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Topic: Can a 3g be damaging overkill? (Read 18323 times) previous topic - next topic

Can a 3g be damaging overkill?

Reply #105 –
Yeah, that looks perfect!  Thanks Scott!
1988 Thunderbird Turbo Coupe
'89 5.0 w/ ported intakes, Mallory Adjustable FPR, BBK shorties and H with 2.5" Flows, 130 amp 3G, 89 Mustang comp/wiring, Aluminum radiator w/ elec fan, T5 trans, King Cobra clutch, 3.55 gears, 13" Cobra brakes (front), Wilwood prop valve, Mustang A-arms, Front Coil-overs, MM CC plates, Silver 17x9 R's, 03 Cobra IRS, Aluminum DS, 2002 Mustang dash/console etc..., custom leather seats

Can a 3g be damaging overkill?

Reply #106 –
anyone else have an opinion or concern?  would like opinions or worries , complaints or diagram conflicts .

Can a 3g be damaging overkill?

Reply #107 –
I believe 3.8 alternator's weren't internally regulated until 1987.
Also, 6AWG is only capable of carrying 100A, so the 120A fuse is overrated.

Can a 3g be damaging overkill?

Reply #108 –
i personally think your correct on both accounts.

however, i still dont know what type wire people are using for the output. If its RHH-RHW, then the note for "or 4awg" applies.

Can a 3g be damaging overkill?

Reply #109 –
84 all engines have external regulators.

Can a 3g be damaging overkill?

Reply #110 –
not to neglect the external regulator people,, but does this look good nuff to stuff up in the sticky?

no one has noticed what i noticed yet in the 2.3 mod.  To me,, there is a problem that is created "if" the ammeter is working fine.  In the drawing "after", it seems that there is an unbalanced resistance with respect to the shut being in parallel with the alt output thus making the meter likely peg one way or the other.

humm,, am i right?

Can a 3g be damaging overkill?

Reply #111 –
Funny you say that!  I had a dream that my gauge pegged out max on my way home from work (the exact same spot where my alternator died last time!!).  It was a total trip!

Anyway, I see what you are saying, but wouldn't that scenario play out whether there is a 3G or not?  Example:

Stock 88 TC (alt included)  Owner adds a large stereo with several power amps...  The regulator compensates by upping the amperage in the entire system.  Being that the shunt is designed to be of a specific resistent based in it's gauge and length the additional power is routed to the parallel circuit and the ammeter sees the up in power and pegs...?

But in reality, I think it'll still do it's job just for the fact that it is connected as factory, only now we have the ability to recieve more power (ability being the key word because the 3g does not automatically mean the system sees massive amperage increases).  So when systems are added to the car (ie: stereo, a/v, etc...) the alternator is prepared to offer more power.

Now, the one thing I CAN see as an issue is the sweep of the gauge is no longer 'calibrated' the same because it was never designed/prepared to read much above 85 or so amps...?
1988 Thunderbird Turbo Coupe
'89 5.0 w/ ported intakes, Mallory Adjustable FPR, BBK shorties and H with 2.5" Flows, 130 amp 3G, 89 Mustang comp/wiring, Aluminum radiator w/ elec fan, T5 trans, King Cobra clutch, 3.55 gears, 13" Cobra brakes (front), Wilwood prop valve, Mustang A-arms, Front Coil-overs, MM CC plates, Silver 17x9 R's, 03 Cobra IRS, Aluminum DS, 2002 Mustang dash/console etc..., custom leather seats

Can a 3g be damaging overkill?

Reply #112 –
Quote from: booksix;179618
because it was never designed/prepared to read much above 85 or so amps...?


that i do not know.  I dont know the voltage drop across the shunt under new conditions.

Can a 3g be damaging overkill?

Reply #113 –
V[SIZE="1"]drop[/SIZE] = I[SIZE="1"]charging[/SIZE] * R[SIZE="1"]shunt[/SIZE]

If the meter is going to be pegged with the higher current from the new higher output alternator (at least when heavy charging), then you need to install a lower value shunt resistor. Ignore this if it is out of context as I have not read every word in the previous posts!
11.96 @ 118 MPH old 306 KB; 428W coming soon.

Can a 3g be damaging overkill?

Reply #114 –
Well, in that case, like you said Scott, a variable resistor could be used to dial this in.  But of course this is all assuming the gauge works in the first place.  Mine, well...  with the battery completely out of the car still sat dead center in it's sweep and I don't see it moving when I up my rpms...
1988 Thunderbird Turbo Coupe
'89 5.0 w/ ported intakes, Mallory Adjustable FPR, BBK shorties and H with 2.5" Flows, 130 amp 3G, 89 Mustang comp/wiring, Aluminum radiator w/ elec fan, T5 trans, King Cobra clutch, 3.55 gears, 13" Cobra brakes (front), Wilwood prop valve, Mustang A-arms, Front Coil-overs, MM CC plates, Silver 17x9 R's, 03 Cobra IRS, Aluminum DS, 2002 Mustang dash/console etc..., custom leather seats

Can a 3g be damaging overkill?

Reply #115 –
Personally, I think you guys are all adding a whole lot of complexity to a very simple upgrade. A 3G needs exactly one wire (other than the output wire) to charge, and that wire is the IGN (or "I") wire. Ford has blessed us by providing that wire at the regulator plug. The "S" and "A" wires both double back to the alternator ("S" to the stator, "A" to the output stud). "A" should be fused at 20 amps or so as it feeds the positive brush to the rotor.

