Alternator question

[Wilson_WWSC]

I have a 1973 240z with a 69' sbc. I have a stereo system (with capacitor and amp) and a couple sets of HID's on the car. I think my alternator is not recharging the battery well, so I was thinking of getting a new chevy 1 wire alternator. Is this a good idea, and what would I need to do? I have to remove the voltage regulator, correct? Also, my alternator mount has the alternator almost right up against the passenger side wheel well. What other affordable mounts will work?

I don't even know where my starter solenoid is or where the starter is. Sorry, I'm at school right now, 350 miles away from my car. I just want to get this info together so that I can work on it right when I get home for Thanksgiving (yes I will be spending lots of time with the family) or Christmas.

 

Thanks

Wilson

[grumpyvette]

theres no reason you can,t convert to a one wire alternator if you do the required modifications to your wiring in the car, read this

http://www.madelectrical.com/electricaltech/onewire-threewire.shtml

 

these guys sell an alternator Ive used on several corvettes with excellent results

http://www.db-starter-alternator.com/c-4913-200-amp.aspx

 

one wire

http://www.db-starter-alternator.com/c-7305-200-amp.aspx

 

good related info

 

http://forum.grumpysperformance.com/viewtopic.php?f=70&t=355&p=436#p436

 

http://forum.grumpysperformance.com/viewtopic.php?f=36&t=1169&p=5267&hilit=corvette+alternator#p5267

Edited November 26, 2010 by grumpyvette

[kamikaZeS30]

Just to re-iterate what grumpy has posted and add a little of my own experience.

 

I ended up using a GM one-wire "mini" 140amp (they sell them on JEGS.com), I went with a mount that positions the alternator directly in front of the passenger's side cylinder head (there's a bolt that goes from the head, through the alt. and out the front of the mount and the other side of the mount attaches to the water-pump). The only concern you might have is if you're using a short water-pump and what mounting position the motor is in. It requires that you use a "long" water-pump, to move the plane of the belt forward enough for the alternator in this position. I went with this because I couldn't find another position that wouldn't bang the alternator against my freshly-painted engine bay when the engine "torques."

 

In truth, 140 amps is overkill, even with the 8 cylinder multi-spark ignition, 30 amp stereo and headlights I'm running, but it's nice to know that my battery is always fully charged when I park the car at the beach/park/buddy's house and want to use the stereo.

Edited November 29, 2010 by kamikaZeS30

[Wilson_WWSC]

Thanks guys.

I will be reading up on all this stuff as soon as time permits (finals and junk). Hopefully will have a good running v8z to bring down to LA next quarter. Still need to swap my turbo 350 for a 700r4 though...

[Geking]

http://www.chevelles.com/techref/tecref14.html

 

This covers everything you need besides how to wire up two of the wires. This is the alternater that I am using, it charged my battery from having to hill start the car to starting with no issues at night with the headlights on in 2 miles.

 

 

[AKZX]

theres no reason you can,t convert to a one wire alternator if you do the required modifications to your wiring in the car, read this

http://www.madelectrical.com/electricaltech/onewire-threewire.shtml

 

these guys sell an alternator Ive used on several corvettes with excellent results

http://www.db-starter-alternator.com/c-4913-200-amp.aspx

 

one wire

http://www.db-starter-alternator.com/c-7305-200-amp.aspx

 

good related info

 

http://forum.grumpysperformance.com/viewtopic.php?f=70&t=355&p=436#p436

 

http://forum.grumpysperformance.com/viewtopic.php?f=36&t=1169&p=5267&hilit=corvette+alternator#p5267

 

So, would one of those 200amp alternators work with a stock S130 or only the V8 conversion? I was about to by a 220 amp for my 1980 280ZX for around $500 dollars, but those are only $200 and still have good output at idle. I don't know much about V8 Zs..

[kamikaZeS30]

I would recommend an alternator with an internal voltage regulator. That is the only real "opinion" I'd like to inject into the discussion.

 

I have always been suspicious of the early 70s era Japanese automotive electrical components. It's equivalent to the stuff that was considered standard in the 1960s in the U.S. (and a lot of it out-dated by the time the Z actually made it over here). The newer alternators (both domestic and import) have much more stable, reliable voltage regulators already integrated into the unit which provide much cleaner power than the stock external one in the Z.

