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CarJway

90 Amp Maxima Alternator Upgrade

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Sooo, I thought of doing a small write up after I did this today, so this will not be my best write up... Pictures will suffer, but I tried to pull all the information together. I have added some generic pictures, and how to re-wire your car to use an internally regulated alternator. (not my instruction on how to rewire)

First things first... WHY do I need to upgrade?! Well, if you're like me, I now two fuel pumps, two electric cooling fans, blah blah blah... When my car was at idle, I could hear the pumps complaining, and if my fans came on, forget about it. Was it a grounding issue? No, my car has a full painless rewire, and I have more grounds then girls you stalk on instagram.

My initial upgrade was to an 84 maxima alternator. While this put out 60 amps, it definitely did not put out enough amps at idle. I am not sure if this lead to the death of 3 Odyessy batteries, but I will soon find out. On to what you came here for.

My first want here was bolt in, as in no cutting, making a brackets. (I have power steering and didn't want to undo a bunch of stuff) This ruled out the GM alternators, as you have to cut up the stock bracket. I spent a few hours on rock auto searching for all the combinations, amp, ear locations and have come up with the below.

1994 SOHC Nissan Maxima GXE Alternator (i believe this starts in 1991 up to 1995)
1990-1995 Nissan Pathfinder Pulley OR 1990-1995 Nissan D21 Pick up Pulley (I ordered a 1992 pathfinder pulley and i know this works)

The Maxima Alternator puts out 90 amps, but at idle put out 58 amps! I looked at the Nissan Quest, and while it puts out 110 amps, it only put out 41 amps. So the clear winner for me here was the Maxima. Plus, it would take no fabrication to "bolt in". (the idle amps may vary, but this is what i found after buying a whole heap of alternators at once)

The Pulley: almost all the higher amp alternators use a ribbed belt, vs a V-belt. After much searching, the best combination was to find, purchase, junk yard the v-belt pulley from a Pathfinder and put that on the 90 amp Maxima alternator.I used an impact to swap the pulleys with a little red loc-tite.

The Wiring: I didn't need to do this due to my Painless harness install, but if you are still stock read the following site! Or search how to swap to a later Datsun alternator for more details on going from an external regulated alternator. (if this applies to you)

Alternator rewire - click me

There is now a plug for the Light/Sensing wire. Below is the diagram of the pins for that plug. You can either buy this connector/plug online for a few bucks or use spade connectors. I had bought the plug, and misplaced it, so I used blue female spade connectors.

Plug-Wiring-Hitachi-Mitsi.jpg

 

The adjustment bracket: I had already bought one of these adjustable guys yearrsss ago, so it worked well with this. You may be able to use the stock one with slight bending or buy/make one of these adjustable guys. I believe the guys over on Ratsun have a how-to on how to make these, or I could just be mixing that up with another site. Otherwise, just buy one them...

alternator adjuster-3-571x598.jpg

 

As always with electrical work, ensure you unplug your battery, etc. I take no liability for you setting everything around you on fire, etc. 
When upgrading anything electrical, be sure all wire upstream are in good shape. I cannot stress this enough; higher amps is not going to fix an electrical system with hacked up wiring, bad grounds, etc. Be sure everything electrical is in good shape before doing this!

 

Edited by CarJway

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I would like to do this upgrade. What were your final results ? Voltage at idle etc. When your fans come on, is the idle stable? 

I have a 60 amp alternator on my Z now and when my 2 cooling fans ( apprx 20 amps total ) come on the idle dips. Was considering the 91 Dodge Monaco alternator swap as well.

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BJSZED: how did the swap turn out? Were you able to confirm some of the questions you had when you did it?

 

Redfogo: I had to use a newer pulley, as mine wasn't a one piece unit, but a two piece pulley. (two halves) I made a video, and get into more of the details there.

 

 

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6 hours ago, CarJway said:

BJSZED: how did the swap turn out? Were you able to confirm some of the questions you had when you did it?

I had 280zx alternator with a one piece pulley and it wouldn't swap over. Where I live the junk yards wont sell an alternator pulley, just the whole alternator. I went to an alternator shop and they gave me a suitable pulley. Havent tried it out yet as the car is put away for winter.

 

Redfogo: I had to use a newer pulley, as mine wasn't a one piece unit, but a two piece pulley. (two halves) I made a video, and get into more of the details there.

 

 

 

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