Just found out its time for a new alternator as my current one is putting out 8.3v at idle speed. I think I want to go with a higher output alternator this time. I'm looking at going with either the 160 amp from RJM injection or a 130 amp from a local parts store. I know that if I go to a 160 I'll need to upgrade the charge cable and add a megafuse, so will I need to do the same thing if I go with the 130? I'd like to get it taken care of asap, so I'm leaning towards the 130 so I can get it right away as I've heard it can take a few weeks to get the one from RJM. Any input?

The pickup is a 1994 f150 302 motor and already has a 3g alternator.

 

Why do you need a higher output alt rather then one that works?

Your alt puts out 8.3v at idle speed because its toast.

What do you run that requires that much juice?

 

I think all of our trucks should have come with a higher amp alternator from the factory. If the AC is on along with the lights, wipers and radio etc, the lights are dim and the voltmeter drops significantly. All of the trucks like ours I have been in are like this. I would like to upgrage mine to a 130 as well.

I have a 100 amp in my 65 Mustang and that works much better than the stock 60 amp.

You can get the Powermaster from Summit?

 

Go for the 3g alt and never look back you will really like it. Mine with full load everything on at idle stays steady at 13.75 volts much better than the original alt which would drop to 10 volts and start draining the battery.

 

I'm interested in an upgrade over my stock 95 amp as well. Primarly to support my Taurus fan when running anything else. However when I look at vendors sites, the ones they "show" are front mount style Alts & not the "cradle" types that 94s & later use.

If anyone has an actual pic of one they've gotten, I'd be interested in seeing it.

 

Like this one from Ryan's site David?
He sells a 160A version as well.
http://rjminjectiontech.com/?p=6

 

on my 96 i am running the 7.3 di 130 amp. couldnt be happier with it . i run a large stereo , extra lights and trailer tow a 30ft camper . no issues whatsoever, its a direct bolt on as well

 

Okay, so I have been trying to educate myself on these alternators, as my truck already has a 3G alternator but it did not have it from the factory. I found out that you can determine what kind of 3G alternator you have by looking at the the front of it - see these three pairs of raised "ridges" that run from the pulley towards the outside ring of the alternator and they get flatter as they go outwards? Notice there are some ventilation holes between the two ridges in each pair - if you have two large holes like the alternator in that picture Jim posted then the alternator is the more powerful 130-amp model, but if instead you see four smaller holes then your alternator is the lower-power model. My alternator is definitely the 130-amp model because it has two large holes there. So if your 3G alternator has two holes as well then it is 130 amps already, so you can simply replace it with another 130-amp alternator from your favorite parts store and you should not have to do anything to the wiring. If you have the weaker 3G alternator you probably should install a bigger cable for your new 130-amp alternator to charge the battery through it. Actually a bigger cable would be nice regardless, I have always been told that when it comes to cables the bigger the better, and so my truck has a very thick cable for the alternator, which may not be really needed at all but it is there anyways.

 

this generation truck had the 2g 95 amp stock, the cases look almost identical to a 3g and the connections are the same .

 

David, if you are looking for a "cradle"-style 130-amp alternator you need one for a 7.3 PowerStroke diesel engine, for example a '96 model. Also there seems to be a giant ambulance-special 215-amp alternator available for these engines as well, which at least in pictures looks like it will easily install in the place where the normal 130-amp alternator goes, but it is very expensive.

 

Then that would be 3G 95-amp (the lower-power 3G model I was referring to), as the 2G is a very very different thing - 2G has a cooling fan-thing right behind the pulley, it looks like a ripsaw and is exposed so you can easily stick your fingers in it and have it eat them.

 

There is a lot of good info in this tread, Excellent post bubblegum reps sent. I am a fan of adding an extra cable from the alt to the battery on a diesel the factory one seems to be to small in my opinion. I am sure that other trucks would benefit from this as well.

 

Yes go ahead and upgrade the charge wire and add a fuse. Better safe than sorry.

I run a 200 amp alternator with 0 gauge and a 250 amp circuit breaker.

I run 14.6 volts cold idle.

 

2 gauge cables, both charge and ground.
I have the 175A Megafuse and no problems since I got rid of my 2G.
Thought I would upgrade to the 160A unit but see no need now.

 

I have 1/0 alternator cable with 175-amp fuse (its says 175 on it, so I assume this is its rating in amps), then both my factory grounds are 2/0 (one for each battery). My factory positive cables are 2/0 from the left battery to the right one, then another 2/0 from there down to the starter. Then not too long ago my neighbor added another 2/0 cable for me that goes from the left battery to the starter directly (so now each battery can deliver its power straight into the starter), also he gave the batteries two more grounds that are 2-gauge (not 2/0). I have 14.6 to 14.8 on the voltage gauge at idle. However, I really cannot take credit for any of this, as the 3G conversion and alternator cable and fuse were done by my ex, and the extra positive and ground cables were suggested by and installed by my neighbor who is an 18-wheeler owner and mechanic.

Oh, that is very nice of you to say, but all I really did was use the search engine and then pretty much copy the relevant information I found here. Now if someone wants to know how to install a 3G then I probably will find that information pretty easy too, but that does not mean I actually have any clue as to what it all means, tehe