 

It was the first thing I did to my Z, even before I contemplated the V8 swap, upgrade the alternator to an internally regulated 60amp from a 280zx and dump the external regulator.

 

One wire is the way to go.

[NewZed]

There's no benefit to one-wire over three-wire in operation, as I understand it. One-wire is just two wires easier, but you lose a few things when you're done. The link below is kind of hammy but it's pretty descriptive. Scroll down a half-page to see the pros and cons. If you don't run a good voltmeter, or at least wire up your ammeter (you're back up to two wires already) with your one-wire alternator, you'll have no idea if it's working right (unless you're really tuned in to your fuel pump buzz and brightness of lights). If you're building a race car it might be the way to go, but long-term dependability is nice for a street car. Easier is rarely better (unfortunately), no offense intended to the one-wire camp.

 

http://www.madelectrical.com/electricaltech/onewire-threewire.shtml

[bjhines]

I used a CS130D alternator. It has a small frame and dual internal cooling fans. It has a common metric shaft thread. It has a modern PWM Pulse Width Modulated field circuit. It has soft start, overheat protection, and was designed to operate computer controlled vehicle systems(think digital CD ignition). You can use the typical 3 wire hookups. http://oljeep.com/gw/alt/edge_Alternator_Theory.html#Section_3

[NewZed]

That's good information bjhines.

 

I was probably confusing things with my one vs three comments, since "one wire" alternators can have multiple wires. The whole "one wire" thing seems like marketing buzz, I don't really get it. If you have a three wire setup in your car, all of the modern technology is there to be used. Why go backwards if you have it?

 

I'm pretty sure that you can hook your S wire to the B terminal on a regular three wire alternator to turn it in to a pseudo one wire, then just rev your engine up every time you start it to get it charging.

 

Anyway...

[TimZ]

I was probably confusing things with my one vs three comments, since "one wire" alternators can have multiple wires. The whole "one wire" thing seems like marketing buzz, I don't really get it. If you have a three wire setup in your car, all of the modern technology is there to be used. Why go backwards if you have it?

 

Agreed - there's really not that much extra work involved with the additional two wires, and they offer definite advantages for voltage regulation. The only advantage of the one-wire setup is very slightly less work, especially if you've already got the 3 wires in your harness.

 

It should also be pointed out that the stock harness is not even close to adequate for a 140-amp alternator, and would most likely start on fire (not an exaggeration) if you tried to run 220 amps through it. You can use high output alts, but you need to make sure you have significantly upped the gauge of any wire path that will likely carry the increased current.

[kamikaZeS30]

I guess I should have phrased my one wire comment differently.

 

I meant "internally regulated alternators are the way to go."

 

The 140 amp "mini" I have will accept quite a few more wires, there's even a plug connection for a much newer OBDII GM (I'm not sure which one, these probably came from a truck). I am hooking it up with one wire, and then keeping the "shunt" for the ammeter.

 

Also, unless I'm completely retarded, how would upping your alternator's amperage rating start fires unless you actually put that kind of load on it? Not to mention you'd have to eliminate any kind of circuit protection like fuses.

[bjhines]

Hmmmm.... If you are going to add things that draw more current then you will run separate power distribution wires and fuse blocks. I have the original S30 harness in my car, but it only operates relays, dash lights, corner markers, tail lights, guages and low current electronics. With everything on; I ~could~ draw more than 100 Amps from the alternator, but the S30 harness never sees more than 10 AMPS TOTAL through it. Even the starter solenoid uses a relay.

 

Have you looked at the tiny wires in the 240Z harnesses? The 8 guage wires leading to the Ammeter are as big as they get anywhere in the harness. You can easily find the maximum current ratings for 12 volt systems in charts all over the web.

 

http://www.powerstream.com/Wire_Size.htm

 

If you look at 8 guage wire then you will find the maximum safe rating when wrapped in a bundle is 73 AMPS(That is the absolute limit for FIRES!!!)

If you want low-loss power transmission then you will be using 1/3(ONE THIRD) that AMPERAGE. Wire choices have a lot more considerations than those.

