Is it safe to use a 170 or 200 amp alternator?

88-378 · Mar 6, 2009

I have a 130 now and with stereo it is just enough. Add and a/c or blower from heat and it suffers.

So, is it safe to go above 130?

93tealstang · Mar 6, 2009

I don't see why it wouldn't be safe. I currently run a 170 amp after using a 130 for years. I didn't need the extra amperage but it's nice. I've got a stereo and underdrives and it's plenty for me so I'd recommend it for you also.

FastDriver · Mar 6, 2009

I put a 200 in mine. I just didn't want to have to upgrade later. It's working fine. I think it's safe.

Chris

jrichker · Mar 6, 2009

You will need to upgrade the wire and fuse that connects the alternator to the starter solenoid. The 4 gauge wire for a 130 amp alternator is too small for a 170 or 200 amp alternator.

5.0Droptop · Mar 6, 2009

FastDriver said:
I put a 200 in mine. I just didn't want to have to upgrade later. It's working fine. I think it's safe.

Chris

Same here.

Do the wire up grades as mentioned.

5.SL0W · Mar 6, 2009

holy smokes vin diesel what kinda stereo yous gots in that thing?!?!?!?!?

MuDDuQ · Mar 6, 2009

I have been running a 200 amp alt for about 10 years in my car and so far it hasnt burned down. I did have the wire changed also when the alt was put in.

88-378 · Mar 7, 2009

5.SL0W said:
holy smokes vin diesel what kinda stereo yous gots in that thing?!?!?!?!?

It's not only the stereo amp, which is a Zapco 360, but the Spal electric fan draws a lot! Plus, if i put a little AC on or run some heat in cloder weather is really sucks the power!

I will get a 2Ga wire. Where do i find this and what fuse do i use?

Pa Performance recommended a 4Ga for their 200amp alt??

HISSIN50 · Mar 8, 2009

If it only suffers at idle, raising the idle or overdriving the alt would be another possibility.

If you have a flow sheet for your existing alt, compare it to the low RPM (note the sheets are generally in alternator RPM) values for the alt you're considering. It might not be real productive if you need more idle-output but both alts have similar low RPM characteristics.

Good luck.

Nova · Mar 8, 2009

you have to add a wire from the alt output to the battery. there are many 3g kits available. one i got was a very nice complete kit.

jrichker · Mar 8, 2009

88-378 said:
It's not only the stereo amp, which is a Zapco 360, but the Spal electric fan draws a lot! Plus, if i put a little AC on or run some heat in cloder weather is really sucks the power!

I will get a 2Ga wire. Where do i find this and what fuse do i use?

Pa Performance recommended a 4Ga for their 200amp alt??

I don't know were PA performance got their wire size information, but a 4 gauge wire is too small for 200 amp current in a hot engine compartment. Use the chart I posted and you will be good to go.

Parts-Express.com - Speakers, Speaker Building, Home Audio and Video, Pro Audio, Electronic Parts & Accessories has the wire and terminals. They are a little pricey, so try your local auto parts store or Home Depot for the fuse and terminals. I recommend solering the termials on, so you'll need a propane torch and some solder.

2 gauge wire.
Don't forget the extra ground that is needed on any high power alternator upgrade. Both the following wires are rated for use in the high temperature of the engine comparment. Home Depot wire may not have the 105 C temp rating, so be careful to check the temp rating if you get wire from them.

See Parts Express:2 AWG Red High Current Power Cable 1 ft. for 2 gauge red wire.
Parts Express:2 AWG Black High Current Power Cable 1 ft. for 2 gauge black wire

Ring terminals for the 2 gauge wire
Parts Express:Gold Ring 2 AWG 5/16" 2 Pair

The secondary power ground is between the back of the
intake manifold and the driver's side firewall. It is often missing or
loose. It supplies ground for the alternator, A/C compressor
clutch and other electrical accessories such as the gauges.
Any car that has a 3G or high output current alternator needs
a extra ground wire running from the block to the chassis
ground where the battery pigtail ground connects. It stands
to reason that the ground side handles just as much current,
so it needs to be same gauge wire as the power feed wire.

The picture shows the common ground point for the battery & extra 3G
alternator ground wire as described above in paragraph 2. A screwdriver
points to the bolt that is the common ground point.
The battery common ground is a 10 gauge pigtail with the computer ground
attached to it.

Picture courtesy timewarped1972

200 amp fuse - also a bit overpriced...
Parts Express:StreetWires FSANL200 200A ANL Wafer Fuse

Fuse holder from local NAPA dealer - Item#: BK 7821143 Price: $10.49
Product Features: Thermal Plastic Holder For AMG Type Fuse Rated From 100 To 300 amp. This one should stand up to the under hood temeratures.

88-378 · Mar 8, 2009

Thanks J! I have those grounds and since the engine is out, i will be upgrqading the grounds from the head to the firewall as well.

Pa performance states their 130 amp gives 80 amps at idle and their 200 amp gives 100+ amps at idle. i will most likely need to go with that 200!

I have the fuse and holder frm PA performance because i purchase the upgraded wire kit. All i need to do is replace the 4ga wire with the 2ga and i will be all set. I also upgraded the ground from the battery to fender too. the guy who installed my stereo did that with 4ga wire.

