black/white wire you show going to the alternator. I'm not positive, but I believe that wire runs to the horn relay right now and it is the voltage sensing wire for the 10SI alternator.

The original brown to ignition source alternator wire you show is used to energize the alternator. For the CS144, it should be reconnected to the L terminal of the alternator but it needs a 35ohm, 1watt resistor. Well, it can vary but that's a minimum. You could use anything in the 50ohm to 100ohm range and at least 1watt.

Speaking alternators, the CS144 comes with PLFS or PLIF as the terminal labels. I'm talking the PLFS version in the above. I don't really know sources to get that version except for mid 90's Camaros.

Another thing to consider is upgrading the ground wires to the body. If you use the body as the ground for any of these new accessories then it needs a better ground wire coming from the alternator or engine block.

 

I love these threads....

OK- here's a couple of thoughts-

The Battery- does MORE than just starts the car. Keeps spikes and surges to a minimum- stabilizes the voltage...Also filters out the AC ripple not cleaned up in the alternator (electronics really like this).

Therefore with this in mind- it doesn't really make sense to connect the fans directly to the alt's output- When the fans starts up it's close to a dead short to get them spinning (please- anyone take their meter and read the impedance of a fan- most are less than .3Ω)...and this usually happens at idle- when the alternator is NO where near it rated output- Most are "rated" at 1500RPM. Not to mention as temp rises the output is even less...

YES- you can hook it up directly to the alt -"It worked for me"...but it is not the best way to do it...

Think of the alternator as your income, the battery as your bank account- and the fans as your mortgage - You do not want the mortgage coming directly from your paycheck- especially if you are "idle!" Get it- idle, as in not working...or the car is idling- double entendre...


Everybody wants to over complicate this-

Run a wire fused from the battery to the relay then to fans...

Just take a large gauge wire run it from the output of the alternator to the started terminal ..DONE

If you feel better about fusing it- go ahead- but IF the wire is run where it's not in the way of a fan belt- suspension-moving part - then is really no need. The fusible link limits current (has resistance) and a fuse - connection points there is small bit of loss...

You'll notice the battery is NOT fused to the starter...fuse at the devise...

I have never claimed to be the best...but I do have a background in this stuff.

Richard