 

You need to consider;

length

voltage drop limitations

duty cycle(you can get away with ~relatively~ small starter and main battery cables because they are short and only pass high current for short periods)

proximity to other wires(bundling makes them get hotter faster, and starter/batt cables are usually kept away from other wires for that reason).

temperature characteristics of the insulator(heat conductivity, softening temps, etc)

 

I found dozens of splice connections in my S30 harness. They get damp and corrode over the years. When they become resistive then they get hot. This throws an entirely new set of problems into the mix. You must also consider the types of terminations and their individual characteristics.

Edited December 4, 2010 by bjhines

[kamikaZeS30]

So, I should be fine, in that case. My Stereo system has its own power circuit, I've otherwise divorced the power for the external lighting from the rest of the electrical system, everything I've added has its own circuits. I replaced the stock primary cables when I first bought the car, with some big 0 gauge.

 

With alternators though, I've always been under the impression that their power production is based on load-demand. I.e. it's not going to produce more power than there is current draw. Otherwise you'd over-charge your battery every time you went on a long road-trip.

 

Am I mistaken?

[bjhines]

The voltage will stay constant and will never overcharge the battery. Current has absolutely nothing to do with it.

 

Power production on load demand is a confusing idea for non-electrical minded people. I think you may have misunderstood the fact that alternators produce 14 volts. The amount of current that will flow depends on the resistance the alternator sees. When the resistance is very low, a large current will flow through the system. When the resistance is high a tiny amount of current will flow. The voltage remains the same(14V) so each device will only draw the amount of current it was designed to use(based on it's resistance).

 

When you operate too many devices and current demand is higher than the alternator can produce, then the voltage will begin to drop until current output is within the limitations of the alternator. This will cause all of the devices in the entire car to operate at a reduced voltage and they will simply draw less current as the voltage drops.

 

When you operate an alternator beyond it's limits it will get very hot. The diodes in the regulator have a fair amount of internal resistance. As the current demands go up they get hotter faster. Eventually they will fail. When they fail they often short internally and will drain the battery even with the car off.

Edited December 5, 2010 by bjhines

[TimZ]

So, I should be fine, in that case. My Stereo system has its own power circuit, I've otherwise divorced the power for the external lighting from the rest of the electrical system, everything I've added has its own circuits. I replaced the stock primary cables when I first bought the car, with some big 0 gauge.

 

With alternators though, I've always been under the impression that their power production is based on load-demand. I.e. it's not going to produce more power than there is current draw. Otherwise you'd over-charge your battery every time you went on a long road-trip.

 

Am I mistaken?

 

I guess I was under the impression that those who were talking about installing a 220amp alt had some need for an alt that big. If you can't draw more current than the stock alt can handle, then there's really no need for anything bigger than a 70 amp alt.

 

In the case above, where are the additional circuits wired to? From the description it sounds like just the battery. If you have constant-current draw high amperage accesories then you need heavy gauge wiring to both the alt and the battery, as the battery only supplies high current for transient loads - the alt will supply the constant current draw.

[bjhines]

There are 2 main power wires in the harness. One is from the Battery(from the starter terminal) and one is from the Alternator(larger alternator terminal). The AMP gauge goes between them. The entire system can be fed through either wire, but the AMP gauge shunt is between the 2 main wires. This was to indicate current draw from the BATT or ALT. If the needle swings positive it means that most of the current is comming from the alternator. If it swings negative then most of the current is comming from the battery.

 

The AMP gauge cannot read higher than stock current loads and it really does not indicate the state of operation as well as a volt meter. If you add circuits to the Batt side(battery + terminal) then you are passing through a 8-10ft of wire and the ammeter shunt(reducing performance). If you add circuits to the ALT side then you won't normally see the extra current on the gauge(it will actually show the additional current load when the engine is off and the BATT supplies the current). You don't want the ammeter shunt burning and the gauge cannot read that high anyway.

 

In fact, there is an even weirder reason not to use the AMP gauge. The factory chose to wire a third of the fuse panel to BATT side and the rest of the fuse panel is wired to ALT side. They made some choices in what circuits they intend to actually read on the gauge. The gauge will never show the TOTAL amperage through the system. It is not actually telling you anything but a general-approximation-of-an-idea of the state of the systems.

 

You can remove the AMP gauge and connect the two heavy gauge wires using a brass bolt and nut(insulate the connection when done). Then connect the Factory BATT and ALT wires near the firewall and make all power-circuit branches at the firewall distribution block.

ie. New ALT wire(with fuseable link 6g), New BATT wire(with fuseable link 6g), Factory ALT wire(w/fuseable link 10g), Factory BATT wire(w/FL 10g), Additional power wires(fused individually), etc(fused ind).

