New bolt in ea series alt upgrade, 95 impreza 78 amp

[mikaleda]

Well I had to put a new alt in my subie the other day and I had a few alternators sitting on a shelf so I decide to see if I could make one work. The one that fit the best came out of a 95 impreza it is very similar to the maxima alternator. Here is some pics

I forgot to take pics of the new alt before modification so here is a couple I got from google

New alt installed but not wired

Old alt had a double pully on it and it turns out that all the parts needed are in the old alt. first thing you need to do is swap the pullys. On the old alt I held the pully with a strap wrench to break it loose, but on the impreza alt I had to hold the pully in a vise to get it off (good thing we don't need that ). The impreza alt has a built in spacer but I found the old alt had just the perfect size spacer on it, so I used it. Then the final thing you have to do to the alt is un bolt the plastic peice on the back that connects to the batt post so the batt post sticks straight out. I had to make an insulater so I took the the one off of the old alt and drilled it out to the size of the post on the new alt. it worked perfectly I did have to use one extra washer but that's easy. Now it will bolt right in the connections are similar to the maxima alt. so you can use the original wiring if you want but I liked having the original plug so I used it. I wired it into a externals voltage regulated subie so my wiring is differant than yours will be. Here is a pic of mine after I wired it

The large white wire is the sense wire and it needs to be connected to 12v constant and the easiest way to do that is to run it straight off the wire that runs to the batt post. The other wire needs to be connected to the charge light so I had to run it around to the old Voltage regulator harness and connect it to the the charge light wire wich is white with red trace. On a internally regulated subie you should be able to use the same wires that went to the old alt. just make sure the small wire is going to the charge light and the the large white wire is going to 12v constant.

 

 

Here is a better explanation of the sense wire and how it should be connected thanks to ferox

The sensor wire should be connected as close to the battery as possible. It doesn't go to 12V constant; it "tells" the alt what the actual charge is on the battery, so the alt "knows" how much to charge the battery. If you just hook it to 12V constant, then the alt won't be responding to the battery charge per se and would most likely result in overcharging the battery. We've already gone over this. The way you have it hooked up will work, but it's less than ideal and doesn't account for resistive losses in the alt power supply wire to the battery.

Okay this alt can be found in subaru imprezas from 93-96 1.8&2.2 and that is the only models or years I can find the same alt in. Edited March 5, 2013 by mikaleda

[987687]

Wow, fantastic info. EJ alts from 90-99? or something should be the same with the two wire connector. I have a few laying around, time to go see if i can replace the tired old alt in my GL.

[mikaleda]

The alts are phisicly the same 90-99 but the wiring differs I know a 97 legacy has the same alt but I know my 90 has a four wire setup but they should all be fairly similar in wiring I believe

[987687]

Huh, as long as it bolts up the wiring doesn't really matter. All alts are gonna have a sense wire and a charge light wire. So if you're wiring the wrong alt to work it's the same thing no matter what you're stuffing in.

[mikaleda]

Yes I agree I just ment I couldn't tell with certainty what wires go where on the other alts is all.

[bratman18]

Huh, as long as it bolts up the wiring doesn't really matter. All alts are gonna have a sense wire and a charge light wire. So if you're wiring the wrong alt to work it's the same thing no matter what you're stuffing in.

Chris, if you do this, I may ask for a hand later on doing it to my Loyale. I'm not confident enough with wiring.

 

My new EA car will already have an EJ alt.

Edited March 2, 2013 by bratman18

[987687]

Chris, if you do this, I may ask for a hand later on doing it to my Loyale. I'm not confident enough with wiring.

 

My new EA car will already have an EJ alt.

 

There are only two wires, hook them up until it works, or blows smoke 

I need to replace the start capacitor on my air compressor, then I can attack the pulleys with air tools. I'm too lazy to do it by hand, heh.

[bratman18]

There are only two wires, hook them up until it works, or blows smoke 

I need to replace the start capacitor on my air compressor, then I can attack the pulleys with air tools. I'm too lazy to do it by hand, heh.

The blowing smoke part is what worries me. I don't want to fry anything.

[987687]

If you hooked up the sense and idiot light wires backwards, it's likely that nothing would happen, it just wouldn't work. But when you get the parts, bring it all over, air tools will make it easier anyway.

[bratman18]

If you hooked up the sense and idiot light wires backwards, it's likely that nothing would happen, it just wouldn't work. But when you get the parts, bring it all over, air tools will make it easier anyway.

Yeah I have a cordless impact gun here as well. 475 lb/ft of torque! Makes things so much easier.

 

And you know me, I already have all the parts! Lol

Edited March 2, 2013 by bratman18

[mikaleda]

I can understand not wanting to fry anything but if I had not tried the gm alt I put in first I probably would have never found out about this alt. lol sometimes you just got to give it a try

I fried the gm alt when I tried wiring it lol

Edited March 2, 2013 by mikaleda

[987687]

Yea, well, all internally regulated alts work more or less the same way. The air chisel is one of my most favourite tools. It's fantastic for beating the crap out of things and making pulleys and whatever else you want come off.

