200A Alternator

[Mike_From_Red_Deer]

So it turns out that with the add-ons to my car, I've stressed out my poor alternator and it's probably going to go south on me before winter.

My mechanic friend suggested a heavy-duty 200A alternator. Has anyone had any success with upsizing their alternators?

Starter motor is starting to go too, but that's a separate issue...

[friskyfrankie]

Year, Make and Model of car?

[gadget73]

never had any need for more than the 130. Is this fancypants alternator available at parts stores, and whats the idle output like? Some of the higher amp units make more output, but only at higher RPM. Sometimes their idle speed performance is worse than a standard size alternator so it ends up not actually working as well.

If you're currently using a 65 amp 2g or a 100 amp 1g, both of those have shit for idle output and the 3g 130 will be a nice improvement.

[Mike_From_Red_Deer]

I believe it's a 65 amp.

The car is a 1986 Mercury Grand Marquis LS with the 5.8L engine.

[Tiggie]

What kinds of electrical upgrades do you have?

If that's an 86 with an 351, it might have the 100 amp. Either way you slice it, you need some wiring changes.

Tell us what it looks like
2G 65A


1G 100A

[Mike_From_Red_Deer]

I took a picture of the engine bay yesterday, including the alternator.

[Mike_From_Red_Deer]

Also I posted this in slightly the wrong forum. Sorry about that.

[Tiggie]

That's the 2G. Highly recommended to upgrade to the 3G. If you need more amps, they are available. I'd suggest calculating what you need.

I'd be double sure all your wiring is protected by fuses, circuit breakers, or fusible links. There's a lot of custom wiring on your ride and I have seen a good number of cars burn up from added unprotected circuits.

[Mike_From_Red_Deer]

In 12 years of owning this thing, it has yet to catch fire.

So would 200 amps be sheer overkill?

[Lutrova]

For regular use, the 130a 3G is more than sufficient. But if you've got a big sound system or a chest freezer in the trunk, then you might need more amps.

[sly]

I have electric radiator fans and at one point had 2 10 inch subs and the 130 is plenty.

Measure the distance between the bolt holes on the alternator to figure out which alternator case size you have to make sure the replacement is the correct size.

LMR has a kit if you have the same size case as 302 panthers.

https://lmr.com/item/SVE-17046K2/Mustang-SVE-130-Amp-Alternator-Upgrade-87-93-50L

[Mike_From_Red_Deer]

I have electric radiator fans and at one point had 2 10 inch subs and the 130 is plenty.

Measure the distance between the bolt holes on the alternator to figure out which alternator case size you have to make sure the replacement is the correct size.

LMR has a kit if you have the same size case as 302 panthers.
https://lmr.com/item/SVE-17046K2/Mus...rade-87-93-50L

I have no idea what the case size is.

I do know that I seem to burn through alternators on this car for some stupid reason. Must be an electrical gremlin hiding in the miles of wires this thing has...

I did in fact order (well my mechanic friend ordered it) a bumper-to-bumper replacement wiring harness; just need to get it installed.

[friskyfrankie]

I'd be taking a GOOD look at all the "special wiring" that is on the car to eliminate all of it as a potential issue.

[Kodachrome Wolf]

I have no idea what the case size is.

I do know that I seem to burn through alternators on this car for some stupid reason. Must be an electrical gremlin hiding in the miles of wires this thing has...

I did in fact order (well my mechanic friend ordered it) a bumper-to-bumper replacement wiring harness; just need to get it installed.

Looks like the small case 2G, so there’s plenty of options to choose from for a small case 3G, like ‘94-‘95 V8 Mustang, ‘94-‘99 V6 Mustang, or ‘95-‘99 OHV 3.0L V6 Taurus/Sable. Those options all offered an appropriate sized 130 amp 3G.

I can’t imagine that 65 amp unit performs well supporting those e-fans with their initial startup draw current.

I’ll echo the sentiment that 3G has always been the way to go over the factory 2G units.

[Mike_From_Red_Deer]

My mechanic friend is telling me I should go with a 6G alternator.

Like....what?