Subaru Outback Forums banner

1 - 9 of 9 Posts

·
Registered
2005 OBW 2.5L, 1989 Subaru Justy, RIP Blu
Joined
·
7,355 Posts
Thats not how an alternator works. Only thing he is going to do is kill his battery and shorten bulb life.

HowStuffWorks "How Alternators Work"

The internal voltage regulator sets voltage. Physics debates power output, as Alt's don't really start cranking out max power till 1800 RPM (which is where tests are done for output) but in reality about 100 rpm or better.
 

·
Registered
2000 Outback Ltd.
Joined
·
205 Posts
This is a well known mod. In theory, it should work but that's in theory. You really don't know if your alternator can handle the increased load over time. You don't know if your stock cables can handle the increased current. What is the current increase? That being said, this has been used even by some HO alternator companies. Check out Mechman Alternator's STI on Youtube.
They're using something called an adjustable voltage boost module (AVBM) which is basically a diode in the wiring harness. Just keep in mind though that their alternators are highly engineered and torture tested for the increase output.
 

·
Registered
2002 Subaru Outback VDC Wagon
Joined
·
188 Posts
hmmmm.. i must find out more about this because 2.5's don't have PCM regulation... but the h6 does...
 

·
Registered
1999 Silver Outback manual trans
Joined
·
93 Posts
I've been considering just hacking the bracket and installing a gm alternator instead. They have stock, internally regulated 144amp alternators. It's just the case mounting design that is most different anyway. The plugs are different, but other then the newer alternators, all the older style function the same.
 

·
Registered
2012 OB , 2017 Impreza
Joined
·
3,277 Posts
Has anyone here try the mod of adding a 6amp 1000V Diode to the alternator to increase the output? is it worth trying?
Here is a link
http://www.scoobymods.com/showthread.php/raise-your-alternator-voltage-10547.html?t=10547&highlight=power+cable+upgrade
Just to put an electrical Engineer spin on it: This 'mod' really only increases the regulated VOLTAGE. (The maximum current is virtually unchaged)

A true 'higher output' alternator is capable of pushing out more CURRENT (at the proper 13.8 volts) To produce more current safely, the winding's within the alternator need to be made of heavier wire and pure copper. I would also suggest the windings should be configured in a "Delta" type of circuit (As compared to "Wye" design.) Also, the ability to generate more current also means it will run hotter. Hence, the cooling-fan needs to move more air thru the alternator.

This is why a 'true' high-output alternator costs over $300 - it has a lot of expensive copper within it as well as electronics capable of handling the additional current and heat.

If you want the ultimate Subaru alternator... get your checkbook ready... it is over $600 ==> https://www.dcpowerinc.com/11024-270-xp.html

A more reasonable alternator for our Outbacks is here ==> http://www.qualitypowerauto.com/item_292/Subaru-Outback.htm
 

·
Registered
Joined
·
177 Posts
Has anyone here try the mod of adding a 6amp 1000V Diode to the alternator to increase the output? is it worth trying?
Here is a link
http://www.scoobymods.com/showthread.php/raise-your-alternator-voltage-10547.html?t=10547&highlight=power+cable+upgrade
There are higher amperage output alternators available that fit the 2.5.

Try here: https://www.dcpowerinc.com/ Punch your car in and get a price and availability.

They have a 180 amp that fits my H6 for $400. Unless I find a comparable one, its gonna get ordered.
I bought this
http://m.ebay.com/itm/HIGH-OUTPUT-AMP-ALTERNATOR-Fits-SUBARU-BAJA-FORESTER-IMPREZA-LEGACY-OUTBACK-180A-/251188257732?nav=SEARCH
180 amps for $180. I did have to swap the serpentine pulleys around because the one that came of the alternator stuck out a tad further, but it now works perfectly, no issues with my electrical (also did the big 3 while I was there) I have yet to find a better deal. IF anyone knows of one, please IM me the details.

Sent from my Nexus 6 using Tapatalk
 

·
Registered
2012 Subaru Outback 3.6R Limited, with custom-added always-on auxillary power for an inverter, 3x DC jacks, and a radio transciever.
Joined
·
639 Posts
I wouldn't do it.

Instead, I'd look into having heavier cables installed to more efficiently move the power around, and consider an aftermarket alternator if you *really* need more current, or just drive in 1 gear lower to keep the RPMs up around 2000-3000 so you get good output.

I'm an amateur radio operator, I have voltage readouts on my radio and inverter in my 2012 3.6R OB...I have noticed with high load in the winter (all defrosters, both heated seats high, low-beams + fog-lights, fans on high) the voltage can sag to 12.2v bit but if I downshift (to get my RPMs up above 2000) it recovers nicely. This also seems helped a good bit by a big group 34 battery I installed when the wimpy OEM gave out after 2 years (would drop down to 11.6v after 2-3 hours).

I've also noticed one time I had to charge up a deep-cycle emergency power battery with jumper cables, the negative cable form the battery to the strut (the obvious place to clamp to) is really tiny, I found significantly better current by hooking negative jumper cables to the back of the engine/transmission bolts near the starter negative bracket (about 3V difference going into a very low deep-cycle with 4AWG jumper cables). I don't do this often, but if I needed high current on a regular basis I would probably determine what AWG the cables are and do a "big 3" upgrade (but not necessarily from them, they just came up as a great explanation when I searched).
 
1 - 9 of 9 Posts
Top