110 amp alternator upgrade for your Subaru conversion CHEAP

[baltik]

Thanks for that, do you know what the two existing wires are by chance? can i reuse either?

[termuehlen]

I don't know how your existing two-wire alternator is connected. The large white is likely 12V+, but you should check that with a multi-meter. You could also check the black/red? wire with a meter.

The dash light operation is non-intuitive. A wire connection from the alternator to the indicator light in the dash will activate the lamp when grounded and turn it off when 12V is applied.
_________________
1988 Westfalia automatic Subaru OBD1
1986 syncro tintop wbx

[20bugsys]

For anyone coming here looking for wiring who has a 2 wire subaru alternator here is what I have found. On my 2 wire alternator plug, there is a 10 gauge white wire and a smaller gauge black wire with a yellow stripe. The black and yellow wire is the gauge/cluster light wire. The large white wire is the 12V+ or SENSE wire.

This is the plug I used.
https://www.amazon.com/dp/B00AY2469A?tag=viglink129040-20

If you look at the image on the amazon plug, there is a diagram of the alternator side of the plug.

Red lead is "L"
Green lead is "S"
Black lead is "D" otherwise known as "C" for computer. You can cut this lead off, it goes unused.

So if you are upgrading an EJ25 with a 2 wire alternator, connect the large white wire to the sense pin, which according to resources in this thread, is the center pin. Connect the black small wire to the light pin (closest to the big B+ lug).

I hope this helps someone. I read all the threads here on this topic a few times and didn't see anything outlining conversion from existing 2 wire alternators with a different plug type like I have. I even contacted Jeff at autoventures, who did my original harness for confirmation.

_________________
1960 | Beetle | Jade Green | 36hp OG Car
1969 | Beetle | Cherry Red | 1914cc
1984 | Vanagon Tin Top | Subaru EJ25, 5 Speed
1986 | Vanagon Syncro | Restoration to bone stock
@myescapepod
@crusty_syncro

[human compass]

so did this mod a few months back, or rather it was done for me at the time of my syncro swap. Has been running fine for 6k miles and now all of a sudden the alternator is putting out less than 13 volts when under load and the charge light is coming on. when measured the voltage at the batt is 12.6 under load. interstingly when the green plug is unhooked from the alternator it goes up to 14+ volts??

swapped alternator with a know good, same. Battery checked out good at NAPA.

sense wire goes to alternator stud. replaced ring term no improvement. gauge wire goes to black box, confirmed all connections good.

I'm at a loss. any thoughts?

thanks!
_________________
84 Westy Syncro- 3.3L SVX stage 2 tune,subaru gears 6speed with tbd, front locker, porche brakes x4, aux tank, radflo susp

[syncrodoka]

Check your grounds.
If they didn't upgrade them from stock it would be a good idea.

[termuehlen]

[human compass]

I did try running a jumper to the battery pos terminal and seemed to make the alternator kick down in voltage. It actually runs best right now with the plug not in at all???

wondering about an internal short within the plug-ordered a new one.

I'll try your suggestion and check all the grounds again. Also may pull the newly purchased alternator and have it tested.

thanks!
_________________
84 Westy Syncro- 3.3L SVX stage 2 tune,subaru gears 6speed with tbd, front locker, porche brakes x4, aux tank, radflo susp

[human compass]

so after literally replacing/upgrading the entire charging system it turns out that the little green alternator plug had some corrosion that was likely shorting or decreasing sensing. replaced that with a new one and all is well
_________________
84 Westy Syncro- 3.3L SVX stage 2 tune,subaru gears 6speed with tbd, front locker, porche brakes x4, aux tank, radflo susp

[Povi]

[termuehlen]

Try unplugging your 2-pin connector from the alternator. Your battery won't charge and your idiot light will be on, but otherwise can you start it up and operate normally? If not, look at what else you have done.
_________________
1988 Westfalia automatic Subaru OBD1
1986 syncro tintop wbx

[Povi]

The old two plug alternator is out and the new one is in. Wire’s we’re temporarily connected as the quoted post suggested

_________________
89' Westy Subaru 2.2

[termuehlen]

Yes, I’m suggesting you temporarily cap those wires and try to start your vehicle. The battery won’t charge & your charge warning light will be on, otherwise you should not have weird issues. If the no start problem goes away, it is the alternator wiring. If problem remains, it is something else.
_________________
1988 Westfalia automatic Subaru OBD1
1986 syncro tintop wbx

[bsrad]

So we were traveling back from Denver a couple weeks ago and I noticed the battery light started to flicker so I toggled the battery voltage switch and checked the starter battery and then the house batteries and both were sitting around 17.2v. I figured that I had an internal voltage regulator going out and the next weekend planned to change the alternator out.

I picked up the “23700AA520 - 2005 Legacy Turbo and 2006-2009 Forester TURBO, 2007-2009 Impreza TURBO“ from Subaru that was recommended in this thread. Easy install with no modifications required.

Couple things though is the output voltage at the alternator is around 15.2v-15.4v and is 14.8v-15.1v at the battery. Is that voltage too high? Also, I still have a little bit of a flicker at the battery light. I’ve read the threads on the sensing wire and also grounding issue and as a tester I ran an 8 guage wire from the neg battery terminal all the way to the alternator mounting bolt but no change in the output voltage or the flicker.

Thoughts?
_________________
Bill

-----------

1987 Syncro Westy
1967 OG Single Cab
1976 FJ40

[dgbeatty]

Do you have the control wire connected? If so where?
It is necessary for proper operation.
_________________
Schau in das Buch

[bsrad]

[1988M5]

https://www.youtube.com/watch?v=jgoIocPgOug&feature=emb_logo

Decent video about power output vs RPM vs cooling. No free lunch still raises its' head. What are you guys lacking or seeking with higher peak output alternators?

BK
_________________
1991 tin top GL
2002 Winnebago Vista. VW VR6 24V Eurovan front clip powered class C 21' RV.
Some BMWs.

[Jake de Villiers]

The higher output alternator means I can run the radio, headlights, both heater blowers and the wipers while sitting at a stoplight - and the wipers don't slow down!!!
_________________
'84 Vanagon GL 1.9 WBX
'86 Westy Weekender Poptop/2.5 Subaru/5 Speed Posi/Audi Front Brakes/16 x 7 Mercedes Wheels - answers to 'Dixie'
@jakedevilliersmusic1
http://sites.google.com/site/subyjake/mydixiedarlin%27
www.crescentbeachguitar.com
www.thebassspa.com

[syncrodoka]

[bsrad]

So I’m gonna throw this out there one more time in hopes someone could give me a hand on this. Been struggling to figure out why this new oe Subaru alternator is putting out 15.5+ volts. Sometimes 15.8v. I took it back to Subaru today to see if they could put it on the tester, but I guess it has to be in the vehicle to test now. Parts guy said it should be 14.8ish volts and would order me another one. Not super optimistic that this truly is the issue. Feel like there should be something that tells the alternator settle down on the voltage. Obviously something more than the voltage regulator that is.

Thanks for the help..
_________________
Bill

-----------

1987 Syncro Westy
1967 OG Single Cab
1976 FJ40

[Sodo]

130 A Tribeca alternator $42 on eBay
Direct replacement.
_________________


'90 Westy EJ25, 2Peloquins, 3knobs, pressure-oiled GT mainshaft, filtered, cooled gearbox
'87 Tintop w 47k 53k, '12 SmallCar EJ25, cooled filtered gearbox
....KTMs, GasGas, SPOT mtb