 

In summary:

If you connected your stereo to the heavy gauge battery cable/lug with 4 gauge wire(thinking this was good)...

then you actually supply current from the alternator, through the wire harness ALT wire(8g), through the AMP shunt, through the BATT wire(8g) then through your 4g oxygen free super wire. You end up running through 8-10 feet of smaller wire before you get to your heavy gauge stereo powere wire. Hooking new stuff up to the battery lugs is next to worthless because you actually use MORE of the smaller gauge wire than any of the factory systems ever did.

Edited December 5, 2010 by bjhines

[kamikaZeS30]

I replaced the wires going from the battery, to the starter and from the alternator to the battery. The electric fan I have is wired up to the alternator (I figured I wouldn't need a fan running while the car is off, thinking that it'd be better to cool the coolant slowly with ambient air on cool-down).

 

I've run the shunt with a 60amp alternator (it's the earlier 45 amp gauge) without issue. Basically, I just want something that will tell me if the alternator is operating, i.e. providing current, because if I know the car is running and I have a load I should see a positive indication from the gauge, I'm not really concerned whether or not it's showing actual amperage. The stereo system has its own power cable from the battery terminal. Which as I mentioned above, has been upgraded between the starter, alternator and battery (I replaced the ground side on the battery as well, because the original grand cable was looking rather tired and worn).

 

I appreciate the input, I was doing all of this without a wire diagram, so there is another path the current takes from the alternator to the battery? Or is the yellow-blue (it might be white/blue it was a little faded) wire that was originally there just between the bat + and alt? That's the only connection I saw.

 

The main reason I got the 140 for mine was it's design (size) and affordability. I believe I would have been okay with like a 70 or 80, but the cheaper 80 I had wouldn't mount/fit where I wanted. I also figured that a higher rated alternator producing a current that's less than 50% of its rated out-put (most of the time) might create less EMF drag and maybe last much longer than something that would "get the job done" but running at 90% most of the time. I do not actually anticipate loads that would severely tax the stock electrical system, 30 amps is just what the circuit for my stereo is fused at, it doesn't actually use that much.

[NewZed]

The guys on that madelectrical site cover what bjhines is saying (Edit - sort of, no offense), plus a little more, from a different starting point, and add some funky pictures. It's an interesting topic, especially with all of the old crimped splices buried under the typical Z's harness tape. These guys suggest a common central terminal to run all of your loads from, plus put your sense wire there. Seems to make sense, although I'm sure there's better looking hardware out there.

 

If my stock 280 harness wasn't in good shape, with low voltage drops, I'd probably tear it out and go with the central distribution point. Second edit - This would allow the shortest, direct path to any new accessories, with dedicated fuses.

 

http://www.madelectrical.com/electricaltech/remotevoltagesensing.shtml

Edited December 5, 2010 by NewZed

[bjhines]

KamikaZeS30....

If you have a 240Z then THERE IS NO WIRE GOING FROM THE ALT TO THE BATT without passing through the AMP gauge and ALL of the factory wiring FIRST. If you connect stereo equipment or big fans to your BATT +post then you are going through every inch of factory wire, every cruddy splice, and the AMP gauge shunt, BEFORE you get power to your ADD-ON stereo/fans/etc. DO NOT CONNECT stuff to your BATT+ post until you eliminate the AMP gauge and bond the factory power wires together in the 2 places I describe.

 

If you have a 240Z; The factory decided to run a power-wire from the alternator to the AMP gauge(in the dash). They also ran a power-wire from the BATT(starter power terminal) to the AMP gauge(in the dash). The fuse panel is spliced into those 2 wires near the AMP gauge(a third is off BATT and the rest is off ALT). The factory system is ~roughly~ a star distribution junction just like I describe doing at the firewall.

 

The problem is that you cannot add anything to the factory junction/star/distribution point because it is buried in the harness near the AMP gauge. additionally the factory junctions are just crimps with NO SOLDER, AT ALL, ANYWHERE. Additionally the factory wires are small by todays standards and unsuitable for big powerful systems.

Edited December 5, 2010 by bjhines