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alternator alternative

Joined
30 September 2011
Messages
282
Location
New Orleans
im having problems with my alternator and i like to purchase an aftermarket one to keep cost down. a brand new oem one cost around $1,500. i tired my local napa and autozone with no luck. also did a rebuild on it and that didnt work also. any leads to where i can get an aftermarket one?
 
I would seriously look at having your existing alternator rebuilt by a professional as there are no drop-in aftermarket replacements. As a result of COVID 19, there are no Denso or Denso rebuilds available. If you actually try to purchase that $1500 OEM alternator from an Acura dealer you are going to find it back-ordered with no expected delivery date. Kaz discussed the current shortage of alternators for the NSX on the NSXCB forum.

There are some alternators that you can use as replacements; but, they all require some level of modification and likely do not interface correctly with the ECU.
 
I bought a rebuild, higher amp output alternator some years ago. It's been fine ever since. I believe our stock one has an output of around 65amp. The high output one I bought was 90amps. It's just a rewind basically. I was running quite a bit of electronics at the time to support a supercharger, air compressor air lift, sound system, etc... not sure i'd recommend a high amp alternator for a stock NSX. A rebuilt unit will be fine IMO.
 
As Old Man said, have yours rebuilt by a local shop. I had mine rebuilt with new bearings, electronics etc. for about $100. Jerry

If you got a rebuild which included a new regulator assembly for $100 you got a deal. The voltage regulator by itself is listing for around $150 on Rock Auto.
 
Check with Science of Speed. They offer a 95A alternator as an option with their SoS Supercharger kit. While I don't see it listed as an individual part they may offer it.
 
It should not be difficult to rebuild the unit as all the internal parts are still available. You need to take the unit to a dedicated alternator shop and specify ONLY Japanese only parts (US/EU bearings also). You can order the parts from a Denso shop or from Honda.

However, do NOT take it to a mass-market auto parts house. They will ruin your unit using low spec parts and bearings.

>a 95A alternator as an option with their SoS Supercharger kit.

Won't work as that is a reverse rotation alternator, very common because that is how Honda rolled back then.
 
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I didn’t think an alternator was rotation specific. Don’t they produce a/c power that is rectified to d/c?

The 'electrical bits' in the alternator don't care which way the rotor turns. The nut that clamps the alternator pulley on to the alternator shaft certainly cares about which way the pulley turns. Could probably fix that with three or four tack welds between the pulley, nut and the shaft for a non repairable solution. However, since the supercharger alternator is mounted in a different location I expect that it won't fit in to the existing mounts.

If you want to use the SOS alternator I expect that you are going to have to fork out for the $10,000 mounting kit which just happens to include a supercharger :smile:.
 
I don't know if the field charges differently or is there is some optimization going on.

Regardless, the supercharger alternator body is different and a lot smaller. The supercharger displaces the large one and replaces it with a small one that is mounted "backward".

You might be able to fabricate an adapter to use the smaller chassis alternator...
 
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I'm curious if anyone has a complete list of components for a full rebuild?

I've watched an DIY rebuild video (not NSX specific) and it wasn't that hard, basically just replace the old with the new parts.

It should not be difficult to rebuild the unit as all the internal parts are still available. You need to take the unit to a dedicated alternator shop and specify ONLY Japanese only parts (US/EU bearings also). You can order the parts from a Denso shop or from Honda.

However, do NOT take it to a mass-market auto parts house. They will ruin your unit using low spec parts and bearings.
 
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i think this is the culprit of it not starting. i brought the alternator back to the rebuild shop and they bench test it saying that it was good. told me to check my wires or the starter. i rebuild the starter myself before i got the alternator rebuild because i thought that was the problem at first. check the wire closely and i see a bit a corrosion so i cut expose parts till i see clean copper wires on both negative and positive cables. but this second wire that was connected with the positive cable was just grayish even after i cut it. is this a ground cable for the positive cable and does anyone know what size gauge this ground wire is? i was trying to buy it from oemacuraparts.com but i cant seem to find it so im guess i have to make one myself?
 

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I don't know if the field charges differently or is there is some optimization going on.

Regardless, the supercharger alternator body is different and a lot smaller. The supercharger displaces the large one and replaces it with a small one that is mounted "backward".

You might be able to fabricate an adapter to use the smaller chassis alternator...

Different size is a horse of a another color!
 
It is hard to tell from your photo. That does not look like oxidation. Copper oxides are normally dark brown or form a greenish bloom on the wire. I think that wire has tinned copper strands. But, you can try cleaning the wire as described in the link provided by Drew; but, it may not turn to copper color. After you have cleaned

1) Measure the diameter of the copper strands. This reference below provides diameters for various stranded conductors. Use the second table. The first table is for solid conductors. Pick the diameter that is closest to what you measure to determine the gauge of the conductor.

AWG Copper Wire Size Table and Data Chart @ 100 Degrees F | Engineers Edge

2) Go to an automotive electrical specialist / battery shop. They normally have a selection of crimp terminals and should be able to supply the correct terminal style and size.
3) That is a large gauge wire and a typical hand crimper will not do the job. You may be able to borrow / rent something like these

IWISS Cable Lug Crimping Tool for Heavy Duty Wire Lugs,Battery Terminal,Copper Lugs AWG 8-1/0 : Amazon.ca: Tools & Home Improvement
Grote 84-9087 Brute Hammer Crimper Wire/Cable Cutter | eBay

5) before crimping the lug, smear the copper with GB Ox-gard (Home Depot sells it). It is a conducting paste which improved the connection and inhibits future corrosion of the copper. Do not use dielectric grease directly on the exposed copper wires
6) when you reconnect the lug, you can coat the outside of the lug with dielectric grease or Vaseline or Ox-gard to further inhibit surface corrosion.
 
It was quite a journey when my alt started wheezing....I ended up getting one from another owner and friend. My take home is there is usually a local shop that does alt rebuilds...we have one within 20 miles of me so that is the plan to get my old one rebuilt.
 
That what i was thinking also. The cable side that is in the box is never expose to water which made me think it suppose to be that color. Can someone look in their fronk and confirm what color is the cable?
 
Just to be clear.....is your problem not starting or not charging? Not starting could be anything from an ignition switch to the clutch pedal switch. Not charging means when the engine is running you arent getting 14-15v to the battery to keep it healthy.
 
Just to be clear.....is your problem not starting or not charging? Not starting could be anything from an ignition switch to the clutch pedal switch. Not charging means when the engine is running you arent getting 14-15v to the battery to keep it healthy.

Its not starting, ive clean and change the ignition switch before. I also bypass the clutch pedal switch too. Everytime i turn the key it does the rapid clicking noise like in the begining of this video.

https://youtu.be/wugmpeJFuec
 
Rapid clicking of the starter solenoid is a sign of low voltage at the starter. This can be a battery problem which can be caused by an alternator failing to charge the battery or a bad battery or a bad primary connection on the cable between the battery and the starter motor. Failed battery post cable clamps are a common cause of no-start conditions on the NSX. If you can twist the clamp on the post its toast. You can find a number of threads on Prime discussing no-start caused by failed battery post connectors.
 
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