[mikaleda]

Yea, well, all internally regulated alts work more or less the same way. The air chisel is one of my most favourite tools. It's fantastic for beating the crap out of things and making pulleys and whatever else you want come off.

Yep that is what I learned from doing this swap I did a lot of searching to find all this info

[ferox]

Well I had to put a new alt in my subie the other day and I had a few alternators sitting on a shelf so I decide to see if I could make one work. The one that fit the best came out of a 95 impreza it is very similar to the maxima alternator. Here is some pics

I forgot to take pics of the new alt before modification so here is a couple I got from google

New alt installed but not wired

Old alt had a double pully on it and it turns out that all the parts needed are in the old alt. first thing you need to do is swap the pullys. On the old alt I held the pully with a strap wrench to break it loose, but on the impreza alt I had to hold the pully in a vise to get it off (good thing we don't need that ). The impreza alt has a built in spacer but I found the old alt had just the perfect size spacer on it, so I used it. Then the final thing you have to do to the alt is un bolt the plastic peice on the back that connects to the batt post so the batt post sticks straight out. I had to make an insulater so I took the the one off of the old alt and drilled it out to the size of the post on the new alt. it worked perfectly I did have to use one extra washer but that's easy. Now it will bolt right in the connections are similar to the maxima alt. so you can use the original wiring if you want but I liked having the original plug so I used it. I wired it into a externals voltage regulated subie so my wiring is differant than yours will be. Here is a pic of mine after I wired it

The large white wire is the sense wire and it needs to be connected to 12v constant and the easiest way to do that is to run it straight off the wire that runs to the batt post. The other wire needs to be connected to the charge light so I had to run it around to the old Voltage regulator harness and connect it to the the charge light wire wich is white with red trace. On a internally regulated subie you should be able to use the same wires that went to the old alt. just make sure the small wire is going to the charge light and the the large white wire is going to 12v constant.

Edit: I couldn't have done this swap without help I got from the usmb about wiring.

 

The sensor wire should be connected as close to the battery as possible.  It doesn't go to 12V constant; it "tells" the alt what the actual charge is on the battery, so the alt "knows" how much to charge the battery.  If you just hook it to 12V constant, then the alt won't be responding to the battery charge per se and would most likely result in overcharging the battery.  We've already gone over this.  The way you have it hooked up will work, but it's less than ideal and doesn't account for resistive losses in the alt power supply wire to the battery.

[mikaleda]

I checked the voltage at the battery it's charging perfectly. From the research I did this setup will be fine on a newer subaru that originally had an internally regulated alt 82 and up connecting it through the old plug will be correct. also i was thinking about running a better gauge wire to the battery and using the old charge wire for sense wire. Also this is not a thread about how to install an internally regulated alt into an externally regulated subaru. That will come latter when I finish the fusible link box I will make sure to add that info and links to the source.

I also edited the first post

Edited March 3, 2013 by mikaleda

[987687]

Of course I forgot my camera with pics in the shop, but I tried to swap in a 95-99 legacy alternator today. Pulled the pulleys off (needed to use a puller, them things stuck on there HARD!). The ea82 pulley won't work on the ej alt.... The shaft coming out of the alt is shorter, and therefor not compatible with the ea pulley. Oh well.

Edited March 4, 2013 by 987687

[mikaleda]

Weird I had no problem with the pullys. did you try using the lock washer? I found that with the lock washer it wouldn't work but it worked fine without one.

 

On another note today I just passed a hundred miles since the swap and everything is working good no problems as of yet.

Edited March 5, 2013 by mikaleda

[987687]

So I'm a potato an didn't get pics of the pulleys, but here are the alternators.

 

Here's the EA82 alternator:

 

And here's my EJ (95-99 legacy) alternator:

 

As you can see, the EJ shaft is quite a bit shorter. The EJ pulley has a high offset down, whereas the EA pulley has much less offset, therefor the shaft coming out of the alt has to be much longer.

So it has nothing to do with one nut vs. the other, it has all to do with the pulley just doesn't physically fit.

Did your ej alt look like my ea one? 

[mikaleda]

That ej alt looks differant than mine, the ea alts are exactly the same from what I can tell.

[mikaleda]

Okay a 95 legacy is an 85 amp alt and is not the same as the one I used, I just cross referenced on rock auto.

[mikaleda]

When I have time I will cross reference part #'s and come up with a list of alts that will work. Just give me some time I am tired

[987687]

I don't care so much about an extra few amps, I'll just grab an early 90's impreza alt next time I'm at the junkyard. 

[mikaleda]

Okay 93-96 1.8&2.2 are all the same alt but none of the legacy alts are the same

[987687]

Okay 93-96 1.8&2.2 are all the same alt but none of the legacy alts are the same

awesome! that's great to know, thanks.

[mikaleda]

Op edited I will do some more searching on part numbers and will come up with a better list than what I have now. It may take a day or two it just depends on the weather