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280zx Alternator Upgrade

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28K views 17 replies 6 participants last post by  steve240Z73  
#1 ·
Been digging and digging and I just want to see what everyone is using for an alternator.

Right now I have a modest stereo (3 channel 2x100w, 1x200w) and relayed headlights, and I get dimming when bass hits. I plan on going water-to-air here in the future, with an electric radiator fan as well. The stock 60a alternator isn't going to put up with my stereo, headlights, water pump, and elec. fan. What are you guys with high power demand using?

I've been doing some reading and there was a post on Ratsun stating that a 90a alt. from a 240sx will bolt right up to the L, using factory brackets. The 240sx guys use a 99 Quest alt. as a 125a upgrade. So I should be able to use the 125a Quest alt. no problem. At least in theory.

Is the GM 100a truly bolt in? I've read that you either have to cut the lower bracket, or flip the thing and make a new upper bracket.

I'm looking for minimal physical modifications here, I don't have a shop anymore like I did in Germany. Wiring is no sweat.
 
#3 ·
Most of the high amp Nissan alternators require a pulley change, from the ribbed belt pulley to the older-style v-belt pulley. It can require some finagling to get a V-belt pulley that fits and then to get it shimmed out to the right location for alignment. The Maxima 90 amp alternator is one example, the case bolts on but the pulley needs work.

One thing to consider is that the quality of the rebuilt auto store alternators has a history of being very bad. That's why they give a lifetime guarantee. Cheaper for them to sell crap and keep replacing it than to rebuild the quality in to the part. Sounds harsh but that seems to be what they're doing. Qwest probably gets their parts from the same giant rebuilding center in Asia.
 
#4 ·
I was referring to the Nissan Quest.

I considered the Z Specialties alt, but the price is a bit crazy to me. Reading the post from Ratsun, all that is required to run the KA alt is a rewire of the connector. Not to mention a NEW OEM alt. is cheaper than the Z Specialties alt. by about $100. The Quest part was about the same cost as the Z Specialties part.

Anyone have words on the GM alt?
 
#5 ·
Thought you meant a $99 alternator.

You'll still need a pulley change. There's a few people around who forget to mention that when they say "bolt on".

I've looked at the GM CS130 option and it's not bolt-on. Needs bracket work and many people run it as a one-wire alt, which is a primitive way to make it work. No charge light and you have to rev it to get it started. It get's the job done though.

Good luck. The Zspecialties alt. is the only true "bolt-on", belt up, and plug in alternator amperage upgrade that I've seen, beside the 70 amp turbo alternator which is NLA.

Many people take their stock alternator to a rebuild shop and have them rebuild it to higher output. If you can find a shop that can do it, that might be an easy option.
 
#6 ·
Personally, I consider nothing more than a pulley swap a "bolt-in." When I have to start making brackets and crap that's when I get a little disinterested.

I called up a local shop, he said to drop it off with him. When I told him I was looking for about 70 amps at idle he replied with, "I'll see what I can do, I love a challenge." Still looking at the GM alt, seems like you don't have to wire it as a one wire. You just need the new pigtail.
 
#10 ·
Installed the new Monaco alternator last night, it definitely bolts in, but I had to grind about 1/8" off the bottom of the adjuster bracket for it to clear the alt. frame. No problems with the lower mount. Make sure you get a pulley that is about 2". The first one I used was about 2.75", and I had undercharging at idle.

It's charging at 14.7 volts. This is with my stereo up to the point where it hurts my ears, wipers on, a/c on full blast, map light on, all park lights on, high beams on, and stop lights on. I even tried rolling my windows up and down at the same time to "brown out" the system, but all is good!

I guess it doesn't fit the needs for those that want 100% plug-and-play, but it physically bolts in and I didn't have to cut any factory wiring.
 
#11 ·
It's charging at 14.7 volts. This is with my stereo up to the point where it hurts my ears, wipers on, a/c on full blast, map light on, all park lights on, high beams on, and stop lights on. I even tried rolling my windows up and down at the same time to "brown out" the system, but all is good!
For the record, what's your idle RPM while all of this happening. This is at idle right? Looks promising.
 
#13 ·
Just to be sure - your new alternator puts out 14.7 volts at 900 RPM with everything that you described turned on and drawing amps.

Sorry to keep asking, but that is the most important reason to do an alternator swap, output at idle speed, and you haven't said the two things together, just inferred it. I just want to be sure that that's what you're saying. Sitting at the stop light in the rain on a hot muggy night with the AC and headlights on, and the amp making your ears bleed, and the engine idling at 900 RPM, you will have no worries about battery charge because the alternator is putting out 14.7 volts.
 
#16 ·
Does the voltage go up at higher RPM, or is it well regulated?
 
#18 ·
It does sound like a winner to me.