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Gen III/IV alternator upgrade (160 amp)
by
digitalsolo
on 19 Jun, 2011 13:32
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So as long as I've had my FC, I've been annoyed by the fact that the alternator doesn't seem to charge particularly well at idle (reman F-Body alternator). I've also killed... 3 of them (1 my fault, 2 that weren't). Not shocking from an Autozone reman, but still, annoying.
Lately, I'd noticed my current alternator starting to get weak at idle (dropping 1-1.5 volts when I had the headlights on and hit the brakes at low RPM). That's annoying, and not exactly healthy for my fuel pump/electric water pump.
I did some research, and it turns out that the Escalade alternator uses the same side mounts (though it does not have a rear mount like the F-Body, not an issue really, especially since my relocated alternator mount doesn't use that at all). It has a slightly larger case, but F-Body guys report they fit fine. The best part? It's 160 amp, and rated for ~80 amps at idle, vs 102 peak and 30 amps at idle like the stocker. The unit I used is off of a 2007 Escalade, and it has a 2 pin plug. These run to the ECU and alternator control box. The catch? Well, my ECU doesn't control it, and I don't have an alternator control box. The best news? Per GM's information, without those hooked up, the alternator regulates internally to 13.8 volts.
Tested it last night, and I now have 13.8 volts, PERIOD. Idle, 5k RPM, lights on, lights off, brakes on, brakes off, whatever. 13.8 volts.
Here's a couple pics of the 'hoss.
[smg id=3383]
[smg id=3384]
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#1
by
Demon
on 19 Jun, 2011 14:42
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Hmm, I wonder how well this would fit in the lower mount.
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#2
by
digitalsolo
on 19 Jun, 2011 14:43
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F-Body guys on 'Tech say it does, though that's not in an RX7, obviously.
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#3
by
Demon
on 19 Jun, 2011 15:09
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Is it any deeper? Do you have a fbody alt to measure against?
I just hate how the voltage drops when brakes are applied and stupid crap like that.
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#4
by
digitalsolo
on 19 Jun, 2011 16:04
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I'll measure it against Nick's. I think it's a little shallower than the F-Body, but is larger in diameter.
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#5
by
zbrown
on 19 Jun, 2011 16:49
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wow that is a nice upgrade
how about compared to a truck alt physically?
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#6
by
mefarri
on 19 Jun, 2011 17:04
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Niiiiice. Any downsides to running a higher output alternator? Don't most alternators regulate over 14 volts while running?
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#7
by
digitalsolo
on 19 Jun, 2011 17:36
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Nothing that's ever been in my car has read >13.8 volts, so I'm happy with this.
I'll take a look at my buddy's truck alternator when I get a chance.
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#8
by
RX7V8Builder
on 19 Jun, 2011 17:50
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Seems like I just added another line in my list of my future upgrades
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#9
by
digitalsolo
on 19 Jun, 2011 18:13
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I didn't bust out the calipers, but string test (and running with the belt) seems to indicate the the belt alignment is fine also. Apparently the fore/aft location of the accessories is set by the brackets, not the accessories themselves.
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#10
by
Sabre002
on 19 Jun, 2011 18:23
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Man this is why I have started buying GM stuff sense I have been working for them. I have a GM AC delco F body one on my car and I would measure it at the battery are it would be in the 14.1v range.
I went through this on my truck old 91 S-10. Had two autozone duralast alternators on it they would only put out 13.3 volts I got sick of it and put a GM one on it from work and bam 13.8 all the time no matter what I got on.
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#11
by
Jordan Innovations
on 19 Jun, 2011 19:22
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Great mod! We did something similar with the LSA Camaro because we were killing the electrical system at idle with huge fans/fuel pump/etc.
Niiiiice. Any downsides to running a higher output alternator? Don't most alternators regulate over 14 volts while running?
No downside to an alternator that can provide higher amperage except possibly more parasitic drag on the acc drive. Not an issue with a V8, IMO.
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#12
by
digitalsolo
on 19 Jun, 2011 19:57
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Great mod! We did something similar with the LSA Camaro because we were killing the electrical system at idle with huge fans/fuel pump/etc.
Niiiiice. Any downsides to running a higher output alternator? Don't most alternators regulate over 14 volts while running?
No downside to an alternator that can provide higher amperage except possibly more parasitic drag on the acc drive. Not an issue with a V8, IMO.
Thanks.
The parasitic increases should be minimal, since the smaller ones were having to work really hard to keep up. If this one isn't having to work as hard, output to output, it should in theory have slightly LESS drag. Like you said though, in a V8, especially a street car, it's pretty inconsequential anyway.
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#13
by
valley
on 19 Jun, 2011 21:31
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Just to be 100%, it's self exciting I assume?
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#14
by
digitalsolo
on 19 Jun, 2011 21:52
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My reading says yes, and my testing on my car also says yes.