hatchsub Posted January 3, 2007 Share Posted January 3, 2007 Ok i just finished swapping in the XT6 alt and am wondering if something is wrong or not. When i have my stereo blairing..with subs and amp the gauge stays right around 13 or 14 ...basically horizontal. The minute i turn on my rear defrost with or without the stereo the gauge dips to 12. Or if i have my turn signal on the gauge dips with the blinking of the turn signal. Do you think everything is ok or is there something wrong with my car to make it do this? Its always done this with stock alternators but i thought that with the higher output that would be a thing of the past. Quote Link to comment Share on other sites More sharing options...
daeron Posted January 3, 2007 Share Posted January 3, 2007 the turn signal will cause it to flicker regardless of the output of the alternator (unless its like 200 amps) Don't forget that the output of the alternator is utterly dependant on the speed at which it is turning.. a 90 amp alt and a 50 amp alt are both rated thusly with the engine RPMs at around 2000-3000, and dont go higher than that. At idle, there isnt as much of a difference between the two as there is at speed. You may have some sort of short somewhere in your rear defrost circuit, that does seem like a pretty significant drop... However, my soob has no voltage meter, and my old Zcar, which did have an ammeter, did not have a functioning rear defrost, so maybe i just dont know nothin about how much those things actually draw.... If you think about the turn signal though, it does make sense to see a pulse in your voltage when they blink. Watch what the meter does when you hit the brake light, or turn on your headlights, start using the AC fan, or even honk your horn. hope this helps! something tells me you probably don't have a problem at all, just some (very very slightly) unrealistic expectations. Happened to me, too, when I installed my 90 amp maxima alternator. Life goes on Quote Link to comment Share on other sites More sharing options...
mcbrat Posted January 3, 2007 Share Posted January 3, 2007 check out my post in this thread from ages ago.... http://www.ultimatesubaru.org/forum/showthread.php?t=4284&highlight=voltmeter I'm not sure it's the ACC circuit, or the IGN fed circuit. if unfasten your fuse box and drop it out enough to see the back, you will see the wire that feeds all the fuses for the rear defogger, and turn sigs, etc... old soobs have pretty frail wiring. after I did the fix in the old thread, it's been fine... 3 years and counting Quote Link to comment Share on other sites More sharing options...
hatchsub Posted January 3, 2007 Author Share Posted January 3, 2007 McBrat could you explain to me a little bit more how you went about this? I think im going to do this fix as well before i go back to school. Quote Link to comment Share on other sites More sharing options...
mcbrat Posted January 3, 2007 Share Posted January 3, 2007 each fuse is part of a group (usually outlined in the owners manual) the way the fuse connectors are, there is one "input wire" for the group (+12V side) and those connectors are on a strip. The load side of the fuse connectors are all individuals... instead of trying to feed the whole group with the old brittle undersized stock wire, you use that feed as the power to flip a relay, which will send power from a new +12V feed direct from battery to that group. Quote Link to comment Share on other sites More sharing options...
mcbrat Posted January 4, 2007 Share Posted January 4, 2007 Quote Link to comment Share on other sites More sharing options...
mikeshoup Posted January 4, 2007 Share Posted January 4, 2007 I like that idea there McBrat. I think I'm gonna use it in my wagon. Another thing I noticed that really helps with this stuff, is redoing grounds. I use 12G wire, and run new grounds to the various ground points. Also, a lot of the factory ground points are painted, so I sand them down to metal and use a dielectric grease to prevent corrosion. Good stuff. Quote Link to comment Share on other sites More sharing options...
hatchsub Posted January 5, 2007 Author Share Posted January 5, 2007 Ok cool thanks McBrat. Now is the relay something that I can pick up at a NAPA? Also what gauge wire should i be running off the battery? Quote Link to comment Share on other sites More sharing options...
mcbrat Posted January 5, 2007 Share Posted January 5, 2007 Ok cool thanks McBrat. Now is the relay something that I can pick up at a NAPA? Also what gauge wire should i be running off the battery? yeah, standard relay available at any auto part store. I usually use 14 or 12 g wire... Quote Link to comment Share on other sites More sharing options...
daeron Posted January 5, 2007 Share Posted January 5, 2007 if you can find late 80s BMW 3 series in your local junkyard, go looking.. they have great little bosch relays in them, and removable plug/brackets.. ive got a box setup with a cover that can hold five relays, or there relays and a small fuse panel to power them all.... one of my proudest junkyard finds, yet.. Quote Link to comment Share on other sites More sharing options...
hatchsub Posted January 10, 2007 Author Share Posted January 10, 2007 McBrat what kind of relay did you use. I just got back from Napa and they told me i needed to know what relay to use. There were pages upon pages of relays that i could have chosen from. You wouldnt happen to have the application that it came from or the # on the relay and brand of relay? Thanks for your help. Quote Link to comment Share on other sites More sharing options...
daeron Posted January 11, 2007 Share Posted January 11, 2007 do what I said. relays are just little switches. The switch is controlled electronically, instead of by your finger. The "BMW" relays are ABSURDLY common, (its a bosch relay.. they get branded all sorts of ways, audi, hella, bosch, unbranded, VW.. ) and available new at a store simply by bosch part #, kind of like a light bulb. Most of the relays I found in the junkyard even had handy pinout diagrams on the side of the relay itself. sometimes those germans have good ideas.. They also come with an amperage rating printed on them. No guesswork involved, just cheap junkyard parts source... I have three or four spare relays in my glovebox, and in my toolbox.. and if i ever want the "peace of mind" of having a "one-owner" relay, i can do so easily.. Quote Link to comment Share on other sites More sharing options...
mcbrat Posted January 11, 2007 Share Posted January 11, 2007 McBrat what kind of relay did you use. I just got back from Napa and they told me i needed to know what relay to use. There were pages upon pages of relays that i could have chosen from. You wouldnt happen to have the application that it came from or the # on the relay and brand of relay? Thanks for your help. any standard lighting relay should work. should be in stock in the store.... no special order or anything.... http://www.partsamerica.com/ProductDetail.aspx?categorycode=3443&mfrcode=OPR&mfrpartnumber=A715 Quote Link to comment Share on other sites More sharing options...
hatchsub Posted January 11, 2007 Author Share Posted January 11, 2007 Thanks so much McBrat. I just finished this rewiring up and it works great. I can still see the voltage move around a bit but not nearly as much as before. It barely moves. I wouldnt think that something like that would make such a difference. Quote Link to comment Share on other sites More sharing options...
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