BoostedSN95 · Feb 27, 2011

jrichker said:
You will need to upgrade the wire and fuse that connects the alternator to the starter solenoid. The 4 gauge wire for a 130 amp alternator is too small for a 170 or 200 amp alternator.

One thing I would like to clarify , as I am trying to figure out my own alternator issues at the moment

If I have a 130 amp alternator (sn95) are you saying I need a 3-4 gauge wire from the alt to the battery? I have to disagree because the sn95 didn't even come with a 3-4 gauge wire from the factory-they game with 8-10 gauge. The point is (I think, please correct me if I am wrong) is that the current field of the alternator draws much less than than the rating-I believe the draw is something closer to a few amps or so, the exact number I am still trying to figure out....

jrichker · Feb 27, 2011

Ford is cheap, copper wire is expensive (especially now in large gauge sizes). Ford also did not plan on monster stereo systems and extra decorative lighting. Therefore, they used smaller gauge copper wire. The large gauge wire is always used for the alternator output to the battery/power distribution point. It is not needed for either the sense or regulator wiring.

If you have any doubts about my recommendations, go ahead and use an 8 gauge wire and push 130 amps through it. Just be sure that you have a way to cut off the power and have a fire extinguisher handy.

For a 130 amp alternator and a 10' feed wire you need 4 gauge wire and an 125 amp fuse. The 5 amp difference is less than 4% of the 130 amp advertised capacity. Since fuses have a long blow time, a slightly smaller fuse isn't going to rob you of any real useful power.

It is really evident that PA Performance did not check the SAE (Society of Automotive Engineers) wiring recommendations. If they had, they would have used a larger gauge wire.

BoostedSN95 · Feb 27, 2011

jrichker said:
Ford is cheap, copper wire is expensive (especially now in large gauge sizes). Ford also did not plan on monster stereo systems and extra decorative lighting. Therefore, they used smaller gauge copper wire. The large gauge wire is always used for the alternator output to the battery/power distribution point. It is not needed for either the sense or regulator wiring.

If you have any doubts about my recommendations, go ahead and use an 8 gauge wire and push 130 amps through it. Just be sure that you have a way to cut off the power and have a fire extinguisher handy.

For a 130 amp alternator and a 10' feed wire you need 4 gauge wire and an 125 amp fuse. The 5 amp difference is less than 4% of the 130 amp advertised capacity. Since fuses have a long blow time, a slightly smaller fuse isn't going to rob you of any real useful power.

It is really evident that PA Performance did not check the SAE (Society of Automotive Engineers) wiring recommendations. If they had, they would have used a larger gauge wire.

I am not doubting your numbers as they seem reasonable, I am questioning the actual amperage that is going through the wire. Like I said I am still trying to understand the alternator.

If it takes 80 amps of current to push my accessories are you saying there is actually 80 amps of current between the alternator and the battery? I was under the impression that the battery is like a capacitor so the current between the battery and the alternator is much less.

I am asking these questions because I burned out my battery disconnect switch-I think it was because of a loose stud on the switch because I ran it for quite a while before it burned out- the stud just recently became loose and caused (i believe) a large current draw somehow.

I wanted to verify my understanding as the disconnect switch rated at 300 amps, but the stud that was loose was only rated for 20. Here is how it was wired. what do you think?

S&B · Feb 28, 2011

i have also been runnning a PA performance 200 amp one with no problem

jrichker · Feb 28, 2011

For a battery cut off switch, see Moroso : Category Display
is the switch http://www.moroso.com/catalog/images/74102_inst.pdf is the installation instructions.
Use the super duty switch and the following tech note to wire it and you will
be good to go.

Use the Moroso plan for the alternator wiring and you risk a fire. The 10 gauge wire they recommend is even less adequate that the stock Mustang wiring.

There is a solution, but it will require about 40' of 18 gauge green wire.

Wire the battery to the two 1/2" posts as shown in the diagram.

The alternator requires a different approach. On the small alternator plug there is a green wire. It is the sense lead that turns the regulator on when the ignition switch is in the run position. Cut the green wire and solder the 40' of green wire between the two pieces. Use some heat shrink to cover the splices. See Ford Fuel Injection » How To Solder Like a Pro for some excellent help on soldering & using heat shrink tubing.

Run the green wire back to the Moroso switch and cut off the excess wire. Try to run the green wire inside the car and protect it from getting cut or chaffed. Crimp a 18 gauge ring terminal (red is 18 gauge color code for the crimp on terminals) on each wire. Bolt one ring terminal to each of the 3/16" studs. Do not add the jumper between the 1/2" stud and the 3/16" stud as shown it the
Moroso diagram.

How it works:
The green wire is the ignition on sense feed to the regulator. It supplies a turn on signal to the regulator when the ignition switch is in the Run position. Turn the Moroso switch to off, and the sense voltage goes away, the voltage regulator shuts off and the alternator quits making power.

The fuse & wiring in the following diagram are for a 3G alternator. The stock alternator uses a dark green fuse link wire that connects to 2 black/orange wires. Always leave them connected to the starter solenoid even if you have a 3G alternator.

