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alternator compatibility 3.0L 2.2L

9K views 15 replies 9 participants last post by  8kGoodENuff 
#1 ·
so I have been digging for a higher output alternator as when I need the defrost blasting my brights and "fog" lights on my 85 amp does not hold up and will tax the battery.....

I'm hoping i can use an alternator from a 3.0 h6 as they are 100amps! has anyone done this or know if they will fit on a 2.2 from 1996?

Thanks!
 
#14 ·
as suggested early on:
if not, then maybe your existing alternator or connections need replaced?
aftermarket alternators are known junk. i wouldn't be surprised in the least to have 3 low grade alternators in a row.

Subaru alternators are only $70 due to a recall around 1996 legacy/outbacks.

or just buy a used Subaru alternator from someone on here or Car-Part.com--Used Auto Parts Market

a used Subaru OEM alternator is 10x better than aftermarket.

you are best to avoid these parts from aftermarket sources at all costs (unless you enjoy your situation of multiple replacements, etc):
alternator, starter, fuel pump, cv axles
 
#5 ·
dag nab it I thought nI was on to something... I live in snow country so to warm up the car in the morning I need defrost lights wipers and if I throw in a turn signal it takes my electrical system so much the alternator stops outputting and the devices start to drain my battery....

if you add in my 1200 watt amp then the car can't even run the cooling fans fast enough to prevent overheating....

ebay has under $200 options but I don't trust ebay and everything online with a decent warranty seems to be over $400...
 
#6 ·
I just "did the math" and do not understand why 85 amp is not enough. Lets review...

85amp X 13Volts 1105Watts available from alternator (Alternator is rated for 13.8Volts so this number is on the low side)

subtract the headlights
1105Watts - (55X2) = 955Watts

Subtract the foglights
955 - (55X2) = 885Watts

Even counting for recharging a battery that just started a cold engine, you have WELL over 800Watts to run the blower-motor and other obscure electrical items.

BOTTOM LINE: You have something else wrong besides needing a higher-output alternator.

HINT: The windshield will defrost faster if you do NOT use the highest fan-speeds. This is because the air moving thru the heater-core has more time to pick-up heat. (Lower fan-speed = hotter air)

Question for you: Why do you feel the battery is being 'taxed'?
 
#7 ·
I just "did the math" and do not understand why 85 amp is not enough. Lets review...
Aren't you forgetting a few items?

• Ignition system/ECU
• rear defrost grid
• marker lights- they come on with the headlights so...
• seat heaters? not mentioned, but we are talking about a cold winter start...
• Transmission control & solenoids (if automatic)
• A/C clutch (many subarus run it in defrost mode)
• the stereo mentioned by OP

Now that said, I still think you're on the right track... 85A should be enough to do all of that. Makes me think the existing alt isn't developing full power, or the car is losing power to high-resistance connections somewhere.
 
#9 ·
One could also remove the alternator and clean up the points of contact where the alternator meets the engine mount bracket. That at times is good for .5V to 1V of losses, which can make a lot of difference.
 
#11 ·
1Volt drop X 85Amp alternator = Up to 85Watts lost

HOWEVER: The bigger problem with having poor connection between alternator and engine is that the regulator (on the 2.5 engine) is also housed within the alternator. Hence, the regulated voltage will be based on incorrect reference-point.

I say again - *ALL* connections need to be clean, and tight before assuming there is an alternator problem.
 
#12 ·
I really notice a loss when I am holding the break at a stop with wipers and lights going. I also notice that the cruse control and ac compressor also draw what seems to be almost to the alternators limit.

this is the 3rd crappy oreilly alternator I have had (warranty return) and I just today swapped a kirkland signature battery for an interstate... hoping that will improve things.

I just figured that if I was going to spend $150-200 on a denso or Subaru alternator I should just spend the money on a higher output so I can run my subwoofer....
 
#16 ·
I really notice a loss when I am holding the break at a stop with wipers and lights going. I also notice that the cruse control and ac compressor also draw what seems to be almost to the alternators limit.

this is the 3rd crappy oreilly alternator I have had (warranty return) and I just today swapped a kirkland signature battery for an interstate... hoping that will improve things...
So I've had the same issue and unfortunately still have the issue, even after cleaning 99% of the grounds (need to clean alt to support bracket).

I posted all symptoms that I've encountered on this thread starting with post #26... http://www.subaruoutback.org/forums...outback-fried-2-new-alternators-so-far-3.html

I still have to find the problem. The next thing for me will be to check the connections of the alternator to the support bracket as mentioned in this thread and also pull the insulation on the cable between battery and alternator to see if it's corroded as mentioned in the link I posted above.
 
#13 ·
I have to agree with brucep. Time to stop throwing parts at it and fix the wiring.

There is a chance that all of those alternators are working right, but because the regulators are internal, they will never notice the voltage dropping in distant circuits in the car, so they never increase the current to compensate.
 
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