Wiring In Alternator

stamp_licker · Post by **stamp_licker** » Thu Nov 02, 2006 9:58 am

The following steps can be used for wiring in any ej ,l,my alternator to any subaru loom.
1 grab your new alt look at the back for a sticker with a wiring diagram,it will be a pic or a round or rectangle plug with a combination of or all of these letters L,S,C,IG.
2now look at your alt you are replacing locate its wiring diagram
3 cut the existing alt plug off and connect the corresponding wires from the new plug to the existing loom by following the pinouts from both alt.eg L to L S to S .
4 The bolt on wire normally white remains the same .
TIPS...... NOT all wires are used in some cases,as long as you have the wires for new alt hooked up just insulate the rest .example going from a early ej with ign wire to a late without.NOT all wires are the same colour for the same pins,Just get the pinouts right.
If you have the new alt and not the plug the wires can be connected from the old plug with spade terminals to the new alt
What the letters mean.... L - light[warning light on dash]
S- sense
ig- ignition on, recieves power when ignition on

maxxair · Post by **maxxair** » Wed Mar 26, 2008 9:24 pm

whats the best (biggest) cranking alternator. for a ej22 brumby rally car. i reckon i need 90-100 A. for 3 thermos, spotties, fuel pump ect. whatll be a good one??

Gannon · Post by **Gannon** » Wed Mar 26, 2008 9:39 pm

Apparently there are a few GM alterators that will fit an EA82. I think holden suburburn was one of them

Ive also heard that the early nissan maxima one will fit too.

vincentvega · Post by **vincentvega** » Wed Mar 26, 2008 9:57 pm

The problem with upgrading to a high capacity alternator is that you will also need to upgrade your wiring loom or you will be blowing fusible links every time you pull some decent current from the alternator.

shuffbag · Post by **shuffbag** » Thu Jul 03, 2008 3:07 pm

now i dont have the car infront of me at the moment but going buy the ea82 and ej22 engine manuals all i have to do is the main wire to the bolt (easy), and a wire labeled "S" seems simple enough. and disregard I L C?

Matt · Post by **Matt** » Thu Jul 03, 2008 6:49 pm

Have a look under the Tech Manual there is a electronic copy of the manual for an EA82 and there might be one for an EJ to...

discopotato03 · Post by **discopotato03** » Wed Jul 09, 2008 5:46 pm

It doesn't have to go via the std cars fusible links .

One car I had converted from Carby to EFI (not Subaru) had extra wires directly off the alternator to power various extras . What you have to do in this case is have fuses close to the alternator to protect it against short circuits .
It was a good way to ensure extras were getting full alternator output voltage and not suffereing voltage drop through ancient std wiring looms .

From memory direct alternator feed power went to ECU/ignition/fuel pumps/headlights . Never had any power issues though the alternator being an 80a star wound Bosch ment you had to give it a slight rev to make it charge after startup . All good except for that trivial bit .

Cheers A .

One to be careful of .

Some late cars have their alternator requlators set at 14.4 volts insted of the older 13.8 volt standard . Make sure you have a battery to suit the charge voltage or you can get a few irritationg probs .
The one I mentioned had an aftermarket Ingrams 14.4 V reg on it .

maxxair · Post by **maxxair** » Wed Jul 16, 2008 10:31 pm

yea, ive askeed good sources, i got..

positive off the threaded bolt. no worries, straight to battery (nice and fat.)

l - light. ignition + thru the light into terminal.
s - is the exiter wire. constant + is good for this ive been told.

phillatdarwin · Post by **phillatdarwin** » Tue Aug 10, 2010 12:29 am

i built onr some 10+ years ago and still got it in my car now it put out 150A and i can run and have run 500watts of lights and had no problems at all with it ..
first u need to work out how much watts u will be needing
then divide that by 12 and u get the amps u need for the alternator to put out and a bit more ..
get a auto lec to build u one like it did to my when i was working as a auto lec a long time a go doing rebuilds

fordmech_SUBI_fan · Post by **fordmech_SUBI_fan** » Sat Feb 26, 2011 1:01 am

suggested altenator for a 98 forester with an ej 20 and 700+ watts (roughly 60 amps) of high beam?? and better yet somewhere to get it? cause i dont thing my 75 amp altenator will last
any help at all would be apreciated

RSR 555 · Post by **RSR 555** » Sat Feb 26, 2011 1:59 am

fordmech_SUBI_fan wrote:suggested altenator for a 98 forester with an ej 20 and 700+ watts (roughly 60 amps) of high beam?? and better yet somewhere to get it? cause i dont thing my 75 amp altenator will last
any help at all would be apreciated

Sorry to say this but is this for real?? 700+ watts?? what are you running and have you ever heard of HIDs?

fordmech_SUBI_fan · Post by **fordmech_SUBI_fan** » Sat Feb 26, 2011 9:13 am

im running 5 spotties: 2 130 watts, a 150 and the other 2 are roughly 100 i think. and i have heard of hids but im more impressed with spotties

Gannon · Post by **Gannon** » Sat Feb 26, 2011 10:43 am

You can put HID kits into spotties

fordmech_SUBI_fan · Post by **fordmech_SUBI_fan** » Sat Feb 26, 2011 4:00 pm

yes yes you can but i cannot afford to get the HID kits to go into my spotties atm

GOD · Post by **GOD** » Sat Feb 26, 2011 6:53 pm

An HID kit, or the removal of a few lights will be cheaper than a new alternator.

Anyhow, just checked the specs on a Gen 3 Liberty alternator, and its max output is 90A. Pretty sure most of the EJ alternators I've looked at have been around there. 75A seems very low.

Dane.