See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host) for help on 88-95 wiring
Mustang FAQ - Wiring & Engine Info Everyone should bookmark this site.

Ignition switch wiring
http://www.veryuseful.com/mustang/tech/engine/images/IgnitionSwitchWiring.gif

Fuel, alternator, A/C and ignition wiring
http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif

Complete computer, actuator & sensor wiring diagram for 88-91 Mass Air Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/88-91_5.0_EEC_Wiring_Diagram.gif

Vacuum diagram 89-93 Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/mustangFoxFordVacuumDiagram.jpg

BoostedSN95 · Feb 28, 2011

jrichker said:
For a battery cut off switch, see Moroso : Category Display
is the switch http://www.moroso.com/catalog/images/74102_inst.pdf is the installation instructions.
Use the super duty switch and the following tech note to wire it and you will
be good to go.

Use the Moroso plan for the alternator wiring and you risk a fire. The 10 gauge wire they recommend is even less adequate that the stock Mustang wiring.

There is a solution, but it will require about 40' of 18 gauge green wire.

Wire the battery to the two 1/2" posts as shown in the diagram.

The alternator requires a different approach. On the small alternator plug there is a green wire. It is the sense lead that turns the regulator on when the ignition switch is in the run position. Cut the green wire and solder the 40' of green wire between the two pieces. Use some heat shrink to cover the splices. See Ford Fuel Injection » How To Solder Like a Pro for some excellent help on soldering & using heat shrink tubing.

Run the green wire back to the Moroso switch and cut off the excess wire. Try to run the green wire inside the car and protect it from getting cut or chaffed. Crimp a 18 gauge ring terminal (red is 18 gauge color code for the crimp on terminals) on each wire. Bolt one ring terminal to each of the 3/16" studs. Do not add the jumper between the 1/2" stud and the 3/16" stud as shown it the
Moroso diagram.

How it works:
The green wire is the ignition on sense feed to the regulator. It supplies a turn on signal to the regulator when the ignition switch is in the Run position. Turn the Moroso switch to off, and the sense voltage goes away, the voltage regulator shuts off and the alternator quits making power.

The fuse & wiring in the following diagram are for a 3G alternator. The stock alternator uses a dark green fuse link wire that connects to 2 black/orange wires. Always leave them connected to the starter solenoid even if you have a 3G alternator.

See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host) for help on 88-95 wiring
Mustang FAQ - Wiring & Engine Info Everyone should bookmark this site.

Ignition switch wiring
http://www.veryuseful.com/mustang/tech/engine/images/IgnitionSwitchWiring.gif

Fuel, alternator, A/C and ignition wiring
http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif

Complete computer, actuator & sensor wiring diagram for 88-91 Mass Air Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/88-91_5.0_EEC_Wiring_Diagram.gif

Vacuum diagram 89-93 Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/mustangFoxFordVacuumDiagram.jpg

Thanks for the tips-I do have the moroso 74102. I wish I had found that diagram a few months ago. Has that wiring scheme been proven? My wire scheme did work until the smaller stud were loosened and now the small studs are no longer continuous. any idea why the jumper wire on 3/16" terminals didn't fry sooner?

jrichker · Feb 28, 2011

BoostedSN95 said:
Thanks for the tips-I do have the moroso 74102. I wish I had found that diagram a few months ago. Has that wiring scheme been proven? My wire scheme did work until the smaller stud were loosened and now the small studs are no longer continuous. any idea why the jumper wire on 3/16" terminals didn't fry sooner?

Check out the date on the diagram - April 2007. That's almost 4 years ago. There have been more than 1 or 2 that have used it in those 4 years. I have had only one negative report, and I am not sure that the switch was wired correctly in that one case..

Study the principle behind the switching the green/red alternator run on and off. When there is no 12 volts from the ignition switch applied to the Green/red wire the alternator regulator does not turn on the alternator field current. Therefore the alternator does not put out electrical power.

The following diagram shows the alternator wiring for a stock alternator. The 3G alternator works the same as the stock alternator with the exception of the 4 gauge power wire.

See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host) for help on 88-95 wiring Mustang FAQ - Wiring & Engine Info Everyone should bookmark this site.

Ignition switch wiring
http://www.veryuseful.com/mustang/tech/engine/images/IgnitionSwitchWiring.gif

Fuel, alternator, A/C and ignition wiring
http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif

Complete computer, actuator & sensor wiring diagram for 88-91 Mass Air Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/88-91_5.0_EEC_Wiring_Diagram.gif

Vacuum diagram 89-93 Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/mustangFoxFordVacuumDiagram.jpg

HVAC vacuum diagram
http://www.veryuseful.com/mustang/tech/engine/images/Mustang_AC_heat_vacuum_controls.gif

TFI module differences & pinout
http://www.veryuseful.com/mustang/tech/engine/images/TFI_5.0_comparison.gif

Fuse box layout
http://www.veryuseful.com/mustang/tech/engine/images/MustangFuseBox.gif

Is it safe to use a 170 or 200 amp alternator?

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Is it safe to use a 170 or 200 amp alternator?

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