All of the efforts to make the AMP gauge work with the 3G WILL NOT WORK. No matter how you wire it, without some very precise calibrating of the shunt wire you WILL NOT HAVE AN ACCURATE, OR EVEN USEFUL, AMP GAUGE. Hell, the  thing is inaccurate at the best of times. The moment you add the second output wire (the 6 or 4 AWG wire) you are creating another path for the alternator's current. Electricity follows the path of least resistance, and a 4 gauge wire run directly to the solenoid has a buttload less resistance than a 10-gauge (factory) output circuit.

The ammeter is designed to work with a 10-gauge wire as a shunt. That 10-gauge wire is supposed to carry the full 65-amp capacity of the alternator, with a very small trickle of current passing through the actual ammeter itself. When you run another wire in parallel with that black/orange shunt wire you are throwing the calibration of the ammeter way off - there is simply no way to ensure that the black-orange shunt wire is carrying the portion of current it's calibrated to.

If you want to monitor your charging system, install a VOLT gauge. It will tell you a helluva lot more than the questionable gauge Ford cursed these cars with, and will be accurate no matter what alternator you've got installed.

Below is the simplest diagram for a 3G install you will find anywhere. All of the other diagrams I've seen posted are actually modified versions of the original diagram I put online years ago, and they have done nothing but add complexity to a simple swap. I made some minor modifications (added fuses and more description) but this is as simple as it gets, folks. Follow this diagram and you will have a fully (and safely) functional 3G alternator, whether you have a TC, 3.8, or 5.0, AND THIS INCLUDES EXTERNALLY REGULATED CARS. It is not rocket science, and it is not worth the extra hassle (and danger, as DMC24Guy found out the hard way) to stray from this diagram in a futile attempt to make an already useless gauge a little less useless.
2015 Mustang GT Premium - 5.0, 6-speed, Guard Green - too much awesome for one car

1988 5.0 Thunderbird :birdsmily: SOLD SEPT 11 2010: TC front clip/hood ♣ Body & paint completed Oct 2007 ♣ 3.55 TC rear end and front brakes ♣ TC interior ♣ CHE rear control arms (adjustable lowers) ♣ 2001 Bullitt springs ♣ Energy suspension poly busings ♣ Kenne Brown subframe connectors ♣ CWE engine mounts ♣ Thundercat sequential turn signals ♣ Explorer overhead console (temp/compass display) ♣ 2.25" off-road dual exhaust ♣ T-5 transmission swap completed Jan 2009 ♣

Can a 3g be damaging overkill?

Reply #116 –
By the way, using my diagram above you can make a 3G work in any application as long as the alt will physically bolt in, and this includes non-Fords. Hell, it doesn't even have to be a car. I built a 12V generator for the old guy across from my camp by mounting a 3G from the same van I got my 351 from to an old 10-horse Tespoogeseh snowblower engine. The "I" wire is switched with a simple toggle switch. The generator is used to charge the bank of batteries he uses to power his trailer. He also has solar and wind charging.
2015 Mustang GT Premium - 5.0, 6-speed, Guard Green - too much awesome for one car

1988 5.0 Thunderbird :birdsmily: SOLD SEPT 11 2010: TC front clip/hood ♣ Body & paint completed Oct 2007 ♣ 3.55 TC rear end and front brakes ♣ TC interior ♣ CHE rear control arms (adjustable lowers) ♣ 2001 Bullitt springs ♣ Energy suspension poly busings ♣ Kenne Brown subframe connectors ♣ CWE engine mounts ♣ Thundercat sequential turn signals ♣ Explorer overhead console (temp/compass display) ♣ 2.25" off-road dual exhaust ♣ T-5 transmission swap completed Jan 2009 ♣

Can a 3g be damaging overkill?

Reply #117 –
To see if your gage works, turn on the headlights with the engine not running. It should show discharge. The headlights are on fuse link H.

The purpose of the gage is to show whether current is flowing toward the battery(charging) or away from the battery(discharging).

In the original hook-up the battery is on one end of the shunt and the alternator on the other.
If the alternator could not handle the load on links G H and I then the battery would take up the slack and the gage would show discharge.
If it could handle the load and send current toward the battery the gage would show charge.

I can't figure out why they hooked links A thru F on the battery side. It makes the set-up less than pure. It could be those are low current loads and don't make that much differance.

It looks to me that you could load up battery side of the shunt by hooking stuff to the starter solenoid and create a situation where the gage shows charge but the battery is actualy discharging.

A volt meter makes more sense to me. You can see if the voltage is above the battery base voltage of 12.5 (good) or below the base (bad).

Started this post before Thunder Chicken posted.
 

Can a 3g be damaging overkill?

Reply #118 –
The more I read, the more glad I am that I got the 95A version.

1) NO bracket modifications

2) Wiring upgrade suggested but NOT required
11.96 @ 118 MPH old 306 KB; 428W coming soon.

Can a 3g be damaging overkill?

Reply #119 –
I am going to side with Thunder Chicken. People that haven't done the upgrade and that don't know alot about cars are going to see this and make a quick decision...not to do the up-grade. Follow the ways of K.I.S.S.

Anyone military will know what that means. Others may well know too.
Brian